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Sample records for early pleistocene evolution

  1. Early Pleistocene occurrence of Acheulian technology in North China

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    Li, Xingwen; Ao, Hong; Dekkers, Mark J.; Roberts, Andrew P.; Zhang, Peng; Lin, Shan; Huang, Weiwen; Hou, Yamei; Zhang, Weihua; An, Zhisheng

    2017-01-01

    Acheulian tools with their associated level of cognizance heralded a major threshold in the evolution of hominin technology, culture and behavior. Thus, unraveling occurrence ages of Acheulian technology across different regions worldwide constitutes a key aspect of understanding the archeology of early human evolution. Here we present a magneto-cyclochronology for the Acheulian assemblage from Sanmenxia Basin, Loess Plateau, North China. Our results place a sequence of stable normal and reversed paleomagnetic polarities within a regional lithostratigraphic context. The Acheulian assemblage is dated to be older than the Matuyama-Brunhes boundary at 0.78 Ma, and is found in strata that are probably equivalent to a weak paleosol subunit within loess layer L9 in the Chinese loess-paleosol sequence, which corresponds to marine isotope stage (MIS) 23, a relatively subdued interglacial period with age range of ∼0.89-0.92 Ma. This age of ∼0.9 Ma implies that Acheulian stone tools were unambiguously present in North China during the Early Pleistocene. It distinctly enlarges the geographic distribution of Acheulian technology and brings its occurrence in North China back into the Early Pleistocene, which is contemporaneous with its first emergence in Europe. Combined with other archeological records, the larger area over which Acheulian technology existed in East Asia during the terminal Early Pleistocene has important implications for understanding early human occupation of North China.

  2. Hominin teeth from the early Late Pleistocene site of Xujiayao, Northern China.

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    Xing, Song; Martinón-Torres, María; Bermúdez de Castro, Jose María; Wu, Xiujie; Liu, Wu

    2015-02-01

    It is generally accepted that from the late Middle to the early Late Pleistocene (∼340-90 ka BP), Neanderthals were occupying Europe and Western Asia, whereas anatomically modern humans were present in the African continent. In contrast, the paucity of hominin fossil evidence from East Asia from this period impedes a complete evolutionary picture of the genus Homo, as well as assessment of the possible contribution of or interaction with Asian hominins in the evolution of Homo sapiens and Homo neanderthalensis. Here we present a comparative study of a hominin dental sample recovered from the Xujiayao site, in Northern China, attributed to the early Late Pleistocene (MIS 5 to 4). Our dental study reveals a mosaic of primitive and derived dental features for the Xujiayao hominins that can be summarized as follows: i) they are different from archaic and recent modern humans, ii) they present some features that are common but not exclusive to the Neanderthal lineage, and iii) they retain some primitive conformations classically found in East Asian Early and Middle Pleistocene hominins despite their young geological age. Thus, our study evinces the existence in China of a population of unclear taxonomic status with regard to other contemporary populations such as H. sapiens and H. neanderthalensis. The morphological and metric studies of the Xujiayao teeth expand the variability known for early Late Pleistocene hominin fossils and suggest the possibility that a primitive hominin lineage may have survived late into the Late Pleistocene in China. Copyright © 2014 Wiley Periodicals, Inc.

  3. The lithic industry of Sima del Elefante (Atapuerca, Burgos, Spain) in the context of Early and Middle Pleistocene technology in Europe.

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    de Lombera-Hermida, Arturo; Bargalló, Amèlia; Terradillos-Bernal, Marcos; Huguet, Rosa; Vallverdú, Josep; García-Antón, Maria-Dolores; Mosquera, Marina; Ollé, Andreu; Sala, Robert; Carbonell, Eudald; Rodríguez-Álvarez, Xosé-Pedro

    2015-05-01

    This paper presents the lithic assemblages documented at Sima del Elefante (TE) and their importance in the context of the Early and Middle Pleistocene human occupation of Europe. We also study changes in human behaviour within the context of the palaeoenvironmental evolution of the Sierra de Atapuerca. This site has characteristics that are of great value for the study of human evolution. The lower levels of TE (Units TE7-TE14) are an essential reference for understanding the early stages of the colonization of Europe. The TE9c level has provided stone tools (Mode 1), faunal remains, and human fossils dated to 1.22 Ma (millions of years ago). Moreover, this is one of the few European sites with a stratigraphic sequence that includes remains of human occupations predating the Jaramillo subchron (Early Pleistocene) and from the Late Middle Pleistocene (Units TE18-TE19). Despite this, the presence of archaeologically sterile units (TE15-17) prevents us from establishing a continuous relationship between the Early and Middle Pleistocene human settlements and, consequently, between their technological and behavioural differences. We can, however compare the technological and palaeoeconomic strategies adopted by different species of hominins during two key phases of the occupation of Europe. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Continuity versus discontinuity of the human settlement of Europe between the late Early Pleistocene and the early Middle Pleistocene. The mandibular evidence

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    Bermúdez de Castro, José María; Martinón-Torres, María; Rosell, Jordi; Blasco, Ruth; Arsuaga, Juan Luís; Carbonell, Eudald

    2016-12-01

    One of the most interesting aspects of the settlement of Europe is the possible continuity or discontinuity of the populations living in this continent during the Early and Middle Pleistocene. In this paper we present an analysis of the mandibular fossil record from four important Pleistocene European sites, Gran Dolina-TD6-2 (Sierra de Atapuerca), Mauer, Arago, and Atapuerca-Sima de los Huesos. We focus this study in the recognition of key derived mandibular features that may be useful to assess the relationship among the populations represented at these sites. In order to make an approach to the ecological scenario, we also present a short review and discussion of the archaeological and paleoenvironmental evidences at that time. Our results suggest that probably there was a demographic discontinuity between the late Early Pleistocene populations (MIS 21-MIS 19), and those dated to the MIS 15. Hybridization between residents and new settlers cannot be discarded. However, some features of the Gran Dolina-TD6 hominins point to some relationship between the population represented in this site (probably dated to the MIS 21) and the European Middle Pleistocene and early Late Pleistocene populations. A hypothetical scenario is presented in order to understand this apparent contradiction with the model of discontinuity.

  5. Pleistocene magnetochronology of the fauna and Paleolithic sites in the Nihewan Basin: Significance for environmental and hominin evolution in North China

    NARCIS (Netherlands)

    Ao, H.; An, Z.; Dekkers, M.J.; Li, Y.; Xiao, G.; Zhao, H.; Qiang, X.

    2013-01-01

    The fluvio-lacustrine sequences in the Nihewan Basin of North China (known as the Nihewan Formation) are rich sources of Early Pleistocene Paleolithic sites and mammalian fossils (known as the Nihewan Fauna sensu lato), which offer an excellent opportunity to investigate the evolution of early

  6. Leaf wax biomarker reconstruction of Early Pleistocene hydrological variation during hominin evolution in West Turkana, Kenya

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    Lupien, R.; Russell, J. M.; Cohen, A. S.; Feibel, C. S.; Beck, C.; Castañeda, I. S.

    2016-12-01

    Climate change is thought to play a critical role in human evolution; however, this hypothesis is difficult to test due to a lack of long, high-quality paleoclimate records from key hominin fossil locales. To address this issue, we examine Plio-Pleistocene lake sediment drill cores from East Africa that were recovered by the Hominin Sites and Paleolakes Drilling Project, an international effort to study the environment in which our hominin ancestors evolved and dispersed. With new data we test various evolutionary hypotheses, such as the "variability selection" hypothesis, which posits that high-frequency environmental variations selected for generalist traits that allowed hominins to expand into variable environments. We analyzed organic geochemical signals of climate in lake cores from West Turkana, Kenya, which span 1.87-1.38 Ma and contain the first fossils from Homo erectus. In particular, we present a compound-specific hydrogen isotopic analysis of terrestrial plant waxes (δDwax) that records regional hydrology. The amount effect dominates water isotope fractionation in the tropics; therefore, these data are interpreted to reflect mean annual rainfall, which affects vegetation structure and thus, hominin habitats. The canonical view of East Africa is that climate became drier and increasingly felt high-latitude glacial-interglacial cycles during the Plio-Pleistocene. However, the drying trend seen in some records is not evident in Turkana δDwax, signifying instead a climate with a steady mean state. Spectral and moving variance analyses indicate paleohydrological variations related to both high-latitude glaciation (41 ky cycle) and local insolation-forced monsoons (21 ky cycle). An interval of particularly high-amplitude rainfall variation occurs at 1.7 Ma, which coincides with the intensification of the Walker Circulation. These results identify high- and low-latitude controls on East African paleohydrology during Homo erectus evolution. In particular, the

  7. A NEW EARLY PLEISTOCENE BIRD ASSOCIATION FROM PIETRAFITTA (PERUGIA, CENTRAL ITALY

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    GILDA ZUCCHETTA

    2003-11-01

    Full Text Available We here present che preliminary results of the analysis of the fossil bird assemblages found in the lignite deposits of the Pietrafitta Mine (Perugia, Central Italy. A rich vertebrate association, mainly mammals, has been retrieved in Pietrafitta, which is the richest local fauna of the Farneta Faunal Unit (late Villafranchian, early Pleistocene. Avian remains of Podicipedidae, Ardeidae, Phalacrocoracidae, Anatidae, Phasianidae and Rallidae have been identified, for most of which Pietrafitta represents the earliest occurrence in Italy. The Pietrafitta fossil bird association is the first Italian bird assemblage of the Early Pleistocene and seems to be one of the most important ones for the early Pleistocene in Europe, especially because it contains mainly aquatic birds, often rare in many other European deposits. 

  8. Early pleistocene sediments at Great Blakenham, Suffolk, England

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    Gibbard, P. L.; Allen, P.; Field, M. H.; Hallam, D. F.

    Detailed investigation of a fine sediment sequence, the College Farm Silty Clay Member, that overlies the Creeting Sands (Early Pleistocene) in Suffolk, is presented. The sedimentary sequence is thought to represent a freshwater pool accumulation in a small coastal embayment. Palaeobotanical investigation of the sediment indicates that it accumulated during the late temperate substage of a temperate (interglacial) event. The occurrence of Tsuga pollen, associated with abundant remains of the water fern Azolla tegeliensis indicate that the deposits are of Early Pleistocene age and are correlated with a later part of the Antian-Bramertonian Stage. Correlation with Tiglian TO substage in The Netherlands' sequence is most likely. The sediments' normal palaeomagnetic polarity reinforces the biostratigraphical correlation.

  9. Land-sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

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    Donders, Timme; Van Helmond, Niels A.G.M.; Verreussel, Roel; Munsterman, Dirk; Veen, Johan Ten; Speijer, Robert P.; Weijers, Johan W.H.; Sangiorgi, Francesca; Peterse, Francien; Reichart, Gert-Jan; Sinninghe Damsté, Jaap S.; Lourens, Lucas; Kuhlmann, Gesa; Brinkhuis, Henk

    2018-01-01

    We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian (ĝ1/4 2.6-1.8ĝ€Ma) multi-proxy record from the southern North Sea basin. The cored sections couple climate evolution on both land and sea during the intensification of

  10. Pliocene –Pleistocene geomorphological evolution of the Adriatic side of Central Italy

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    Gentili Bernardino

    2017-02-01

    Full Text Available This work is a significant contribution to knowledge of the Quaternary and pre-Quaternary morphogenesis of a wide sector of central Italy, from the Apennine chain to the Adriatic Sea. The goal is achieved through a careful analysis and interpretation of stratigraphic and tectonic data relating to marine and continental sediments and, mostly, through the study of relict limbs of ancient landscapes (erosional surfaces shaped by prevailing planation processes. The most important scientific datum is the definition of the time span in which the modelling of the oldest morphological element (the “summit relict surface” occurred: it started during Messinian in the westernmost portion and after a significant phase during middle-late Pliocene, ended in the early Pleistocene. During the middle and late Pleistocene, the rapid tectonic uplift of the area and the climate fluctuations favoured the deepening of the hydrographic network and the genesis of three orders of fluvial terraces, thus completing the fundamental features of the landscape. The subsequent Holocene evolution reshaped the minor elements, but not the basic ones.

  11. Snapshots of the Greenland ice sheet configuration in the Pliocene to early Pleistocene

    DEFF Research Database (Denmark)

    Solgaard, Anne M.; Reeh, Niels; Japsen, Peter

    2011-01-01

    The geometry of the ice sheets during the Pliocene to early Pleistocene is not well constrained. Here we apply an ice-flow model in the study of the Greenland ice sheet (GIS) during three extreme intervals of this period constrained by geological observations and climate reconstructions. We study...... the extent of the GIS during the Mid-Pliocene Warmth (3.3-3.0 Ma), its advance across the continental shelf during the late Pliocene to early Pleistocene glaciations (3.0-2.4 Ma) as implied by offshore geological studies, and the transition from glacial to interglacial conditions around 2.4 Ma as deduced...... the variability of the GIS during the Pliocene to early Pleistocene and underline the importance of including independent estimates of the GIS in studies of climate during this period. We conclude that the GIS did not exist throughout the Pliocene to early Pleistocene, and that it melted during interglacials even...

  12. Early Pleistocene aquatic resource use in the Turkana Basin.

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    Archer, Will; Braun, David R; Harris, Jack W K; McCoy, Jack T; Richmond, Brian G

    2014-12-01

    Evidence for the acquisition of nutritionally dense food resources by early Pleistocene hominins has implications for both hominin biology and behavior. Aquatic fauna may have comprised a source of highly nutritious resources to hominins in the Turkana Basin at ∼1.95 Ma. Here we employ multiple datasets to examine the issue of aquatic resource use in the early Pleistocene. This study focuses on four components of aquatic faunal assemblages (1) taxonomic diversity, (2) skeletal element proportion, (3) bone fragmentation and (4) bone surface modification. These components are used to identify associations between early Pleistocene aquatic remains and hominin behavior at the site of FwJj20 in the Koobi Fora Fm. (Kenya). We focus on two dominant aquatic species: catfish and turtles. Further we suggest that data on aquatic resource availability as well as ethnographic examples of aquatic resource use complement our observations on the archaeological remains from FwJj20. Aquatic food items provided hominins with a valuable nutritional alternative to an exclusively terrestrial resource base. We argue that specific advantages afforded by an aquatic alternative to terrestrial resources include (1) a probable reduction in required investment of energy relative to economic return in the form of nutritionally dense food items, (2) a decrease in the technological costs of resource acquisition, and (3) a reduced level of inter-specific competition associated with carcass access and an associated reduction of predation risk relative to terrestrial sources of food. The combined evidence from FwJj20 suggests that aquatic resources may have played a substantial role in early Pleistocene diets and these resources may have been overlooked in previous interpretations of hominin behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. A new record of late Pliocene-early Pleistocene aeolian loess-red clay deposits from the western Chinese Loess Plateau and its palaeoenvironmental implications

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    Zan, Jinbo; Fang, Xiaomin; Zhang, Weilin; Yan, Maodu; Zhang, Dawen

    2018-04-01

    The loess-red clay sequences in northern China provide high-resolution terrestrial records of Asian monsoon evolution and aridification of the Asian interior. To date, however, aeolian deposits of late Pliocene-early Pleistocene age (3.5-2.4 Ma) have only rarely been reported from the western Chinese Loess Plateau (CLP), which significantly hinders our understanding of the distribution of aeolian deposits and the palaeoenvironmental evolution of the region. Here, we present magnetostratigraphic, lithologic and magnetic susceptibility results for two recently-drilled boreholes from the north bank of Baxie River, central Linxia Basin, which are highly correlative with those of the loess-red clay deposits spanning the interval from 3.6 to 2.4 Ma in the eastern CLP. Our results provide the first direct evidence for the occurrence of late Pliocene-early Pleistocene aeolian deposits in the western CLP and provide new insights into the distribution of aeolian deposits in northern China. The spatial coherence of the magnetic susceptibility fluctuations further indicates that magnetic susceptibility is a powerful tool for stratigraphic correlation of late Pliocene aeolian deposits in the western CLP. In addition, our results demonstrate that erosional events may have occurred in the early or middle Pleistocene, and they may provide new insights into the reasons for the absence of loess-red clay deposits from 3.5 to 2.4 Ma in most parts of the western CLP.

  14. Patterns of myoxid evolution in the Pliocene and Pleistocene of Europe

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    Adam Nadachoswki

    1995-05-01

    Full Text Available Abstract The origin of recent species belonging to the genera Myoxus, Muscardinus, Glirulus, Eliomys, Dryomys and Myomimus is discussed. Evolution of myoxids in the Pliocene and Pleistocene is expressed by gradual size increase of their cheek teeth. No gradual change in the dental pattern is observed. Riassunto Modelli di evoluzione dei Mioxidi nel Pliocene e Pleistocene in Europa - Viene discussa l'origine delle specie recenti appartenenti ai generi Myoxus, Muscardinus, Glirulus, Eliomys, Dryomys e Myomimus. L'evoluzione dei Mioxidi nel Pliocene e nel Pleistocene è espressa da un graduale aumento delle dimensioni dei molari. Non è stato osservato alcun cambiamento graduale nel pattern dentale.

  15. Late Pleistocene climate drivers of early human migration

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    Timmermann, Axel; Friedrich, Tobias

    2016-10-01

    On the basis of fossil and archaeological data it has been hypothesized that the exodus of Homo sapiens out of Africa and into Eurasia between ~50-120 thousand years ago occurred in several orbitally paced migration episodes. Crossing vegetated pluvial corridors from northeastern Africa into the Arabian Peninsula and the Levant and expanding further into Eurasia, Australia and the Americas, early H. sapiens experienced massive time-varying climate and sea level conditions on a variety of timescales. Hitherto it has remained difficult to quantify the effect of glacial- and millennial-scale climate variability on early human dispersal and evolution. Here we present results from a numerical human dispersal model, which is forced by spatiotemporal estimates of climate and sea level changes over the past 125 thousand years. The model simulates the overall dispersal of H. sapiens in close agreement with archaeological and fossil data and features prominent glacial migration waves across the Arabian Peninsula and the Levant region around 106-94, 89-73, 59-47 and 45-29 thousand years ago. The findings document that orbital-scale global climate swings played a key role in shaping Late Pleistocene global population distributions, whereas millennial-scale abrupt climate changes, associated with Dansgaard-Oeschger events, had a more limited regional effect.

  16. Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse.

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    Orlando, Ludovic; Ginolhac, Aurélien; Zhang, Guojie; Froese, Duane; Albrechtsen, Anders; Stiller, Mathias; Schubert, Mikkel; Cappellini, Enrico; Petersen, Bent; Moltke, Ida; Johnson, Philip L F; Fumagalli, Matteo; Vilstrup, Julia T; Raghavan, Maanasa; Korneliussen, Thorfinn; Malaspinas, Anna-Sapfo; Vogt, Josef; Szklarczyk, Damian; Kelstrup, Christian D; Vinther, Jakob; Dolocan, Andrei; Stenderup, Jesper; Velazquez, Amhed M V; Cahill, James; Rasmussen, Morten; Wang, Xiaoli; Min, Jiumeng; Zazula, Grant D; Seguin-Orlando, Andaine; Mortensen, Cecilie; Magnussen, Kim; Thompson, John F; Weinstock, Jacobo; Gregersen, Kristian; Røed, Knut H; Eisenmann, Véra; Rubin, Carl J; Miller, Donald C; Antczak, Douglas F; Bertelsen, Mads F; Brunak, Søren; Al-Rasheid, Khaled A S; Ryder, Oliver; Andersson, Leif; Mundy, John; Krogh, Anders; Gilbert, M Thomas P; Kjær, Kurt; Sicheritz-Ponten, Thomas; Jensen, Lars Juhl; Olsen, Jesper V; Hofreiter, Michael; Nielsen, Rasmus; Shapiro, Beth; Wang, Jun; Willerslev, Eske

    2013-07-04

    The rich fossil record of equids has made them a model for evolutionary processes. Here we present a 1.12-times coverage draft genome from a horse bone recovered from permafrost dated to approximately 560-780 thousand years before present (kyr BP). Our data represent the oldest full genome sequence determined so far by almost an order of magnitude. For comparison, we sequenced the genome of a Late Pleistocene horse (43 kyr BP), and modern genomes of five domestic horse breeds (Equus ferus caballus), a Przewalski's horse (E. f. przewalskii) and a donkey (E. asinus). Our analyses suggest that the Equus lineage giving rise to all contemporary horses, zebras and donkeys originated 4.0-4.5 million years before present (Myr BP), twice the conventionally accepted time to the most recent common ancestor of the genus Equus. We also find that horse population size fluctuated multiple times over the past 2 Myr, particularly during periods of severe climatic changes. We estimate that the Przewalski's and domestic horse populations diverged 38-72 kyr BP, and find no evidence of recent admixture between the domestic horse breeds and the Przewalski's horse investigated. This supports the contention that Przewalski's horses represent the last surviving wild horse population. We find similar levels of genetic variation among Przewalski's and domestic populations, indicating that the former are genetically viable and worthy of conservation efforts. We also find evidence for continuous selection on the immune system and olfaction throughout horse evolution. Finally, we identify 29 genomic regions among horse breeds that deviate from neutrality and show low levels of genetic variation compared to the Przewalski's horse. Such regions could correspond to loci selected early during domestication.

  17. The Pliocene initiation and Early Pleistocene volcanic disruption of the palaeo-Gediz fluvial system, Western Turkey

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    Maddy, D.; Demir, T.; Bridgland, D.R.; Veldkamp, A.; Stemerdink, C.; Schriek, van der T.; Schreve, D.

    2007-01-01

    In this paper, we report our latest observations concerning a Pliocene and Early Pleistocene record from Western Turkey. The sedimentary sequence described comprises the fluvial deposits of an Early Pleistocene palaeo-Gediz river system and its tributaries prior to the onset of volcanism around Kula

  18. Dietary traits of the late Early Pleistocene Bison menneri (Bovidae, Mammalia) from its type site Untermassfeld (Central Germany) and the problem of Pleistocene 'wood bison'

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    van Asperen, Eline N.; Kahlke, Ralf-Dietrich

    2017-12-01

    Over the course of the Early and early Middle Pleistocene, a climatic cooling trend led to the partial opening up of landscapes in the western Palaearctic. This led to a gradual replacement of browsers by grazers, whilst some herbivore species shifted their diet towards including more grass. Wear patterns of herbivore cheek teeth can inform our understanding of the timing and extent of this change and indicate levels of dietary plasticity. One of the indicator species of the faunal turnover is the first large-sized form of bison in the Palaearctic, Bison menneri. The dental mesowear of the palaeopopulation from the species' late Early Pleistocene type site of Untermassfeld in Central Germany and the Late Pleistocene B. priscus from Taubach, both from habitat mosaics of forested habitats and more open landscapes, have a mixed feeder profile similar to that of North American wood bison, which has a distinct preference for open habitats but occasionally consumes a high amount of browse as a fall-back food. In contrast, the grazer mesowear signature of early Middle Pleistocene B. schoetensacki voigtstedtensis from Voigtstedt indicates these animals likely did not regularly feed in the densely forested area around the site. The mesowear of B. schoetensacki from Süssenborn, in a more open environment, is similar to that of extant European bison. Both Pleistocene and extant bison are grazers to mixed feeders with relatively high tolerance of a suboptimal browsing diet. None of these species can be regarded as true 'wood bison'.

  19. Early Pleistocene archaeological occurrences at the Feiliang site, and the archaeology of human origins in the Nihewan Basin, North China.

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    Shuwen Pei

    Full Text Available The Early Pleistocene archaeological evidence from the fluvio-lacustrine sequence of the Nihewan Basin (North China offers an excellent opportunity to explore early human evolution and behavior in a temperate setting in East Asia, following the earliest 'Out of Africa'. Here we present the first comprehensive study of the Feiliang (FL site, with emphasis on the archaeological sequence, site integrity, and stone artifact assemblages. Magnetostratigraphic dating results show that early humans occupied the site ca. 1.2 Ma. Archaeological deposits were buried rapidly in primary context within shallow lake margin deposits, with only minor post-depositional disturbance from relatively low energy hydraulic forces. The FL lithic assemblage is characterized by a core and flake, Oldowan-like or Mode 1 technology, with a low degree of standardization, expedient knapping techniques, and casually retouched flakes. The bone assemblage suggests that hominin occupation of the FL site was in an open habitat of temperate grassland with areas of steppe and water. The main features of the FL assemblage are discussed in the context of the early Pleistocene archaeology of Nihewan, for which an assessment of current and future research is also presented.

  20. Evolution of Early Pleistocene fluvial systems in central Poland prior to the first ice sheet advance – a case study from the Bełchatów lignite mine

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    Goździk Jan

    2017-06-01

    fluvio-periglacial conditions are identified in the foreground of the advance of the oldest ice sheet into this part of central Poland. The series studied have been compared with other fluvial successions which accumulated in the Kleszczów Graben during subsequent glaciations so as to document general changes in fluvial systems as reactions to climatic evolution. Thus, a palaeoenvironmental scenario has emerged which could be considered to be characteristic of central Poland during the Early Pleistocene.

  1. The medial pterygoid tubercle in the Atapuerca Early and Middle Pleistocene mandibles: evolutionary implications.

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    Bermúdez de Castro, José-María; Quam, Rolf; Martinón-Torres, María; Martínez, Ignacio; Gracia-Téllez, Ana; Arsuaga, Juan Luís; Carbonell, Eudald

    2015-01-01

    Numerous studies have attempted to identify the presence of uniquely derived (autoapomorphic) Neandertal features. Here, we deal with the medial pterygoid tubercle (MTP), which is usually present on the internal face of the ascending ramus of Neandertal specimens. Our study stems from the identification of a hypertrophied tubercle in ATD6-96, an Early Pleistocene mandible recovered from the TD6 level of the Atapuerca-Gran Dolina site and attributed to Homo antecessor. Our review of the literature and study of numerous original fossil specimens and high quality replicas confirm that the MTP occurs at a high frequency in Neandertals (ca. 89%) and is also present in over half (ca. 55%) of the Middle Pleistocene Sima de los Huesos (SH) hominins. In contrast, it is generally absent or minimally developed in other extinct hominins, but can be found in variable frequencies (Pleistocene and recent H. sapiens samples. The presence of this feature in ATD6-96 joins other traits shared by H. antecessor, the SH hominins and Neandertals. Since the TD6 hominins have been attributed either to MIS 21 or to MIS 25, it seems that a suite of assumed derived Neandertal features appeared in the Early Pleistocene, and they should be interpreted as synapomorphies shared among different taxa. We suggest that H. antecessor, the SH hominins and Neandertals shared a common ancestor in which these features appeared during the Early Pleistocene. The presence of the MTP in taxa other than H. neanderthalensis precludes this feature from being a Neandertal autapomorphy. © 2014 Wiley Periodicals, Inc.

  2. Paleosoils and pedogenic calcretes formations in Fray Bentos (Oligocene - early miocene) Raigon (late pliocene and middle pleistocene) and Libertad (early - middle pleistocene)

    International Nuclear Information System (INIS)

    Tofalo, O.; Morras, H.; Sanchez-Bettucci, L.

    2012-01-01

    The Fray Bentos formation is composed by loessic deposits based on paleosoils and pedogenic calcretes (Oligocene - early miocene). In this deposits are tubular and lamellar formations which would have been formed in arid climates.The fluvial origen of Raigon Formation, (late pliocene and middle pleistocene) presents a paleosoil roof which is generated under a subhumid climate.The Libertad Formation during the glacial intervals consisted of loess deposits

  3. Land-sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

    Science.gov (United States)

    Donders, Timme H.; van Helmond, Niels A. G. M.; Verreussel, Roel; Munsterman, Dirk; ten Veen, Johan; Speijer, Robert P.; Weijers, Johan W. H.; Sangiorgi, Francesca; Peterse, Francien; Reichart, Gert-Jan; Sinninghe Damsté, Jaap S.; Lourens, Lucas; Kuhlmann, Gesa; Brinkhuis, Henk

    2018-03-01

    We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian (˜ 2.6-1.8 Ma) multi-proxy record from the southern North Sea basin. The cored sections couple climate evolution on both land and sea during the intensification of Northern Hemisphere glaciation (NHG) in NW Europe, providing the first well-constrained stratigraphic sequence of the classic terrestrial Praetiglian stage. Terrestrial signals were derived from the Eridanos paleoriver, a major fluvial system that contributed a large amount of freshwater to the northeast Atlantic. Due to its latitudinal position, the Eridanos catchment was likely affected by early Pleistocene NHG, leading to intermittent shutdown and reactivation of river flow and sediment transport. Here we apply organic geochemistry, palynology, carbonate isotope geochemistry, and seismostratigraphy to document both vegetation changes in the Eridanos catchment and regional surface water conditions and relate them to early Pleistocene glacial-interglacial cycles and relative sea level changes. Paleomagnetic and palynological data provide a solid integrated timeframe that ties the obliquity cycles, expressed in the borehole geophysical logs, to Marine Isotope Stages (MIS) 103 to 92, independently confirmed by a local benthic oxygen isotope record. Marine and terrestrial palynological and organic geochemical records provide high-resolution reconstructions of relative terrestrial and sea surface temperature (TT and SST), vegetation, relative sea level, and coastal influence.During the prominent cold stages MIS 98 and 96, as well as 94, the record indicates increased non-arboreal vegetation, low SST and TT, and low relative sea level. During the warm stages MIS 99, 97, and 95 we infer increased stratification of the water column together with a higher percentage of arboreal vegetation, high SST, and relative sea level maxima. The early Pleistocene distinct warm-cold alterations are

  4. Mineralogical evidence of reduced East Asian summer monsoon rainfall on the Chinese loess plateau during the early Pleistocene interglacials

    Science.gov (United States)

    Meng, Xianqiang; Liu, Lianwen; Wang, Xingchen T.; Balsam, William; Chen, Jun; Ji, Junfeng

    2018-03-01

    The East Asian summer monsoon (EASM) is an important component of the global climate system. A better understanding of EASM rainfall variability in the past can help constrain climate models and better predict the response of EASM to ongoing global warming. The warm early Pleistocene, a potential analog of future climate, is an important period to study EASM dynamics. However, existing monsoon proxies for reconstruction of EASM rainfall during the early Pleistocene fail to disentangle monsoon rainfall changes from temperature variations, complicating the comparison of these monsoon records with climate models. Here, we present three 2.6 million-year-long EASM rainfall records from the Chinese Loess Plateau (CLP) based on carbonate dissolution, a novel proxy for rainfall intensity. These records show that the interglacial rainfall on the CLP was lower during the early Pleistocene and then gradually increased with global cooling during the middle and late Pleistocene. These results are contrary to previous suggestions that a warmer climate leads to higher monsoon rainfall on tectonic timescales. We propose that the lower interglacial EASM rainfall during the early Pleistocene was caused by reduced sea surface temperature gradients across the equatorial Pacific, providing a testable hypothesis for climate models.

  5. Spinal cord evolution in early Homo.

    Science.gov (United States)

    Meyer, Marc R; Haeusler, Martin

    2015-11-01

    The discovery at Nariokotome of the Homo erectus skeleton KNM-WT 15000, with a narrow spinal canal, seemed to show that this relatively large-brained hominin retained the primitive spinal cord size of African apes and that brain size expansion preceded postcranial neurological evolution. Here we compare the size and shape of the KNM-WT 15000 spinal canal with modern and fossil taxa including H. erectus from Dmanisi, Homo antecessor, the European middle Pleistocene hominins from Sima de los Huesos, and Pan troglodytes. In terms of shape and absolute and relative size of the spinal canal, we find all of the Dmanisi and most of the vertebrae of KNM-WT 15000 are within the human range of variation except for the C7, T2, and T3 of KNM-WT 15000, which are constricted, suggesting spinal stenosis. While additional fossils might definitively indicate whether H. erectus had evolved a human-like enlarged spinal canal, the evidence from the Dmanisi spinal canal and the unaffected levels of KNM-WT 15000 show that unlike Australopithecus, H. erectus had a spinal canal size and shape equivalent to that of modern humans. Subadult status is unlikely to affect our results, as spinal canal growth is complete in both individuals. We contest the notion that vertebrae yield information about respiratory control or language evolution, but suggest that, like H. antecessor and European middle Pleistocene hominins from Sima de los Huesos, early Homo possessed a postcranial neurological endowment roughly commensurate to modern humans, with implications for neurological, structural, and vascular improvements over Pan and Australopithecus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Land–sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

    Directory of Open Access Journals (Sweden)

    T. H. Donders

    2018-03-01

    Full Text Available We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian (∼ 2.6–1.8 Ma multi-proxy record from the southern North Sea basin. The cored sections couple climate evolution on both land and sea during the intensification of Northern Hemisphere glaciation (NHG in NW Europe, providing the first well-constrained stratigraphic sequence of the classic terrestrial Praetiglian stage. Terrestrial signals were derived from the Eridanos paleoriver, a major fluvial system that contributed a large amount of freshwater to the northeast Atlantic. Due to its latitudinal position, the Eridanos catchment was likely affected by early Pleistocene NHG, leading to intermittent shutdown and reactivation of river flow and sediment transport. Here we apply organic geochemistry, palynology, carbonate isotope geochemistry, and seismostratigraphy to document both vegetation changes in the Eridanos catchment and regional surface water conditions and relate them to early Pleistocene glacial–interglacial cycles and relative sea level changes. Paleomagnetic and palynological data provide a solid integrated timeframe that ties the obliquity cycles, expressed in the borehole geophysical logs, to Marine Isotope Stages (MIS 103 to 92, independently confirmed by a local benthic oxygen isotope record. Marine and terrestrial palynological and organic geochemical records provide high-resolution reconstructions of relative terrestrial and sea surface temperature (TT and SST, vegetation, relative sea level, and coastal influence.During the prominent cold stages MIS 98 and 96, as well as 94, the record indicates increased non-arboreal vegetation, low SST and TT, and low relative sea level. During the warm stages MIS 99, 97, and 95 we infer increased stratification of the water column together with a higher percentage of arboreal vegetation, high SST, and relative sea level maxima. The early Pleistocene distinct

  7. 3D Architecture and evolution of the Po Plain-Northern Adriatic Foreland basin during Plio-Pleistocene time

    Science.gov (United States)

    Amadori, Chiara; Toscani, Giovanni; Ghielmi, Manlio; Maesano, Francesco Emanuele; D'Ambrogi, Chiara; Lombardi, Stefano; Milanesi, Riccardo; Panara, Yuri; Di Giulio, Andrea

    2017-04-01

    The Pliocene-Pleistocene tectonic and sedimentary evolution of the eastern Po Plain and northern Adriatic Foreland Basin (PPAF) (extended ca. 35,000 km2) was the consequence of severe Northern Apennine compressional activity and climate-driven eustatic changes. According with the 2D seismic interpretation, facies analysis and sequence stratigraphy approach by Ghielmi et al. (2013 and references therein), these tectono-eustatic phases generated six basin-scale unconformities referred as Base Pliocene (PL1), Intra-Zanclean (PL2), Intra-Piacenzian (PL3), Gelasian (PL4), Base Calabrian (PS1) and Late Calabrian (PS2). We present a basin-wide detailed 3D model of the PPAF region, derived from the interpretation of these unconformities in a dense network of seismic lines (ca. 6,000 km) correlated with more than 200 well stratigraphies (courtesy of ENI E&P). The initial 3D time-model has been time-to-depth converted using the 3D velocity model created with Vel-IO 3D, a tool for 3D depth conversions and then validated and integrated with depth domain dataset from bibliography and well log. Resultant isobath and isopach maps are produced to inspect step-by-step the basin paleogeographic evolution; it occurred through alternating stages of simple and fragmented foredeeps. Changes in the basin geometry through time, from the inner sector located in the Emilia-Romagna Apennines to the outermost region (Veneto and northern Adriatic Sea), were marked by repeated phases of outward migration of two large deep depocenters located in front of Emilia arcs on the west, and in front of Ferrara-Romagna thrusts on the east. During late Pliocene-early Pleistocene, the inner side of the Emilia-Romagna arcs evolved into an elongated deep thrust-top basin due to a strong foredeep fragmentation then, an overall tectono-stratigraphic analysis shows also a decreasing trend of tectonic intensity of the Northern Apennine since Pleistocene until present.

  8. The British Lower Palaeolithic of the early Middle Pleistocene

    Science.gov (United States)

    Hosfield, Robert

    2011-06-01

    The archaeology of Britain during the early Middle Pleistocene (MIS 19-12) is represented by a number of key sites across eastern and southern England. These sites include Pakefield, Happisburgh 1, High Lodge, Warren Hill, Waverley Wood, Boxgrove, Kent's Cavern, and Westbury-sub-Mendip, alongside a 'background scatter' lithic record associated with the principal river systems (Bytham, pre-diversion Thames, and Solent) and raised beaches (Westbourne-Arundel). Hominin behaviour can be characterised in terms of: preferences for temperate or cool temperate climates and open/woodland mosaic habitats (indicated by mammalian fauna, mollusca, insects, and sediments); a biface-dominated material culture characterised by technological diversity, although with accompanying evidence for distinctive core and flake (Pakefield) and flake tool (High Lodge) assemblages; probable direct hunting-based subsistence strategies (with a focus upon large mammal fauna); and generally locally-focused spatial and landscape behaviours (principally indicated by raw material sources data), although with some evidence of dynamic, mobile and structured technological systems. The British data continues to support a 'modified short chronology' to the north of the Alps and the Pyrenees, with highly sporadic evidence for a hominin presence prior to 500-600 ka, although the ages of key assemblages are subject to ongoing debates regarding the chronology of the Bytham river terraces and the early Middle Pleistocene glaciations of East Anglia.

  9. Early Pleistocene human hand phalanx from the Sima del Elefante (TE) cave site in Sierra de Atapuerca (Spain).

    Science.gov (United States)

    Lorenzo, Carlos; Pablos, Adrián; Carretero, José Miguel; Huguet, Rosa; Valverdú, Josep; Martinón-Torres, María; Arsuaga, Juan Luis; Carbonell, Eudald; Bermúdez de Castro, José María

    2015-01-01

    In this study, a new Early Pleistocene proximal hand phalanx (ATE9-2) from the Sima del Elefante cave site (TE - Sierra de Atapuerca, Spain), ascribed to Homo sp., is presented and comparatively described in the context of the evolution of the genus Homo. The ATE9-2 specimen is especially important because of the paucity of hand bones in the human fossil record during the Early Pleistocene. The morphological and metrical analyses of the phalanx ATE9-2 indicate that there are no essential differences between it and comparator fossil specimens for the genus Homo after 1.3 Ma (millions of years ago). Similar to Sima de los Huesos and Neandertal specimens, ATE9-2 is a robust proximal hand phalanx, probably reflecting greater overall body robusticity in these populations or a higher gracility in modern humans. The age of level TE9 from Sima del Elefante and morphological and metrical studies of ATE9-2 suggest that the morphology of the proximal hand phalanges and, thus, the morphology of the hand could have remained stable over the last 1.2-1.3 Ma. Taking into account the evidence recently provided by a metacarpal from Kaitio (Kenya) from around 1.42 Ma, we argue that modern hand morphology is present in the genus Homo subsequent to Homo habilis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. The ESR dating of fossil enamel samples from palaeo-anthropological and Palaeolithic sites of Early Pleistocene

    International Nuclear Information System (INIS)

    Chen Qi; Chen Tiemei; Li Jiuqiang

    1999-01-01

    The following problems regarding the ESR dating of fossil enamel samples from palaeo-anthropological and Palaeolithic sites of Early Pleistocene are discussed: 1) the applicability of exponential fitting in the additive method for reliable AD determination; 2) the thermo-stability of the g = 2.0018 line of hydroxyapatite and its influence on apparent ESR ages; 3) the right selection of U-uptake models; and 4) the effect of high U-content in enamel on the ESR ages. It is concluded that the ESR-EU ages of Early Pleistocene enamel samples can only be regarded as the lower limit of the true ages if no appropriate corrections for the factors discussed above are made

  11. Implications of the avian fauna for paleoecology in the Early Pleistocene of the Iberian Peninsula.

    Science.gov (United States)

    Sánchez-Marco, A

    1999-01-01

    The aim of this paper is to reconstruct the landscape and climate during the formation of the Lower Pleistocene TD6 layer at Gran Dolina, Atapuerca. Habitat preferences and phenetic behavioural spectra of fossil birds are reconstructed using comparisons of fossil bird assemblages with modern avian communities. This method is based upon the phenology (seasonality and breeding status) of each species for both the fossil association and modern communities. The results indicate that more open country and wetter conditions prevailed during the early Pleistocene than were previously inferred. Copyright 1999 Academic Press.

  12. Quantifying the Eocene to Pleistocene topographic evolution of the southwestern Alps, France and Italy

    Science.gov (United States)

    Fauquette, Séverine; Bernet, Matthias; Suc, Jean-Pierre; Grosjean, Anne-Sabine; Guillot, Stéphane; van der Beek, Peter; Jourdan, Sébastien; Popescu, Speranta-Maria; Jiménez-Moreno, Gonzalo; Bertini, Adele; Pittet, Bernard; Tricart, Pierre; Dumont, Thierry; Schwartz, Stéphane; Zheng, Zhuo; Roche, Emile; Pavia, Giulio; Gardien, Véronique

    2015-02-01

    We evaluate the topographic evolution of the southwestern Alps using Eocene to Pleistocene pollen data combined with existing sedimentological, petrographic and detrital geo- and thermochronological data. We report 32 new pollen analyses from 10 sites completed by an existing dataset of 83 samples from 14 localities situated across the southwestern Alps, including both the pro- and the retro-foreland basins. The presence of microthermic tree pollen (mainly Abies, Picea) indicates that this part of the mountain belt attained elevations over 1900 m as early as the Oligocene. Inferred rapid surface uplift during the mid-Oligocene coincided with a previously documented brief phase of rapid erosional exhumation, when maximum erosion rates may have reached values of up to 1.5-2 km/Myr. Slower long-term average exhumation rates of ∼0.3 km/Myr since the Late Oligocene helped maintaining the high Alpine topography of the southwestern Alps until today. The relative abundances of meso-microthermic tree pollen (Cathaya, Cedrus and Tsuga) and microthermic tree pollen (Abies, Picea) in the pro- and retro-foreland basin deposits, indicate that the present-day asymmetric topography, with a relatively gentle western flank and steeper eastern flank, was established early in the southwestern Alps, at least since the Early Miocene, and possibly since the Oligocene or Late Eocene. Therefore, the high topography and asymmetric morphology of this part of the Alps has been maintained throughout the past ∼30 Ma.

  13. A New Tephrochronology for Early Diverse Stone Tool Technologies and Long-Distance Raw Material Transport in the Middle-Late Pleistocene Kapthurin Formation, East Africa.

    Science.gov (United States)

    Blegen, N.; Jicha, B.

    2017-12-01

    The Middle to Late Pleistocene (780-10 ka) of East Africa records significant behavioral change, the earliest fossils of Homo sapiens and the dispersals of our species across and out of Africa. Studying human evolution in the Middle to Late Pleistocene thus requires an extensive and precise chronology relating the appearances of various behaviors preserved in archaeological sequences to aspects of hominin biology and evidence of past environments preserved in the fossils and geological sequences. Tephrochronology provides the chronostratigraphic resolution to achieve this through correlation and dating of volcanic ashes. The tephrochronology of the Kapthurin Formation presented here, based on tephra correlations and 40Ar/ 39Ar dates, provides new ages between 396.3 ± 3.4 ka and 465.3 ± 1.0 ka for nine sites showing some of the earliest evidence of diverse blade and Levallois methods of core reduction. These are >110 kyr older than previously known in East Africa. New 40Ar/ 39Ar dates provide a refined age of 222.5 ± 0.6 ka for early evidence of long-distance obsidian transport at the Sibilo School Road Site. Long-distance tephra correlation between the Baringo and Lake Victoria basins also provides a new date of 100 ka for the Middle Stone Age site of Keraswanin. By providing new or older dates for 11 sites containing several important aspects of hominin behavior and extending the chronology of the Kapthurin Formation forward by 130,000 years, the tephrochronology presented here contributes one of the longest and most refined chronostratigraphic frameworks relevant to modern human evolution. In conjunction with recent archaeological and paleoenvironmental data, this tephrochronology provides the foundation to understand the process of modern human behavioral evolution through the East African Middle and Late Pleistocene as it relates to biological and paleoenvironmental circumstances.

  14. Temporal evolution of the Roccamonfina volcanic complex (Pleistocene), Central Italy

    Science.gov (United States)

    Rouchon, V.; Gillot, P. Y.; Quidelleur, X.; Chiesa, S.; Floris, B.

    2008-10-01

    The Roccamonfina volcanic complex (RVC), in southern Italy, is an Early to Middle Pleistocene stratovolcano sharing temporal and morphological characteristics with the Somma-Vesuvius and the Alban Hills; both being associated with high volcanic hazard for the cities of Naples and Rome, respectively. The RVC is important for the understanding of volcanic evolution in the Roman and Campanian volcanic provinces. We report a comprehensive study of its evolution based on morphological, geochemical and K-Ar geochronological data. The RVC was active from c.a. 550 ka to 150 ka. Its evolution is divided into five stages, defining a volcanic pulse recurrence time of c.a. 90-100 kyr. The two initial stages, consisted in the construction of two successive stratovolcanoes of the tephrite-phonolite, namely "High-K series". The first stage was terminated by a major plinian eruption emplacing the trachytic Rio Rava pumices at 439 ± 9 ka. At the end of the second stage, the last High-K series stratovolcano was destroyed by a large sector collapse and the emplacement of the Brown Leucitic Tuff (BLT) at 353 ± 5 ka. The central caldera of the RVC is the result of the overlapping of the Rio Rava and of the BLT explosions. The plinian eruption of the BLT is related to the emptying of a stratified, deep-seated HKS magma chamber during the upwelling of K series (KS) magma, marking a major geochemical transition and plumbing system re-organization. The following stage was responsible for the emplacement of the Lower White Trachytic Tuff at 331 ± 2 ka, and of basaltic-trachytic effusive products erupted through the main vent. The subsequent activity was mainly restricted to the emplacement of basaltic-shoshonitic parasitic cones and lava flows, and of minor subplinian deposits of the Upper White Trachytic Tuff between 275 and 230 ka. The northern crater is most probably a maar that formed by the phreatomagmatic explosion of the Yellow Trachytic Tuff at 230 ka. The latest stage of

  15. Pollen analyses of Pleistocene hyaena coprolites from Montenegro and Serbia

    Directory of Open Access Journals (Sweden)

    Argant Jacqueline

    2007-01-01

    Full Text Available The results of pollen analyses of hyaena coprolites from the Early Pleistocene cave of Trlica in northern Montenegro and the Late Pleistocene cave of Baranica in southeast Serbia are described. The Early Pleistocene Pachycrocuta brevirostris, and the Late Pleistocene Crocuta spelaea are coprolite-producing species. Although the pollen concentration was rather low, the presented analyses add considerably to the much-needed knowledge of the vegetation of the central Balkans during the Pleistocene. Pollen extracted from a coprolite from the Baranica cave indicates an open landscape with the presence of steppe taxa, which is in accordance with the recorded conditions and faunal remains. Pollen analysis of the Early Pleistocene samples from Trlica indicate fresh and temperate humid climatic conditions, as well as the co-existence of several biotopes which formed a mosaic landscape in the vicinity of the cave.

  16. The morphology and distribution of submerged reefs in the Maui-Nui Complex, Hawaii: New insights into their evolution since the Early Pleistocene

    Science.gov (United States)

    Faichney, Iain D.E.; Webster, James M.; Clague, David A.; Kelley, Chris; Applegate, Bruce; Moore, James G.

    2009-01-01

    Reef drowning and backstepping have long been recognised as reef responses to sea-level rise on subsiding margins. During the Late Pleistocene (~500–14 ka) Hawaiian reefs grew in response to rapid subsidence and 120 m 100 kyr sea-level cycles, with recent work on the submerged drowned reefs around the big island of Hawaii, and in other locations from the last deglacial, providing insight into reef development under these conditions. In contrast, reefs of the Early Pleistocene (~1.8–0.8 Ma) remain largely unexplored despite developing in response to significantly different 60–70 m 41 kyr sea-level cycles. The Maui-Nui Complex (MNC — forming the islands of Maui, Molokai, Lanai and Kahoolawe), provides a natural laboratory to study reef evolution throughout this time period as recent data indicate the reefs grew from 1.1 to 0.5 Ma. We use new high resolution bathymetric and backscatter data as well as sub-bottom profiling seismic data and field observations from ROV and submersible dives to make a detailed analysis of reef morphology and structure around the MNC. We focus specifically on the south-central region of the complex that provides the best reef exposure and find that the morphology of the reefs varies both regionally and temporally within this region. Barrier and pinnacle features dominate the steeper margins in the north of the study area whilst broad backstepping of the reefs is observed in the south. Within the Au'au channel in the central region between the islands, closely spaced reef and karst morphology indicates repeated subaerial exposure. We propose that this variation in the morphology and structure of the reefs within the MNC has been controlled by three main factors; the subsidence rate of the complex, the amplitude and period of eustatic sea-level cycles, and the slope and continuity of the basement substrate. We provide a model of reef development within the MNC over the last 1.2 Ma highlighting the effect that the interaction

  17. Balanced Cross Section for Restoration of Tectonic Evolution in the Southwest Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    Wu Shiguo; Ni Xianglong; Guo Junhua

    2007-01-01

    On the basis of the multi-channel seismic data and the other data, using 2DMove software,the tectonic evolution in three seismic profiles was restored since Pliocene. The tectonic restoration results show that: (1) the initial active center lay in the west slope and then was transferred to east and south via trough center during the evolution process; (2) several main normal faults controlled the evolution of the southern Okinawa Trough; (3) since Late Pliocene, the southern Okinawa Trough has experienced two spreading stages. The early is depression in Early-Middle Pleistocene and the late is back-arc spreading in Late Pleistocene and Holocene, which is in primary oceanic crust spreading stage.

  18. The origin and evolution of Homo sapiens.

    Science.gov (United States)

    Stringer, Chris

    2016-07-05

    If we restrict the use of Homo sapiens in the fossil record to specimens which share a significant number of derived features in the skeleton with extant H. sapiens, the origin of our species would be placed in the African late middle Pleistocene, based on fossils such as Omo Kibish 1, Herto 1 and 2, and the Levantine material from Skhul and Qafzeh. However, genetic data suggest that we and our sister species Homo neanderthalensis shared a last common ancestor in the middle Pleistocene approximately 400-700 ka, which is at least 200 000 years earlier than the species origin indicated from the fossils already mentioned. Thus, it is likely that the African fossil record will document early members of the sapiens lineage showing only some of the derived features of late members of the lineage. On that basis, I argue that human fossils such as those from Jebel Irhoud, Florisbad, Eliye Springs and Omo Kibish 2 do represent early members of the species, but variation across the African later middle Pleistocene/early Middle Stone Age fossils shows that there was not a simple linear progression towards later sapiens morphology, and there was chronological overlap between different 'archaic' and 'modern' morphs. Even in the late Pleistocene within and outside Africa, we find H. sapiens specimens which are clearly outside the range of Holocene members of the species, showing the complexity of recent human evolution. The impact on species recognition of late Pleistocene gene flow between the lineages of modern humans, Neanderthals and Denisovans is also discussed, and finally, I reconsider the nature of the middle Pleistocene ancestor of these lineages, based on recent morphological and genetic data.This article is part of the themed issue 'Major transitions in human evolution'. © 2016 The Author(s).

  19. Reconsideration of the systematics of the Early Pleistocene Cervavitus (Cervidae, Artiodactyla, Mammalia

    Directory of Open Access Journals (Sweden)

    Dong, W.

    2011-12-01

    Full Text Available Cervavitus were usually found from the Late Miocene and Pliocene deposits in East Europe, Middle Asia and North China, but they were found recently in many Early Pleistocene localities in southern China. The latter resulted in the discussion of their systematic status between Cervavitus and Cervus. Here we show the Early Pleistocene forms from southern China are morphometrically more similar to northern China Cervavitus species, and the cladistic analysis shows that the southern China forms are closer to classic Cervavitus species than Cervus and that also proves their systematic status in Cervavitus rather than in Cervus. Cervavitus originated in Moldovan forests of East Europe in the late Vallesian (MN10 from a brachyodont and holometacarpal ancestor with two/three-tined antlers and Palaeomeryx fold and evolved into C. novorossiae. It dispersed into West Europe forests in the earliest Turolian and further west to France in the Ruscinian. It dispersed into northern China forests in the early Turolian and represented by C. shanxius. The great quantity of C. shanxius specimens with brachyodont teeth and complete lateral metacarpals implies the arid Loess Plateau of today was a humid forested region in the Late Miocene. C. shanxius migrated southwards in the Plio-Pleistocene probably due to the drying environment in northern China with uplifting of Himalayas and evolved into C. ultimus and C. fenqii, which survived in southern China until the Early Pleistocene (MNQ18.La revisión sistemática de Cervivatus sugiere que deriva del principal clado de los cérvidos posteriores a los muntiacinos, e implica que Procervulinae, Dicrocerinae y la primeras formas de Munticiacinae serían holometacarpales, como también lo es Cervivatus, originario en los bosques de Moldavia (Europa del Este durante el Vallesiense final (MN 10, a partir de un antecesor braquiodonto y holometacarpal, con astas con dos o tres candiles y pliegue paleomerícido, y que da lugar a

  20. The Pleistocene rivers of the English Channel region

    Science.gov (United States)

    Antoine, Pierre; Coutard, Jean-Pierre; Gibbard, Philip; Hallegouet, Bernard; Lautridou, Jean-Pierre; Ozouf, Jean-Claude

    2003-02-01

    The Pleistocene history of river systems that enter the English Channel from northern France and southern England is reviewed. During periods of low sea-level (cold stages) these streams were tributaries of the Channel River. In southern England the largest, the River Solent, is an axial stream that has drained the Hampshire Basin from the Early Pleistocene or late Pliocene. Other streams of southern England may be of similar antiquity but their records are generally short and their sedimentary history have been destroyed, as in northern Brittany, by coastal erosion and valley deepening as a consequence of tectonic uplift. In northern France, the Seine and Somme rivers have very well developed terrace systems recording incision that began at around 1 Ma. The uplift rate, deduced from the study of these terrace systems, is of 55 to 60 m myr-1 since the end of the Early Pleistocene. Generally the facies and sedimentary structures indicate that the bulk of the deposits in these rivers accumulated in braided river environments under periglacial climates in all the area around the Channel. Evolution of the rivers reflects their responses to climatic change, local geological structure and long-term tectonic activity. In this context the Middle Somme valley is characterised by a regular pattern in which incision occurs at the beginning of each glacial period within a general background of uplift. Nevertheless the response of the different rivers to climatic variations, uplift and sea-level changes is complex and variable according to the different parts of the river courses.

  1. Continuity or discontinuity in the European Early Pleistocene human settlement: the Atapuerca evidence

    Science.gov (United States)

    Bermúdez de Castro, José María; Martinón-Torres, María; Blasco, Ruth; Rosell, Jordi; Carbonell, Eudald

    2013-09-01

    The nature, timing, pattern, favourable circumstances and impediments of the human occupation of the European continent during the Early Pleistocene are hot topics in Quaternary studies. In particular, the problem of the (dis) continuity of the settlement of Europe in this period is an important matter of discussion, which has been approached in the last decade from different points of view. The Gran Dolina (TD) and Sima del Elefante (TE) cave sites in the Sierra de Atapuerca, (Spain) include large and quasi-continuous stratigraphic sequences that stretch back from at least 1.2 million years ago (Ma) to the Matuyama/Brunhes boundary. The archaeological and paleontological record from these sites can help to test different hypotheses about the character of the human settlement in this region and period. Furthermore, the TD6 level has yielded a large collection of human fossil remains attributed to Homo antecessor. According to different geochronological methods, as well as to paleomagnetic and biostratigraphical analyses, these hominins belong to an age range of 0.96-0.80 Ma. Unfortunately, the finding in 2007 of some human fossil remains in the TE9 level, dated to about 1.22 Ma, was not enough to conclude whether H. antecessor had deep roots in the European Early Pleistocene. A set of derived features of H. antecessor shared with both the Neanderthal lineage and modern humans suggests that this species is related, and not far, from the most recent common ancestor (MRCA) of Homo neanderthalensis and Homo sapiens. If we assume that there was a lineal biological relationship between the TE9 and TD6 hominins, we should reconsider many of the conclusions achieved in previous paleontological and genetic studies. In addition, we would be obliged to build a highly complicated paleogeographical scenario for the origin of the MRCA. Although continuity in the settlement of Europe during the entire late Early Pleistocene is not discarded (e.g. in refuge areas), it seems that

  2. Spatial prediction of the variability of early pleistocene subsurface sediments in the Netherlands part 2: geochemistry

    NARCIS (Netherlands)

    Huisman, D.J.; Weijers, J.P.; Dijkshoorn, L.; Veldkamp, A.

    2000-01-01

    We started a geochemical mapping campaign in the Early Pleistocene fluviatile Kedichem Formation in the Netherlands in order to meet the demand for more information about subsurface sediment compositions. Geochemical data were collected during a sampling campaign, and about 600 samples from the

  3. Spatial prediction of the variability of Early Pleistocene subsurface sediments in the Netherlands - Part 2 : Geochemistry

    NARCIS (Netherlands)

    Huisman, D.J.; Weijers, J.P.; Dijkshoorn, L.; Veldkamp, A.

    2000-01-01

    We started a geochemical mapping campaign in the Early Pleistocene fluviatile Kedichem Formation in the Netherlands in order to meet the demand for more information about subsurface sediment compositions. Geochemical data were collected during a sampling campaign, and about 600 samples from the

  4. PLIO-PLEISTOCENE FOSSIL VERTEBRATES OF MONTE TUTTAVISTA (OROSEI, EASTERN SARDINIA, ITALY, AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    LAURA ABBAZZI

    2004-11-01

    Full Text Available The preliminary results of the analisys of fossil vertebrate remains from 19 fissure fillings in the karst network at Monte Tuttavista (Orosei, NMoro are reported. about 80 taxa, among fishes, amphibians, reptiles, birds and mammals have been recognised.These remains document the evolution of vertebrate assemblages in the Sardinian insular domain, during a time interval apparently spanning the Late Pliocene to Late Pleistocene or Holocene. A succession of at least four populating complexes has been identified which document the vertebrate colonisation phases from the Italian mainland and the following periods of insularity. Indeed, the occurrence of endemic taxa such as the murid Rhagapodemus minor, the primate Macaca cf. M. majori and the caprine Nesogoral, suggest some fissure fillings date to a phase close to the Plio/Pleistocene boundary since these taxa occur at the Sardinian locality Capo Figari I which has been dated to about 1.8 Ma. However, the presence of the "hunting-hyaena" Chasmaporthetes, never reported before in Sardinia, could suggest that the beginning of the vertebrate record of Monte Tuttavista is older, given that this carnivore is documented in European Middle Pliocene-Early Pleistocene localities. The vertebrate assemblages that document the most recent migratory phases in the karst network of Monte Tuttavista are characterised by the occurrence of the endemic megalocerine cervid Praemegaceros cazioti and the arvicolid Tyrrhenicola henseli which are comparable with those occurring in other Late Pleistocene and early Holocene Sardinian sites.

  5. Early Human Evolution in the Western Palaearctic: Ecological Scenarios

    Science.gov (United States)

    Carrión, José S.; Rose, James; Stringer, Chris

    2011-06-01

    This review presents the themes of a special issue dealing with environmental scenarios of human evolution during the Early Pleistocene (2.6-0.78 Ma; MIS 103-MIS 19) and early Middle Pleistocene (0.78-0.47 Ma; MIS 19-base of MIS 12) within the western Palaearctic. This period is one of dramatic changes in the climates and the distribution of Palaearctic biota. These changes have played their role in generating adaptive and phyletic patterns within the human ancestry, involving several species such as Homo habilis, "Homo georgicus", Homo erectus, Homo antecessor and Homo heidelbergensis. In the archaeological record, these species include the Oldowan (Mode 1) and Acheulian (Mode 2) lithic technologies. Taphonomic considerations of palaeoecological research in hominin-bearing sites are provided and evaluated. Syntheses are provided for north Africa, western Asia, the Mediterranean Basin, Britain, and continental Europe. Palaeoenvironmental reconstructions based on multidisciplinary data are given for Ain Boucherit, Ain Hanech and El-Kherba in Algeria, Dmanisi in Georgia, Atapuerca, Cueva Negra, and the Orce Basin in Spain, Monte Poggiolo and Pirro Nord in Italy, Pont-de-Lavaud in France, and Mauer in Germany. The state of the art with the Out of Africa 1 dispersal model is reviewed. A source-sink dynamics model for Palaeolithic Europe is described to explain the morphological disparity of H. heidelbergensis (we will sometimes use the informal name "Heidelbergs") and early Neanderthals. Other aspects debated here are the selective value of habitat mosaics including reconstructions based on mammal and avian databases, and the role of geological instability combined with topographic complexity. This review is completed by addressing the question of whether the appearance of evolutionary trends within hominins is concentrated in regions of highest worldwide biological diversity (biodiversity hotspots). It is concluded that the keys for the activation of evolutionary

  6. Independent evolution of baleen whale gigantism linked to Plio-Pleistocene ocean dynamics.

    Science.gov (United States)

    Slater, Graham J; Goldbogen, Jeremy A; Pyenson, Nicholas D

    2017-05-31

    Vertebrates have evolved to gigantic sizes repeatedly over the past 250 Myr, reaching their extreme in today's baleen whales (Mysticeti). Hypotheses for the evolution of exceptionally large size in mysticetes range from niche partitioning to predator avoidance, but there has been no quantitative examination of body size evolutionary dynamics in this clade and it remains unclear when, why or how gigantism evolved. By fitting phylogenetic macroevolutionary models to a dataset consisting of living and extinct species, we show that mysticetes underwent a clade-wide shift in their mode of body size evolution during the Plio-Pleistocene. This transition, from Brownian motion-like dynamics to a trended random walk towards larger size, is temporally linked to the onset of seasonally intensified upwelling along coastal ecosystems. High prey densities resulting from wind-driven upwelling, rather than abundant resources alone, are the primary determinant of efficient foraging in extant mysticetes and Late Pliocene changes in ocean dynamics may have provided an ecological pathway to gigantism in multiple independent lineages. © 2017 The Author(s).

  7. Reconstructing Early Pleistocene (1.3 Ma) terrestrial environmental change in western Anatolia: Did it drive fluvial terrace formation?

    NARCIS (Netherlands)

    Veldkamp, A.; Candy, I.; Jongmans, A.G.; Maddy, D.; Demir, T.; Schoorl, J.M.; Schreve, D.; Stemerdink, C.; Schriek, van der T.

    2015-01-01

    A terrestrial environmental reconstruction of an Early Pleistocene landscape from western Anatolia is presented. The basis of this reconstruction is a sedimentary stack comprising fluvial and colluvial slope deposits. Contained within this stack is a sequence comprising two massive laminar calcretes

  8. New radiocarbon dates for terminal Pleistocene and early Holocene settlements in West Turkana, northern Kenya

    Science.gov (United States)

    Beyin, Amanuel; Prendergast, Mary E.; Grillo, Katherine M.; Wang, Hong

    2017-07-01

    The Turkana Basin in northern Kenya is located in an environmentally sensitive region along the eastern African Rift system. Lake Turkana's sensitivity to fluctuations in precipitation makes this an ideal place to study prehistoric human adaptations during key climatic transitions. Here we present eleven radiocarbon dates from two recently excavated sites in West Turkana, Kokito 01 and Kokito 02. The sites span the Pleistocene-Holocene transition, a time of fluctuating lake levels and novel cultural responses within the region. Several scenarios are laid out for the interpretation of site chronologies, and these are discussed with reference to the terminal Pleistocene and early Holocene chronological record for the region. Given the paucity of well-dated sites from this timespan in the Turkana Basin, the new radiocarbon dates are an important step toward establishing human settlement history and associated cultural developments in the region.

  9. A new tephrochronology for early diverse stone tool technologies and long-distance raw material transport in the Middle to Late Pleistocene Kapthurin Formation, East Africa.

    Science.gov (United States)

    Blegen, Nick; Jicha, Brian R; McBrearty, Sally

    2018-05-09

    The Middle to Late Pleistocene (780-10 ka) of East Africa records evidence of significant behavioral change, early fossils of Homo sapiens, and the dispersals of our species across and out of Africa. Studying human evolution in this time period thus requires an extensive and precise chronology relating behavioral evidence from archaeological sequences to aspects of hominin biology and evidence of past environments from fossils and geological sequences. Tephrochronology provides the chronostratigraphic resolution to achieve this through correlation and dating of volcanic ashes. The tephrochronology of the Kapthurin Formation presented here, based on tephra correlations and 40 Ar/ 39 Ar dates, provides new ages between 395.6 ± 3.5 ka and 465.3 ± 1.0 ka for nine sites showing diverse blade and Levallois methods of core reduction. These are >110 kyr older than previously known in East Africa. New 40 Ar/ 39 Ar dates provide a refined age of 222.5 ± 0.6 ka for early evidence of long-distance (166 km) obsidian transport at the Sibilo School Road Site. A tephra correlation between the Baringo and Victoria basins also provides a new date of ∼100 ka for the Middle Stone Age site of Keraswanin. By providing new and older dates for 11 sites containing several important aspects of hominin behavior and extending the chronology of the Kapthurin Formation forward by ∼130,000 years, the tephrochronology presented here contributes one of the longest and most refined chronostratigraphic frameworks of Middle through Late Pleistocene East Africa. This tephrochronology thus provides the foundation to understand the process of modern human behavioral evolution as it relates to biological and paleoenvironmental circumstances. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Brain size and encephalization in early to Mid-Pleistocene Homo.

    Science.gov (United States)

    Rightmire, G Philip

    2004-06-01

    Important changes in the brain have occurred during the course of human evolution. Both absolute and relative size increases can be documented for species of Homo, culminating in the appearance of modern humans. One species that is particularly well-represented by fossil crania is Homo erectus. The mean capacity for 30 individuals is 973 cm(3). Within this group there is substantial variation, but brain size increases slightly in specimens from later time periods. Other Middle Pleistocene crania differ from those of Homo erectus. Characters of the facial skeleton, vault, and cranial base suggest that fossils from sites such as Arago Cave in France, the Sima de los Huesos in Spain, Bodo in Ethiopia, Broken Hill in Zambia, and perhaps Dali in China belong to the taxon Homo heidelbergensis. Ten of these mid-Quaternary hominins have brains averaging 1,206 cm(3) in volume, and many fall beyond the limits of size predicted for Homo erectus of equivalent age. When orbit height is used to construct an index of relative brain size, it is apparent that the (significant) increase in volume documented for the Middle Pleistocene individuals is not simply a consequence of larger body mass. Encephalization quotient values confirm this finding. These changes in absolute and relative brain size can be taken as further corroborative evidence for a speciation event, in which Homo erectus produced a daughter lineage. It is probable that Homo heidelbergensis originated in Africa or western Eurasia and then ranged widely across the Old World. Archaeological traces indicate that these populations differed in their technology and behavior from earlier hominins. Copyright 2003 Wiley-Liss, Inc.

  11. Pedogenic carbonate stable isotopic evidence for wooded habitat preference of early Pleistocene tool makers in the Turkana Basin.

    Science.gov (United States)

    Quinn, Rhonda L; Lepre, Christopher J; Feibel, Craig S; Wright, James D; Mortlock, Richard A; Harmand, Sonia; Brugal, Jean-Philip; Roche, Hélène

    2013-07-01

    The origin and evolution of early Pleistocene hominin lithic technologies in Africa occurred within the context of savanna grassland ecosystems. The Nachukui Formation of the Turkana Basin in northern Kenya, containing Oldowan and Acheulean tool assemblages and fossil evidence for early members of Homo and Paranthropus, provides an extensive spatial and temporal paleosol record of early Pleistocene savanna flora. Here we present new carbon isotopic (δ(13)CVPDB) values of pedogenic carbonates (68 nodules, 193 analyses) from the Nachukui Formation in order to characterize past vegetation structure and change through time. We compared three members (Kalochoro, Kaitio, and Natoo) at five locations spanning 2.4-1.4Ma and sampled in proximity to hominin archaeological and paleontological sites. Our results indicate diverse habitats showing a mosaic pattern of vegetation cover at each location yet demonstrate grassland expansion through time influenced by paleogeography. Kalochoro floodplains occurred adjacent to large river systems, and paleosols show evidence of C3 woodlands averaging 46-50% woody cover. Kaitio habitats were located along smaller rivers and lake margins. Paleosols yielded evidence for reduced portions of woody vegetation averaging 34-37% woody cover. Natoo environments had the highest percentage of grasslands averaging 21% woody cover near a diminishing Lake Turkana precursor. We also compared paleosol δ(13)CVPDB values of lithic archaeological sites with paleosol δ(13)CVPDB values of all environments available to hominins at 2.4-1.4Ma in the Nachukui and Koobi Fora Formations. Grassy environments became more widespread during this interval; woody canopy cover mean percentages steadily decreased by 12%. However, significantly more wooded savanna habitats were present in the vicinity of lithic archaeological sites and did not mirror the basin-wide trend of grassland spread. Hominin lithic archaeological sites consistently demonstrated woody cover

  12. Early human symbolic behavior in the Late Pleistocene of Wallacea

    Science.gov (United States)

    Brumm, Adam; Hakim, Budianto; Ramli, Muhammad; Sumantri, Iwan; Burhan, Basran; Saiful, Andi Muhammad; Siagian, Linda; Suryatman; Sardi, Ratno; Jusdi, Andi; Abdullah; Mubarak, Andi Pampang; Hasliana; Hasrianti; Oktaviana, Adhi Agus; Adhityatama, Shinatria; van den Bergh, Gerrit D.; Aubert, Maxime; Zhao, Jian-xin; Huntley, Jillian; Li, Bo; Roberts, Richard G.; Saptomo, E. Wahyu; Perston, Yinika; Grün, Rainer

    2017-01-01

    Wallacea, the zone of oceanic islands separating the continental regions of Southeast Asia and Australia, has yielded sparse evidence for the symbolic culture of early modern humans. Here we report evidence for symbolic activity 30,000–22,000 y ago at Leang Bulu Bettue, a cave and rock-shelter site on the Wallacean island of Sulawesi. We describe hitherto undocumented practices of personal ornamentation and portable art, alongside evidence for pigment processing and use in deposits that are the same age as dated rock art in the surrounding karst region. Previously, assemblages of multiple and diverse types of Pleistocene “symbolic” artifacts were entirely unknown from this region. The Leang Bulu Bettue assemblage provides insight into the complexity and diversification of modern human culture during a key period in the global dispersal of our species. It also shows that early inhabitants of Sulawesi fashioned ornaments from body parts of endemic animals, suggesting modern humans integrated exotic faunas and other novel resources into their symbolic world as they colonized the biogeographically unique regions southeast of continental Eurasia. PMID:28373568

  13. Pleistocene Palaeoart of Asia

    Directory of Open Access Journals (Sweden)

    Robert G. Bednarik

    2013-06-01

    Full Text Available This comprehensive overview considers the currently known Pleistocene palaeoart of Asia on a common basis, which suggests that the available data are entirely inadequate to form any cohesive synthesis about this corpus. In comparison to the attention lavished on the corresponding record available from Eurasia’s small western appendage, Europe, it is evident that Pleistocene palaeoart from the rest of the world has been severely neglected. Southern Asia, in particular, holds great promise for the study of early cognitive development of hominins, and yet this potential has remained almost entirely unexplored. Asia is suggested to be the key continent in any global synthesis of ‘art’ origins, emphasising the need for a comprehensive pan-continental research program. This is not just to counter-balance the incredible imbalance in favour of Europe, but to examine the topic of Middle Pleistocene palaeoart development effectively.

  14. Evolution, systematics, and phylogeography of pleistocene horses in the new world: a molecular perspective.

    Directory of Open Access Journals (Sweden)

    2005-08-01

    Full Text Available The rich fossil record of horses has made them a classic example of evolutionary processes. However, while the overall picture of equid evolution is well known, the details are surprisingly poorly understood, especially for the later Pliocene and Pleistocene, c. 3 million to 0.01 million years (Ma ago, and nowhere more so than in the Americas. There is no consensus on the number of equid species or even the number of lineages that existed in these continents. Likewise, the origin of the endemic South American genus Hippidion is unresolved, as is the phylogenetic position of the "stilt-legged" horses of North America. Using ancient DNA sequences, we show that, in contrast to current models based on morphology and a recent genetic study, Hippidion was phylogenetically close to the caballine (true horses, with origins considerably more recent than the currently accepted date of c. 10 Ma. Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species.

  15. Evolution, systematics, and phylogeography of pleistocene horses in the new world: a molecular perspective.

    Science.gov (United States)

    Weinstock, Jaco; Willerslev, Eske; Sher, Andrei; Tong, Wenfei; Ho, Simon Y W; Rubenstein, Dan; Storer, John; Burns, James; Martin, Larry; Bravi, Claudio; Prieto, Alfredo; Froese, Duane; Scott, Eric; Xulong, Lai; Cooper, Alan

    2005-08-01

    The rich fossil record of horses has made them a classic example of evolutionary processes. However, while the overall picture of equid evolution is well known, the details are surprisingly poorly understood, especially for the later Pliocene and Pleistocene, c. 3 million to 0.01 million years (Ma) ago, and nowhere more so than in the Americas. There is no consensus on the number of equid species or even the number of lineages that existed in these continents. Likewise, the origin of the endemic South American genus Hippidion is unresolved, as is the phylogenetic position of the "stilt-legged" horses of North America. Using ancient DNA sequences, we show that, in contrast to current models based on morphology and a recent genetic study, Hippidion was phylogenetically close to the caballine (true) horses, with origins considerably more recent than the currently accepted date of c. 10 Ma. Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species.

  16. Dama roberti, a new species of deer from the early Middle Pleistocene of Europe, and the origins of modern fallow deer

    Science.gov (United States)

    Breda, Marzia; Lister, Adrian M.

    2013-06-01

    The ancestry of the modern fallow deer, Dama dama, has been tentatively traced back to Pliocene/Early Pleistocene forms referred to 'Pseudodama', characterized by unpalmated three- or four-point antlers. By the late Middle Pleistocene, Dama with palmated antlers appears, as Dama dama clactoniana. However, fallow deer from the interim period, the early Middle Pleistocene, are poorly-known. A new specimen from Pakefield (Suffolk, UK), represented by a portion of cranium with a substantial part of both antlers plus a mandible and scapula, is the most complete medium-sized deer specimen from the British early Middle Pleistocene (ca 700 ka). The position and orientation of the basal tine, together with dental characters and mandibular morphology, are typical of fallow deer. The narrow palmation is reminiscent of D. dama clactoniana, but the lack of palmation tines is unique. Moreover, the lack of second (and third) tines in an adult specimen differs from both D. dama dama and D. d. clactoniana, being a primitive character shared with the last representatives of 'Pseudodama' which, on the other hand, has a circular beam lacking any palmation. This combination of features justifies the erection of a new species provisionally placed within the genus Dama, Dama roberti n. sp. Another specimen, from Soleilhac (Auvergne, France), represented by portions of the two antlers, a mandible and a tibia, shares antler morphology with the Pakefield specimen and can be ascribed to the same new species. Isolated antler and dental remains from coeval British sites are tentatively ascribed to D. roberti n. sp. The new species has implications for the ancestry of modern fallow deer.

  17. A reassessment of the early archaeological record at Leang Burung 2, a Late Pleistocene rock-shelter site on the Indonesian island of Sulawesi

    Science.gov (United States)

    Hakim, Budianto; Ramli, Muhammad; Aubert, Maxime; van den Bergh, Gerrit D.; Li, Bo; Burhan, Basran; Saiful, Andi Muhammad; Siagian, Linda; Sardi, Ratno; Jusdi, Andi; Abdullah; Mubarak, Andi Pampang; Moore, Mark W.; Roberts, Richard G.; Zhao, Jian-xin; McGahan, David; Jones, Brian G.; Perston, Yinika; Szabó, Katherine; Mahmud, M. Irfan; Westaway, Kira; Jatmiko; Saptomo, E. Wahyu; van der Kaars, Sander; Grün, Rainer; Wood, Rachel; Dodson, John

    2018-01-01

    This paper presents a reassessment of the archaeological record at Leang Burung 2, a key early human occupation site in the Late Pleistocene of Southeast Asia. Excavated originally by Ian Glover in 1975, this limestone rock-shelter in the Maros karsts of Sulawesi, Indonesia, has long held significance in our understanding of early human dispersals into ‘Wallacea’, the vast zone of oceanic islands between continental Asia and Australia. We present new stratigraphic information and dating evidence from Leang Burung 2 collected during the course of our excavations at this site in 2007 and 2011–13. Our findings suggest that the classic Late Pleistocene modern human occupation sequence identified previously at Leang Burung 2, and proposed to span around 31,000 to 19,000 conventional 14C years BP (~35–24 ka cal BP), may actually represent an amalgam of reworked archaeological materials. Sources for cultural materials of mixed ages comprise breccias from the rear wall of the rock-shelter–remnants of older, eroded deposits dated to 35–23 ka cal BP–and cultural remains of early Holocene antiquity. Below the upper levels affected by the mass loss of Late Pleistocene deposits, our deep-trench excavations uncovered evidence for an earlier hominin presence at the site. These findings include fossils of now-extinct proboscideans and other ‘megafauna’ in stratified context, as well as a cobble-based stone artifact technology comparable to that produced by late Middle Pleistocene hominins elsewhere on Sulawesi. PMID:29641524

  18. Pliocene warmth, polar amplification, and stepped Pleistocene cooling recorded in NE Arctic Russia.

    Science.gov (United States)

    Brigham-Grette, Julie; Melles, Martin; Minyuk, Pavel; Andreev, Andrei; Tarasov, Pavel; DeConto, Robert; Koenig, Sebastian; Nowaczyk, Norbert; Wennrich, Volker; Rosén, Peter; Haltia, Eeva; Cook, Tim; Gebhardt, Catalina; Meyer-Jacob, Carsten; Snyder, Jeff; Herzschuh, Ulrike

    2013-06-21

    Understanding the evolution of Arctic polar climate from the protracted warmth of the middle Pliocene into the earliest glacial cycles in the Northern Hemisphere has been hindered by the lack of continuous, highly resolved Arctic time series. Evidence from Lake El'gygytgyn, in northeast (NE) Arctic Russia, shows that 3.6 to 3.4 million years ago, summer temperatures were ~8°C warmer than today, when the partial pressure of CO2 was ~400 parts per million. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, sudden stepped cooling events during the Pliocene-Pleistocene transition, and warmer than present Arctic summers until ~2.2 million years ago, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was insufficient to support large-scale ice sheets until the early Pleistocene.

  19. Relationship between geohydrology and Upper Pleistocene-Holocene evolution of the eastern region of the Province of Buenos Aires, Argentina

    Science.gov (United States)

    Capítulo, Leandro Rodrigues; Kruse, Eduardo E.

    2017-07-01

    The Upper Pleistocene-Holocene geological evolution, which is characterized by its landscape-forming energy and is related to geological and geomorphological complexity, has an impact on the groundwater dynamics of coastal aquifers. The geological configuration of a sector of the east coast of the Province of Buenos Aires was analyzed, as well as its connection with the geological and geomorphological history of the region during the Late Pleistocene and Holocene, and its influence on the regional and local geohydrological behaviour. This analysis was based on the application of the concept of hydrofacies. Boreholes were drilled and sampled (with depths of up to 40 m), and vertical electrical sounding, electrical tomography and pumping tests were undertaken. The description of the cutting samples by means of a stereo microscope, the interpretation of satellite images, and the construction of lithological and hydrogeological profiles and flow charts were carried out in the laboratory, and then integrated in a GIS. The identification of the lithological units and their distribution in the area allowed the construction of an evolutionary geological model for the Late Pleistocene and Holocene. Three aquifer units can be recognized: one of Late Pleistocene age (hydrofacies E) and the other two of Holocene age (hydrofacies A and C); their hydraulic connection depends on the occurrence and thickness variation of the aquitard units (hydrofacies B and D). The approach adopted allows the examination of the possibilities for groundwater exploitation and constitutes an applied conceptual framework to be taken into consideration when developing conceptual and numerical models at the local and regional scales.

  20. Paleoenvironmental evolution and geomorphic dynamics recorded in the Homo-bearing Pleistocene stratigraphic succession of Aalat (Eritrea, East Africa): A pedological perspective

    Science.gov (United States)

    Scarciglia, Fabio; Mercatante, Giuseppe; Donato, Paola; Ghinassi, Massimiliano; Carnevale, Giorgio; Delfino, Massimo; Oms, Oriol; Papini, Mauro; Pavia, Marco; Sani, Federico; Rook, Lorenzo

    2017-04-01

    these cemented horizons with layers affected by local to extensive staining of the matrix with reddish to yellowish iron-oxides/hydroxides, suggests cyclical changes from dry to wet environmental conditions. This pattern is quite consistent with the main Pleistocene climate oscillations evidenced in global-scale paleoclimatic curves, where glacial/interglacial cycles of higher latitudes well correspond to the formation of carbonate- or gypsum-cemented and the iron-stained layers, respectively. In addition, some carbonate parent material enhancing secondary carbonate dynamics within the soil system, dominated by siliciclastic grains sourced from the metamorphic basement rocks prevailing in the Dandiero basin, could have been supplied as eolian dust during dryer (glacial) periods. A comparison of the different evolutionary (maturity-related) stages of calcic/petrocalcic and petrogypsic horizons of the chronologically well-constrained Aalat succession suggests that their time ranges of development were between 102 - 103 years and a few tens of thousands years. Further investigations are required to assess the potential role of paleoenvironmental changes recorded in the Dandiero basin fill on human settlement, dispersal and evolution in East Africa during the Early-Middle Pleistocene transition.

  1. Systematics and paleobiogeography of .i.Sardolagus obscurus./i. n. gen. n. sp. (Leporidae, Lagomorpha) from the early Pleistocene of Sardinia

    Czech Academy of Sciences Publication Activity Database

    Angelone, Ch.; Čermák, Stanislav; Moncunill-Solé, B.; Quintana, J.; Tuveri, C.; Arca, M.; Kotsakis, T.

    2018-01-01

    Roč. 92, č. 3 (2018) ISSN 0022-3360 Institutional support: RVO:67985831 Keywords : Sardolagus obscurus n. gen. n. sp. * Leporidae * early Pleistocene * Sardinia * systematics Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Paleontology Impact factor: 1.591, year: 2016

  2. Unexpected Convergent Evolution of Nasal Domes between Pleistocene Bovids and Cretaceous Hadrosaur Dinosaurs.

    Science.gov (United States)

    O'Brien, Haley D; Faith, J Tyler; Jenkins, Kirsten E; Peppe, Daniel J; Plummer, Thomas W; Jacobs, Zenobia L; Li, Bo; Joannes-Boyau, Renaud; Price, Gilbert; Feng, Yue-Xing; Tryon, Christian A

    2016-02-22

    The fossil record provides tangible, historical evidence for the mode and operation of evolution across deep time. Striking patterns of convergence are some of the strongest examples of these operations, whereby, over time, similar environmental and/or behavioral pressures precipitate similarity in form and function between disparately related taxa. Here we present fossil evidence for an unexpected convergence between gregarious plant-eating mammals and dinosaurs. Recent excavations of Late Pleistocene deposits on Rusinga Island, Kenya, have uncovered a catastrophic assemblage of the wildebeest-like bovid Rusingoryx atopocranion. Previously known from fragmentary material, these new specimens reveal large, hollow, osseous nasal crests: a craniofacial novelty for mammals that is remarkably comparable to the nasal crests of lambeosaurine hadrosaur dinosaurs. Using adult and juvenile material from this assemblage, as well as computed tomographic imaging, we investigate this convergence from morphological, developmental, functional, and paleoenvironmental perspectives. Our detailed analyses reveal broad parallels between R. atopocranion and basal Lambeosaurinae, suggesting that osseous nasal crests may require a highly specific combination of ontogeny, evolution, and environmental pressures in order to develop. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. An enlarged parietal foramen in the late archaic Xujiayao 11 neurocranium from Northern China, and rare anomalies among Pleistocene Homo.

    Science.gov (United States)

    Wu, Xiu-Jie; Xing, Song; Trinkaus, Erik

    2013-01-01

    We report here a neurocranial abnormality previously undescribed in Pleistocene human fossils, an enlarged parietal foramen (EPF) in the early Late Pleistocene Xujiayao 11 parietal bones from the Xujiayao (Houjiayao) site, northern China. Xujiayao 11 is a pair of partial posteromedial parietal bones from an adult. It exhibits thick cranial vault bones, arachnoid granulations, a deviated posterior sagittal suture, and a unilateral (right) parietal lacuna with a posteriorly-directed and enlarged endocranial vascular sulcus. Differential diagnosis indicates that the perforation is a congenital defect, an enlarged parietal foramen, commonly associated with cerebral venous and cranial vault anomalies. It was not lethal given the individual's age-at-death, but it may have been associated with secondary neurological deficiencies. The fossil constitutes the oldest evidence in human evolution of this very rare condition (a single enlarged parietal foramen). In combination with developmental and degenerative abnormalities in other Pleistocene human remains, it suggests demographic and survival patterns among Pleistocene Homo that led to an elevated frequency of conditions unknown or rare among recent humans.

  4. An enlarged parietal foramen in the late archaic Xujiayao 11 neurocranium from Northern China, and rare anomalies among Pleistocene Homo.

    Directory of Open Access Journals (Sweden)

    Xiu-Jie Wu

    Full Text Available We report here a neurocranial abnormality previously undescribed in Pleistocene human fossils, an enlarged parietal foramen (EPF in the early Late Pleistocene Xujiayao 11 parietal bones from the Xujiayao (Houjiayao site, northern China. Xujiayao 11 is a pair of partial posteromedial parietal bones from an adult. It exhibits thick cranial vault bones, arachnoid granulations, a deviated posterior sagittal suture, and a unilateral (right parietal lacuna with a posteriorly-directed and enlarged endocranial vascular sulcus. Differential diagnosis indicates that the perforation is a congenital defect, an enlarged parietal foramen, commonly associated with cerebral venous and cranial vault anomalies. It was not lethal given the individual's age-at-death, but it may have been associated with secondary neurological deficiencies. The fossil constitutes the oldest evidence in human evolution of this very rare condition (a single enlarged parietal foramen. In combination with developmental and degenerative abnormalities in other Pleistocene human remains, it suggests demographic and survival patterns among Pleistocene Homo that led to an elevated frequency of conditions unknown or rare among recent humans.

  5. MALACOLOGICAL RESPONSE TO PLEISTOCENE SEA-LEVEL CHANGE IN THE NORTHERN PO PLAIN, N. ITALY: DETAILED PALAEOENVIRONMENTAL RECONSTRUCTIONS FROM TWO LOMBARDIAN CORES

    Directory of Open Access Journals (Sweden)

    DANIELE GIANOLLA

    2010-03-01

    Full Text Available The interdisciplinary study of two deep cores drilled in Pleistocene basin fill at Northern margin of Po Plain, has been integrated with qualitative and quantitative malacological analysis. The potential of quantitative malacological analysis, to refine results obtained from interdisciplinary studies, is here highlighted. The evolution of malacological assemblages has been recorded and correlated to the general regressive trend recognized all over the Po Basin. Lower Pleistocene marine deposits, found at core base (Jaramillo Subchron and older, were gradually replaced by transitional and continental deposits since latest early Pleistocene. Area was eventually covered by continental conglomerate deposits (“Ceppo” facies during middle-late Pleistocene. Within this general trend, regional significance of a major unconformity (“r” surface, related to onset of Pleistocene glacial cycle, is confirmed. However, as evidenced by malacology, the roughly synchronous onset of coarse clastic progradation did not result in a synchronous shift from marine to transitional and continental settings all over the study area, as an effect of inherited topography and other local factors. During marine sedimentation, fossil record allowed us to recognize a transgressive event, reliably correlated to Marine Isotope Stage 35. 

  6. Replicating the Ice-Volume Signal of the Early Pleistocene with a Complex Earth System Model

    Science.gov (United States)

    Tabor, C. R.; Poulsen, C. J.; Pollard, D.

    2013-12-01

    Milankovitch theory proposes high-latitude summer insolation intensity paces the ice ages by controlling perennial snow cover amounts (Milankovitch, 1941). According to theory, the ~21 kyr cycle of precession should dominate the ice-volume records since it has the greatest influence on high-latitude summer insolation. Modeling experiments frequently support Milankovitch theory by attributing the majority of Northern Hemisphere high-latitude summer snowmelt to changes in the cycle of precession (e.g. Jackson and Broccoli, 2003). However, ice-volume proxy records, especially those of the Early Pleistocene (2.6-0.8 Ma), display variability with a period of ~41 kyr (Raymo and Lisiecki, 2005), indicative of insolation forcing from obliquity, which has a much smaller influence on summer insolation intensity than precession. Several hypotheses attempt to explain the discrepancies between Milkankovitch theory and the proxy records by invoking phenomena such as insolation gradients (Raymo and Nisancioglu, 2003), hemispheric offset (Raymo et al., 2006; Lee and Poulsen, 2009), and integrated summer energy (Huybers, 2006); however, all of these hypotheses contain caveats (Ruddiman, 2006) and have yet to be supported by modeling studies that use a complex GCM. To explore potential solutions to this '41 kyr problem,' we use an Earth system model composed of the GENESIS GCM and Land Surface model, the BIOME4 vegetation model, and the Pennsylvania State ice-sheet model. Using an asynchronous coupling technique, we run four idealized transient combinations of obliquity and precession, representing the orbital extremes of the Pleistocene (Berger and Loutre, 1991). Each experiment is run through several complete orbital cycles with a dynamic ice domain spanning North America and Greenland, and fixed preindustrial greenhouse-gas concentrations. For all orbital configurations, model results produce greater ice-volume spectral power at the frequency of obliquity despite significantly

  7. Discontinuity of human presence at Atapuerca during the early Middle Pleistocene: a matter of ecological competition?

    Science.gov (United States)

    Rodríguez-Gómez, Guillermo; Mateos, Ana; Martín-González, Jesús Angel; Blasco, Ruth; Rosell, Jordi; Rodríguez, Jesús

    2014-01-01

    Increasing evidence suggests that the European human settlement is older than 1.2 Ma. However, there is a fierce debate about the continuity or discontinuity of the early human settlement of Europe. In particular, evidence of human presence in the interval 0.7-0.5 Ma is scarce in comparison with evidence for the previous and later periods. Here, we present a case study in which the environmental conditions at Sierra de Atapuerca in the early Middle Pleistocene, a period without evidence of human presence, are compared with the conditions in the previous period, for which a relatively intense human occupation is documented. With this objective in mind, the available resources for a human population and the intensity of competition between secondary consumers during the two periods are compared using a mathematical model. The Gran Dolina site TD8 level, dated to 0.7-0.6 Ma, is taken as representative of the period during which Atapuerca was apparently not occupied by humans. Conditions at TD8 are compared with those of the previous period, represented by the TD6-2 level, which has yielded abundant evidence of intense human occupation. The results show that survival opportunities for a hypothetical human population were lower at TD8 than they were at TD6-2. Increased resource competition between secondary consumers arises as a possible explanation for the absence of human occupation at Atapuerca in the early Middle Pleistocene.

  8. Modeling the imprint of Milankovitch cycles on early Pleistocene ice volume

    Science.gov (United States)

    Roychowdhury, R.; DeConto, R.; Pollard, D.

    2017-12-01

    Global climate during Quaternary and Late Pliocene (present-3.1 Ma) is characterized by alternating glacial and interglacial conditions. Several proposed theories associate these cycles with variations in the Earth's orbital configuration. In this study, we attempt to address the anomalously strong obliquity forcing in the Late Pliocene/Early Pleistocene ice volume records (41 kyr world), which stands in sharp contrast to the primary cyclicity of insolation, which is at precessional periods (23 kyr). Model results from GCM simulations show that at low eccentricities (e0.015), precessional response is important, and the insolation metrics vary out-of-phase between the two hemispheres. Using simulations from a GCM-driven ice sheet model, we simulate time continuous ice volume changes from Northern and Southern Hemispheres. Under eccentricities lower than 0.015, ice sheets in both hemispheres respond only to obliquity cycle, and grow and melt together (in-phase). If the ice sheet is simulated with eccentricity higher than 0.015, both hemispheres become more sensitive to precessional variation, and vary out-of-phase with each other, which is consistent with proxy observations from the late Pleistocene glaciations. We use the simulated ice volumes from 2.0 to 1.0 ma to empirically calculate global benthic δ18O variations based on the assumption that relationships between collapse and growth of ice-sheets and sea level is linear and symmetric and that the isotopic signature of the individual ice-sheets has not changed with time. Our modeled global benthic δ18O values are broadly consistent with the paleoclimate proxy records such as the LR04 stack.

  9. Probe into the origin, development and evolution model of shelf desertizational environment in the last stage of Late Pleistocene

    Science.gov (United States)

    Yu, Hong-Jun; Liu, Jing-Pu; Shan, Qiu-Mei

    1998-12-01

    Based on study of China's shelf paleoenvironment, this paper summarises the definition of shelf desertization that occurred in the last stage of Late Pleistocene, and discusses the background of its formation and evolution process. Study of shallow layer profiler records and core data revealed that cold-dry aeolian erosion was the major exogenic force on the exposed shelf. Under the prevailing paleo-winter monsoon, part of the exposed marine stratum disintegrated into sand and then desertization occurred. The fine sediments were blown away and deposited on the leeward to form derivative loess deposits.

  10. Three new human skulls from the Sima de los Huesos Middle Pleistocene site in Sierra de Atapuerca, Spain.

    Science.gov (United States)

    Arsuaga, J L; Martínez, I; Gracia, A; Carretero, J M; Carbonell, E

    1993-04-08

    Three important fossil hominids were found in July 1992 in the Middle Pleistocene cave site called Sima de los Huesos (Sierra de Atapuerca, Burgos, Northern Spain). One is a complete calvaria (cranium 4), the second a virtually complete cranium (cranium 5), the third represents a more fragmentary cranium of an immature individual (cranium 6). There is a large difference in size between the two adult specimens (for example endocranial volume 1,125 cm3 versus 1,390 cm3). The Atapuerca human remains are dated to > 300,000 years. The Atapuerca cranial sample fits within the 'archaic Homo sapiens' group, but is well differentiated from the Asian Homo erectus group. The extensive Atapuerca human collection is the most complete sample of Middle Pleistocene humans yet discovered from one site, and appears to document an early stage in Neanderthal evolution.

  11. The Cova des Pas de Vallgornera (Llucmajor, Mallorca: a singular deposit bearing an exceptional well preserved Early Pleistocene vertebrate fauna

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    Pere Bover

    2014-05-01

    Full Text Available The Cova des Pas de Vallgornera is the longest cave of Mallorca (Balearic Islands, Western Mediterranean and one of the 30 longest caves in the world. The exploration of one of the galleries allowed the discovery of a fossiliferous deposit of vertebrate remains in a remarkable preservation state. The fossil faunal complex found in this gallery is composed of up to 5 mammalian species (Myotragus aff. kopperi, Hypnomys onicensis, Nesiotites aff. ponsi, Rhinolophus aff. mehelyi and Pipistrellus sp., at least 14 bird species (among them two Mallorcan endemic taxa: Pica mourerae and Athene vallgornerensis, one reptile (Podarcis aff. lilfordi and one amphibian (Discoglossus sp.. This faunal composition is similar to the one recorded in the Pedrera de s’Ònix, a well known deposit from the Early Pleistocene of Mallorca, and shared morphological characteristics between taxa of both deposits suggest that the chronology of the Cova des Pas de Vallgornera should be considered Early Pleistocene as well. Both taxonomical analysis and chronology of this fauna furnished information on some speleological aspects of the cave.

  12. The challenge of dating Early Pleistocene fossil teeth by the combined uranium series-electron spin resonance method: the Venta Micena palaeontological site (Orce, Spain)

    International Nuclear Information System (INIS)

    Duval, M.; Falgueres, Ch.; Bahain, J.J.; Shao, Q.; Grun, R.; Aubert, M.; Hellstrom, J.; Dolo, J.M.; Agusti, J.; Martinez-Navarro, B.; Palmqvist, P.; Toro-Moyano, I.

    2011-01-01

    The palaeontological site of Venta Micena (Orce, Andalusia, Spain) lies in the eastern sector of the Guadix-Baza basin, one of the best documented areas in Europe for Plio-Pleistocene bio-stratigraphy. The combination of bio-chronological and palaeo-magnetic results, combined with the radiometric data obtained for Atapuerca Sima del Elefante, indicated that the Venta Micena stratum was formed between the Jaramillo and Olduvai palaeo-magnetic events, most likely between 1.22 and 1.77 Ma. Five fossil teeth from two outcrops (sites A and B) were selected to assess the potential of combined uranium series-electron spin resonance (US-ESR) dating of Early Pleistocene sites. Although the US-ESR results of the first outcrop showed a large scatter between the three teeth, the mean age of 1.37 ± 0.24 Ma can be considered a reasonable age estimate for Venta Micena. The mean ESR age of 0.62 ± 0.03 Ma obtained for site B seems to be a severe underestimation when compared with the independent age control. This underestimation is attributed to a relative recent U-mobilization event that led to some U-leaching. The results show that any ESR age calculations of old samples are extremely sensitive to variations in the measured 230 Th/ 234 U ratios in dental tissues. Although the results demonstrate that ESR can in principle be applied to Early Pleistocene sites, they also reveal the complexity of dating such old teeth. It is necessary to continue research in several directions, such as study of the behaviour of ESR signals in old teeth and understanding recent U-mobilization processes, to improve the reliability of the combined US-ESR dating method applied to Early Pleistocene times, a period for which the number of available numerical dating techniques is very limited. (authors)

  13. Late Pleistocene and Early Holocene Rock Art from the Mongolian Altai: The Material and its Cultural Implications

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    Esther Jacobson-Tepfer

    2013-09-01

    Full Text Available Rock-pecked images from the northern Mongolian Altai attest to the presence of human communities within the high valleys of that region during the Late Pleistocene and Early Holocene. The material provides evidence that is hitherto largely missing from the archaeological record of that region. This paper reviews the rock art, its find sites and larger physical contexts and uses evidence from paleoenvironmental studies to propose dating and cultural significance. The material is compared with other sites said to have Paleolithic imagery from Mongolia and the adjoining Russian Altai. The body of presented material offers a major resource for the study of early hunter-gatherer communities at the interface of Central and North Asia.

  14. CANIS LUPUS (MAMMALIA, CANIDAE FROM THE LATE PLEISTOCENE DEPOSIT OF AVETRANA (TARANTO, SOUTHERN ITALY

    Directory of Open Access Journals (Sweden)

    DAVIDE F.BERTÈ

    2014-11-01

    Full Text Available Here we described the remains of Canis lupus from the bed 8 of Avetrana karst filling (Late Pleistocene; Taranto, Southern Italy. The studied specimens are larger than those collected from the early Late Pleistocene Apulian localities and those referred to the recent Italian wolf. Moreover, the remains from Avetrana are morphometrically close to Canis lupus maximus from France and to C. lupus collected from Central and Northern Italian localities, chronologically related to MIS 2 and MIS 3. Morphologically, the studied specimens slightly differ from both C. l. maximus and other Pleistocene Apulian wolves. The dimensional differences between the Avetrana wolves and those collected from the other early Late Pleistocene Apulian localities could be explained through a spread of a large-sized morphotype from the Northern Italy.

  15. The role of ice sheets in the pleistocene climate

    NARCIS (Netherlands)

    Oerlemans, J.

    1991-01-01

    Northern hemisphere ice sheets have played an important role in the climatic evolution of the Pleistocene. The characteristic time-scale of icesheet growth has the same order-of-magnitude as that for the orbital insolation variations. The interaction with the solid earth, the importance of the

  16. Contribution of changes in opal productivity and nutrient distribution in the coastal upwelling systems to Late Pliocene/Early Pleistocene climate cooling

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    J. Etourneau

    2012-09-01

    Full Text Available The global Late Pliocene/Early Pleistocene cooling (~3.0–2.0 million years ago – Ma concurred with extremely high diatom and biogenic opal production in most of the major coastal upwelling regions. This phenomenon was particularly pronounced in the Benguela upwelling system (BUS, off Namibia, where it is known as the Matuyama Diatom Maximum (MDM. Our study focuses on a new diatom silicon isotope (δ30Si record covering the MDM in the BUS. Unexpectedly, the variations in δ30Si signal follow biogenic opal content, whereby the highest δ30Si values correspond to the highest biogenic opal content. We interpret the higher δ30Si values during the MDM as a result of a stronger degree of silicate utilisation in the surface waters caused by high productivity of mat-forming diatom species. This was most likely promoted by weak upwelling intensity dominating the BUS during the Late Pliocene/Early Pleistocene cooling combined with a large silicate supply derived from a strong Southern Ocean nutrient leakage responding to the expansion of Antarctic ice cover and the resulting stratification of the polar ocean 3.0–2.7 Ma ago. A similar scenario is hypothesized for other major coastal upwelling systems (e.g. off California during this time interval, suggesting that the efficiency of the biological carbon pump was probably sufficiently enhanced in these regions during the MDM to have significantly increased the transport of atmospheric CO2 to the deep ocean. In addition, the coeval extension of the area of surface water stratification in both the Southern Ocean and the North Pacific, which decreased CO2 release to the atmosphere, led to further enhanced atmospheric CO2 drawn-down and thus contributed significantly to Late Pliocene/Early Pleistocene cooling.

  17. Postcranial morphology of the middle Pleistocene humans from Sima de los Huesos, Spain.

    Science.gov (United States)

    Arsuaga, Juan Luis; Carretero, José-Miguel; Lorenzo, Carlos; Gómez-Olivencia, Asier; Pablos, Adrián; Rodríguez, Laura; García-González, Rebeca; Bonmatí, Alejandro; Quam, Rolf M; Pantoja-Pérez, Ana; Martínez, Ignacio; Aranburu, Arantza; Gracia-Téllez, Ana; Poza-Rey, Eva; Sala, Nohemi; García, Nuria; Alcázar de Velasco, Almudena; Cuenca-Bescós, Gloria; Bermúdez de Castro, José María; Carbonell, Eudald

    2015-09-15

    Current knowledge of the evolution of the postcranial skeleton in the genus Homo is hampered by a geographically and chronologically scattered fossil record. Here we present a complete characterization of the postcranium of the middle Pleistocene paleodeme from the Sima de los Huesos (SH) and its paleobiological implications. The SH hominins show the following: (i) wide bodies, a plesiomorphic character in the genus Homo inherited from their early hominin ancestors; (ii) statures that can be found in modern human middle-latitude populations that first appeared 1.6-1.5 Mya; and (iii) large femoral heads in some individuals, a trait that first appeared during the middle Pleistocene in Africa and Europe. The intrapopulational size variation in SH shows that the level of dimorphism was similar to modern humans (MH), but the SH hominins were less encephalized than Neandertals. SH shares many postcranial anatomical features with Neandertals. Although most of these features appear to be either plesiomorphic retentions or are of uncertain phylogenetic polarity, a few represent Neandertal apomorphies. Nevertheless, the full suite of Neandertal-derived features is not yet present in the SH population. The postcranial evidence is consistent with the hypothesis based on the cranial morphology that the SH hominins are a sister group to the later Neandertals. Comparison of the SH postcranial skeleton to other hominins suggests that the evolution of the postcranium occurred in a mosaic mode, both at a general and at a detailed level.

  18. A reassessment of the early archaeological record at Leang Burung 2, a Late Pleistocene rock-shelter site on the Indonesian island of Sulawesi

    NARCIS (Netherlands)

    Brumm, Adam; Hakim, Budianto; Ramli, Muhammad; Aubert, Maxime; van den Bergh, Gerrit D.; Li, Bo; Burhan, Basran; Saiful, Andi Muhammad; Siagian, Linda; Sardi, Ratno; Jusdi, Andi; Said, Abdullah; Mubarak, Andi Pampang; Moore, Mark W.; Roberts, Richard G.; Zhao, Jian-xin; McGahan, David; Jones, Brian G.; Perston, Yinika; Szabó, Katherine; Mahmud, M. Irfan; Westaway, Kira; [Unknown], Jatmiko; Saptomo, E. Wahyu; van der Kaars, Sander; Grün, Rainer; Wood, Rachel; Dodson, John; Morwood, Michael J.

    2018-01-01

    This paper presents a reassessment of the archaeological record at Leang Burung 2, a key early human occupation site in the Late Pleistocene of Southeast Asia. Excavated originally by Ian Glover in 1975, this limestone rock-shelter in the Maros karsts of Sulawesi, Indonesia, has long held

  19. Late Pleistocene dune activity in the central Great Plains, USA

    Science.gov (United States)

    Mason, J.A.; Swinehart, J.B.; Hanson, P.R.; Loope, D.B.; Goble, R.J.; Miao, X.; Schmeisser, R.L.

    2011-01-01

    Stabilized dunes of the central Great Plains, especially the megabarchans and large barchanoid ridges of the Nebraska Sand Hills, provide dramatic evidence of late Quaternary environmental change. Episodic Holocene dune activity in this region is now well-documented, but Late Pleistocene dune mobility has remained poorly documented, despite early interpretations of the Sand Hills dunes as Pleistocene relicts. New optically stimulated luminescence (OSL) ages from drill cores and outcrops provide evidence of Late Pleistocene dune activity at sites distributed across the central Great Plains. In addition, Late Pleistocene eolian sands deposited at 20-25 ka are interbedded with loess south of the Sand Hills. Several of the large dunes sampled in the Sand Hills clearly contain a substantial core of Late Pleistocene sand; thus, they had developed by the Late Pleistocene and were fully mobile at that time, although substantial sand deposition and extensive longitudinal dune construction occurred during the Holocene. Many of the Late Pleistocene OSL ages fall between 17 and 14 ka, but it is likely that these ages represent only the later part of a longer period of dune construction and migration. At several sites, significant Late Pleistocene or Holocene large-dune migration also probably occurred after the time represented by the Pleistocene OSL ages. Sedimentary structures in Late Pleistocene eolian sand and the forms of large dunes potentially constructed in the Late Pleistocene both indicate sand transport dominated by northerly to westerly winds, consistent with Late Pleistocene loess transport directions. Numerical modeling of the climate of the Last Glacial Maximum has often yielded mean monthly surface winds southwest of the Laurentide Ice Sheet that are consistent with this geologic evidence, despite strengthened anticyclonic circulation over the ice sheet. Mobility of large dunes during the Late Pleistocene on the central Great Plains may have been the result of

  20. Stochastic evolution of cosmological parameters in the early universe

    Indian Academy of Sciences (India)

    We develop a stochastic formulation of cosmology in the early universe, after considering the scatter in the redshift-apparent magnitude diagram in the early epochs as an observational evidence for the non-deterministic evolution of early universe. We consider the stochastic evolution of density parameter in the early ...

  1. Before the Emergence of Homo sapiens: Overview on the Early-to-Middle Pleistocene Fossil Record (with a Proposal about Homo heidelbergensis at the subspecific level)

    Science.gov (United States)

    Manzi, Giorgio

    2011-01-01

    The origin of H. sapiens has deep roots, which include two crucial nodes: (1) the emergence and diffusion of the last common ancestor of later Homo (in the Early Pleistocene) and (2) the tempo and mode of the appearance of distinct evolutionary lineages (in the Middle Pleistocene). The window between 1,000 and 500 thousand years before present appears of crucial importance, including the generation of a new and more encephalised kind of humanity, referred to by many authors as H. heidelbergensis. This species greatly diversified during the Middle Pleistocene up to the formation of new variants (i.e., incipient species) that, eventually, led to the allopatric speciation of H. neanderthalensis and H. sapiens. The special case furnished by the calvarium found near Ceprano (Italy), dated to 430–385 ka, offers the opportunity to investigate this matter from an original perspective. It is proposed to separate the hypodigm of a single, widespread, and polymorphic human taxon of the Middle Pleistocene into distinct subspecies (i.e., incipient species). The ancestral one should be H. heidelbergensis, including specimens such as Ceprano and the mandible from Mauer. PMID:21716742

  2. Reticulate Pleistocene evolution of Ethiopian rodent genus along remarkable altitudinal gradient.

    Science.gov (United States)

    Bryja, Josef; Kostin, Danila; Meheretu, Yonas; Šumbera, Radim; Bryjová, Anna; Kasso, Mohammed; Mikula, Ondřej; Lavrenchenko, Leonid A

    2018-01-01

    The Ethiopian highlands are the most extensive complex of mountainous habitats in Africa. The presence of the Great Rift Valley (GRV) and the striking elevational ecological gradients inhabited by recently radiated Ethiopian endemics, provide a wide spectrum of model situations for evolutionary studies. The extant species of endemic rodents, often markedly phenotypically differentiated, are expected to possess complex genetic features which evolved asa consequence of the interplay between geomorphology and past climatic changes. In this study, we used the largest available multi-locus genetic dataset of the murid genus Stenocephalemys (347 specimens from ca 40 localities across the known distributional area of all taxa) to investigate the relative importance of disruptive selection, temporary geographic isolation and introgression in their adaptive radiations in the Pleistocene. We confirmed the four main highly supported mitochondrial (mtDNA) clades that were proposed as four species in a previous pilot study: S. albipes is a sister species of S. griseicauda (both lineages are present on both sides of the GRV), while the second clade is formed by two Afro-alpine species, S. albocaudata (east of GRV) and the undescribed Stenocephalemys sp. A (west of GRV). There is a clear elevational gradient in the distribution of the Stenocephalemys taxa with two to three species present at different elevations of the same mountain range. Surprisingly, the nuclear species tree corresponded only a little to the mtDNA tree. Multispecies coalescent models based on six nuclear markers revealed the presence of six separate gene pools (i.e. candidate species), with different topology. Phylogenetic analysis, together with the geographic distribution of the genetic groups, suggests a complex reticulate evolution. We propose a scenario that involves (besides classical allopatric speciation) two cases of disruptive selection along the elevational ecological gradient, multiple crosses of

  3. Middle and Late Pleistocene glaciations in the southwestern Pamir and their effects on topography [Topography of the SW Pamir shaped by middle-late Pleistocene glaciation

    International Nuclear Information System (INIS)

    Stübner, Konstanze; Grin, Elena; Hidy, Alan J.; Schaller, Mirjam; Gold, Ryan D.

    2017-01-01

    Glacial chronologies provide insight into the evolution of paleo-landscapes, paleoclimate, topography, and the erosion processes that shape mountain ranges. In the Pamir of Central Asia, glacial morphologies and deposits indicate extensive past glaciations, whose timing and extent remain poorly constrained. Geomorphic data and 15 new "1"0Be exposure ages from moraine boulders and roches moutonnées in the southwestern Pamir document multiple Pleistocene glacial stages. The oldest exposure ages, View the MathML source113 ± 10ka, underestimate the age of the earliest preserved glacial advance and imply that the modern relief of the southwestern Pamir (peaks at ~5000–6000 m a.s.l.; valleys at ~2000–3000 m a.s.l.) already existed in the late Middle Pleistocene. Younger exposure ages (~40–80 ka, ~30 ka) complement the existing Central Asian glacial chronology and reflect successively less extensive Late Pleistocene glaciations. The topography of the Pamir and the glacial chronologies suggest that, in the Middle Pleistocene, an ice cap or ice field occupied the eastern Pamir high-altitude plateau, whereas westward flowing valley glaciers incised the southwestern Pamir. Since the Late Pleistocene deglaciation, the rivers of the southwestern Pamir adjusted to the glacially shaped landscape. As a result, localized rapid fluvial incision and drainage network reorganization reflect the transient nature of the deglaciated landscape.

  4. Paleogeographic variations of pedogenic carbonate delta13C values from Koobi Fora, Kenya: implications for floral compositions of Plio-Pleistocene hominin environments.

    Science.gov (United States)

    Quinn, Rhonda L; Lepre, Christopher J; Wright, James D; Feibel, Craig S

    2007-11-01

    Plio-Pleistocene East African grassland expansion and faunal macroevolution, including that of our own lineage, are attributed to global climate change. To further understand environmental factors of early hominin evolution, we reconstruct the paleogeographic distribution of vegetation (C(3)-C(4) pathways) by stable carbon isotope (delta(13)C) analysis of pedogenic carbonates from the Plio-Pleistocene Koobi Fora region, northeast Lake Turkana Basin, Kenya. We analyzed 202 nodules (530 measurements) from ten paleontological/archaeological collecting areas spanning environments over a 50-km(2) area. We compared results across subregions in evolving fluviolacustrine depositional environments in the Koobi Fora Formation from 2.0-1.5 Ma, a stratigraphic interval that temporally brackets grassland ascendancy in East Africa. Significant differences in delta(13)C values between subregions are explained by paleogeographic controls on floral composition and distribution. Our results indicate grassland expansion between 2.0 and 1.75 Ma, coincident with major shifts in basin-wide sedimentation and hydrology. Hypotheses may be correct in linking Plio-Pleistocene hominin evolution to environmental changes from global climate; however, based on our results, we interpret complexity from proximate forces that mitigated basin evolution. An approximately 2.5 Ma tectonic event in southern Ethiopia and northern Kenya exerted strong effects on paleography in the Turkana Basin from 2.0-1.5 Ma, contributing to the shift from a closed, lacustrine basin to one dominated by open, fluvial conditions. We propose basin transformation decreased residence time for Omo River water and expanded subaerial floodplain landscapes, ultimately leading to reduced proportions of wooded floras and the establishment of habitats suitable for grassland communities.

  5. Long-term climate record inferred from early-middle Pleistocene amphibian and squamate reptile assemblages at the Gran Dolina Cave, Atapuerca, Spain.

    Science.gov (United States)

    Blain, Hugues-Alexandre; Bailon, Salvador; Cuenca-Bescós, Gloria; Arsuaga, Juan Luis; Bermúdez de Castro, José Maria; Carbonell, Eudald

    2009-01-01

    The Gran Dolina cave site is famous for having delivered some of the oldest hominin remains of Western Europe (Homo antecessor, ca. 960 ka). Moreover, the evidence of lithic industries throughout the long vertical section suggests occupation on the part of hominins from the latest early Pleistocene (levels TD3/4, TD5, and TD6) to the late middle Pleistocene (level TD10). The Gran Dolina Sondeo Sur (TDS) has furnished a great number of small-vertebrate remains; among them some 40,000 bones are attributed to amphibians and squamates. Although they do not differ specifically from the extant herpetofauna of the Iberian Peninsula, the overlap of their current distribution areas (= mutual climatic range method) in Spain can provide mean annual temperatures (MAT), the mean temperatures of the coldest (MTC) and warmest (MTW) months, and mean annual precipitation (MAP) estimations for each sub-level, and their change can be studied throughout the sequence. Results from the squamate and amphibian study indicate that during hominin occupation the MAT (10-13 degrees C) was always slightly warmer than at present in the vicinity of the Gran Dolina Cave, and the MAP (800-1000mm) was greater than today in the Burgos area. Climatic differences between "glacial" and "interglacial" phases are poorly marked. Summer temperatures (MTW) show stronger oscillations than winter temperatures (MTC), but seasonality remains almost unchanged throughout the sequence. These results are compared with those for large mammals, small mammals, and pollen analysis, giving a scenario for the palaeoclimatic conditions that occurred during the early to middle Pleistocene in Atapuerca, and hence a scenario for the hominins that once lived in the Sierra de Atapuerca.

  6. ON THE PALEOFAUNA INVERTEBRATES (MOLLUSCA, ARTROPODA; INSECTA OF DIATOMITE DEPOSITS OF SHAMB–1 LOCALITY (SISIAN SUITE, EARLY PLEISTOCENE, ARMENIA

    Directory of Open Access Journals (Sweden)

    М. A. Маrjanyan

    2016-01-01

    Full Text Available Aim. The study of fossil insects from diatomaceous sediments of Shamb-1 locality of Sisian Suite (Early Pleistocene. The collection of fossils plants and animals of Institute of Botany of NAS RA and authors' findings served as material for study.Methods. The material is processed and prepared for study by conventional methods in paleontology for prints and fossils of insects from diatomaceous sediments. There are 654 samples studied: 2 samples were with mollusks’ imprints and 652 samples with imprints of insects, from which preserved marks on 291samples allowed to identify them up to order, family, genus and species.Results. The studied material refers to the Mollusca and Arthropoda (Insecta types. Insects are represented by species of orders Orthoptera (2 fam., Homoptera (1 fam., Heteroptera (2 fam., Coleoptera (15 fam., Hymenoptera (2 fam., Diptera (1 fam.. Coleopteras dominate among them and are presented with following species of the family – Carabidae, Dytiscidae, Hydrophilidae, Histeridae, Staphylinidae, Silphidae, Elateridae, Buprestidae, Lampyridae, Scarabaeidae, Chrysomelidae, Tenebrionidae, Coccinellidae, Cerambycidae, Curculionidae.Main conclusions. An analysis of the taxonomic composition of paleofauna was done, which corresponds to the recent fauna and with considering modern ecological characteristics of systematical groups and species. In the investigated location of Shamb-1 a version is suggested about the palaeolandscapes and palaeoclimate in the Early Pleistocene.

  7. Revision of the early Middle Pleistocene bears (Ursidae, Mammalia) of Central Europe, with special respect to possible co-occurrence of spelaeoid and arctoid lineages

    Czech Academy of Sciences Publication Activity Database

    Wagner, J.; Čermák, Stanislav

    2012-01-01

    Roč. 87, č. 3 (2012), s. 461-496 ISSN 1214-1119 Institutional research plan: CEZ:AV0Z30130516 Keywords : Ursus deningeri * U. arctos, * Late Biharian * Early Toringian * Middle Pleistocene Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.141, year: 2012 http://www.geology.cz/bulletin/fulltext/1354_Wagner.pdf

  8. Loess deposits since early Pleistocene in northeast China and implications for desert evolution in east China

    Science.gov (United States)

    Sun, Miao; Zhang, Xujiao; Tian, Mingzhong; Liu, Ru; He, Zexin; Qi, Lin; Qiao, Yansong

    2018-04-01

    Loess deposits and deserts are regarded as coupled geological systems and loess deposits on the periphery of deserts can often be used to reconstruct desert evolution. Previous studies of desert evolution in Asia are mainly concentrated in northwest China and the China Loess Plateau, and little is known about long-term desert evolution in east China. In this study, we selected the Sishijiazi loess section in the Chifeng area in northeast China to study the long-term evolution of the desert in east China. A high-resolution magnetostratigraphy combined with optically stimulated luminescence dating indicated that the age of the section base is approximately 1.02 Ma. The Brunhes-Matuyama boundary is at the depth of 39.8 m in loess unit L8, and the upper boundary of the Jaramillo Subchron is at the depth of 60.8 m in paleosol S10. The results of grain-size analysis indicate a coarsening grain-size trend in the past 1.0 Ma. In addition, based on grain-size variations, the desert evolution in east China since ∼1.0 Ma can be divided into three stages: stability from 1.0 to 0.8 Ma, desert recession from 0.8 to 0.5 Ma, and gradual expansion since 0.5 Ma. Our results further indicate that the evolution of desert in east China was mainly controlled by changes in global ice volume, and that the uplift of the Tibetan Plateau may have had an additional effect.

  9. Hominin teeth from the Middle Pleistocene site of Yiyuan, Eastern China.

    Science.gov (United States)

    Xing, Song; Sun, Chengkai; Martinón-Torres, María; Bermúdez de Castro, José María; Han, Fei; Zhang, Yingqi; Liu, Wu

    2016-06-01

    In 1981-1982, some hominin fossils, including a relatively complete skull and seven isolated teeth, were recovered from the Middle Pleistocene site of Yiyuan in Eastern China. In the present study we provide a detailed metric and morphological comparison of the Yiyuan dental sample in order to characterize better the variability of the human populations that inhabited China during the Middle Pleistocene. Aside from taxonomic and phylogenetic questions, the lack of understanding and/or knowledge about the morphological variability of these populations have caused concern about the human versus non-human nature of some of the hominin dental remains found in East Asia during the Early and the Middle Pleistocene. Thus, our study aims to present a detailed description and comparison of the Yiyuan isolated teeth to 1) discuss and support their human nature and 2) to explore their taxonomic affinities with regard to other penecontemporaneous populations from Asia. Our results clearly differentiate the Yiyuan sample from Pongo specimens and support a human attribution for the Yiyuan material. Our analyses also suggest that the Yiyuan teeth form a morphologically coherent group together with samples from Zhoukoudian, Chaoxian and Hexian. They are different from the more derived specimens from Panxian Dadong, suggesting a pattern of biogeographic isolation and different evolutionary trends between northern and southern China during the Middle Pleistocene. In addition, and despite sharing a common morphological bauplan with Homo erectus sensu stricto (s.s.), the Yiyuan, Zhoukoudian and Hexian teeth are also different from the Indonesian Early Pleistocene samples. In particular, the expression of a highly crenulated or dendritic enamel-dentine surface could be unique to these groups. Our study supports the notion that the taxonomy of the Pleistocene hominins from Asia may have been oversimplified. Future studies should explore the variability of the Asian specimens and

  10. Solar Radiation as Driving Force In Early Evolution

    Science.gov (United States)

    Rothschild, Lynn J.; Peterson, David L. (Technical Monitor)

    2002-01-01

    Ultraviolet radiation (UVR) has provided an evolutionary challenge to life on Earth in that it is both an agent of mutation and as well as a selective force. Today surface fluxes of UVR vary diurnally, seasonally, etc. Still, the UVR flux was probably substantially higher during the early phases of evolution, suggesting that its role in evolution was even more prominent during this time. In this presentation, the creative role of UVR in evolution is discussed, specifically in connection with the role that UVR may have played in the evolution of early microbial ecosystems. The presentation will include discussions of the direct influence of UVR on such processes as photosynthesis and genetic damage, as well as the indirect influence of UVR as mediated through the production of reactive oxygen species. These biological effects of UVR will be viewed against the backdrop of the physical nature of the early Earth, surely a very different place then than now.

  11. Assessment of geomorphological and hydrological changes produced by Pleistocene glaciations in a Patagonian basin

    Science.gov (United States)

    Scordo, Facundo; Seitz, Carina; Melo, Walter D.; Piccolo, M. Cintia; Perillo, Gerardo M. E.

    2018-04-01

    This work aims to assess how Pleistocene glaciations modeled the landscape in the upper Senguer River basin and its relationship to current watershed features (drainage surface and fluvial hydrological regime). During the Pleistocene six glacial lobes developed in the upper basin of the Senguer River localized east of the Andean range in southern Argentinean Patagonia between 43° 36' - 46° 27‧ S. To describe the topography and hydrology, map the geomorphology, and propose an evolution of the study area during the Pleistocene we employed multitemporal Landsat images, national geological sheets and a mosaic of the digital elevation model (Shuttle Radar Topography Mission) along with fieldwork. The main conclusion is that until the Middle Pleistocene, the drainage divide of the Senguer River basin was located to the west of its current limits and its rivers drained the meltwater of the glaciers during interglacial periods. However, processes of drainage inversion and drainage surface reduction occurred in the headwater of most rivers of the basin during the Late Pleistocene. Those processes were favored by a relative shorter glacial extension during LGM and the dam effect produced by the moraines of the Post GPG I and III glaciations. Thus, since the Late Pleistocene, the headwaters of several rivers in the basin have been reduced, and the moraines corresponding to the Middle Pleistocene glaciations currently divide the watersheds that drain towards the Senguer River from those that flow west towards the Pacific Ocean.

  12. Preliminary Study of Late Pleistocene to Early Holocene Plant Food Strategies in China

    Science.gov (United States)

    Hayashi Tang, M.; Liu, X.; Fritz, G.; Zhao, Z.

    2017-12-01

    In recent decades, studies on the domestication and early cultivation of seed crops have contributed significantly to how we understand human-plant interactions, and their impact on human social organisation and the environment. It is becoming clear, however, that plants have been critical to the human diet for much longer and in more diverse ways than previously assumed. This paper is a preliminary attempt at identifying and addressing early prehistoric plant food strategies in China. In particular, very little is known about the use of vegetatively propagated plants, despite their significant representation in modern crops. Many ingredients of Chinese medicine are also roots and tubers (or vegetative storage organs, VSOs). Unlike seed crops, however, we lack a systematic criterion for examining diagnostic characters of different VSO taxa in the archaeological record. To address this issue, we characterized commonly consumed and historically significant VSOs in China, by studying experimentally charred modern samples under the optical microscope and scanning electron microscope. We then compared the characteristics of these modern VSO samples against plant remains from Late Pleistocene to early Holocene archaeological sites in China, such as Zengpiyan (Guangxi), Zhaoguodong (Guizhou), and Jiahu (Henan) sites. We found that different taxa of VSOs can be differentiated by using multiple lines of evidence, including: shape and size of various cells, texture and arrangement of cell walls, as well as anatomical arrangements of organs, especially the vascular bundles. Though identification can be difficult when fragile cell structures have collapsed or deteriorated, more robust features are often preserved for diagnosis. Our results suggest that the potential for studying the role of vegetatively propagated plants in early human-environmental interactions is overlooked, and can be expanded significantly with further investment in their systematic identification.

  13. Late Miocene-Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley-Costilla Plain, San Luis Basin, New Mexico and Colorado

    Science.gov (United States)

    Ruleman, C.A.; Thompson, R.A.; Shroba, R.R.; Anderson, M.; Drenth, B.J.; Rotzien, J.; Lyon, J.

    2013-01-01

    The Sunshine Valley-Costilla Plain, a structural subbasin of the greater San Luis Basin of the northern Rio Grande rift, is bounded to the north and south by the San Luis Hills and the Red River fault zone, respectively. Surficial mapping, neotectonic investigations, geochronology, and geophysics demonstrate that the structural, volcanic, and geomorphic evolution of the basin involves the intermingling of climatic cycles and spatially and temporally varying tectonic activity of the Rio Grande rift system. Tectonic activity has transferred between range-bounding and intrabasin faults creating relict landforms of higher tectonic-activity rates along the mountain-piedmont junction. Pliocene–Pleistocene average long-term slip rates along the southern Sangre de Cristo fault zone range between 0.1 and 0.2 mm/year with late Pleistocene slip rates approximately half (0.06 mm/year) of the longer Quaternary slip rate. During the late Pleistocene, climatic influences have been dominant over tectonic influences on mountain-front geomorphic processes. Geomorphic evidence suggests that this once-closed subbasin was integrated into the Rio Grande prior to the integration of the once-closed northern San Luis Basin, north of the San Luis Hills, Colorado; however, deep canyon incision, north of the Red River and south of the San Luis Hills, initiated relatively coeval to the integration of the northern San Luis Basin.Long-term projections of slip rates applied to a 1.6 km basin depth defined from geophysical modeling suggests that rifting initiated within this subbasin between 20 and 10 Ma. Geologic mapping and geophysical interpretations reveal a complex network of northwest-, northeast-, and north-south–trending faults. Northwest- and northeast-trending faults show dual polarity and are crosscut by north-south– trending faults. This structural model possibly provides an analog for how some intracontinental rift structures evolve through time.

  14. A synthesis of Plio-Pleistocene leaf wax biomarker records of hydrological variation in East Africa and their relationship with hominin evolution

    Science.gov (United States)

    Lupien, R.; Russell, J. M.; Campisano, C. J.; Feibel, C. S.; Deino, A. L.; Kingston, J.; Potts, R.; Cohen, A. S.

    2017-12-01

    Climate change is thought to play a critical role in human evolution. However, the mechanisms behind this relationship are difficult to test due to a lack of long, high-quality paleoclimate records from hominin fossil locales. We improve the understanding of this relationship by examining Plio-Pleistocene lake sediment cores from East Africa that were drilled by the Hominin Sites and Paleolakes Drilling Project, an international effort to study the environment in which our hominin ancestors evolved and dispersed. We have analyzed organic geochemical signals of climate from drill cores from Ethiopia and Kenya spanning the Pliocene to recent time (from north to south: paleolake Hadar, Lake Turkana, Lake Baringo, and paleolake Koora). Specifically, we analyzed the hydrogen isotopic composition of terrestrial leaf waxes, which records changes in regional atmospheric circulation and hydrology. We reconstructed quantitative records of rainfall amount at each of the study sites, which host sediment spanning different geologic times and regions. By compiling these records, we test hominin evolutionary hypotheses as well as crucial questions about climate trend and variability. We find that there is a gradual or step-wise enrichment in δDwax, signifying a trend from a wet to dry climate, from the Pliocene to the Pleistocene, perhaps implying an influence of global temperature, ice sheet extent, and/or atmospheric greenhouse gas concentrations on East African climate. However, the shift is small relative to the amplitude of orbital-scale isotopic variations. The records indicate a strong influence of eccentricity-modulated orbital precession, and imply that local insolation effects are the likely cause of East African precipitation. Several of the intervals of high isotopic variability coincide with key hominin fossil or technological transitions, suggesting that climate variability plays a key role in hominin evolution.

  15. Anthropogenic Origin of Siliceous Scoria Droplets from Pleistocene and Holocene Archeaological Sites in Northern Syria

    DEFF Research Database (Denmark)

    Thy, Peter; Willcox, George; Barfod, Gry

    2015-01-01

    Siliceous scoria droplets, measuring from 1 to 10 mm, from one late Pleistocene and four early Holocene archaeological sites in northern Syria are compared to similar droplets previously suggested to be the result of a cosmic impact at the onset of the Younger Dryas global cooling event. The !ndi......Siliceous scoria droplets, measuring from 1 to 10 mm, from one late Pleistocene and four early Holocene archaeological sites in northern Syria are compared to similar droplets previously suggested to be the result of a cosmic impact at the onset of the Younger Dryas global cooling event...

  16. External auditory exostoses in the Xuchang and Xujiayao human remains: Patterns and implications among eastern Eurasian Middle and Late Pleistocene crania.

    Science.gov (United States)

    Trinkaus, Erik; Wu, Xiu-Jie

    2017-01-01

    In the context of Middle and Late Pleistocene eastern Eurasian human crania, the external auditory exostoses (EAE) of the late archaic Xuchang 1 and 2 and the Xujiayao 15 early Late Pleistocene human temporal bones are described. Xujiayao 15 has small EAE (Grade 1), Xuchang 1 presents bilateral medium EAE (Grade 2), and Xuchang 2 exhibits bilaterally large EAE (Grade 3), especially on the right side. These cranial remains join the other eastern Eurasian later Pleistocene humans in providing frequencies of 61% (N = 18) and 58% (N = 12) respectively for archaic and early modern human samples. These values are near the upper limits of recent human frequencies, and they imply frequent aquatic exposure among these Pleistocene humans. In addition, the medial extents of the Xuchang 1 and 2 EAE would have impinged on their tympanic membranes, and the large EAE of Xuchang 2 would have resulted in cerumen impaction. Both effects would have produced conductive hearing loss, a serious impairment in a Pleistocene foraging context.

  17. Latest Pleistocene to Holocene Evolution of the Baie de Port au Prince, Haiti

    Science.gov (United States)

    Rios, J. K.; McHugh, C. M.; Seeber, L.; Blair, S.; Sorlien, C. C.

    2012-12-01

    The Baie de Port au Prince (BPP) is adjacent a restraining segment of the sinistral Caribbean-North America plate boundary and is therefore situated between converging high-relief thrust systems, the Massif Selle (Peninsula Range) to the south and the Chaine de Matheux (Hispaniola highlands) to the north. To evaluate neotectonic deformation, seismic hazards and sedimentation patterns for the BPP, six gravity cores were studied within the framework of chirp profiles collected from the R/V Endeavor in 2010. The cores were recovered from 76 m to 148 m of water depth sampling sediment from the carbonate platform that rims the BPP and from the slope. We studied the biostratigraphy (foraminifers, nannoplankton), geochemical elemental composition and physical properties of the sediment. An age model from the last glacial to the present (~20 ka BP) was derived from radiocarbon. Nannoplankton biostratigraphy provide constraints on the late Pleistocene. The BPP is 150 m maximum water depth and is rimmed by an ~30 m deep carbonate platform that has undergone dissolution. Terraces characterize the sub-bottom topography to the NE. This topography was covered by sediment during at least one relative sea-level cycle. Sediment progradation and mass-wasting on the northern and southern flanks of the BPP respectively, occurred during the latest Pleistocene low stand (~20 ka BP). Increased sedimentation from 0.2 mm/year to 0.8 mm/year occurred from 14.2 ka BP to 9.5 ka BP. This period also corresponds with a global rapid rate in sea-level rise from -94 m to -37 m. A basin wide acoustically transparent layer of sediment ~10 m thick covered the BPP. Mass-wasting, microfaulting, fluidization and turbidites caused by erosion triggered by pre-historic earthquakes possibly associated with EPG transform fault are found in the cores. One such deposit is possibly associated to the 2010 earthquake and another to an unconformable surface that separates early- from late-Holocene sediment on the

  18. The Taxonomic and Phylogenetic Affinities of Bunopithecus sericus, a Fossil Hylobatid from the Pleistocene of China

    Science.gov (United States)

    Ortiz, Alejandra; Pilbrow, Varsha; Villamil, Catalina I.; Korsgaard, Jessica G.; Bailey, Shara E.; Harrison, Terry

    2015-01-01

    Fossil hylobatids are rare, but are known from late Miocene and Pleistocene sites throughout East Asia. The best-known fossil hylobatid from the Pleistocene of China is a left mandibular fragment with M2-3 (AMNH 18534), recovered from a pit deposit near the village of Yanjinggou in Wanzhou District, Chongqing Province. Matthew and Granger described this specimen in 1923 as a new genus and species, Bunopithecus sericus. Establishing the age of Bunopithecus has proved difficult because the Yanjinggou collection represents a mixed fauna of different ages, but it likely comes from early or middle Pleistocene deposits. Although the Bunopithecus specimen has featured prominently in discussions of hylobatid evolution and nomenclature, its systematic status has never been satisfactorily resolved. The present study reexamines the taxonomic and phylogenetic relationships of Bunopithecus by carrying out a detailed comparative morphometric study of its lower molars in relation to a large sample of modern hylobatids. Our results show that differences in M2 and M3 discriminate extant hylobatids fairly well, at least at the generic level, and that AMNH 18534 is not attributable to Hylobates, Nomascus or Symphalangus. Support for a close relationship between Bunopithecus and Hoolock is more equivocal. In most multivariate analyses, Bunopithecus presents a unique morphological pattern that falls outside the range of variation of any hylobatid taxon, although its distance from the cluster represented by extant hoolocks is relatively small. Our results support the generic distinction of Bunopithecus, which most likely represents an extinct crown hylobatid, and one that may possibly represent the sister taxon to Hoolock. PMID:26154175

  19. A comparative study of frontal bone morphology among Pleistocene hominin fossil groups.

    Science.gov (United States)

    Athreya, Sheela

    2009-12-01

    Features of the frontal bone that are conventionally used to distinguish among fossil hominin groups were quantitatively examined. Fifty-five fossil crania dating from the early to the late Pleistocene were analyzed. Using a modified pantograph, outlines of the frontal bone were collected along the midsagittal and two parasagittal planes. The profile from nasion to bregma, as well as two profiles above the medial and lateral sections of the orbit, respectively, extending from the orbital margin to the coronal suture were traced. The outlines were measured using Elliptical Fourier Function Analysis (EFFA), which enabled a quantification of aspects of the frontal bone that have historically been described primarily in nonmetric or linear terms. Four measurements were obtained: 1) overall morphology as expressed in the Fourier harmonic amplitudes; 2) maximum projection of the supraorbital torus at three points along the browridge (glabella and the medial and lateral aspects of the torus above the orbit); 3) maximum distance of the frontal squama from the frontal chord, capturing forehead curvature; and 4) nasion-bregma chord length. The results indicate that the midsagittal profile is significantly different among all Pleistocene groups in analyses that include both size and shape, as well as size-adjusted data. Homo erectus is significantly different from the late Pleistocene groups (Neandertals and early modern H. sapiens) in glabellar projection. Anatomically modern humans are significantly different from all other groups in both raw and size-standardized analyses of all three outlines that captured overall morphology, as well as forehead curvature and lateral supraorbital torus prominence, and middle Pleistocene Homo are significantly different in both medial and lateral overall parasagittal form. However, for the majority of analyses there were no significant differences among the Pleistocene archaic groups in supraorbital torus projection, frontal squama

  20. Silent innovation: corporate strategizing in early nanotechnology evolution

    DEFF Research Database (Denmark)

    Andersen, Maj Munch

    2011-01-01

    Nanotechnology offers a rare opportunity to study the early evolution of a new generic technology in real time. This paper suggests focusing more on the market formation side, rather than technology generation, when seeking to explain technology evolution. Applying an evolutionary capabilities...... perspective, the paper examines how firms organize innovation in the early embryonic stages of a technology and how the market as a selective device undergoes qualitative change as part of economic evolution. The traditional Danish window chain is used as a case. A model of nanotechnology evolution...... is proposed which suggests that nanotechnology commercialization is significantly driven by small and medium-sized firms based on their internal knowhow, with larger firms as important suppliers of know how. These smaller firms are adept at addressing social needs which appear to be key factors in the nano...

  1. Transient nature of late Pleistocene climate variability.

    Science.gov (United States)

    Crowley, Thomas J; Hyde, William T

    2008-11-13

    Climate in the early Pleistocene varied with a period of 41 kyr and was related to variations in Earth's obliquity. About 900 kyr ago, variability increased and oscillated primarily at a period of approximately 100 kyr, suggesting that the link was then with the eccentricity of Earth's orbit. This transition has often been attributed to a nonlinear response to small changes in external boundary conditions. Here we propose that increasing variablility within the past million years may indicate that the climate system was approaching a second climate bifurcation point, after which it would transition again to a new stable state characterized by permanent mid-latitude Northern Hemisphere glaciation. From this perspective the past million years can be viewed as a transient interval in the evolution of Earth's climate. We support our hypothesis using a coupled energy-balance/ice-sheet model, which furthermore predicts that the future transition would involve a large expansion of the Eurasian ice sheet. The process responsible for the abrupt change seems to be the albedo discontinuity at the snow-ice edge. The best-fit model run, which explains almost 60% of the variance in global ice volume during the past 400 kyr, predicts a rapid transition in the geologically near future to the proposed glacial state. Should it be attained, this state would be more 'symmetric' than the present climate, with comparable areas of ice/sea-ice cover in each hemisphere, and would represent the culmination of 50 million years of evolution from bipolar nonglacial climates to bipolar glacial climates.

  2. Hominin responses to environmental changes during the Middle Pleistocene in central and southern Italy

    Directory of Open Access Journals (Sweden)

    R. Orain

    2013-03-01

    Full Text Available The palaeobotanical record of early Palaeolithic sites from Western Europe indicates that hominins settled in different kinds of environments. During the "mid-Pleistocene transition (MPT", from about 1 to 0.6 Ma, the transition from 41- to 100-ka dominant climatic oscillations, occurring within a long-term cooling trend, was associated with an aridity crisis which strongly modified the ecosystems. Starting from the MPT the more favourable climate of central and southern Italy provided propitious environmental conditions for long-term human occupations even during the glacial times. In fact, the human strategy of territory occupation was certainly driven by the availabilities of resources. Prehistoric sites such as Notarchirico (ca. 680–600 ka, La Pineta (ca. 600–620 ka, Guado San Nicola (ca. 380–350 ka or Ceprano (ca. 345–355 ka testify to a preferential occupation of the central and southern Apennines valleys during interglacial phases, while later interglacial occupations were oriented towards the coastal plains, as attested by the numerous settlements of the Roma Basin (ca. 300 ka. Faunal remains indicate that human subsistence behaviours benefited from a diversity of exploitable ecosystems, from semi-open to closed environments. In central and southern Italy, several palynological records have already illustrated the regional- and local-scale vegetation dynamic trends. During the Middle Pleistocene climate cycles, mixed mesophytic forests developed during the interglacial periods and withdrew in response to increasing aridity during the glacial episodes. New pollen data from the Boiano Basin (Molise, Italy attest to the evolution of vegetation and climate between MIS 13 and 9 (ca. 500 to 300 ka. In this basin the persistence of high edaphic humidity, even during the glacial phases, could have favoured the establishment of a refuge area for the arboreal flora and provided subsistence resources for the animal and hominin communities

  3. Hominin responses to environmental changes during the Middle Pleistocene in central and southern Italy

    Science.gov (United States)

    Orain, R.; Lebreton, V.; Russo Ermolli, E.; Sémah, A.-M.; Nomade, S.; Shao, Q.; Bahain, J.-J.; Thun Hohenstein, U.; Peretto, C.

    2013-03-01

    The palaeobotanical record of early Palaeolithic sites from Western Europe indicates that hominins settled in different kinds of environments. During the "mid-Pleistocene transition (MPT)", from about 1 to 0.6 Ma, the transition from 41- to 100-ka dominant climatic oscillations, occurring within a long-term cooling trend, was associated with an aridity crisis which strongly modified the ecosystems. Starting from the MPT the more favourable climate of central and southern Italy provided propitious environmental conditions for long-term human occupations even during the glacial times. In fact, the human strategy of territory occupation was certainly driven by the availabilities of resources. Prehistoric sites such as Notarchirico (ca. 680-600 ka), La Pineta (ca. 600-620 ka), Guado San Nicola (ca. 380-350 ka) or Ceprano (ca. 345-355 ka) testify to a preferential occupation of the central and southern Apennines valleys during interglacial phases, while later interglacial occupations were oriented towards the coastal plains, as attested by the numerous settlements of the Roma Basin (ca. 300 ka). Faunal remains indicate that human subsistence behaviours benefited from a diversity of exploitable ecosystems, from semi-open to closed environments. In central and southern Italy, several palynological records have already illustrated the regional- and local-scale vegetation dynamic trends. During the Middle Pleistocene climate cycles, mixed mesophytic forests developed during the interglacial periods and withdrew in response to increasing aridity during the glacial episodes. New pollen data from the Boiano Basin (Molise, Italy) attest to the evolution of vegetation and climate between MIS 13 and 9 (ca. 500 to 300 ka). In this basin the persistence of high edaphic humidity, even during the glacial phases, could have favoured the establishment of a refuge area for the arboreal flora and provided subsistence resources for the animal and hominin communities during the Middle

  4. Pleistocene vertebrates of the Yukon Territory

    Science.gov (United States)

    Harington, C. R.

    2011-08-01

    Unglaciated parts of the Yukon constitute one of the most important areas in North America for yielding Pleistocene vertebrate fossils. Nearly 30 vertebrate faunal localities are reviewed spanning a period of about 1.6 Ma (million years ago) to the close of the Pleistocene some 10 000 BP (radiocarbon years before present, taken as 1950). The vertebrate fossils represent at least 8 species of fishes, 1 amphibian, 41 species of birds and 83 species of mammals. Dominant among the large mammals are: steppe bison ( Bison priscus), horse ( Equus sp.), woolly mammoth ( Mammuthus primigenius), and caribou ( Rangifer tarandus) - signature species of the Mammoth Steppe fauna ( Fig. 1), which was widespread from the British Isles, through northern Europe, and Siberia to Alaska, Yukon and adjacent Northwest Territories. The Yukon faunas extend from Herschel Island in the north to Revenue Creek in the south and from the Alaskan border in the west to Ketza River in the east. The Yukon holds evidence of the earliest-known people in North America. Artifacts made from bison, mammoth and caribou bones from Bluefish Caves, Old Crow Basin and Dawson City areas show that people had a substantial knowledge of making and using bone tools at least by 25 000 BP, and possibly as early as 40 000 BP. A suggested chronological sequence of Yukon Pleistocene vertebrates ( Table 1) facilitates comparison of selected faunas and indicates the known duration of various taxa.

  5. Oldest known pantherine skull and evolution of the tiger.

    Science.gov (United States)

    Mazák, Ji H; Christiansen, Per; Kitchener, Andrew C

    2011-01-01

    The tiger is one of the most iconic extant animals, and its origin and evolution have been intensely debated. Fossils attributable to extant pantherine species-lineages are less than 2 MYA and the earliest tiger fossils are from the Calabrian, Lower Pleistocene. Molecular studies predict a much younger age for the divergence of modern tiger subspecies at tigers would likely have differed markedly anatomically from extant tigers. Such inferences are hampered by the fact that well-known fossil tiger material is middle to late Pleistocene in age. Here we describe a new species of pantherine cat from Longdan, Gansu Province, China, Panthera zdanskyi sp. nov. With an estimated age of 2.55-2.16 MYA it represents the oldest complete skull of a pantherine cat hitherto found. Although smaller, it appears morphologically to be surprisingly similar to modern tigers considering its age. Morphological, morphometric, and cladistic analyses are congruent in confirming its very close affinity to the tiger, and it may be regarded as the most primitive species of the tiger lineage, demonstrating the first unequivocal presence of a modern pantherine species-lineage in the basal stage of the Pleistocene (Gelasian; traditionally considered to be Late Pliocene). This find supports a north-central Chinese origin of the tiger lineage, and demonstrates that various parts of the cranium, mandible, and dentition evolved at different rates. An increase in size and a reduction in the relative size of parts of the dentition appear to have been prominent features of tiger evolution, whereas the distinctive cranial morphology of modern tigers was established very early in their evolutionary history. The evolutionary trend of increasing size in the tiger lineage is likely coupled to the evolution of its primary prey species.

  6. Pleistocene and Holocene Iberian flora: a complete picture and review

    Science.gov (United States)

    González Sampériz, Penélope

    2010-05-01

    A detailed analysis of the location and composition of Iberian vegetation types during the whole Pleistocene and Holocene periods shows a complex patched landscape with persistence of different types of ecosystems, even during glacial times. In addition, recent, high-resolution palaeoecological records are changing the traditional picture of post-glacial vegetation succession in the Iberian Peninsula. The main available charcoal and pollen sequences include, coniferous and deciduous forest, steppes, shrublands, savannahs and glacial refugia during the Pleistocene for Meso-thermophytes (phytodiversity reservoirs), in different proportions. This panorama suggests an environmental complexity that relates biotic responses to climate changes forced by Milankovitch cycles, suborbital forcings and by the latitudinal and physiographic particularities of the Iberian Peninsula. Thus, many factors are critical in the course of vegetational developments and strong regional differences are observed since the Early Pleistocene. Currently, the flora of Iberia is located in two biogeographical/climatic regions: the Eurosiberian and the Mediterranean. The first one includes northern and northwestern areas of the peninsula, where post-glacial responses of vegetation are very similar to Central Europe, although with some particularities due to its proximity to both the Atlantic Ocean and the Mediterranean region. The second one comprises the main territory of Iberia and shows more complex patterns and singularities, now and in the past. Steppe landscapes dominated extensive areas over all the territory during the cold spells of the Quaternary, especially during the Late Pleistocene up to the Last Glacial Maximum, but differences in composition of the dominant taxa (Compositae versus Artemisia) are observed since the Early Pleistocene, probably related to moisture regional gradients. Coastal shelves and intramountainous valleys, even in continental areas, are spots of floristic

  7. The origin and disappearance of the late Pleistocene-early Holocene short-lived coastal wetlands along the Carmel coast, Israel

    Science.gov (United States)

    Sivan, Dorit; Greenbaum, Noam; Cohen-Seffer, Ronit; Sisma-Ventura, Guy; Almogi-Labin, Ahuva

    The formation of short-lived backswamps along the Carmel coast of Israel coincides with the rapid global sea-level rise during the late Pleistocene-early Holocene transition. The current study shows that the wetland phenomena originated around 10,000 yr ago and dried up shortly before the local Pre-Pottery Neolithic humans settled on the wetland dark clay sediments 9430 cal yr BP. Palaeontological and stable-isotope data were used in this study to elucidate previously published sedimentological reconstruction obtained from a core drilled into the western trough of the Carmel coastal plain. The water body contained typical brackish calcareous fauna, with variable numerical abundance and low species richness of ostracods and foraminifera. The δ 18O and δ 13C of the ostracod Cyprideis torosa show close similarity to the present Pleistocene coastal aquifer isotopic values. This study therefore concludes that the wetlands were shallow-water bodies fed by groundwater, with no evidence of sea-water mixing. It seems that they developed as the result of high groundwater levels, transportation of sediments landward, and deposition of sand bars at the paleo-river mouths. It is still not fully understood why these wetlands deteriorated abruptly and disappeared within less than 1000 yr.

  8. New Middle Pleistocene hominin cranium from Gruta da Aroeira (Portugal).

    Science.gov (United States)

    Daura, Joan; Sanz, Montserrat; Arsuaga, Juan Luis; Hoffmann, Dirk L; Quam, Rolf M; Ortega, María Cruz; Santos, Elena; Gómez, Sandra; Rubio, Angel; Villaescusa, Lucía; Souto, Pedro; Mauricio, João; Rodrigues, Filipa; Ferreira, Artur; Godinho, Paulo; Trinkaus, Erik; Zilhão, João

    2017-03-28

    The Middle Pleistocene is a crucial time period for studying human evolution in Europe, because it marks the appearance of both fossil hominins ancestral to the later Neandertals and the Acheulean technology. Nevertheless, European sites containing well-dated human remains associated with an Acheulean toolkit remain scarce. The earliest European hominin crania associated with Acheulean handaxes are at the sites of Arago, Atapuerca Sima de los Huesos (SH), and Swanscombe, dating to 400-500 ka (Marine Isotope Stage 11-12). The Atapuerca (SH) fossils and the Swanscombe cranium belong to the Neandertal clade, whereas the Arago hominins have been attributed to an incipient stage of Neandertal evolution, to Homo heidelbergensis , or to a subspecies of Homo erectus A recently discovered cranium (Aroeira 3) from the Gruta da Aroeira (Almonda karst system, Portugal) dating to 390-436 ka provides important evidence on the earliest European Acheulean-bearing hominins. This cranium is represented by most of the right half of a calvarium (with the exception of the missing occipital bone) and a fragmentary right maxilla preserving part of the nasal floor and two fragmentary molars. The combination of traits in the Aroeira 3 cranium augments the previously documented diversity in the European Middle Pleistocene fossil record.

  9. Upper Pleistocene Human Dispersals out of Africa: A Review of the Current State of the Debate

    Science.gov (United States)

    Beyin, Amanuel

    2011-01-01

    Although there is a general consensus on African origin of early modern humans, there is disagreement about how and when they dispersed to Eurasia. This paper reviews genetic and Middle Stone Age/Middle Paleolithic archaeological literature from northeast Africa, Arabia, and the Levant to assess the timing and geographic backgrounds of Upper Pleistocene human colonization of Eurasia. At the center of the discussion lies the question of whether eastern Africa alone was the source of Upper Pleistocene human dispersals into Eurasia or were there other loci of human expansions outside of Africa? The reviewed literature hints at two modes of early modern human colonization of Eurasia in the Upper Pleistocene: (i) from multiple Homo sapiens source populations that had entered Arabia, South Asia, and the Levant prior to and soon after the onset of the Last Interglacial (MIS-5), (ii) from a rapid dispersal out of East Africa via the Southern Route (across the Red Sea basin), dating to ~74–60 kya. PMID:21716744

  10. Accretion and early evolution of Earth

    DEFF Research Database (Denmark)

    Saji, Nikitha Susan

    in solar system materials is found to be related to selective thermal processing of dust in the early nebula given the correlation observed for these eects with Fe-peak neutron-rich isotope anomalies, whose origin is attributed to distinct nucleosnythetic sites other than classical s-, r- or p......-sized dust, of which the early protoplanetary disk is initially composed of, coalesce over the course of several millions of years to form the precursors to planets that make up the solar system today. The final assembly of Earth-like planets is complete only after a protracted latestage evolution...... that extends over at least 100 Myr, characterized by violent collisions between Mars- to Moon-sized planetary embryos. Evidence for the many details of solar system evolution - such as the diverse stellar sources that contributed material to solar system bodies to what role disk processes and late...

  11. Early resistance change and stress/electromigration evolution in near bamboo interconnects

    NARCIS (Netherlands)

    Petrescu, V.; Mouthaan, A.J.; Dima, G.; Govoreanu, B.; Mitrea, O.; Profirescu, M.

    1997-01-01

    A complete description for early resistance change and mechanical stress evolution in near-bamboo interconnects, related to the electromigration, is given in this paper. The proposed model, for the first time, combines the stress/vacancy concentration evolution with the early resistance change of

  12. The early thermal evolution of Mars

    Science.gov (United States)

    Bhatia, G. K.; Sahijpal, S.

    2016-01-01

    Hf-W isotopic systematics of Martian meteorites have provided evidence for the early accretion and rapid core formation of Mars. We present the results of numerical simulations performed to study the early thermal evolution and planetary scale differentiation of Mars. The simulations are confined to the initial 50 Myr (Ma) of the formation of solar system. The accretion energy produced during the growth of Mars and the decay energy due to the short-lived radio-nuclides 26Al, 60Fe, and the long-lived nuclides, 40K, 235U, 238U, and 232Th are incorporated as the heat sources for the thermal evolution of Mars. During the core-mantle differentiation of Mars, the molten metallic blobs were numerically moved using Stoke's law toward the center with descent velocity that depends on the local acceleration due to gravity. Apart from the accretion and the radioactive heat energies, the gravitational energy produced during the differentiation of Mars and the associated heat transfer is also parametrically incorporated in the present work to make an assessment of its contribution to the early thermal evolution of Mars. We conclude that the accretion energy alone cannot produce widespread melting and differentiation of Mars even with an efficient consumption of the accretion energy. This makes 26Al the prime source for the heating and planetary scale differentiation of Mars. We demonstrate a rapid accretion and core-mantle differentiation of Mars within the initial ~1.5 Myr. This is consistent with the chronological records of Martian meteorites.

  13. Plio-Pleistocene aardvarks (Mammalia, Tubulidentata from East Africa

    Directory of Open Access Journals (Sweden)

    T. Lehmann

    2008-08-01

    might have co-existed in Kenya during the early Pleistocene. doi:10.1002/mmng.200800003

  14. Pliocene to early Middle Pleistocene ursine bears in Europe: a taxonomic overview

    Czech Academy of Sciences Publication Activity Database

    Wagner, Jan

    2010-01-01

    Roč. 179, - (2010), s. 197-215 ISSN 1802-6842 R&D Projects: GA ČR GA205/09/0184; GA AV ČR IAA300130701 Institutional research plan: CEZ:AV0Z30130516 Keywords : Ursus * taxonomy * Pliocene * Pleistocene Subject RIV: DB - Geology ; Mineralogy http://www.nm.cz/publikace/publikace-download.php?name=File1&dir=archiv&table=tabPublikaceArchiv&id=2796

  15. Paleocene-Eocene and Plio-Pleistocene sea-level changes as "species pumps" in Southeast Asia: Evidence from Althepus spiders.

    Science.gov (United States)

    Li, Fengyuan; Li, Shuqiang

    2018-05-17

    Sea-level change has been viewed as a primary driver in the formation of biodiversity. Early studies confirmed that Plio-Pleistocene sea-level changes led to the isolation and subsequent genetic differentiation of Southeast (SE) Asian organisms over short geological timescales. However, long-time consequences of sea-level fluctuations remain unclear. Herein, we analyze the evolutionary history of Althepus (spiders) whose distribution encompasses Indo-Burma and the Sunda shelf islands to understand how sea-level changes over shallow and deep timescales effected their history. Our integrative analyses, including phylogeny, divergence times, ancestral area reconstruction and diversification dynamics, reveal an intricate pattern of diversification, probably triggered by sea-level fluctuations during the Paleocene-Eocene and Plio-Pleistocene. The timing of one early divergence between the Indo-Burmese and Sundaic species coincides with late Paleocene and early Eocene high global sea levels, which induced the formation of inland seaways in the Thai-Malay Peninsula. Subsequent lowered sea levels could have provided a land bridge for its dispersal colonization across the Isthmus of Kra. Analyses suggest that Plio-Pleistocene sea-level rises contributed to recent divergence of many species. Thus, our findings cannot reject the hypothesis that sea-level changes during the Paleocene-Eocene and Plio-Pleistocene played a major role in generating biodiversity in SE Asia; sea-level changes can act as "species pumps". Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Acinonyx pardinensis (Carnivora, Felidae) from the Early Pleistocene of Pantalla (Italy): predatory behavior and ecological role of the giant Plio-Pleistocene cheetah

    Science.gov (United States)

    Cherin, Marco; Iurino, Dawid Adam; Sardella, Raffaele; Rook, Lorenzo

    2014-03-01

    The site of Pantalla (central Italy) yielded a rich late Villafranchian (Early Pleistocene) faunal assemblage, which includes some well-preserved large mammal skulls. We describe here two nearly complete crania and a left hemimandible of Acinonyx pardinensis from this locality, representing the most complete cranial material of this species in Europe. These finds allowed us to define more clearly the craniodental morphology of A. pardinensis. Similarly to the forms from North Africa and China, the giant cheetah from Pantalla has a more generalized skull than the living Acinonyx jubatus, showing some primitive, pantherine-like features such as the less domed dorsal outline of the cranium, the more developed sagittal and nuchal crests and the less bowed zygomatic arches. High-resolution CT scans of the specimens were used to obtain the first 3D model of a cranium with articulated mandible of A. pardinensis. Starting from the insertion areas on this model we reconstructed the jaw muscles of the Pantalla felid, confirming its affinities with pantherine felines. In the light of the musculoskeletal skull anatomy and the average body mass (about 80 kg), it is likely that A. pardinensis could kill large prey through a hunting strategy more similar to pantherine cats than to the living cheetah.

  17. The first hominin from the early Pleistocene paleocave of Haasgat, South Africa.

    Science.gov (United States)

    Leece, A B; Kegley, Anthony D T; Lacruz, Rodrigo S; Herries, Andy I R; Hemingway, Jason; Kgasi, Lazarus; Potze, Stephany; Adams, Justin W

    2016-01-01

    localities in the topographically-distinct northern World Heritage Site. When coupled with the substantial differences in the mammalian faunal communities between the northern localities (e.g., Haasgat, Gondolin) and well-sampled Bloubank Valley sites (e.g., Sterkfontein, Swartkrans, Kromdraai), the recovery of the HGT 500 specimen highlights the potential for further research at the Haasgat locality for understanding the distribution and interactions of hominin populations across the landscape, ecosystems and fossil mammalian communities of early Pleistocene South Africa. Such contextual data from sites like Haasgat is critical for understanding the transition in hominin representation at ∼2 Ma sites in the region from Australopithecus to Paranthropus and early Homo.

  18. The first hominin from the early Pleistocene paleocave of Haasgat, South Africa

    Directory of Open Access Journals (Sweden)

    AB Leece

    2016-05-01

    one of the few hominin localities in the topographically-distinct northern World Heritage Site. When coupled with the substantial differences in the mammalian faunal communities between the northern localities (e.g., Haasgat, Gondolin and well-sampled Bloubank Valley sites (e.g., Sterkfontein, Swartkrans, Kromdraai, the recovery of the HGT 500 specimen highlights the potential for further research at the Haasgat locality for understanding the distribution and interactions of hominin populations across the landscape, ecosystems and fossil mammalian communities of early Pleistocene South Africa. Such contextual data from sites like Haasgat is critical for understanding the transition in hominin representation at ∼2 Ma sites in the region from Australopithecus to Paranthropus and early Homo.

  19. Early evolution without a tree of life.

    Science.gov (United States)

    Martin, William F

    2011-06-30

    Life is a chemical reaction. Three major transitions in early evolution are considered without recourse to a tree of life. The origin of prokaryotes required a steady supply of energy and electrons, probably in the form of molecular hydrogen stemming from serpentinization. Microbial genome evolution is not a treelike process because of lateral gene transfer and the endosymbiotic origins of organelles. The lack of true intermediates in the prokaryote-to-eukaryote transition has a bioenergetic cause.

  20. Simple technologies and diverse food strategies of the Late Pleistocene and Early Holocene at Huaca Prieta, Coastal Peru.

    Science.gov (United States)

    Dillehay, Tom D; Goodbred, Steve; Pino, Mario; Vásquez Sánchez, Víctor F; Tham, Teresa Rosales; Adovasio, James; Collins, Michael B; Netherly, Patricia J; Hastorf, Christine A; Chiou, Katherine L; Piperno, Dolores; Rey, Isabel; Velchoff, Nancy

    2017-05-01

    Simple pebble tools, ephemeral cultural features, and the remains of maritime and terrestrial foods are present in undisturbed Late Pleistocene and Early Holocene deposits underneath a large human-made mound at Huaca Prieta and nearby sites on the Pacific coast of northern Peru. Radiocarbon ages indicate an intermittent human presence dated between ~15,000 and 8000 calendar years ago before the mound was built. The absence of fishhooks, harpoons, and bifacial stone tools suggests that technologies of gathering, trapping, clubbing, and exchange were used primarily to procure food resources along the shoreline and in estuarine wetlands and distant mountains. The stone artifacts are minimally worked unifacial stone tools characteristic of several areas of South America. Remains of avocado, bean, and possibly cultivated squash and chile pepper are also present, suggesting human transport and consumption. Our new findings emphasize an early coastal lifeway of diverse food procurement strategies that suggest detailed observation of resource availability in multiple environments and a knowledgeable economic organization, although technologies were simple and campsites were seemingly ephemeral and discontinuous. These findings raise questions about the pace of early human movement along some areas of the Pacific coast and the level of knowledge and technology required to exploit maritime and inland resources.

  1. Fracture patterns of the drainage basin of Wadi Dahab in relation to tectonic-landscape evolution of the Gulf of Aqaba - Dead Sea transform fault

    Science.gov (United States)

    Shalaby, Ahmed

    2017-10-01

    Crustal rifting of the Arabian-Nubian Shield and formation of the Afro-Arabian rifts since the Miocene resulted in uplifting and subsequent terrain evolution of Sinai landscapes; including drainage systems and fault scarps. Geomorphic evolution of these landscapes in relation to tectonic evolution of the Afro-Arabian rifts is the prime target of this study. The fracture patterns and landscape evolution of the Wadi Dahab drainage basin (WDDB), in which its landscape is modeled by the tectonic evolution of the Gulf of Aqaba-Dead Sea transform fault, are investigated as a case study of landscape modifications of tectonically-controlled drainage systems. The early developed drainage system of the WDDB was achieved when the Sinai terrain subaerially emerged in post Eocene and initiation of the Afro-Arabian rifts in the Oligo-Miocene. Conjugate shear fractures, parallel to trends of the Afro-Arabian rifts, are synthesized with tensional fracture arrays to adapt some of inland basins, which represent the early destination of the Sinai drainage systems as paleolakes trapping alluvial sediments. Once the Gulf of Aqaba rift basin attains its deeps through sinistral movements on the Gulf of Aqaba-Dead Sea transform fault in the Pleistocene and the consequent rise of the Southern Sinai mountainous peaks, relief potential energy is significantly maintained through time so that it forced the Pleistocene runoffs to flow via drainage systems externally into the Gulf of Aqaba. Hence the older alluvial sediments are (1) carved within the paleolakes by a new generation of drainage systems; followed up through an erosional surface by sandy- to silty-based younger alluvium; and (2) brought on footslopes of fault scarps reviving the early developed scarps and inselbergs. These features argue for crustal uplifting of Sinai landscapes syn-rifting of the Gulf of Aqaba rift basin. Oblique orientation of the Red Sea-Gulf of Suez rift relative to the WNW-trending Precambrian Najd faults; and

  2. ON THE SIZE AND COMOVING MASS DENSITY EVOLUTION OF EARLY-TYPE GALAXIES

    International Nuclear Information System (INIS)

    Van der Wel, Arjen; Bell, Eric F.; Van den Bosch, Frank C.; Gallazzi, Anna; Rix, Hans-Walter

    2009-01-01

    We present a simple, empirically motivated model that simultaneously predicts the evolution of the mean size and the comoving mass density of massive (>10 11 M sun ) early-type galaxies from z = 2 to the present. First, we demonstrate that some size evolution of the population can be expected simply due to the continuous emergence of early-type galaxies. The Sloan Digital Sky Survey (SDSS) data reveal that in the present-day universe more compact early-type galaxies with a given dynamical mass have older stellar populations. This implies that with increasing look-back time, the more extended galaxies will be more and more absent from the population. In contrast, at a given stellar velocity dispersion, SDSS data show that there is no relation between size and age, which implies that the velocity dispersion can be used to estimate the epoch at which galaxies stopped forming stars, turning into early-type galaxies. Based on this, we define an empirically motivated, redshift-dependent velocity dispersion threshold above which galaxies do not form stars at a significant rate, which we associate with the transformation into early-type galaxies. Applying this 'formation' criterion to a large sample of nearby early-type galaxies, we predict the redshift evolution in the size distribution and the comoving mass density. The resulting evolution in the mean size is roughly half of the observed evolution. Then we include a prescription for the merger histories of galaxies between the 'formation' redshift and the present, based on cosmological simulations of the assembly of dark matter halos. Such mergers after the transformation into an early-type galaxy are presumably dissipationless ('dry'), where the increase in size is expected to be approximately proportional to the increase in mass. This model successfully reproduces the observed evolution since z ∼ 2 in the mean size and in the comoving mass density of early-type galaxies with mass M > 10 11 M sun . We conclude that

  3. The Origin and Early Evolution of Membrane Proteins

    Science.gov (United States)

    Pohorille, Andrew; Schweighofter, Karl; Wilson, Michael A.

    2006-01-01

    The origin and early evolution of membrane proteins, and in particular ion channels, are considered from the point of view that the transmembrane segments of membrane proteins are structurally quite simple and do not require specific sequences to fold. We argue that the transport of solute species, especially ions, required an early evolution of efficient transport mechanisms, and that the emergence of simple ion channels was protobiologically plausible. We also argue that, despite their simple structure, such channels could possess properties that, at the first sight, appear to require markedly larger complexity. These properties can be subtly modulated by local modifications to the sequence rather than global changes in molecular architecture. In order to address the evolution and development of ion channels, we focus on identifying those protein domains that are commonly associated with ion channel proteins and are conserved throughout the three main domains of life (Eukarya, Prokarya, and Archaea). We discuss the potassium-sodium-calcium superfamily of voltage-gated ion channels, mechanosensitive channels, porins, and ABC-transporters and argue that these families of membrane channels have sufficiently universal architectures that they can readily adapt to the diverse functional demands arising during evolution.

  4. Chemical evolution of the early Martian hydrosphere

    International Nuclear Information System (INIS)

    Schaefer, M.W.

    1990-01-01

    The chemical evolution of the early Martian hydrosphere is discussed. The early Martian ocean can be modeled as a body of relatively pure water in equilibrium with a dense carbon dioxide atmosphere. The chemical weathering of lavas, pyroclastic deposits, and impact melt sheets would have the effect of neutralizing the acidity of the juvenile water. As calcium and other cations are added to the water by chemical weathering, they are quickly removed by the precipitation of calcium carbonate and other minerals, forming a deposit of limestone beneath the surface of the ocean. As the atmospheric carbon dioxide pressure and the temperature decrease, the Martian ocean would be completely frozen. Given the scenario for the chemical evolution of the northern lowland plains of Mars, it should be possible to draw a few conclusions about the expected mineralogy and geomorphology of this regions

  5. An arid episod in the climatic evolution of the Atakor mountains (Hoggar) about 1.5 m.y. (K/Ar datations). Its signification in the paleoclimatic context during the Plio-Pleistocene of Africa

    International Nuclear Information System (INIS)

    Rognon, Pierre; Gourinard, Yves; Bandet, Y.

    1981-01-01

    Nine K/Ar datations of some basaltic lavas from the Atakor mountains allow to date, for the first time, an arid period at 1.5 m.y. +- 0.1. This arid period takes place after the drying of the Plio-Pleistocene tropical lakes and after the first cool Pluvial, during an important turning phase of the geomorphologic and climatic evolution. These environmental changes are similar to those pointed out in Eastern Africa [fr

  6. Hosting Early Evolution in Heated Pores of Rock

    Science.gov (United States)

    Mast, C. B.; Möller, F.; Lanzmich, S.; Keil, L.; Braun, D.

    2017-07-01

    Recent experiments with non-equilibrium micro­systems suggest that porous rock conditions drive early molecular evolution in many ways, including accumulation, polymerization, replication, length selection and gelation.

  7. The late Middle Pleistocene hominin fossil record of eastern Asia: synthesis and review.

    Science.gov (United States)

    Bae, Christopher J

    2010-01-01

    Traditionally, Middle Pleistocene hominin fossils that cannot be allocated to Homo erectus sensu lato or modern H. sapiens have been assigned to different specific taxa. For example, in eastern Asia, these hominin fossils have been classified as archaic, early, or premodern H. sapiens. An increasing number of Middle Pleistocene hominin fossils are currently being assigned to H. heidelbergensis. This is particularly the case for the African and European Middle Pleistocene hominin fossil record. There have been suggestions that perhaps the eastern Asian late Middle Pleistocene hominins can also be allocated to the H. heidelbergensis hypodigm. In this article, I review the current state of the late Middle Pleistocene hominin fossil record from eastern Asia and examine the various arguments for assigning these hominins to the different specific taxa. The two primary conclusions drawn from this review are as follows: 1) little evidence currently exists in the eastern Asian Middle Pleistocene hominin fossil record to support their assignment to H. heidelbergensis; and 2) rather than add to the growing list of hominin fossil taxa by using taxonomic names like H. daliensis for northeast Asian fossils and H. mabaensis for Southeast Asian fossils, it is better to err on the side of caution and continue to use the term archaic H. sapiens to represent all of these hominin fossils. What should be evident from this review is the need for an increase in the quality and quantity of the eastern Asian hominin fossil data set. Fortunately, with the increasing number of large-scale multidisciplinary paleoanthropological field and laboratory research projects in eastern Asia, the record is quickly becoming better understood. Copyright © 2010 Wiley-Liss, Inc.

  8. Rates of morphological evolution are heterogeneous in Early Cretaceous birds

    Science.gov (United States)

    Lloyd, Graeme T.

    2016-01-01

    The Early Cretaceous is a critical interval in the early history of birds. Exceptional fossils indicate that important evolutionary novelties such as a pygostyle and a keeled sternum had already arisen in Early Cretaceous taxa, bridging much of the morphological gap between Archaeopteryx and crown birds. However, detailed features of basal bird evolution remain obscure because of both the small sample of fossil taxa previously considered and a lack of quantitative studies assessing rates of morphological evolution. Here we apply a recently available phylogenetic method and associated sensitivity tests to a large data matrix of morphological characters to quantify rates of morphological evolution in Early Cretaceous birds. Our results reveal that although rates were highly heterogeneous between different Early Cretaceous avian lineages, consistent patterns of significantly high or low rates were harder to pinpoint. Nevertheless, evidence for accelerated evolutionary rates is strongest at the point when Ornithuromorpha (the clade comprises all extant birds and descendants from their most recent common ancestors) split from Enantiornithes (a diverse clade that went extinct at the end-Cretaceous), consistent with the hypothesis that this key split opened up new niches and ultimately led to greater diversity for these two dominant clades of Mesozoic birds. PMID:27053742

  9. Earliest Pleistocene hominid cranial remains from Dmanisi, Republic of Georgia: taxonomy, geological setting, and age.

    Science.gov (United States)

    Gabunia, L; Vekua, A; Lordkipanidze, D; Swisher, C C; Ferring, R; Justus, A; Nioradze, M; Tvalchrelidze, M; Antón, S C; Bosinski, G; Jöris, O; Lumley, M A; Majsuradze, G; Mouskhelishvili, A

    2000-05-12

    Archaeological excavations at the site of Dmanisi in the Republic of Georgia have uncovered two partial early Pleistocene hominid crania. The new fossils consist of a relatively complete cranium and a second relatively complete calvaria from the same site and stratigraphic unit that yielded a hominid mandible in 1991. In contrast with the uncertain taxonomic affinity of the mandible, the new fossils are comparable in size and morphology with Homo ergaster from Koobi Fora, Kenya. Paleontological, archaeological, geochronological, and paleomagnetic data from Dmanisi all indicate an earliest Pleistocene age of about 1.7 million years ago, supporting correlation of the new specimens with the Koobi Fora fossils. The Dmanisi fossils, in contrast with Pleistocene hominids from Western Europe and Eastern Asia, show clear African affinity and may represent the species that first migrated out of Africa.

  10. Evolution, Systematics, and Phylogeography of Pleistocene Horses in the New World: A Molecular Perspective

    DEFF Research Database (Denmark)

    Weinstock, Jaco; Willerslev, Eske; Sher, A.

    2005-01-01

    . Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological...... grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species....

  11. High resolution magnetostratigraphy and raio-isotope dating of early Pleistocene lake sediments from southern Armenia

    NARCIS (Netherlands)

    Kirscher, U.; Bruch, A.A.; Gabrielyan, I.; Scharrer, S.; Kuiper, K.F.; Bachtadse, V.

    2014-01-01

    The Pleistocene geology of Armenia is dominated by widespread occurrence of sediments recording recurring rapid and drastic changes of the environmental conditions during at least the last 2 million years. These sediments, predominantly diatomites, contain a huge variety of various fossil remains,

  12. Pleistocene Paleoart of Australia

    Directory of Open Access Journals (Sweden)

    Robert G. Bednarik

    2014-02-01

    Full Text Available Pleistocene rock art is abundant in Australia, but has so far received only limited attention. Instead there has been a trend, begun over a century ago, to search for presumed depictions of extinct megafauna and the tracks of such species. All these notions have been discredited, however, and the current evidence suggests that figurative depiction was introduced only during the Holocene, never reaching Tasmania. Nevertheless, some Australian rock art has been attributed to the Pleistocene by direct dating methods, and its nature implies that a significant portion of the surviving corpus of rock art may also be of such age. In particular much of Australian cave art is of the Ice Age, or appears to be so, and any heavily weathered or patinated petroglyphs on particularly hard rocks are good candidates for Pleistocene antiquity. On the other hand, there is very limited evidence of mobiliary paleoart of such age in Australia.

  13. Early evolution without a tree of life

    Directory of Open Access Journals (Sweden)

    Martin William F

    2011-06-01

    Full Text Available Abstract Life is a chemical reaction. Three major transitions in early evolution are considered without recourse to a tree of life. The origin of prokaryotes required a steady supply of energy and electrons, probably in the form of molecular hydrogen stemming from serpentinization. Microbial genome evolution is not a treelike process because of lateral gene transfer and the endosymbiotic origins of organelles. The lack of true intermediates in the prokaryote-to-eukaryote transition has a bioenergetic cause. This article was reviewed by Dan Graur, W. Ford Doolittle, Eugene V. Koonin and Christophe Malaterre.

  14. Bovids as indicators of Plio-Pleistocene paleoenvironments in east Africa.

    Science.gov (United States)

    Kappelman, J; Plummer, T; Bishop, L; Duncan, A; Appleton, S

    1997-01-01

    Reconstructions of the paleoenvironments of early hominids offer a framework for understanding hominid ecological and behavioral adaptations. Habitat reconstructions typically rely upon various biological or physical habitat indicators, and here we present reconstructions of the Plio-Pleistocene paleohabitats of Koobi Fora and Olduvai Gorge as based on fossil bovids (Artiodactyla: Bovidae). Bovids are the most common faunal element at most Neogene hominid and hominoid fossil localities and have been widely studied. This study addresses the functional morphology of the bovid femur through discriminant function analysis and provides additional support for the observation that certain features of the femur demonstrate clear correlations with the amount of vegetative cover in different modern habitats. The reconstructions for both Koobi Fora and Olduvai Gorge suggest that the full range of environments inhabited by living bovids was present during the Plio-Pleistocene. Koobi Fora appears to have had a somewhat higher percentage of more closed habitats than the relatively more open habitats of Olduvai Gorge. These habitat reconstructions are in broad agreement with other reconstructions based on a purely taxonomic approach to the bovid remains. Grounding our reconstructions of paleoenvironments in studies of functional morphology can help to develop a richer idea of the habitats and resources available to early hominids.

  15. Pleistocene aridification cycles shaped the contemporary genetic architecture of Southern African baboons.

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    Riashna Sithaldeen

    Full Text Available Plio-Pleistocene environmental change influenced the evolutionary history of many animal lineages in Africa, highlighting key roles for both climate and tectonics in the evolution of Africa's faunal diversity. Here, we explore diversification in the southern African chacma baboon Papio ursinus sensu lato and reveal a dominant role for increasingly arid landscapes during past glacial cycles in shaping contemporary genetic structure. Recent work on baboons (Papio spp. supports complex lineage structuring with a dominant pulse of diversification occurring 1-2Ma, and yet the link to palaeoenvironmental change remains largely untested. Phylogeographic reconstruction based on mitochondrial DNA sequence data supports a scenario where chacma baboon populations were likely restricted to refugia during periods of regional cooling and drying through the Late Pleistocene. The two lineages of chacma baboon, ursinus and griseipes, are strongly geographically structured, and demographic reconstruction together with spatial analysis of genetic variation point to possible climate-driven isolating events where baboons may have retreated to more optimum conditions during cooler, drier periods. Our analysis highlights a period of continuous population growth beginning in the Middle to Late Pleistocene in both the ursinus and the PG2 griseipes lineages. All three clades identified in the study then enter a state of declining population size (Nef through to the Holocene; this is particularly marked in the last 20,000 years, most likely coincident with the Last Glacial Maximum. The pattern recovered here conforms to expectations based on the dynamic regional climate trends in southern Africa through the Pleistocene and provides further support for complex patterns of diversification in the region's biodiversity.

  16. Successful combination of electron spin resonance, luminescence and palaeomagnetic dating methods allows reconstruction of the Pleistocene evolution of the lower Moulouya river (NE Morocco)

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    Bartz, Melanie; Rixhon, Gilles; Duval, Mathieu; King, Georgina E.; Álvarez Posada, Claudia; Parés, Josep M.; Brückner, Helmut

    2018-04-01

    Based on a combination of Electron Spin Resonance (ESR) dating of quartz, luminescence dating of K-feldspar and palaeomagnetism, this study presents the first chronostratigraphic framework for the Pleistocene fluvial deposits of the lower Moulouya river in the Triffa basin (NE Morocco). K-feldspar pIRIR225 and pIRIR290 signals of all samples are saturated, suggesting fluvial deposition at least as early as the Middle Pleistocene (∼0.39-0.80 Ma). Consequently, further chronological information was obtained with ESR dating of quartz grains from the ancient Pleistocene fluvial deposits. As for ESR, the multiple centres approach provides equivalent dose values derived from the Al and Ti centres that mostly agree within 1σ-error, suggesting complete signal resetting from the former during fluvial transport. ESR dating results yield Calabrian deposition ages for all river profiles from ∼1.1 to ∼1.5 Ma. These ages are remarkably consistent with the palaeomagnetic results: the occurrence of mostly reversed polarity in the deposits indicates a Matuyama age (>0.78 Ma). While low incision rates in the Triffa basin (0.025 ± 0.003 mm/a) related to thrusting activity during the Calabrian could be inferred, the fluvial record points to an acyclic and discontinuous sedimentation pattern over the last ∼1.3 Ma. It thereby probably rules out climate as the main driver for fluvial aggradation in the lowermost sedimentary basin. At a regional scale, several indicators point to transient fluvial response resulting from major Quaternary tectonic activity along the Beni Snassen gorge, located directly upstream of the investigated basin. We suggest that a capture event at the margin of the uplifting Beni Snassen massif occurred between 1.04 and 1.36 Ma at the latest and subsequently led to the creation of the gorge.

  17. Possible linkage between supernovae, increased terrestrial lightning, and wildfire activity in the Late Miocene and Early Pleistocene

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    Thomas, B. C.; Feulner, G.; Melott, A. L.; Kirsten, T.; von Bloh, W.

    2017-12-01

    Radioisotopes from deep-sea deposits show that Earth was affected by nearby supernovae about 2.5 and 8 million years ago. Recent modelling work shows that high-energy particles from these events resulted in greatly enhanced ionization of the troposphere. This could have led to an increase in wildfires via more frequent lightning. Here we show that published data on global fire activity from charcoal records reveal a marked increase in wildfires around the times of the supernova explosions. We use a dynamic global vegetation model to assess the impact of increased lightning frequency on vegetation patterns, finding a patchy global decrease in tree cover. Regionally, vegetation changes are particularly pronounced in western North America, the Mediterranean, Central Asia, Northern Indochina, subtropical South America, Africa and Australia, and notably East Africa, in agreement with empirical evidence for a global shift towards savannas during the Pleistocene. Our results demonstrate that moderately nearby supernovae have the potential to affect life on Earth even if they are too distant to initiate a mass extinction. Finally, we note that the shift from forest to savannah biomes in the East African Rift Valley region has been tentatively linked to hominin evolution in this region.

  18. A new hypothesis of dinosaur relationships and early dinosaur evolution.

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    Baron, Matthew G; Norman, David B; Barrett, Paul M

    2017-03-22

    For 130 years, dinosaurs have been divided into two distinct clades-Ornithischia and Saurischia. Here we present a hypothesis for the phylogenetic relationships of the major dinosaurian groups that challenges the current consensus concerning early dinosaur evolution and highlights problematic aspects of current cladistic definitions. Our study has found a sister-group relationship between Ornithischia and Theropoda (united in the new clade Ornithoscelida), with Sauropodomorpha and Herrerasauridae (as the redefined Saurischia) forming its monophyletic outgroup. This new tree topology requires redefinition and rediagnosis of Dinosauria and the subsidiary dinosaurian clades. In addition, it forces re-evaluations of early dinosaur cladogenesis and character evolution, suggests that hypercarnivory was acquired independently in herrerasaurids and theropods, and offers an explanation for many of the anatomical features previously regarded as notable convergences between theropods and early ornithischians.

  19. The southernmost record of a large erethizontid rodent (Hystricomorpha: Erethizontoidea) in the Pleistocene of South America: Biogeographic and paleoenvironmental implications

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    Vezzosi, Raúl I.; Kerber, Leonardo

    2018-03-01

    The South American porcupines (Erethizontidae) are included in two genera: Chaetomys and Coendou. The latter is a very speciose taxon, with about 13 living species. During at least the late Pliocene-early Pleistocene, erethizontids immigrated to Central and North America during the Great American Biotic Interchange. Although some Pleistocene fossils have been reported, the Quaternary history of this clade is still understudied. The only known extinct species is Coendou magnus. In this work, a fossil of a porcupine is reported from an Upper Pleistocene fluvial sedimentary sequence cropping out in the Northern Pampa geomorphological region, Santa Fe Province, Argentina. Despite this group having different living forms widely distributed in South American Neotropical woodland habitats, the Pleistocene occurrences of Erethizontidae are scarce and limited to Upper Pleistocene deposits from Bolivia, Brazil, and Uruguay. Currently, the specimen here reported represents the only Pleistocene porcupine from Argentina with a stratigraphical context. The morphological characters as well as the dimensions indicate that it is close to the Pleistocene erethizontid Coendou magnus. In this context, the presence of this erethizontid in such a southern locality, together with other taxa recorded from this site and the associated geological and paleoenvironmental evidence, indicates subtropical conditions, compared with the current conditions, which may have allowed a southern displacement of taxa more related to woodlands and xeric subtropical environments.

  20. The Pleistocene evolution of the East Antarctic Ice Sheet in the Prydz bay region: Stable isotopic evidence from ODP Site 1167

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    Theissen, K.M.; Dunbar, R.B.; Cooper, A. K.; Mucciarone, D.A.; Hoffmann, D.

    2003-01-01

    Ocean Drilling Program Leg 188, Prydz Bay, East Antarctica is part of a larger initiative to explore the Cenozoic history of the Antarctic Ice Sheet through direct drilling and sampling of the continental margins. In this paper, we present stable isotopic results from Ocean Drilling Program (ODP) Site 1167 located on the Prydz Channel Trough Mouth Fan (TMF), the first Antarctic TMF to be drilled. The foraminifer-based ??18O record is interpreted along with sedimentary and downhole logging evidence to reconstruct the Quaternary glacial history of Prydz Bay and the adjacent Lambert Glacier Amery Ice Shelf System (LGAISS). We report an electron spin resonance age date of 36. 9 ?? 3.3 ka at 0.45 m below sea floor and correlate suspected glacial-interglacial cycles with the global isotopic stratigraphy to improve the chronology for Site 1167. The ??18O record based on planktonic (Neogloboquadrina pachyderma (s.)) and limited benthic results (Globocassidulina crassa), indicates a trend of ice sheet expansion that was interrupted by a period of reduced ice volume and possibly warmer conditions during the early-mid-Pleistocene (0.9-1.38 Ma). An increase in ?? 18O values after ??? 900 ka appears to coincide with the mid-Pleistocene climate transition and the expansion of the northern hemisphere ice sheet. The ??18O record in the upper 50 m of the stratigraphic section indicates as few as three glacial-interglacial cycles, tentatively assigned as marine isotopic stages (MIS) 16-21, are preserved since the Brunhes/Matuyama paleomagnetic reversal (780 ka). This suggests that there is a large unconformity near the top of the section and/or that there may have been few extreme advances of the ice sheet since the mid-Pleistocene climate transition resulting in lowered sedimentation rates on the Prydz Channel TMF. The stable isotopic record from Site 1167 is one of the few available from the area south of the Antarctic Polar Front that has been linked with the global isotopic

  1. Did warfare among ancestral hunter-gatherers affect the evolution of human social behaviors?

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    Bowles, Samuel

    2009-06-05

    Since Darwin, intergroup hostilities have figured prominently in explanations of the evolution of human social behavior. Yet whether ancestral humans were largely "peaceful" or "warlike" remains controversial. I ask a more precise question: If more cooperative groups were more likely to prevail in conflicts with other groups, was the level of intergroup violence sufficient to influence the evolution of human social behavior? Using a model of the evolutionary impact of between-group competition and a new data set that combines archaeological evidence on causes of death during the Late Pleistocene and early Holocene with ethnographic and historical reports on hunter-gatherer populations, I find that the estimated level of mortality in intergroup conflicts would have had substantial effects, allowing the proliferation of group-beneficial behaviors that were quite costly to the individual altruist.

  2. Lineage-specific late pleistocene expansion of an endemic subtropical gossamer-wing damselfly, Euphaea formosa, in Taiwan

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    Huang Jen-Pan

    2011-04-01

    Full Text Available Abstract Background Pleistocene glacial oscillations have significantly affected the historical population dynamics of temperate taxa. However, the general effects of recent climatic changes on the evolutionary history and genetic structure of extant subtropical species remain poorly understood. In the present study, phylogeographic and historical demographic analyses based on mitochondrial and nuclear DNA sequences were used. The aim was to investigate whether Pleistocene climatic cycles, paleo-drainages or mountain vicariance of Taiwan shaped the evolutionary diversification of a subtropical gossamer-wing damselfly, Euphaea formosa. Results E. formosa populations originated in the middle Pleistocene period (0.3 Mya and consisted of two evolutionarily independent lineages. It is likely that they derived from the Pleistocene paleo-drainages of northern and southern Minjiang, or alternatively by divergence within Taiwan. The ancestral North-central lineage colonized northwestern Taiwan first and maintained a slowly growing population throughout much of the early to middle Pleistocene period. The ancestral widespread lineage reached central-southern Taiwan and experienced a spatial and demographic expansion into eastern Taiwan. This expansion began approximately 30,000 years ago in the Holocene interglacial period. The ancestral southern expansion into eastern Taiwan indicates that the central mountain range (CMR formed a barrier to east-west expansion. However, E. formosa populations in the three major biogeographic regions (East, South, and North-Central exhibit no significant genetic partitions, suggesting that river drainages and mountains did not form strong geographical barriers against gene flow among extant populations. Conclusions The present study implies that the antiquity of E. formosa's colonization is associated with its high dispersal ability and larval tolerance to the late Pleistocene dry grasslands. The effect of late Pleistocene

  3. Size variation in Middle Pleistocene humans.

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    Arsuaga, J L; Carretero, J M; Lorenzo, C; Gracia, A; Martínez, I; Bermúdez de Castro, J M; Carbonell, E

    1997-08-22

    It has been suggested that European Middle Pleistocene humans, Neandertals, and prehistoric modern humans had a greater sexual dimorphism than modern humans. Analysis of body size variation and cranial capacity variation in the large sample from the Sima de los Huesos site in Spain showed instead that the sexual dimorphism is comparable in Middle Pleistocene and modern populations.

  4. Pleistocene Palaeoart of the Americas

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    Robert G. Bednarik

    2014-04-01

    Full Text Available In contrast to the great time depth of Pleistocene rock art and mobiliary ‘art’ in the four other continents, the available evidence from the Americas is very limited, and restricted at best to the last part of the final Pleistocene. A review of what has so far become available is hampered by a considerable burden of literature presenting material contended to be of the Ice Age, even of the Mesozoic in some cases, that needs to be sifted through to find a minute number of credible claims. Even the timing of the first colonization of the Americas remains unresolved, and the lack of clear-cut substantiation of palaeoart finds predating about 12,000 years bp is conspicuous. There are vague hints of earlier human presence, rendering it likely that archaeology has failed to define its manifestations adequately, and Pleistocene palaeoart remains almost unexplored at this stage.

  5. Ancient divergence time estimates in Eutropis rugifera support the existence of Pleistocene barriers on the exposed Sunda Shelf

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    Benjamin R. Karin

    2017-10-01

    Full Text Available Episodic sea level changes that repeatedly exposed and inundated the Sunda Shelf characterize the Pleistocene. Available evidence points to a more xeric central Sunda Shelf during periods of low sea levels, and despite the broad land connections that persisted during this time, some organisms are assumed to have faced barriers to dispersal between land-masses on the Sunda Shelf. Eutropis rugifera is a secretive, forest adapted scincid lizard that ranges across the Sunda Shelf. In this study, we sequenced one mitochondrial (ND2 and four nuclear (BRCA1, BRCA2, RAG1, and MC1R markers and generated a time-calibrated phylogeny in BEAST to test whether divergence times between Sundaic populations of E. rugifera occurred during Pleistocene sea-level changes, or if they predate the Pleistocene. We find that E. rugifera shows pre-Pleistocene divergences between populations on different Sundaic land-masses. The earliest divergence within E. rugifera separates the Philippine samples from the Sundaic samples approximately 16 Ma; the Philippine populations thus cannot be considered conspecific with Sundaic congeners. Sundaic populations diverged approximately 6 Ma, and populations within Borneo from Sabah and Sarawak separated approximately 4.5 Ma in the early Pliocene, followed by further cladogenesis in Sarawak through the Pleistocene. Divergence of peninsular Malaysian populations from the Mentawai Archipelago occurred approximately 5 Ma. Separation among island populations from the Mentawai Archipelago likely dates to the Pliocene/Pleistocene boundary approximately 3.5 Ma, and our samples from peninsular Malaysia appear to coalesce in the middle Pleistocene, about 1 Ma. Coupled with the monophyly of these populations, these divergence times suggest that despite consistent land-connections between these regions throughout the Pleistocene E. rugifera still faced barriers to dispersal, which may be a result of environmental shifts that accompanied the

  6. Archean komatiite volcanism controlled by the evolution of early continents.

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    Mole, David R; Fiorentini, Marco L; Thebaud, Nicolas; Cassidy, Kevin F; McCuaig, T Campbell; Kirkland, Christopher L; Romano, Sandra S; Doublier, Michael P; Belousova, Elena A; Barnes, Stephen J; Miller, John

    2014-07-15

    The generation and evolution of Earth's continental crust has played a fundamental role in the development of the planet. Its formation modified the composition of the mantle, contributed to the establishment of the atmosphere, and led to the creation of ecological niches important for early life. Here we show that in the Archean, the formation and stabilization of continents also controlled the location, geochemistry, and volcanology of the hottest preserved lavas on Earth: komatiites. These magmas typically represent 50-30% partial melting of the mantle and subsequently record important information on the thermal and chemical evolution of the Archean-Proterozoic Earth. As a result, it is vital to constrain and understand the processes that govern their localization and emplacement. Here, we combined Lu-Hf isotopes and U-Pb geochronology to map the four-dimensional evolution of the Yilgarn Craton, Western Australia, and reveal the progressive development of an Archean microcontinent. Our results show that in the early Earth, relatively small crustal blocks, analogous to modern microplates, progressively amalgamated to form larger continental masses, and eventually the first cratons. This cratonization process drove the hottest and most voluminous komatiite eruptions to the edge of established continental blocks. The dynamic evolution of the early continents thus directly influenced the addition of deep mantle material to the Archean crust, oceans, and atmosphere, while also providing a fundamental control on the distribution of major magmatic ore deposits.

  7. The Sima de los Huesos (Burgos, northern Spain): palaeoenvironment and habitats of Homo heidelbergensis during the Middle Pleistocene

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    García, Nuria; Arsuaga, Juan Luis

    2011-06-01

    Interpreting how environmental dynamics respond to global climate change and how this has affected human evolution and dispersal is an on-going topic of debate. During the early Middle Pleistocene (˜0.6-0.4 Ma), as compared to earlier, environmental conditions were relatively more stable, with longer climatic cycles alternating between open and forested landscapes. During this interval, humans spread successfully providing an important number of fossil sites where fossils or tools are reported. The Atapuerca-Sima de los Huesos (Burgos, northern Spain) site (Atapuerca-SH) is one of the earliest localities with hominin evidence in the European Middle Pleistocene, with the most important accumulation of Homo heidelbergensis so far. We have analyzed the abundant faunal record from Sima de los Huesos, which is mainly comprised of carnivores, in order to approach an interpretation of the palaeoenvironmental circumstances where these hominids inhabited within the Sierra. Other sites from Sierra de Atapuerca referred to the same Faunal Unit (FU 6), are roughly contemporaneous, and include important ungulates, which are here analyzed with Atapuerca-SH. Additional information provided by isotopic analysis helps elucidate the ancient ecology of taxa present in Sima de los Huesos allowing for an accurate portrayal of the setting in which humans lived. The timing of the spread of Homo heidelbergensis is dominated by a relative climatic and environmental stability and points to a landscape dominated by savannah-like open woodland.

  8. From Pleistocene to Holocene: the prehistory of southwest Asia in evolutionary context.

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    Watkins, Trevor

    2017-08-14

    In this paper I seek to show how cultural niche construction theory offers the potential to extend the human evolutionary story beyond the Pleistocene, through the Neolithic, towards the kind of very large-scale societies in which we live today. The study of the human past has been compartmentalised, each compartment using different analytical vocabularies, so that their accounts are written in mutually incompatible languages. In recent years social, cognitive and cultural evolutionary theories, building on a growing body of archaeological evidence, have made substantial sense of the social and cultural evolution of the genus Homo. However, specialists in this field of studies have found it difficult to extend their kind of analysis into the Holocene human world. Within southwest Asia the three or four millennia of the Neolithic period at the beginning of the Holocene represents a pivotal point, which saw the transformation of human society in the emergence of the first large-scale, permanent communities, the domestication of plants and animals, and the establishment of effective farming economies. Following the Neolithic, the pace of human social, economic and cultural evolution continued to increase. By 5000 years ago, in parts of southwest Asia and northeast Africa there were very large-scale urban societies, and the first large-scale states (kingdoms). An extension of cultural niche construction theory enables us to extend the evolutionary narrative of the Pleistocene into the Holocene, opening the way to developing a single, long-term, evolutionary account of human history.

  9. The Evolution of Northern Hemisphere Glaciation

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    Wright, J. D.

    2001-05-01

    For much of the last 50 million years, high-latitude regions remained too warm to allow snow to accumulate and form ice sheets. Shackleton et al. (1984) published a landmark paper correlating the first occurrence of ice-rafted detritus (IRD) observed at Rockall Plateau with a prominent increase in benthic foraminiferal d18O values during the late Pliocene. These late Pliocene to Pleistocene ice sheets were modulated on an orbital frequency and have characterized the global climate over the past 2.6 myr (Shackleton and Opdyke, 1973; Shackleton et al., 1984; Ruddiman, et al., 1986). During the early Pliocene, northern hemisphere glaciation (NHG) variations were less significant (Jansen et al., 1993). Our understanding of the Plio-Pleistocene ice sheet cycles can be viewed from two different perspectives. When viewed from the late Pleistocene, the fundamental question is what changed near the early/late Pliocene boundary to produce the large-scale, glacial-interglacial cycles of the past 2.6 Ma. In contrast, the view from the middle to late Miocene is quite different. Since the pioneering work of Shackleton et al. (1984), the record of NHG has been extended further back in time with drilling in the Norwegian Sea (ODP Leg 104). At Sites 642 and 644, IRD was found throughout the late Miocene and back to ~12 Ma. More recent drilling in the high northern latitudes occurred on ODP Leg 151. Site 909 recovered a middle Miocene section from the Fram Straits with rounded quartz grains that were interpreted as IRD (Wolf-Welling et al., 1996). Age estimates for those sediments place the first northern hemisphere ice sheets at least as old as 14 Ma. The occurrence of sand-sized particles (>1000 μm) and coal below this level indicates the possibility of glacial activity in the Northern Hemisphere as early as 16 Ma. Thus, the late Pliocene to Pleistocene cycles appear to be the resumption of the glacial-interglacial pattern that began during the Miocene. While the Miocene ice

  10. Latest Pleistocene and Holocene surficial deposits and landforms of Yosemite Valley, California

    Science.gov (United States)

    Haddon, E. K.; Stock, G. M.; Booth, D. B.

    2016-12-01

    Field studies on the surficial geology and geomorphology of Yosemite Valley since the 1870's formed an early basis for our understanding of Quaternary landscape evolution in the central Sierra Nevada. These landmark studies described the erosional origin of Yosemite's iconic scenery, but left details of the latest Pleistocene and Holocene sedimentary record for later investigation. We combined mapping of deposits and landforms with geochronology to reconstruct the geomorphic evolution of Yosemite Valley since the 15 ka retreat of the Last Glacial Maximum (LGM) valley glacier. We document a sustained period of relative landscape stability, characterized by valley-bottom aggradation of glacial till, fluvial sediments, and lacustrine silts, as well as valley-margin accumulation of talus and fan alluvium. Recessional moraines, episodically emplaced rock avalanches, and alluvial fans impeded surface flow and controlled the local base level. This predominantly aggradational regime then shifted to incision in the earliest Holocene, likely due to a diminishing supply of glacial sediment, and created a flight of fluvial terraces inset by up to 9 m. The volume of fringing talus and fan alluvium in comparison with fluvial terrace sequences emphasizes the importance of valley-wall erosion as a sediment source. Cosmogenic 10Be exposure ages from rock avalanche boulders and 14C charcoal ages from deltaic sequences and inset fluvial gravels suggest variable rates of Holocene river incision. Although some incision events likely record local base level changes at the El Capitan LGM recessional moraine, the presence of perched, well-developed outwash terraces downstream indicates a more regional climatic forcing. These findings, including the depositional record of land-use disturbances over the past two centuries, help illuminate the geologic evolution of this celebrated landscape and inform ongoing river-restoration work.

  11. Early Microbial Evolution: The Age of Anaerobes.

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    Martin, William F; Sousa, Filipa L

    2015-12-18

    In this article, the term "early microbial evolution" refers to the phase of biological history from the emergence of life to the diversification of the first microbial lineages. In the modern era (since we knew about archaea), three debates have emerged on the subject that deserve discussion: (1) thermophilic origins versus mesophilic origins, (2) autotrophic origins versus heterotrophic origins, and (3) how do eukaryotes figure into early evolution. Here, we revisit those debates from the standpoint of newer data. We also consider the perhaps more pressing issue that molecular phylogenies need to recover anaerobic lineages at the base of prokaryotic trees, because O2 is a product of biological evolution; hence, the first microbes had to be anaerobes. If molecular phylogenies do not recover anaerobes basal, something is wrong. Among the anaerobes, hydrogen-dependent autotrophs--acetogens and methanogens--look like good candidates for the ancestral state of physiology in the bacteria and archaea, respectively. New trees tend to indicate that eukaryote cytosolic ribosomes branch within their archaeal homologs, not as sisters to them and, furthermore tend to root archaea within the methanogens. These are major changes in the tree of life, and open up new avenues of thought. Geochemical methane synthesis occurs as a spontaneous, abiotic exergonic reaction at hydrothermal vents. The overall similarity between that reaction and biological methanogenesis fits well with the concept of a methanogenic root for archaea and an autotrophic origin of microbial physiology. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

  12. Multiplicity in Early Stellar Evolution

    Science.gov (United States)

    Reipurth, B.; Clarke, C. J.; Boss, A. P.; Goodwin, S. P.; Rodríguez, L. F.; Stassun, K. G.; Tokovinin, A.; Zinnecker, H.

    Observations from optical to centimeter wavelengths have demonstrated that multiple systems of two or more bodies is the norm at all stellar evolutionary stages. Multiple systems are widely agreed to result from the collapse and fragmentation of cloud cores, despite the inhibiting influence of magnetic fields. Surveys of class 0 protostars with millimeter interferometers have revealed a very high multiplicity frequency of about 2/3, even though there are observational difficulties in resolving close protobinaries, thus supporting the possibility that all stars could be born in multiple systems. Near-infrared adaptive optics observations of class I protostars show a lower binary frequency relative to the class 0 phase, a declining trend that continues through the class II/III stages to the field population. This loss of companions is a natural consequence of dynamical interplay in small multiple systems, leading to ejection of members. We discuss observational consequences of this dynamical evolution, and its influence on circumstellar disks, and we review the evolution of circumbinary disks and their role in defining binary mass ratios. Special attention is paid to eclipsing PMS binaries, which allow for observational tests of evolutionary models of early stellar evolution. Many stars are born in clusters and small groups, and we discuss how interactions in dense stellar environments can significantly alter the distribution of binary separations through dissolution of wider binaries. The binaries and multiples we find in the field are the survivors of these internal and external destructive processes, and we provide a detailed overview of the multiplicity statistics of the field, which form a boundary condition for all models of binary evolution. Finally, we discuss various formation mechanisms for massive binaries, and the properties of massive trapezia.

  13. Early evolution of Tubulogenerina during the Paleogene of Europe

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    Gibson, T.G.; Barbin, V.; Poignant, A.; Sztrakos, K.

    1991-01-01

    The early evolution of Tubulogenerina took place in Europe where eight species occur in lower Eocene to uppermost Oligocene or lower Miocene strata. Species diversity within Tubulogenerina dropped significantly in the early Oligocne; only a single species persisted from the late Eocene, and it became extinct before the end of the early Oligocene. Morphologic changes during the European phylogeny of Tubulogenerina include (1) the development of costate and more complex tubulopore ornamentation, and (2) the change from a single elongated apertural slit with a single toothplate to multiple apertures and toothplates. Three new Tubulogenerina species are described. -from Authors

  14. Effects of climatic and geological processes during the pleistocene on the evolutionary history of the northern cavefish, Amblyopsis spelaea (teleostei: amblyopsidae).

    Science.gov (United States)

    Niemiller, Matthew L; McCandless, James R; Reynolds, R Graham; Caddle, James; Near, Thomas J; Tillquist, Christopher R; Pearson, William D; Fitzpatrick, Benjamin M

    2013-04-01

    Climatic and geological processes associated with glaciation cycles during the Pleistocene have been implicated in influencing patterns of genetic variation and promoting speciation of temperate flora and fauna. However, determining the factors promoting divergence and speciation is often difficult in many groups because of our limited understanding of potential vicariant barriers and connectivity between populations. Pleistocene glacial cycles are thought to have significantly influenced the distribution and diversity of subterranean invertebrates; however, impacts on subterranean aquatic vertebrates are less clear. We employed several hypothesis-driven approaches to assess the impacts of Pleistocene climatic and geological changes on the Northern Cavefish, Amblyopsis spelaea, whose current distribution occurs near the southern extent of glacial advances in North America. Our results show that the modern Ohio River has been a significant barrier to dispersal and is correlated with patterns of genetic divergence. We infer that populations were isolated in two refugia located north and south of the Ohio River during the most recent two glacial cycles with evidence of demographic expansion in the northern isolate. Finally, we conclude that climatic and geological processes have resulted in the formation of cryptic forms and advocate recognition of two distinct phylogenetic lineages currently recognized as A. spelaea. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  15. Open Listening: Creative Evolution in Early Childhood Settings

    Science.gov (United States)

    Davies, Bronwyn

    2011-01-01

    This article sketches out a philosophy and practice of open listening, linking open listening to Bergson's (1998) concept of creative evolution. I draw on examples of small children at play from a variety of sources, including Reggio-Emilia-inspired preschools in Sweden. The article offers a challenge to early childhood educators to listen and to…

  16. Pleistocene changes in the fauna and flora of South america.

    Science.gov (United States)

    Vuilleumier, B S

    1971-08-27

    In recent years, the view that Pleistocene climatic events played a major role in the evolution of the biotas of southern, primarily tropical continents has begun to displace the previously held conviction that these areas remained relatively stable during the Quaternary. Studies of speciation patterns of high Andean plant and avian taxa (7-14) have led to the conclusion that Pleistocene climatic events were the factors that ultimately shaped the patterns now observed in the paramo-puna and the related Patagonian flora and fauna. The final uplift of the Andes at the end of the Tertiary automatically limits the age of the high Andean habitats and their biotas to the Quaternary. Within this period, the number of ecological fluctuations caused by the glaciations could easily have provided the mechanism behind the patterns now present in these habitats (Appendix, 1; Figs. 1 and 2; Table 1). In glacial periods, when vegetation belts, were lowered, organisms in the paramo-puna habitat were allowed to expand their ranges. In interglacial periods, these taxa were isolated on disjunct peaks, where differentiation could occur. At times of ice expansion, glacial tongues and lakes provided local barriers to gene exchange, whereas in warm, interglacial times, dry river valleys were a major deterrent to the interbreeding of populations on different mountains (Fig. 2; Table 2). A preliminary analysis of about 10 to 12 percent of the total South American avifauna (14), subsequent to the study of the high Andean biota, suggested that the birds of all the major habitats of the continent possess, with about equal frequency, similar stages of speciation. This correspondence in levels of evolution indicated that the avifauna of vegetation zones which were thought to have been more stable (for example, tropical rainforests) are as actively speciating as are those of the more recent paramo-puna habitats. More intensive work on lowland tropical taxa (16, 19-21) and recent work on montane

  17. The early evolution of the Archegoniatae: a re-appraisal

    NARCIS (Netherlands)

    Meeuse, A.D.J.

    1966-01-01

    After a re-appraisal of the alternative hypotheses concerning the origin and the early evolution of the archegoniate land plants, the postulation of a thalassiophytic group of precursors with free isomorphic alternating generations by Church, Zimmermann, and several others is rejected. Several

  18. Plio-Pleistocene landscape and vegetation reconstruction of the coastal area of the Tjörnes Peninsula, Northern Iceland

    DEFF Research Database (Denmark)

    Verhoeven, Koen; Louwye, Stephen; Eiriksson, Jón

    2013-01-01

    Marine and continental deposits from the Tjornes area in northern Iceland were studied to obtain their pollen/spore content. Six Pollen Zones (PZ) were defined in the Early Pliocene Tjornes beds and the Early Pleistocene Breidavik Group. The pollen is most diverse during the deposition of the low......Marine and continental deposits from the Tjornes area in northern Iceland were studied to obtain their pollen/spore content. Six Pollen Zones (PZ) were defined in the Early Pliocene Tjornes beds and the Early Pleistocene Breidavik Group. The pollen is most diverse during the deposition...... of the lowest Tapes Zone (PZ 1) and the lower part of the overlying Mactra Zone (PZ 2). Local pollen from marshland, levee and foothill forests was deposited on a large coastal plain. The pollen spectrum reflects transgression and deepening during the second part of the Mactra Zone (PZ 3) and the lower part...... of the Serripes Zone (PZ 4). Gymnosperm pollen derived from the higher inland plateau increases in PZ 3. This background pollen was of minor importance during periods with an extensive coastal plain (PZ 1, 2, 4, 6). PZ 5 did not yield sufficient pollen for analysis. The pollen analysis allowed refinement...

  19. The evolution of early-type galaxies in distant clusters

    International Nuclear Information System (INIS)

    Stanford, S.A.; Eisenhardt, P.R.; Dickinson, M.

    1998-01-01

    We present results from an optical-infrared photometric study of early-type (E+S0) galaxies in 19 galaxy clusters out to z=0.9. The galaxy sample is selected on the basis of morphologies determined from Hubble Space Telescope (HST) WFPC2 images and is photometrically defined in the K band in order to minimize redshift-dependent selection biases. Using new ground-based photometry in five optical and infrared bands for each cluster, we examine the evolution of the color-magnitude relation for early-type cluster galaxies, considering its slope, intercept, and color scatter around the mean relation. New multiwavelength photometry of galaxies in the Coma Cluster is used to provide a baseline sample at z∼0 with which to compare the distant clusters. The optical - IR colors of the early-type cluster galaxies become bluer with increasing redshift in a manner consistent with the passive evolution of an old stellar population formed at an early cosmic epoch. The degree of color evolution is similar for clusters at similar redshift and does not depend strongly on the optical richness or X-ray luminosity of the cluster, which suggests that the history of early-type galaxies is relatively insensitive to environment, at least above a certain density threshold. The slope of the color-magnitude relationship shows no significant change out to z=0.9, which provides evidence that it arises from a correlation between galaxy mass and metallicity, not age. Finally, the intrinsic scatter in the optical - IR colors of the galaxies is small and nearly constant with redshift, which indicates that the majority of giant, early-type galaxies in clusters share a common star formation history, with little perturbation due to uncorrelated episodes of later star formation. Taken together, our results are consistent with models in which most early-type galaxies in rich clusters are old, formed the majority of their stars at high redshift in a well-synchronized fashion, and evolved quiescently

  20. Magma evolution in the Pliocene Pleistocene succession of Kos, South Aegean arc (Greece)

    Science.gov (United States)

    Pe-Piper, Georgia; Moulton, Ben

    2008-11-01

    This study investigates the petrogenesis of Pliocene-Quaternary andesites, dacites and rhyolites of the island of Kos. These volcanic rocks differ from other volcanic centres in the South Aegean arc in the narrow range of Pliocene volcanic products, the abundance of high-silica rhyolite, the lower ɛNd for a given Sr isotope composition, and greater depth to the subducting slab. Pliocene and early Pleistocene dacite stocks and rhyolite domes are succeeded by younger tuffs, notably the 0.16 Ma Kos Plateau Tuff derived from a super-eruption of an andesite stratocone now subsided beneath the sea south of Kos. Volcanic products in tuffs have been sampled from lithic clasts. Andesite, dacite and rhyolite all have ɛNd ˜+ 1.5 to -1.5 and 86Sr/ 87Sr ˜ 0.7042; this unusual composition is argued to be the result of subduction of sediments derived from the River Nile. All rock types show structures indicative of widespread magma mixing, including complexly zoned plagioclase, clinopyroxene and amphibole containing glass inclusions of trachyte and rhyolite compositions. The observed rocks result from fractionation and mixing of three principal magma types: (a) calc-alkaline high-Al basalt that fractionated to andesite at the base of crust; (b) partially melted metabasaltic amphibolite underplated at the base of crust, that fractionated to produce high-SiO 2 rhyolite; and (c) a minor component of trachytic magma from partial melting of enriched subcontinental lithospheric mantle. The complexly zoned phenocrysts with glass inclusions provide specific evidence for mixing of these three components. Specifically, it was the emplacement of the andesite into a voluminous rhyolite magma in a mid-crustal magma chamber that led to the explosive Kos Plateau Tuff super-eruption.

  1. Expansion of the known distribution of Asiatic mouflon (Ovis orientalis) in the Late Pleistocene of the Southern Levant

    Science.gov (United States)

    Yeomans, Lisa; Martin, Louise; Richter, Tobias

    2017-08-01

    Wild sheep (Ovis orientalis) bones recovered from the Natufian site of Shubayqa 1 demonstrate a wider distribution of mouflon in the Late Pleistocene of the Southern Levant than previously known. Early Epipalaeolithic sites are common in the limestone steppe region of eastern Jordan but have yielded only a handful of caprine bones that cannot be identified to species level and few faunal remains from excavated Late Epipalaeolithic sites have been reported. Analysis of animal bone from Shubayqa 1 suggests a significant population of wild sheep could be found concentrated in the basalt desert environment of eastern Jordan during the Late Pleistocene, especially where higher rainfall over the Jebel Druze provided more water. A population of wild sheep was still present in the Pre-Pottery Neolithic A when the nearby site of Shubayqa 6 was occupied. Hunting of diverse, locally available resources including wild sheep at the end of the Pleistocene illustrates the flexible and adaptive exploitation strategies that hunter-forager groups engaged in. This provides further evidence to the increasing body of data showing the creative and opportunistic approach of terminal Pleistocene groups allowing continued occupation even in more marginal environments in a period of environmental change.

  2. The early evolution of the atmospheres of terrestrial planets

    CERN Document Server

    Raulin, François; Muller, Christian; Nixon, Conor; Astrophysics and Space Science Proceedings : Volume 35

    2013-01-01

    “The Early Evolution of the Atmospheres of Terrestrial Planets” presents the main processes participating in the atmospheric evolution of terrestrial planets. A group of experts in the different fields provide an update of our current knowledge on this topic. Several papers in this book discuss the key role of nitrogen in the atmospheric evolution of terrestrial planets. The earliest setting and evolution of planetary atmospheres of terrestrial planets is directly associated with accretion, chemical differentiation, outgassing, stochastic impacts, and extremely high energy fluxes from their host stars. This book provides an overview of the present knowledge of the initial atmospheric composition of the terrestrial planets. Additionally it includes some papers about the current exoplanet discoveries and provides additional clues to our understanding of Earth’s transition from a hot accretionary phase into a habitable world. All papers included were reviewed by experts in their respective fields. We are ...

  3. Human evolution. Evolution of early Homo: an integrated biological perspective.

    Science.gov (United States)

    Antón, Susan C; Potts, Richard; Aiello, Leslie C

    2014-07-04

    Integration of evidence over the past decade has revised understandings about the major adaptations underlying the origin and early evolution of the genus Homo. Many features associated with Homo sapiens, including our large linear bodies, elongated hind limbs, large energy-expensive brains, reduced sexual dimorphism, increased carnivory, and unique life history traits, were once thought to have evolved near the origin of the genus in response to heightened aridity and open habitats in Africa. However, recent analyses of fossil, archaeological, and environmental data indicate that such traits did not arise as a single package. Instead, some arose substantially earlier and some later than previously thought. From ~2.5 to 1.5 million years ago, three lineages of early Homo evolved in a context of habitat instability and fragmentation on seasonal, intergenerational, and evolutionary time scales. These contexts gave a selective advantage to traits, such as dietary flexibility and larger body size, that facilitated survival in shifting environments. Copyright © 2014, American Association for the Advancement of Science.

  4. Signatures of Late Pleistocene fluvial incision in an Alpine landscape

    Science.gov (United States)

    Leith, Kerry; Fox, Matthew; Moore, Jeffrey R.

    2018-02-01

    Uncertainty regarding the relative efficacy of fluvial and glacial erosion has hindered attempts to quantitatively analyse the Pleistocene evolution of alpine landscapes. Here we show that the morphology of major tributaries of the Rhone River, Switzerland, is consistent with that predicted for a landscape shaped primarily by multiple phases of fluvial incision following a period of intense glacial erosion after the mid-Pleistocene transition (∼0.7 Ma). This is despite major ice sheets reoccupying the region during cold intervals since the mid-Pleistocene. We use high-resolution LiDAR data to identify a series of convex reaches within the long-profiles of 18 tributary channels. We propose these reaches represent knickpoints, which developed as regional uplift raised tributary bedrock channels above the local fluvial baselevel during glacial intervals, and migrated upstream as the fluvial system was re-established during interglacial periods. Using a combination of integral long-profile analysis and stream-power modelling, we find that the locations of ∼80% of knickpoints in our study region are consistent with that predicted for a fluvial origin, while the mean residual error over ∼100 km of modelled channels is just 26.3 m. Breaks in cross-valley profiles project toward the elevation of former end-of-interglacial channel elevations, supporting our model results. Calculated long-term uplift rates are within ∼15% of present-day measurements, while modelled rates of bedrock incision range from ∼1 mm/yr for low gradient reaches between knickpoints to ∼6-10 mm/yr close to retreating knickpoints, typical of observed rates in alpine settings. Together, our results reveal approximately 800 m of regional uplift, river incision, and hillslope erosion in the lower half of each tributary catchment since 0.7 Ma.

  5. A Late Pleistocene clockwise rotation phase of Zakynthos (Greece) and implications for the evolution of the western Aegean arc

    NARCIS (Netherlands)

    Duermeijer, C.E.; Krijgsman, W.; Langereis, C.G.; Meulenkamp, J.E.; Triantaphyllou, M.V.; Zachariasse, W.J.

    1999-01-01

    Palaeomagnetic measurements have been carried out on Eocene to Pleistocene sediments on the Ionian island of Zakynthos, NW Greece. Magnetostratigraphic constraints, biostratigraphic analyses of planktonic foraminifera and calcareous nannofossils provide a reliable time frame for these deposits.

  6. Fossil amphibians and reptiles from Tegelen (Province of Limburg) and the early Pleistocene palaeoclimate of The Netherlands

    Science.gov (United States)

    Villa, Andrea; Blain, Hugues-Alexandre; van den Hoek Ostende, Lars W.; Delfino, Massimo

    2018-05-01

    Few Quaternary herpetofaunas have been recovered from The Netherlands. Among these, the one coming from the early Pleistocene site of the Russel-Tiglia-Egypte pit near Tegelen is of particular interest, because it is the type locality of the recently described, last western European palaeobatrachid anuran, Palaeobatrachus eurydices. The large number of fossil remains of amphibians and reptiles found in the pit are representative of a very diverse fauna, including at least 17 taxa: Triturus gr. T. cristatus, Lissotriton sp., Pelobates fuscus, Bufo bufo, Bombina sp., Pelophylax sp., Rana sp., Hyla gr. H. arborea, Pelodytes sp., Mauremys sp., Lacerta sp., Lacertidae indet., Anguis gr. A. fragilis, cf. Pseudopus sp., "colubrines" indet., Natrix natrix and Vipera sp. Emys orbicularis, previously reported from a different Tegelen pit, is not present in this assemblage. Palaeoclimatic conditions reconstructed based on the herpetofaunistic association indicate a humid subtropical climate (Cfa according to the Köppen-Geiger classification of climates) for Tegelen during the TC5 section of the Tiglian, with low, but fairly regular rainfalls during the year. Mean annual temperature was 13.4 ± 0.3 °C and mean annual precipitation was 542 ± 50 mm. Moreover, three dry months were present during summer and early autumn, resulting in a much drier climate than the one present at Tegelen today. Nevertheless, the occurrence of the water-dwelling P. eurydices suggests the persistence of suitable permanent water bodies during the whole year, and the survival of this taxon in this part of Europe might have been allowed by the generally humid climate.

  7. MEVTV Workshop on Early Tectonic and Volcanic Evolution of Mars

    International Nuclear Information System (INIS)

    Frey, H.

    1988-01-01

    Although not ignored, the problems of the early tectonic and volcanic evolution of Mars have generally received less attention than those later in the evolution of the planet. Specifically, much attention was devoted to the evolution of the Tharsis region of Mars and to the planet itself at the time following the establishment of this major tectonic and volcanic province. By contrast, little attention was directed at fundamental questions, such as the conditions that led to the development of Tharsis and the cause of the basic fundamental dichotomy of the Martian crust. It was to address these and related questions of the earliest evolution of Mars that a workshop was organized under the auspices of the Mars: Evolution of Volcanism, Tectonism, and Volatiles (MEVTV) Program. Four sessions were held: crustal dichotomy; crustal differentiation/volcanism; Tharsis, Elysium, and Valles Marineris; and ridges and fault tectonics

  8. Craniosynostosis in the Middle Pleistocene human Cranium 14 from the Sima de los Huesos, Atapuerca, Spain.

    Science.gov (United States)

    Gracia, Ana; Arsuaga, Juan Luis; Martínez, Ignacio; Lorenzo, Carlos; Carretero, José Miguel; Bermúdez de Castro, José María; Carbonell, Eudald

    2009-04-21

    We report here a previously undescribed human Middle Pleistocene immature specimen, Cranium 14, recovered at the Sima de los Huesos (SH) site (Atapuerca, Spain), that constitutes the oldest evidence in human evolution of a very rare pathology in our own species, lambdoid single suture craniosynostosis (SSC). Both the ecto- and endo-cranial deformities observed in this specimen are severe. All of the evidence points out that this severity implies that the SSC occurred before birth, and that facial asymmetries, as well as motor/cognitive disorders, were likely to be associated with this condition. The analysis of the present etiological data of this specimen lead us to consider that Cranium 14 is a case of isolated SSC, probably of traumatic origin. The existence of this pathological individual among the SH sample represents also a fact to take into account when referring to sociobiological behavior in Middle Pleistocene humans.

  9. Ecospaces occupied by Homo erectus and Homo sapiens in insular Southeast Asia in the Pleistocene

    Science.gov (United States)

    Hertler, Christine; Haupt, Susanne; Volmer, Rebekka; Bruch, Angela

    2014-05-01

    Hominins migrated to the islands of the Sunda Shelf multiple times. At least two immigration events are evident, an early immigration of Homo erectus in the late Early Pleistocene and a second immigration of Homo sapiens during the Late Pleistocene. Regional environments changed considerably in the Pleistocene. Expansion patterns among hominins are at least co-determined by their ecologies and environmental change. We examine these expansion patterns on the basis of habitat reconstructions. Mammalian communities provide a geographically extensive record and permit to assess hominin ecospaces. Although chronological resolution is low, they represent the most complete record of habitat changes associated with hominin expansion patterns. In order to reconstruct and compare hominin ecospaces on a quantitative scale, we set up a reference sample consisting of mammalian communities of 117 national parks in South Asia and Sub-Saharan Africa. The diversity of such communities is assessed by ecological profiling of specialized herbivore taxa. Moreover, datasets on climate and vegetation correlate with the diversity structure of such specialized herbivore communities. Reconstructing the diversity structure of communities at key sites in Pleistocene Southeast Asia permits to infer features of the climatic and vegetation framework associated with different hominin taxa. Our results show that Homo erectus and Homo sapiens did not occupy similar ecospaces. The ecospace of Homo erectus is characterized by comparatively low diversity among frugivorous and folivorous taxa, while obligate grazers are part of the assemblages. Specialized herbivore communities with such a diversity structure occur at present in East Africa, while they are absent in Southeast Asia. In the reference sample, this type of ecospace corresponds to seasonal wetlands. Although Homo sapiens still inhabits this type of environment in Southeast Asia, his ecospace is wider. Homo sapiens is associated with

  10. Late Pleistocene to early Holocene environmental changes on Store Koldewey, coastal north-east Greenland

    Directory of Open Access Journals (Sweden)

    Martin Klug

    2016-12-01

    Full Text Available A lake sediment sequence from southern Store Koldewey, north-east Greenland, has been investigated using a multidisciplinary approach, including geophysical, geochemical, biogeochemical, biological and sedimentological methods. Chronological constraints are provided by accelerator mass spectrometry (AMS 14C dating of bulk sediment and complemented with published water moss ages. The record consists of three major sediment units. Their individual structural, textural, geophysical and geochemical characteristics indicate variable input of sediment and meltwater due to variable proximity of the ice margin and therefore reflect the growth and decay of a local glacier during the late Weichselian. Radiocarbon dating of bulk sediment samples from the lowermost unit gave ages of 42 to 34 calibrated thousand years (cal Ky B.P. and indicates that this material is redeposited in the lake basin during or after the ice advance at the end of the Pleistocene. Increased meltwater and sediment input from a retreating ice margin following the Younger Dryas is indicated by the occurrence of a sandy to gravely section. Fine-grained and laminated sediments were deposited during the Pleistocene–Holocene transition and indicate calm sedimentation conditions with an ice margin outside of the lake catchment. The reoccurrence of coarse sediments during the early Holocene may indicate increased meltwater input in response to the cold spell at about 9.3 Kya with increased snow accumulation rather than fluctuations of local glaciers. The dating results furthermore show that AMS 14C dating of bulk sediment samples deposited during glacier decay in High Arctic environments can give problematic ages.

  11. Evolution of the Puente Hills Thrust Fault

    Science.gov (United States)

    Bergen, K. J.; Shaw, J. H.; Dolan, J. F.

    2013-12-01

    This study aims to assess the evolution of the blind Puente Hills thrust fault system (PHT) by determining its age of initiation, lateral propagation history, and changes in slip rate over time. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. The PHT is comprised of three fault segments: the Los Angeles (LA), Santa Fe Springs (SFS), and Coyote Hills (CH). The LA and SFS segments are characterized by growth stratigraphy where folds formed by uplift on the fault segments have been continually buried by sediment from the Los Angeles and San Gabriel rivers. The CH segment has developed topography and is characterized by onlapping growth stratigraphy. This depositional setting gives us the unique opportunity to measure uplift on the LA and SFS fault segments, and minimum uplift on the CH fault segment, as the difference in sediment thicknesses across the buried folds. We utilize depth converted oil industry seismic reflection data to image the fold geometries. Identifying time-correlative stratigraphic markers for slip rate determination in the basin has been a problem for researchers in the past, however, as the faunal assemblages observed in wells are time-transgressive by nature. To overcome this, we utilize the sequence stratigraphic model and well picks of Ponti et al. (2007) as a basis for mapping time-correlative sequence boundaries throughout our industry seismic reflection data from the present to the Pleistocene. From the Pleistocene to Miocene we identify additional sequence boundaries in our seismic reflection data from imaged sequence geometries and by correlating industry well formation tops. The sequence and formation top picks are then used to build 3-dimensional surfaces in the modeling program Gocad. From these surfaces we measure the change in thicknesses across the folds to obtain uplift rates between each sequence boundary. Our results show three distinct phases of

  12. A ~600 kyr duration Early Pleistocene record from the West Turkana (Kenya) HSPDP drill site: elemental XRF variability to reconstruct climate change in Turkana Boy's backyard

    Science.gov (United States)

    Stockhecke, M.; Beck, C. C.; Brown, E. T.; Cohen, A.; Deino, A. L.; Feibel, C. S.; Sier, M.

    2015-12-01

    Outcrops in the Kenyan and Ethiopian rift valleys document repeated occurrences of freshwater lakes and wooded landscapes over the past 4 million years at locations that are currently seasonally-dry savanna. Studies of the rich fossil records, in combination with outcropping lacustrine sequences, led to major breakthroughs in our knowledge of driving factors in human evolution. However, study of continuous drill core from ancient lake basins provides a basis for to unravel East African climate dynamics in an unseen fashion. The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project, recovered ~2 km of drill core since 2012. A major project goal is characterization of East African paleoclimate in order to evaluate its impact on hominin evolution. XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the HSPDP records contain complex lithologies reflecting repeated episodes of inundation and desiccation of the lake basins. Nevertheless, careful data evaluation based on detailed lithostratigraphy, which includes smear-slide microscopic analyses and X-radiographic images, allows disentanglement of complex signals and robust identification of continuous sequences for any cyclostratigraphic and statistical analysis. At the HSPDP Turkana Basin site a 175.6 m-long core the covers the Early Pleistocene time window during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. This drill site carries particular interest as it is located in only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Turkana Boy). Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive and environmentally meaningful paleoclimate timeseries

  13. Biogeography and molar morphology of Pleistocene African elephants: new evidence from Elandsfontein, Western Cape Province, South Africa

    Science.gov (United States)

    Smith, Kathlyn M.; Stynder, Deano D.

    2015-05-01

    Elandsfontein (EFT) is a Middle Pleistocene archaeological/paleontological site located in the Western Cape Province of South Africa. The largest herbivore in the assemblage is Loxodonta atlantica zulu, an extinct member of the genus that includes modern African elephants. No Elephas recki specimens were recovered at EFT, despite their common occurrence in other regions of Africa at the same time. Because E. recki and L. atlantica molars are similar in appearance, but the two species are traditionally viewed as dominating different regions of Africa during the Pleistocene, isolated molars may on occasions have been assessed to species level on the basis of geography rather than morphology. The last morphologic evaluation of EFT elephants was conducted in the 1970s, and revisiting this issue with new specimens provides added insight into the evolution of elephants in Africa. Reevaluating morphological characteristics of EFT elephant molars, through qualitative and quantitative description and comparison with Middle Pleistocene E. recki recki, L. atlantica atlantica, and L. atlantica zulu molar morphology, corroborates assessment of EFT elephants as L. a. zulu. Two recently discovered, previously undescribed molars from EFT show that molars of L. a. zulu exhibit greater variation in enamel thickness, lamellar frequency, and occlusal surface morphology than previously reported. An update of the Pleistocene biogeography of Loxodonta and Elephas indicates that fossil remains of both are often found at the same localities in eastern Africa. Their rare co-occurrences in the north and south, however, suggest geographic separation of the two genera in at least some regions of Africa, which may have been based on habitat preference.

  14. Pleistocene megafaunal interaction networks became more vulnerable after human arrival.

    Science.gov (United States)

    Pires, Mathias M; Koch, Paul L; Fariña, Richard A; de Aguiar, Marcus A M; dos Reis, Sérgio F; Guimarães, Paulo R

    2015-09-07

    The end of the Pleistocene was marked by the extinction of almost all large land mammals worldwide except in Africa. Although the debate on Pleistocene extinctions has focused on the roles of climate change and humans, the impact of perturbations depends on properties of ecological communities, such as species composition and the organization of ecological interactions. Here, we combined palaeoecological and ecological data, food-web models and community stability analysis to investigate if differences between Pleistocene and modern mammalian assemblages help us understand why the megafauna died out in the Americas while persisting in Africa. We show Pleistocene and modern assemblages share similar network topology, but differences in richness and body size distributions made Pleistocene communities significantly more vulnerable to the effects of human arrival. The structural changes promoted by humans in Pleistocene networks would have increased the likelihood of unstable dynamics, which may favour extinction cascades in communities facing extrinsic perturbations. Our findings suggest that the basic aspects of the organization of ecological communities may have played an important role in major extinction events in the past. Knowledge of community-level properties and their consequences to dynamics may be critical to understand past and future extinctions. © 2015 The Author(s).

  15. Pleistocene North African genomes link Near Eastern and sub-Saharan African human populations.

    Science.gov (United States)

    van de Loosdrecht, Marieke; Bouzouggar, Abdeljalil; Humphrey, Louise; Posth, Cosimo; Barton, Nick; Aximu-Petri, Ayinuer; Nickel, Birgit; Nagel, Sarah; Talbi, El Hassan; El Hajraoui, Mohammed Abdeljalil; Amzazi, Saaïd; Hublin, Jean-Jacques; Pääbo, Svante; Schiffels, Stephan; Meyer, Matthias; Haak, Wolfgang; Jeong, Choongwon; Krause, Johannes

    2018-05-04

    North Africa is a key region for understanding human history, but the genetic history of its people is largely unknown. We present genomic data from seven 15,000-year-old modern humans, attributed to the Iberomaurusian culture, from Morocco. We find a genetic affinity with early Holocene Near Easterners, best represented by Levantine Natufians, suggesting a pre-agricultural connection between Africa and the Near East. We do not find evidence for gene flow from Paleolithic Europeans to Late Pleistocene North Africans. The Taforalt individuals derive one-third of their ancestry from sub-Saharan Africans, best approximated by a mixture of genetic components preserved in present-day West and East Africans. Thus, we provide direct evidence for genetic interactions between modern humans across Africa and Eurasia in the Pleistocene. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  16. Early Stages of the Evolution of Life: a Cybernetic Approach

    Science.gov (United States)

    Melkikh, Alexey V.; Seleznev, Vladimir D.

    2008-08-01

    Early stages of the evolution of life are considered in terms of control theory. A model is proposed for the transport of substances in a protocell possessing the property of robustness with regard to changes in the environmental concentration of a substance.

  17. BIOCHRONOLOGY OF SELECTED MAMMALS, MOLLUSCS AND OSTRACODS FROM THE MIDDLE PLIOCENE TO THE LATE PLEISTOCENE IN ITALY. THE STATE OF THE ART

    Directory of Open Access Journals (Sweden)

    E. GLIOZZI

    1997-11-01

    Full Text Available The Authors have elaborated four range charts of mammalian (large and micro, molluscs and fresh-water and brackish ostracodes faunas, for the selected Plio-Pleistocene fossiliferous localities of the Italy. A new Mammal Age (Aurelian correlatable to late Middle and Late Pleistocene has been defined. Inside this age two Faunal Units (Torre in Pietra and Vitinia have been defined as characteristic for Early and Middle Aurelian, while no gisements have been chosen for the late Aurelian. Biochronological units are calibrated on magnetostratigraphic and isotopic scales and by radiometric datings.    

  18. THE ROLE OF DUST IN THE EARLY UNIVERSE. I. PROTOGALAXY EVOLUTION

    International Nuclear Information System (INIS)

    Yamasawa, Daisuke; Habe, Asao; Kozasa, Takashi; Nozawa, Takaya; Nomoto, Ken'ichi; Hirashita, Hiroyuki; Umeda, Hideyuki

    2011-01-01

    We develop one-zone galaxy formation models in the early universe, taking into account dust formation and evolution by supernova (SN) explosions. We focus on the time evolution of dust size distribution, because H 2 formation on the dust surface plays a critical role in the star formation process in the early universe. In the model, we assume that star formation rate (SFR) is proportional to the total amount of H 2 . We consistently treat (1) the formation and size evolution of dust, (2) the chemical reaction networks including H 2 formation both on the surface of dust and in gas phase, and (3) the SFR in the model. First, we find that, because of dust destruction due to both reverse and forward shocks driven by SNe, H 2 formation is more suppressed than in situations without such dust destruction. At the galaxy age of ∼0.8 Gyr, for galaxy models with virial mass M vir = 10 9 M sun and formation redshift z vir = 10, the molecular fraction is 2.5 orders of magnitude less in the model with dust destruction by both shocks than that in the model without dust destruction. Second, we show that the H 2 formation rate strongly depends on the interstellar medium (ISM) density around SN progenitors. The SFR in higher ISM density is lower, since dust destruction by reverse shocks is more effective in higher ISM density. We conclude that not only the amount but also the size distribution of dust related to star formation activity strongly affects the evolution of galaxies in the early universe.

  19. A taxonomic revision of the Pleistocene Hystrix (Hystricidae, Rodentia) from Eurasia with notes on the evolution of the family

    NARCIS (Netherlands)

    Weers, van D.J.

    2005-01-01

    Measurements of many hundreds of the high-crowned cheek teeth of Hystrix specimens from the Euro-Asiatic Pleistocene in the collections of European and Asiatic institutions have been compared with extant species for a revision of the genus. A review is given about the extant genera and species of

  20. Lethal Interpersonal Violence in the Middle Pleistocene

    OpenAIRE

    Sala, Nohemi; Arsuaga, Juan Luis; Pantoja-P?rez, Ana; Pablos, Adri?n; Mart?nez, Ignacio; Quam, Rolf M.; G?mez-Olivencia, Asier; Berm?dez de Castro, Jos? Mar?a; Carbonell, Eudald

    2015-01-01

    Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force ...

  1. Upper Pleistocene and Holocene palaeoenvironmental records in Cueva Mayor karst (Atapuerca, Spain from different proxies: speleothem crystal fabrics, palynology and archaeology.

    Directory of Open Access Journals (Sweden)

    Virginia Martínez-Pillado

    2014-01-01

    Full Text Available The Cueva Mayor karst system of Atapuerca, in Northern Spain, hosts a highly significant record of human occupation from the Pleistocene. The climatic context of the human activities during the Pleistocene-Holocene for this inland site has not been well constrained, since existing records of the palaeoclimatic evolution of the Northern Iberian Peninsula are from more distal coastal and high-elevation sites. In this study, we interpret the palaeoenvironmental information recorded on the petrography of a stalagmite and the pollen spectra of the Sierra de Atapuerca karst system during the last 20 kyr. The integration of both types of records has allowed us to define four palaeoenvironmental stages. During the Upper Pleistocene and until 12.8 kyr BP, the climate was cold and dry, toward the end of the interval evolving to wetter and warmer conditions. From 12.8 to 7.7 kyr BP, during the Mesolithic-Neolithic, a major erosion event in both records marks the Pleistocene-Holocene transition. Around 5.9 kyr BP, the Late Neolithic, environmental conditions indicate a climatic optimum with a marked seasonality. The environmental conditions became drier from 4.2 kyr BP until the present, with a decrease in the woodlands. This aridity signal might be amplified by the impact of a more intense human agricultural activity after 3.1 kyr BP, during the Bronze Age.

  2. Middle Pleistocene palaeoenvironmental changes of the eastern Canary Islands - revealed by the Mála dune-palaeosol-sequence at Lanzarote (Canary Islands)

    Science.gov (United States)

    von Suchodoletz, H.; Zöller, L.; Hilgers, A.; Radtke, U.; Faust, D.

    2012-04-01

    The Canary Islands are located at the transition between the Mediterranean and the Saharan climate off NW-Africa. Thus, they are a key area for the investigation of palaeoenvironmental changes. Several terrestrial studies investigated the palaeoenvironmental development of that region during the later part of the last glacial cycle. However, apart from recent investigations of "vega" sediments on Lanzarote Island (Suchodoletz et al. 2010) the palaeoenvironmental evolution during the Middle Pleistocene is hardly studied yet, basically due to the lack of reliable geochronological data. The Mála dune-palaeosol-sequence is located in the north of Lanzarote. It consists of marine shell detritus originally blown out from the insular shelf during periods of low global sea level, and to a small part of Saharan dust and fine quartz sand. The aeolian layers are intercalated with up to eight silty-clayey palaeosol horizons. Unlike the dune sands, the soils indicate stable landscape conditions with trapping of Saharan dust. Using a combination of ESR and luminescence dating techniques, we are able to place this sequence into the Middle Pleistocene, in contrast to former investigations based on 14C datings postulating a Late Pleistocene age (Ortiz et al. 2006). As a consequence, clayey-silty palaeosols represent periods of stable landscape conditions in the Canarian region during the Middle Pleistocene, which we compare with marine palaeoclimatic studies from the area.

  3. TERRESTRIAL EFFECTS OF NEARBY SUPERNOVAE IN THE EARLY PLEISTOCENE

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, B. C.; Engler, E. E. [Department of Physics and Astronomy, Washburn University, Topeka, KS 66621 (United States); Kachelrieß, M. [Institutt for fysikk, NTNU, Trondheim (Norway); Melott, A. L. [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States); Overholt, A. C. [Department of Science and Mathematics, MidAmerica Nazarene University, Olathe, KS 66062 (United States); Semikoz, D. V., E-mail: brian.thomas@washburn.edu [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, F-119 75205 Paris (France)

    2016-07-20

    Recent results have strongly confirmed that multiple supernovae happened at distances of ∼100 pc, consisting of two main events: one at 1.7–3.2 million years ago, and the other at 6.5–8.7 million years ago. These events are said to be responsible for excavating the Local Bubble in the interstellar medium and depositing {sup 60}Fe on Earth and the Moon. Other events are indicated by effects in the local cosmic ray (CR) spectrum. Given this updated and refined picture, we ask whether such supernovae are expected to have had substantial effects on the terrestrial atmosphere and biota. In a first look at the most probable cases, combining photon and CR effects, we find that a supernova at 100 pc can have only a small effect on terrestrial organisms from visible light and that chemical changes such as ozone depletion are weak. However, tropospheric ionization right down to the ground, due to the penetration of ≥TeV CRs, will increase by nearly an order of magnitude for thousands of years, and irradiation by muons on the ground and in the upper ocean will increase twentyfold, which will approximately triple the overall radiation load on terrestrial organisms. Such irradiation has been linked to possible changes in climate and increased cancer and mutation rates. This may be related to a minor mass extinction around the Pliocene-Pleistocene boundary, and further research on the effects is needed.

  4. On the Paleobiogeography of Pleistocenic Italian Mammals / Osservazioni sulla paleobiogeografia dei mammiferi del Pleistocene italiano

    Directory of Open Access Journals (Sweden)

    Lucia Caloi

    1986-06-01

    Full Text Available Abstract In this paper the main Italian Pleistocene mammalofaunas are examined and a chronological sequence of the main deposits is proposed. Centers of spreading, times of first appearence in Italy and ranges through the peninsula of the more representative species are indicated, as far as possible. The insular faunas and the different degrees of endemism they show, are particularly discussed. Riassunto Vengono esaminate sinteticamente le principali faune a mammiferi del Pleistocene d'Italia e viene proposta una successione cronologica per i principali giacimenti. Per le specie più rappresentative vengono indicati, per quanto possibile, le aree di provenienza, il momento della comparsa e la loro diffusione nella penisola. Particolare attenzione viene posta alle forme insulari ed al loro carattere endemico.

  5. On the limits of using combined U-series/ESR method to date fossil teeth from two Early Pleistocene archaeological sites of the Orce area (Guadix-Baza basin, Spain)

    International Nuclear Information System (INIS)

    Duval, Mathieu; Falgueres, Christophe; Bahain, Jean-Jacques; Shao, Qingfeng; Grun, Rainer; Aubert, Maxime; Dolo, Jean-Michel; Agusti, Jordi; Martinez-Navarro, Bienvenido; Palmqvist, Paul; Toro-Moyano, Isidro

    2012-01-01

    The combined U-series/electron spin resonance (ESR) dating method was applied to nine teeth from two Early Pleistocene archaeological sites located in the Orce area (Guadix-Baza Basin, Southern Spain): Fuente Nueva-3 (FN-3) and Barranco Leon (BL). The combination of bio-stratigraphy and magneto-stratigraphy places both sites between the Olduvai and Jaramillo sub-chrons (1.78-1.07 Ma). Our results highlight the difficulty of dating such old sites and point out the limits of the combined U-series/ ESR dating method based on the US model. We identified several sources of uncertainties that may lead to inaccurate age estimates. Seven samples could not be dated because the dental tissues had ( 230 Th/ 234 U) activity ratios higher than equilibrium, indicating that uranium had probably leached from these tissues. It was however possible to calculate numerical estimates for two of the teeth, both from FN-3. One yielded a Middle Pleistocene age that seems to be strongly underestimated; the other provided an age of 1.19±0.21 Ma, in agreement with data obtained from independent methods. The latter result gives encouragement that there are samples that can be used for routine dating of old sites. (authors)

  6. Late Pleistocene and Holocene mammal extinctions on continental Africa

    Science.gov (United States)

    Faith, J. Tyler

    2014-01-01

    Understanding the cause of late Quaternary mammal extinctions is the subject of intense debate spanning the fields of archeology and paleontology. In the global context, the losses on continental Africa have received little attention and are poorly understood. This study aims to inspire new discussion of African extinctions through a review of the extinct species and the chronology and possible causes of those extinctions. There are at least 24 large mammal (> 5 kg) species known to have disappeared from continental Africa during the late Pleistocene or Holocene, indicating a much greater taxonomic breadth than previously recognized. Among the better sampled taxa, these losses are restricted to the terminal Pleistocene and early Holocene, between 13,000 and 6000 yrs ago. The African extinctions preferentially affected species that are grazers or prefer grasslands. Where good terrestrial paleoenvironmental records are present, extinctions are associated with changes in the availability, productivity, or structure of grassland habitats, suggesting that environmental changes played a decisive role in the losses. In the broader evolutionary context, these extinctions represent recent examples of selective taxonomic winnowing characterized by the loss of grassland specialists and the establishment of large mammal communities composed of more ecologically flexible taxa over the last million years. There is little reason to believe that humans played an important role in African extinctions.

  7. Human calcanei from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca, Burgos, Spain).

    Science.gov (United States)

    Pablos, Adrián; Martínez, Ignacio; Lorenzo, Carlos; Sala, Nohemi; Gracia-Téllez, Ana; Arsuaga, Juan Luis

    2014-11-01

    The existence of calcanei in the fossil record prior to modern humans and Neandertals is very scarce. This skeletal element is fundamental to understanding the evolution of the morphology of the foot in human evolution. Here we present and metrically and comparatively describe 29 calcaneus remains from the Middle Pleistocene site of Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain). These calcanei belong to 15 individuals (nine adults, two adolescents and four immature individuals). The metric and morphological differences in the calcanei among Middle and Late Pleistocene hominins tend to be subtle. However, the calcanei from SH are broad and robust with large articular surfaces and most significantly, exhibit a very projected sustentaculum tali. A biomechanical and phylogenetic interpretation is proffered to explain the observed morphology of these calcanei. It has been possible to propose tentative sex assignments for the SH calcanei based on size, using methods similar to those used to establish sex from the talus bones from SH. The estimation of stature based on the calcaneus provides a mean of 175.3 cm for males and 160.6 for females, which is similar to that obtained using other skeletal parts from the site. In sum, the SH calcanei are robust with a proportionally long tubercle and a projected sustentaculum tali, which are traits shared by Neandertals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Coral zonation and diagenesis of an emergent Pleistocene patch reef, Belize, Central America

    Energy Technology Data Exchange (ETDEWEB)

    Lighty, R.G.; Russell, K.L.

    1985-01-01

    Transect mapping and petrologic studies reveal a new depositional model and limited diagenesis of a well-exposed Pleistocene reef outcrop at Ambergris Cay, northern Belize. This emergent shelf-edge reef forms a rocky wave-washed headland at the northern terminus of the present-day 250 km long flourishing Belize Barrier Reef. Previously, the Belize reef outcrop was thought to extend southward in the subsurface beneath the modern barrier reef as a Pleistocene equivalent. The authors study indicate that this outcrop is a large, coral patch reef and not part of a barrier reef trend. Sixteen transects 12.5 m apart described in continuous cm increments from fore reef to back reef identified: extensive deposits of broken Acropora cervicornis; small thickets of A. palmata with small, oriented branches; and muddy skeletal sediments with few corals or reef rubble. Thin section and SEM studies show three phases of early submarine cementation: syntaxial and rosette aragonite; Mg-calcite rim cement and peloids; and colloidal Mg-calcite geopetal fill. Subaerial exposure in semi-arid northern Belize caused only minor skeletal dissolution, some precipitation of vadose whisker calcite, and no meteoric phreatic diagenesis. Facies geometry, coral assemblages, lack of rubble deposits, coralline algal encrustations and Millepora framework, and recognition of common but discrete submarine cements, all indicate that this Pleistocene reef was an isolated, coral-fringed sediment buildup similar to may large patch reefs existing today in moderate-energy shelf environments behind the modern barrier reef in central and southern Belize.

  9. Overview of the Plio-Pleistocene geology of Rhodes, Greece. Lithology, calcareous nannofossil biostratigraphy, and sampling of the Kallithea Bay section

    DEFF Research Database (Denmark)

    Thomsen, Erik; Rasmussen, Tine Lander; Hastrup, Annette

    2005-01-01

    -water deposits are assigned to the Lindos Bay clay. Calcareous nannofossil biostratigraphy shows that the age of the marine sequence is early Pleistocene. The brackish water sediments are difficult to date, but they are probably of late Pliocene age. Sixty-nine samples representing all environments were...

  10. Fossils, feet and the evolution of human bipedal locomotion.

    Science.gov (United States)

    Harcourt-Smith, W E H; Aiello, L C

    2004-05-01

    We review the evolution of human bipedal locomotion with a particular emphasis on the evolution of the foot. We begin in the early twentieth century and focus particularly on hypotheses of an ape-like ancestor for humans and human bipedal locomotion put forward by a succession of Gregory, Keith, Morton and Schultz. We give consideration to Morton's (1935) synthesis of foot evolution, in which he argues that the foot of the common ancestor of modern humans and the African apes would be intermediate between the foot of Pan and Hylobates whereas the foot of a hypothetical early hominin would be intermediate between that of a gorilla and a modern human. From this base rooted in comparative anatomy of living primates we trace changing ideas about the evolution of human bipedalism as increasing amounts of postcranial fossil material were discovered. Attention is given to the work of John Napier and John Robinson who were pioneers in the interpretation of Plio-Pleistocene hominin skeletons in the 1960s. This is the period when the wealth of evidence from the southern African australopithecine sites was beginning to be appreciated and Olduvai Gorge was revealing its first evidence for Homo habilis. In more recent years, the discovery of the Laetoli footprint trail, the AL 288-1 (A. afarensis) skeleton, the wealth of postcranial material from Koobi Fora, the Nariokotome Homo ergaster skeleton, Little Foot (Stw 573) from Sterkfontein in South Africa, and more recently tantalizing material assigned to the new and very early taxa Orrorin tugenensis, Ardipithecus ramidus and Sahelanthropus tchadensis has fuelled debate and speculation. The varying interpretations based on this material, together with changing theoretical insights and analytical approaches, is discussed and assessed in the context of new three-dimensional morphometric analyses of australopithecine and Homo foot bones, suggesting that there may have been greater diversity in human bipedalism in the earlier phases

  11. Stratigraphic record of Pliocene-Pleistocene basin evolution and deformation within the Southern San Andreas Fault Zone, Mecca Hills, California

    Science.gov (United States)

    McNabb, James C.; Dorsey, Rebecca J.; Housen, Bernard A.; Dimitroff, Cassidy W.; Messé, Graham T.

    2017-11-01

    A thick section of Pliocene-Pleistocene nonmarine sedimentary rocks exposed in the Mecca Hills, California, provides a record of fault-zone evolution along the Coachella Valley segment of the San Andreas fault (SAF). Geologic mapping, measured sections, detailed sedimentology, and paleomagnetic data document a 3-5 Myr history of deformation and sedimentation in this area. SW-side down offset on the Painted Canyon fault (PCF) starting 3.7 Ma resulted in deposition of the Mecca Conglomerate southwest of the fault. The lower member of the Palm Spring Formation accumulated across the PCF from 3.0 to 2.6 Ma during regional subsidence. SW-side up slip on the PCF and related transpressive deformation from 2.6 to 2.3 Ma created a time-transgressive angular unconformity between the lower and upper members of the Palm Spring Formation. The upper member accumulated in discrete fault-bounded depocenters until initiation of modern deformation, uplift, and basin inversion starting at 0.7 Ma. Some spatially restricted deposits can be attributed to the evolution of fault-zone geometric complexities. However, the deformation events at ca. 2.6 Ma and 0.7 Ma are recorded regionally along 80 km of the SAF through Coachella Valley, covering an area much larger than mapped fault-zone irregularities, and thus require regional explanations. We therefore conclude that late Cenozoic deformation and sedimentation along the SAF in Coachella Valley has been controlled by a combination of regional tectonic drivers and local deformation due to dextral slip through fault-zone complexities. We further propose a kinematic link between the 2.6-2.3 Ma angular unconformity and a previously documented but poorly dated reorganization of plate-boundary faults in the northern Gulf of California at 3.3-2.0 Ma. This analysis highlights the potential for high-precision chronologies in deformed terrestrial deposits to provide improved understanding of local- to regional-scale structural controls on basin

  12. Pliocene and Pleistocene chronostratigraphy of continental sediments underlying the Altiplano at La Paz, Bolivia

    Science.gov (United States)

    Roberts, Nicholas J.; Barendregt, René W.; Clague, John J.

    2018-06-01

    Continental sediments underlying the Altiplano plateau provide insight into the late Cenozoic evolution of the Central Andes. We characterize the magnetostratigraphy and lithostratigraphy of the upper part of this fill sequence along a transect extending southwestward from the Cordillera Real at La Paz, Bolivia, where it is best exposed. Multiple polarity reversals and the locally extensive, 2.74-Ma Chijini Tuff enable correlation between our six sections and three previously reported sections. The tuff ties the composite polarity sequence to the geomagnetic polarity time scale, demonstrating that the stratigraphic record extends from the latest Gilbert Chron (ca. 3.8 Ma) to the late Olduvai subchron (ca. 1.8 Ma), or possibly Jaramillo subchron (ca. 1.0 Ma). The sequence provides Earth's longest known record of low-latitude glaciation and the only record of Pliocene tropical glaciation. It includes evidence for 16 late Pliocene and Early Pleistocene glaciations, separated by interglacials of sufficient length (>103-104 a) to produce mature soil profiles. Successively larger ice caps formed directly before, during, and after the globally warm mid-Piacenzian (3.265-3.025 Ma), and throughout Plio-Pleistocene climate deterioration. The late Pliocene glacial units predate the onset of widespread Northern Hemisphere continental glaciation and in most cases unambiguously correspond to specific cool peaks of the astronomically tuned, benthic oxygen isotope (δ18O) record, including marine isotope stages MG2, M2, KM2, and G10. The glacial events broadly coincide with those nearer both poles, suggesting inter-hemispheric climate linkages. The early formation and subsequent expansion of ice caps beyond glacier margins of the Last Glacial Maximum suggest that the Cordillera Real likely attained its modern height before ca. 3.4 Ma. The number and timing of glaciations, and long-term sediment accumulation and incision rates suggest that the local Altiplano surface formed by ca

  13. Line Evolution of the Nova V5587 Sgr from Early to Nebula Phase

    Directory of Open Access Journals (Sweden)

    T. Kajikawa

    2015-02-01

    Full Text Available The spectral evolution of the nova V5587 Sgr has been monitored at Koyama Astronomical Observatory and Higashi-Hiroshima Observatory, Japan, from the early to nebula phase. The nova rebrightened several times. The spectra during the early phase showed emission lines of H α, H β, O I, He I, He II, N II, Fe II. Nova V5587 Sgr is classified into the Fe II type. The helium abundance of the nova is estimated as N(He/N(H = 0.134 ± 0.09. The light curve, the spectral evolution, and the helium abundance in V5587 Sgr are similar to those of the nova PW Vul.

  14. Quaternary deposits and landscape evolution of the central Blue Ridge of Virginia

    Science.gov (United States)

    Eaton, L. Scott; Morgan, Benjamin A.; Kochel, R. Craig; Howard, Alan D.

    2003-01-01

    A catastrophic storm that struck the central Virginia Blue Ridge Mountains in June 1995 delivered over 775 mm (30.5 in) of rain in 16 h. The deluge triggered more than 1000 slope failures; and stream channels and debris fans were deeply incised, exposing the stratigraphy of earlier mass movement and fluvial deposits. The synthesis of data obtained from detailed pollen studies and 39 radiometrically dated surficial deposits in the Rapidan basin gives new insights into Quaternary climatic change and landscape evolution of the central Blue Ridge Mountains.The oldest depositional landforms in the study area are fluvial terraces. Their deposits have weathering characteristics similar to both early Pleistocene and late Tertiary terrace surfaces located near the Fall Zone of Virginia. Terraces of similar ages are also present in nearby basins and suggest regional incision of streams in the area since early Pleistocene–late Tertiary time. The oldest debris-flow deposits in the study area are much older than Wisconsinan glaciation as indicated by 2.5YR colors, thick argillic horizons, and fully disintegrated granitic cobbles. Radiocarbon dating indicates that debris flow activity since 25,000 YBP has recurred, on average, at least every 2500 years. The presence of stratified slope deposits, emplaced from 27,410 through 15,800 YBP, indicates hillslope stripping and reduced vegetation cover on upland slopes during the Wisconsinan glacial maximum.Regolith generated from mechanical weathering during the Pleistocene collected in low-order stream channels and was episodically delivered to the valley floor by debris flows. Debris fans prograded onto flood plains during the late Pleistocene but have been incised by Holocene stream entrenchment. The fan incision allows Holocene debris flows to largely bypass many of the higher elevation debris fan surfaces and deposit onto the topographically lower surfaces. These episodic, high-magnitude storm events are responsible for

  15. New ESR/U-series data for the early Middle Pleistocene site of Isernia la Pineta, Italy

    International Nuclear Information System (INIS)

    Shao Qingfeng; Bahain, Jean-Jacques; Falgueres, Christophe; Peretto, Carlo; Arzarello, Marta; Minelli, Antonella; Thun Hohenstein, Ursula; Dolo, Jean-Michel; Garcia, Tristan; Frank, Norbert; Douville, Eric

    2011-01-01

    Located in Southern Italy, the Early Palaeolithic site of Isernia la Pineta has provided numerous palaeontological remains and artefacts in well-defined fluvio-lacustrine sequence. The normal magnetization of the main archaeological layer t3a and 39 Ar/ 40 Ar date of 610 ± 10 (2σ) ka, obtained from the immediately overlaying geological level, put the Isernia assemblage in the first part of the Middle Pleistocene. Previous ESR/U-series analyses of Isernia fossil teeth have displayed both recent U-uptake and severe underestimation of the ESR/U-series dates in comparison with the 39 Ar/ 40 Ar age. In order to identify the cause of this age underestimation, new analyses were realized in the present study on four bovid teeth directly recovered from the archaeological surface t3a. The ESR/U-series dates obtained were once again strongly underestimated, with an error weighted mean age of 435 ± 24 (1σ) ka. These too young dates could be associated to a change of the environmental γ-dose rate during the geological history of the Isernia site, related to the revealed recent U-uptake into the palaeontological remains of the archaeological level. If we consider that this dose rate change was coeval with a wet interglacial period and taking the 39 Ar/ 40 Ar age as geochronological reference, simulations with two dose rate steps indicate that this change could be correlated with marine isotopic stage 7 (MIS 7).

  16. New ESR/U-series data for the early Middle Pleistocene site of Isernia la Pineta, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Shao Qingfeng, E-mail: shao@mnhn.fr [Departement de Prehistoire du Museum National d' Histoire Naturelle, UMR 7194 CNRS, 1 rue Rene Panhard, F-75013 Paris (France); Bahain, Jean-Jacques; Falgueres, Christophe [Departement de Prehistoire du Museum National d' Histoire Naturelle, UMR 7194 CNRS, 1 rue Rene Panhard, F-75013 Paris (France); Peretto, Carlo; Arzarello, Marta; Minelli, Antonella; Thun Hohenstein, Ursula [Dipartimento di Biologia ed Evoluzione, Universita di Ferrara, C.so Ercole I d' Este 32, I-44121 Ferrara (Italy); Dolo, Jean-Michel; Garcia, Tristan [CEA, LIST, Laboratoire National Henri Becquerel, F-91191 Gif-sur-Yvette cedex (France); Frank, Norbert; Douville, Eric [Laboratoire des Sciences du Climat et de l' Environnement, LSCE/IPSL, UMR 8212 CNRS-CEA-UVSQ, Domaine du CNRS, F-91198 Gif/Yvette cedex (France)

    2011-09-15

    Located in Southern Italy, the Early Palaeolithic site of Isernia la Pineta has provided numerous palaeontological remains and artefacts in well-defined fluvio-lacustrine sequence. The normal magnetization of the main archaeological layer t3a and {sup 39}Ar/{sup 40}Ar date of 610 {+-} 10 (2{sigma}) ka, obtained from the immediately overlaying geological level, put the Isernia assemblage in the first part of the Middle Pleistocene. Previous ESR/U-series analyses of Isernia fossil teeth have displayed both recent U-uptake and severe underestimation of the ESR/U-series dates in comparison with the {sup 39}Ar/{sup 40}Ar age. In order to identify the cause of this age underestimation, new analyses were realized in the present study on four bovid teeth directly recovered from the archaeological surface t3a. The ESR/U-series dates obtained were once again strongly underestimated, with an error weighted mean age of 435 {+-} 24 (1{sigma}) ka. These too young dates could be associated to a change of the environmental {gamma}-dose rate during the geological history of the Isernia site, related to the revealed recent U-uptake into the palaeontological remains of the archaeological level. If we consider that this dose rate change was coeval with a wet interglacial period and taking the {sup 39}Ar/{sup 40}Ar age as geochronological reference, simulations with two dose rate steps indicate that this change could be correlated with marine isotopic stage 7 (MIS 7).

  17. Chloroplast Genome Evolution in Early Diverged Leptosporangiate Ferns

    OpenAIRE

    Kim, Hyoung Tae; Chung, Myong Gi; Kim, Ki-Joong

    2014-01-01

    In this study, the chloroplast (cp) genome sequences from three early diverged leptosporangiate ferns were completed and analyzed in order to understand the evolution of the genome of the fern lineages. The complete cp genome sequence of Osmunda cinnamomea (Osmundales) was 142,812 base pairs (bp). The cp genome structure was similar to that of eusporangiate ferns. The gene/intron losses that frequently occurred in the cp genome of leptosporangiate ferns were not found in the cp genome of O. c...

  18. Water location, piospheres and a review of evolution in African ...

    African Journals Online (AJOL)

    The main radiation of large mammalian herbivores in Africa took place in the Pliocene–Pleistocene, when a long-term trend towards aridification promoted grasslands and the diversification of ruminant grazers. Traditional models of this evolution identify habitat fragmentation in response to climate change as the primary ...

  19. The Middle Pleistocene vertebrate fauna from Khok Sung (Nakhon Ratchasima, Thailand): biochronological and paleobiogeographical implications

    Science.gov (United States)

    Suraprasit, Kantapon; Jaeger, Jean-Jacques; Chaimanee, Yaowalak; Chavasseau, Olivier; Yamee, Chotima; Tian, Pannipa; Panha, Somsak

    2016-01-01

    Abstract The fluviatile terrace deposits of Khok Sung, Nakhon Ratchasima province, have yielded more than one thousand fossils, making this the richest Pleistocene vertebrate fauna of Thailand. The excellent preservation of the specimens allows precise characterization of the faunal composition. The mammalian fauna consists of fifteen species in thirteen genera, including a primate, a canid, a hyaenid, proboscideans, rhinoceroses, a suid, cervids, and bovids. Most species correspond to living taxa but globally (Stegodon cf. orientalis) and locally (Crocuta crocuta ultima, Rhinoceros unicornis, Sus barbatus, and Axis axis) extinct taxa were also present. The identification of Axis axis in Khok Sung, a chital currently restricted to the Indian Subcontinent, represents the first record of the species in Southeast Asia. Three reptilian taxa: Crocodylus cf. siamensis, Python sp., and Varanus sp., are also identified. Faunal correlations with other Southeast Asian sites suggest a late Middle to early Late Pleistocene age for the Khok Sung assemblage. However, the Khok Sung mammalian fauna is most similar to that of Thum Wiman Nakin, dated to older than 169 ka. The Khok Sung large mammal assemblage mostly comprises mainland Southeast Asian taxa that migrated to Java during the latest Middle Pleistocene, supporting the hypothesis that Thailand was a biogeographic pathway for the Sino-Malayan migration event from South China to Java. PMID:27667928

  20. The Punta Lucero Quarry site (Zierbena, Bizkaia): a window into the Middle Pleistocene in the Northern Iberian Peninsula

    Science.gov (United States)

    Gómez-Olivencia, Asier; Sala, Nohemi; Arceredillo, Diego; García, Nuria; Martínez-Pillado, Virginia; Rios-Garaizar, Joseba; Garate, Diego; Solar, Gonzalo; Libano, Iñaki

    2015-08-01

    The period between the end of the Early Pleistocene and the mid-Middle Pleistocene (roughly between 1.0 and 0.4 Ma BP) is of great interest in Western Europe. It witnessed several climatic oscillations and changes in the fauna, the demise of a hominin species and the appearance of another, along with important cultural and technological changes. Thus, the few available sites with these chronologies is vital to the understanding of the tempo and mode of these changes. Middle Pleistocene sites in the Northern Iberian Peninsula are very rare. Here we present the study of the site found at the Punta Lucero Quarry (Biscay province, Northern Iberian Peninsula), which includes for the first time the complete collection from the site. The fossil association from this site includes several ungulates, such as a Megacerine deer, Cervus elaphus, large bovids (likely both Bos primigenius and Bison sp. are present), Stephanorhinus sp., and carnivores, such as Homotherium latidens, Panthera gombaszoegensis, Canis mosbachensis and Vulpes sp. This association is typical of a middle Middle Pleistocene chronology and would be the oldest macro-mammal site in the Eastern Cantabrian region. This site would likely correspond to a chronology after Mode 1 technological complex and before the arrival of Mode 2 technology in this region. Thus, it offers a glimpse into the paleoecological conditions slightly prior to or contemporaneous with the first Acheulian makers in the northern fringe of the Iberian Peninsula.

  1. A new basal sauropod dinosaur from the middle Jurassic of Niger and the early evolution of sauropoda.

    Directory of Open Access Journals (Sweden)

    Kristian Remes

    2009-09-01

    Full Text Available The early evolution of sauropod dinosaurs is poorly understood because of a highly incomplete fossil record. New discoveries of Early and Middle Jurassic sauropods have a great potential to lead to a better understanding of early sauropod evolution and to reevaluate the patterns of sauropod diversification.A new sauropod from the Middle Jurassic of Niger, Spinophorosaurus nigerensis n. gen. et sp., is the most complete basal sauropod currently known. The taxon shares many anatomical characters with Middle Jurassic East Asian sauropods, while it is strongly dissimilar to Lower and Middle Jurassic South American and Indian forms. A possible explanation for this pattern is a separation of Laurasian and South Gondwanan Middle Jurassic sauropod faunas by geographic barriers. Integration of phylogenetic analyses and paleogeographic data reveals congruence between early sauropod evolution and hypotheses about Jurassic paleoclimate and phytogeography.Spinophorosaurus demonstrates that many putatively derived characters of Middle Jurassic East Asian sauropods are plesiomorphic for eusauropods, while South Gondwanan eusauropods may represent a specialized line. The anatomy of Spinophorosaurus indicates that key innovations in Jurassic sauropod evolution might have taken place in North Africa, an area close to the equator with summer-wet climate at that time. Jurassic climatic zones and phytogeography possibly controlled early sauropod diversification.

  2. Complete mitochondrial genome sequence of a Middle Pleistocene cave bear reconstructed from ultrashort DNA fragments.

    Science.gov (United States)

    Dabney, Jesse; Knapp, Michael; Glocke, Isabelle; Gansauge, Marie-Theres; Weihmann, Antje; Nickel, Birgit; Valdiosera, Cristina; García, Nuria; Pääbo, Svante; Arsuaga, Juan-Luis; Meyer, Matthias

    2013-09-24

    Although an inverse relationship is expected in ancient DNA samples between the number of surviving DNA fragments and their length, ancient DNA sequencing libraries are strikingly deficient in molecules shorter than 40 bp. We find that a loss of short molecules can occur during DNA extraction and present an improved silica-based extraction protocol that enables their efficient retrieval. In combination with single-stranded DNA library preparation, this method enabled us to reconstruct the mitochondrial genome sequence from a Middle Pleistocene cave bear (Ursus deningeri) bone excavated at Sima de los Huesos in the Sierra de Atapuerca, Spain. Phylogenetic reconstructions indicate that the U. deningeri sequence forms an early diverging sister lineage to all Western European Late Pleistocene cave bears. Our results prove that authentic ancient DNA can be preserved for hundreds of thousand years outside of permafrost. Moreover, the techniques presented enable the retrieval of phylogenetically informative sequences from samples in which virtually all DNA is diminished to fragments shorter than 50 bp.

  3. Millennial-scale climate variations in western Mediterranean during late Pleistocene-early Holocene: multi-proxy analyses from Padul peatbog (southern Iberian Peninsula)

    Science.gov (United States)

    Camuera, Jon; Jiménez-Moreno, Gonzalo; José Ramos-Román, María; García-Alix, Antonio; Jiménez-Espejo, Francisco; Toney, Jaime L.; Anderson, R. Scott; Kaufman, Darrell; Bright, Jordon; Sachse, Dirk

    2017-04-01

    Padul peatbog, located in southern Iberian Peninsula (western Mediterranean region) is a unique area for palaeoenvironmental studies due to its location, between arid and temperate climates. Previous studies showed that the Padul peatbog contains a continuous record of the last ca. 0.8-1 Ma, so it is an extraordinary site to identify glacial-interglacial phases as well as Heinrich and D-O events, linked to orbital- and suborbital-scale variations. In 2015, a new 42 m long core was taken from this area, providing an excellent sediment record probably for the last ca. 300,000 years. This study is focused on the paleoenvironmental and climatic reconstruction of the late Pleistocene and the early Holocene (ca. from 50,000 to 9,500 cal. yrs BP), using AMS 14C and AAR dating, high-resolution pollen analysis, lithology, continuous XRF-scanning, X-ray diffraction, magnetic susceptibility and organic geochemistry. These different proxies provide information not only about the regional environment change but also about local changes in the conditions of the Padul lake/peatbog due to variations in water temperature, pH or nutrients.

  4. Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya.

    Science.gov (United States)

    Spoor, F; Leakey, M G; Gathogo, P N; Brown, F H; Antón, S C; McDougall, I; Kiarie, C; Manthi, F K; Leakey, L N

    2007-08-09

    Sites in eastern Africa have shed light on the emergence and early evolution of the genus Homo. The best known early hominin species, H. habilis and H. erectus, have often been interpreted as time-successive segments of a single anagenetic evolutionary lineage. The case for this was strengthened by the discovery of small early Pleistocene hominin crania from Dmanisi in Georgia that apparently provide evidence of morphological continuity between the two taxa. Here we describe two new cranial fossils from the Koobi Fora Formation, east of Lake Turkana in Kenya, that have bearing on the relationship between species of early Homo. A partial maxilla assigned to H. habilis reliably demonstrates that this species survived until later than previously recognized, making an anagenetic relationship with H. erectus unlikely. The discovery of a particularly small calvaria of H. erectus indicates that this taxon overlapped in size with H. habilis, and may have shown marked sexual dimorphism. The new fossils confirm the distinctiveness of H. habilis and H. erectus, independently of overall cranial size, and suggest that these two early taxa were living broadly sympatrically in the same lake basin for almost half a million years.

  5. Plio-Pleistocene facies environments from the KBS Member, Koobi Fora Formation: implications for climate controls on the development of lake-margin hominin habitats in the northeast Turkana Basin (northwest Kenya)

    NARCIS (Netherlands)

    Lepre, C.J.; Quinn, R.L.; Joordens, J.C.A.; Swisher III, C.S.; Feibel, C.S.

    2007-01-01

    Climate change is hypothesized as a cause of major events of Plio-Pleistocene East African hominin evolution, but the vertically discontinuous and laterally confined nature of the relevant geological records has led to difficulties with assessing probable links between the two. High-resolution

  6. Middle Pleistocene protein sequences from the rhinoceros genus Stephanorhinus and the phylogeny of extant and extinct Middle/Late Pleistocene Rhinocerotidae.

    Science.gov (United States)

    Welker, Frido; Smith, Geoff M; Hutson, Jarod M; Kindler, Lutz; Garcia-Moreno, Alejandro; Villaluenga, Aritza; Turner, Elaine; Gaudzinski-Windheuser, Sabine

    2017-01-01

    Ancient protein sequences are increasingly used to elucidate the phylogenetic relationships between extinct and extant mammalian taxa. Here, we apply these recent developments to Middle Pleistocene bone specimens of the rhinoceros genus Stephanorhinus . No biomolecular sequence data is currently available for this genus, leaving phylogenetic hypotheses on its evolutionary relationships to extant and extinct rhinoceroses untested. Furthermore, recent phylogenies based on Rhinocerotidae (partial or complete) mitochondrial DNA sequences differ in the placement of the Sumatran rhinoceros ( Dicerorhinus sumatrensis ). Therefore, studies utilising ancient protein sequences from Middle Pleistocene contexts have the potential to provide further insights into the phylogenetic relationships between extant and extinct species, including Stephanorhinus and Dicerorhinus . ZooMS screening (zooarchaeology by mass spectrometry) was performed on several Late and Middle Pleistocene specimens from the genus Stephanorhinus , subsequently followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to obtain ancient protein sequences from a Middle Pleistocene Stephanorhinus specimen. We performed parallel analysis on a Late Pleistocene woolly rhinoceros specimen and extant species of rhinoceroses, resulting in the availability of protein sequence data for five extant species and two extinct genera. Phylogenetic analysis additionally included all extant Perissodactyla genera ( Equus , Tapirus ), and was conducted using Bayesian (MrBayes) and maximum-likelihood (RAxML) methods. Various ancient proteins were identified in both the Middle and Late Pleistocene rhinoceros samples. Protein degradation and proteome complexity are consistent with an endogenous origin of the identified proteins. Phylogenetic analysis of informative proteins resolved the Perissodactyla phylogeny in agreement with previous studies in regards to the placement of the families Equidae, Tapiridae, and

  7. Late Pliocene - Early Pleistocene paleoenvironmental reconstruction based on stable isotope compositions of Stephanorhinus sp. and Mammut sp. teeth

    Science.gov (United States)

    Szabó, Péter; Kovács, János; Kocsis, László; Gasparik, Mihály; Vennemann, Torsten; Demény, Attila; Virág, Attila

    2014-05-01

    Stable isotope measurements of skeletal apatite from herbivorous mammals are often used to provide information on the terrestrial paleoenvironment and paleoclimate. In this study fossil teeth of Stephanorhinus Kretzoi 1942 (rhinoceros) and Mammut Blumenbach 1799 (mastodon), amongst others, were investigated from the Carpathian Basin. According to the biostratigraphy, the age of the samples has a range from Late Pliocene to Early Pleistocene. Reconstructing paleoclimate and paleoenvironment of this era is important as it can be an analogue for the future climate. Oxygen and carbon isotopic compositions were measured from the tooth enamel, because it is believed to be the most resistant to diagenetic alteration (e.g., Kohn & Cerling, 2002). The carbon isotopic composition in the carbonate fraction of apatite can be related to the diet of the animal (Kohn & Cerling, 2002). Hence, it can reflect the photosynthetic pathway (C3 or C4) of the plants consumed by these herbivores. The δ18O values were determined in the phosphate fraction of apatite. In the case of large mammals that are obligate drinkers, the δ18O values closely track those of the environmental water (Bryant & Froelich, 1995). Knowing the δ18O values of environmental water and relating it to local precipitation, the mean annual temperature (MAT) of the site can be calculated (Dansgaard, 1964). The δ13C values range from -10 to -15 o (VPDB). The result clearly shows that these animals consumed C3 plants. Most of the δ13C values indicate mixed grassland-open woodland rather than a closed canopy forest. Although there is variation in the δ18O values (mean 14.2 ± 1.0 o VSMOW, n=17), most of the samples would support a MAT range of 8-12 ° C. This is in good agreement with other proxies for the localities and time period (Kovács et al., 2013). Bryant, D.J. & Froelich, P.N. (1995) A model of oxygen-isotope fractionation in bodywater of large-mammals. Geochimica et Cosmochimica Acta 59, 4523

  8. The early Pleistocene deciduous hominid molar FS-72 from the Sangiran Dome of Java, Indonesia: A taxonomic reappraisal based on its comparative endostructural characterization.

    Science.gov (United States)

    Zanolli, Clément; Grine, Frederick E; Kullmer, Ottmar; Schrenk, Friedemann; Macchiarelli, Roberto

    2015-08-01

    Among the ten fossil hominid deciduous teeth reported so far from the Pleistocene sediments of the Sangiran Dome of Java are two isolated lower second molars: specimens PCG.2 from the Kabuh Formation and FS-72 from the Pucangan Formation. While PCG.2 appears to be certainly attributable to Homo erectus, FS-72 is somewhat more problematic, even though it is commonly listed within the Indonesian H. erectus hypodigm. Largely because of its large size, it was originally attributed to Meganthropus paleojavanicus. Subsequent study highlighted a set of metric and nonmetric crown features also found in Australopith and African early Homo (notably H. habilis) homologues. An additional problem with the taxonomic assignment of isolated teeth from the Pleistocene of Java is the presence of Pongo in these same deposits. To assess the taxonomic affinity of FS-72, we investigated its inner structure (tissue proportions and enamel-dentine junction morphology) by using techniques of 2-3D virtual imaging coupled with geometric morphometric analyses. The results show that FS-72 has thinner enamel compared to fossil and recent humans and that its topographic repartition more closely follows the pongine pattern. It also exhibits a Pongo-like elongated morphology of the enamel-dentine junction, with proportionally lower and mesiodistally spaced dentine horns. Given the morphological and metric similarities between fossil orangutan and H. erectus molars, we tested the hypothesis that its internal morphology more closely resembles the patterns evinced by PCG.2 and modern humans than Pongo. Accordingly, we consider that FS-72 more likely represents a dm2 of Pongo rather than Homo. © 2015 Wiley Periodicals, Inc.

  9. Growth response of a deep-water ferromanganese crust to evolution of the Neogene Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.; Hein, J.R.

    of crust accretion. PSsPleistocene; PLsPliocene; LMsLate Miocene; MMsMiddle Miocene; EMsEarly Miocene; LOsLate Oligocene; EOsEarly Oligocene; LEsLate Eocene; MEsMiddle Eocene; EEsEarly Eocene; and PsPalaeocene. High carbonate accumulation due to substantial...

  10. Long-term patterns of body mass and stature evolution within the hominin lineage.

    Science.gov (United States)

    Will, Manuel; Pablos, Adrián; Stock, Jay T

    2017-11-01

    Body size is a central determinant of a species' biology and adaptive strategy, but the number of reliable estimates of hominin body mass and stature have been insufficient to determine long-term patterns and subtle interactions in these size components within our lineage. Here, we analyse 254 body mass and 204 stature estimates from a total of 311 hominin specimens dating from 4.4 Ma to the Holocene using multi-level chronological and taxonomic analytical categories. The results demonstrate complex temporal patterns of body size variation with phases of relative stasis intermitted by periods of rapid increases. The observed trajectories could result from punctuated increases at speciation events, but also differential proliferation of large-bodied taxa or the extinction of small-bodied populations. Combined taxonomic and temporal analyses show that in relation to australopithecines, early Homo is characterized by significantly larger average body mass and stature but retains considerable diversity, including small body sizes. Within later Homo , stature and body mass evolution follow different trajectories: average modern stature is maintained from ca 1.6 Ma, while consistently higher body masses are not established until the Middle Pleistocene at ca 0.5-0.4 Ma, likely caused by directional selection related to colonizing higher latitudes. Selection against small-bodied individuals (less than 40 kg; less than 140 cm) after 1.4 Ma is associated with a decrease in relative size variability in later Homo species compared with earlier Homo and australopithecines. The isolated small-bodied individuals of Homo naledi ( ca 0.3 Ma) and Homo floresiensis ( ca 100-60 ka) constitute important exceptions to these general patterns, adding further layers of complexity to the evolution of body size within the genus Homo . At the end of the Late Pleistocene and Holocene, body size in Homo sapiens declines on average, but also extends to lower limits not seen in

  11. Quantitative palaeodrainage analysis in the Pleistocene of the Po Plain (Italy)

    Science.gov (United States)

    Vezzoli, G.; Garzanti, E.; Sciunnach, D.

    2009-04-01

    During the Pleistocene, Po Plain deposits recorded repeated waxing and waning of Alpine ice caps, and thus provide an excellent opportunity to investigate the interactions between pronounced climatic fluctuations and background tectonic activity (Scardia et al., 2006), resulting in frequent changes of drainage patterns. A high-resolution Pleistocene stratigraphy, with a complete sedimentological, paleontological, petrographic-mineralogical, magneto-stratigraphic, and seismic data base, was recently obtained from eleven continuous cores drilled in the Lombardy Po Plain north of the Po River (ENI and Regione Lombardia, 2002). In the present study we focus on two cores in the proximal (Cilavegna) and distal plain (Pianengo), which best exemplify the drastic change in sedimentary systems and drainage patterns associated with the onset of major Pleistocene glaciations in the Alps (˜870ky; Muttoni et al., 2003). This climatic event is recorded by a regional unconformity (named R-unconformity by Muttoni et al., 2003), traced all across the Po Basin and encountered at -81 m depth in the Pianengo Core and at -98 m depth in the Cilavegna Core. The Cilavegna Core consists of metamorphiclastic floodplain sediments, capped by the R-unconformity and overlain by quartzofeldspathic braidplain deposits. The Pianengo Core consists of metamorphiclastic deltaic to floodpain sediments, capped by the R-unconformity and overlain by alluvial-fan gravels rich in carbonate pebbles; another unconformity at -39 m depth is overlain by metamorphiclastic braidplain deposits. Our quantitative approach to paleodrainage analysis is based on comprehensive information obtained from modern settings (Garzanti et al., 2004; 2006). End-member modelling and similarity analysis allows us to objectively compare detrital modes from modern and ancient deposits, and to reconstruct the evolution of sediment pathways through geologic time (Vezzoli and Garzanti 2009). The Cilavegna Core documents stepwise south

  12. Tectonic evolution of the central-eastern sector of Trans Mexican Volcanic Belt and its influence on the eruptive history of the Nevado de Toluca volcano (Mexico)

    Science.gov (United States)

    Bellotti, F.; Capra, L.; Groppelli, G.; Norini, G.

    2006-11-01

    The Nevado de Toluca is an andesitic to dacitic stratovolcano of Late Pliocene-Holocene age located within the central and eastern sectors of the Trans Mexican Volcanic Belt. Morphostructural analysis, aerial photograph and satellite image interpretation, structural analysis and geological fieldwork were methods used to investigate the relationship between the evolution of the volcano and the tectonic framework of its basement. The study revealed that the area of Nevado de Toluca is affected by three main fault systems that intersect close to the volcanic edifice. These are from oldest to youngest, the Taxco-Querétaro, San Antonio and Tenango fault systems. The NNW-SSE Taxco-Querétaro fault system was active in the area since Early Miocene, and is characterized by right-lateral transtensive movement. Its reactivation during Early to Middle Pleistocene was responsible for the emplacement of andesitic to dacitic lava flows and domes of La Cieneguilla Supersynthem. The NE-SW San Antonio fault system was active during Late Pliocene, before the reactivation of the Taxco-Querétaro fault system, and is characterized by extensional left-lateral oblique-slip kinematics. The youngest is the E-W Tenango fault system that has been active since Late Pleistocene. This fault system is characterized by transtensive left-lateral strike-slip movement, and partly coeval with the youngest eruptive phase, the Nevado Supersynthem, which formed the present summit cone of the Nevado de Toluca volcano. The stress re-orientation from the Taxco-Querétaro to the Tenango fault system during Late Pleistocene is responsible for the ˜ 1 Ma hiatus in the magmatic activity between 1.15 Ma and 42 ka. After this period of repose, the eruptive style drastically changed from effusive to explosive with the emission of dacitic products. The methodology presented here furnish new data that can be used to better assess the complex structural evolution of this sector of the Trans Mexican Volcanic Belt

  13. Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America.

    Science.gov (United States)

    Mitchell, Kieren J; Bray, Sarah C; Bover, Pere; Soibelzon, Leopoldo; Schubert, Blaine W; Prevosti, Francisco; Prieto, Alfredo; Martin, Fabiana; Austin, Jeremy J; Cooper, Alan

    2016-04-01

    The Tremarctinae are a subfamily of bears endemic to the New World, including two of the largest terrestrial mammalian carnivores that have ever lived: the giant, short-faced bears Arctodus simus from North America and Arctotherium angustidens from South America (greater than or equal to 1000 kg). Arctotherium angustidens became extinct during the Early Pleistocene, whereas Arctodus simus went extinct at the very end of the Pleistocene. The only living tremarctine is the spectacled bear (Tremarctos ornatus), a largely herbivorous bear that is today only found in South America. The relationships among the spectacled bears (Tremarctos), South American short-faced bears (Arctotherium) and North American short-faced bears (Arctodus) remain uncertain. In this study, we sequenced a mitochondrial genome from an Arctotherium femur preserved in a Chilean cave. Our molecular phylogenetic analyses revealed that the South American short-faced bears were more closely related to the extant South American spectacled bear than to the North American short-faced bears. This result suggests striking convergent evolution of giant forms in the two groups of short-faced bears (Arctodus and Arctotherium), potentially as an adaptation to dominate competition for megafaunal carcasses. © 2016 The Author(s).

  14. Significance of Two New Pleistocene Plant Records from Western Europe

    Science.gov (United States)

    Field, Michael H.; Velichkevich, Felix Y.; Andrieu-Ponel, Valerie; Woltz, Phillipe

    2000-09-01

    The first records of extinct Caulinia goretskyi (Dorofeev) Dorofeev (synonym Najas goretskyi Dorofeev) in western Europe and of Potamogeton occidentalis M.H. Field sp. nov. were obtained from plant macrofossil analyses of Middle Pleistocene temperate stage deposits exposed at Trez Rouz, Brittany, France. Palynological assemblages recovered suggest correlation with the Holsteinian Stage. This discovery greatly expands the western limit of the paleogeographical distribution of Caulinia goretskyi. The record of Potamogeton occidentalis indicates an affinity with the eastern Asiatic flora, as the fruits resemble those of the extant Potamogeton maackianus A. Bennett. Other extinct Pleistocene species related to P. maackianus have been described, and it is possible to follow the development of this group through the Pleistocene in the European fossil record. These new finds illustrate the importance of a complete paleobotanical approach (both plant macrofossil and palynological analyses). The plant macrofossil assemblages not only provide detailed insight into local vegetation and environment, because they are often not transported long distances (in temperate areas) and can frequently be identified to species level; they can also offer the opportunity to investigate Pleistocene evolutionary trends.

  15. Human Remains from the Pleistocene-Holocene Transition of Southwest China Suggest a Complex Evolutionary History for East Asians

    Science.gov (United States)

    Curnoe, Darren; Xueping, Ji; Herries, Andy I. R.; Kanning, Bai; Taçon, Paul S. C.; Zhende, Bao; Fink, David; Yunsheng, Zhu; Hellstrom, John; Yun, Luo; Cassis, Gerasimos; Bing, Su; Wroe, Stephen; Shi, Hong; Parr, William C. H.; Shengmin, Huang; Rogers, Natalie

    2012-01-01

    Background Later Pleistocene human evolution in East Asia remains poorly understood owing to a scarcity of well described, reliably classified and accurately dated fossils. Southwest China has been identified from genetic research as a hotspot of human diversity, containing ancient mtDNA and Y-DNA lineages, and has yielded a number of human remains thought to derive from Pleistocene deposits. We have prepared, reconstructed, described and dated a new partial skull from a consolidated sediment block collected in 1979 from the site of Longlin Cave (Guangxi Province). We also undertook new excavations at Maludong (Yunnan Province) to clarify the stratigraphy and dating of a large sample of mostly undescribed human remains from the site. Methodology/Principal Findings We undertook a detailed comparison of cranial, including a virtual endocast for the Maludong calotte, mandibular and dental remains from these two localities. Both samples probably derive from the same population, exhibiting an unusual mixture of modern human traits, characters probably plesiomorphic for later Homo, and some unusual features. We dated charcoal with AMS radiocarbon dating and speleothem with the Uranium-series technique and the results show both samples to be from the Pleistocene-Holocene transition: ∼14.3-11.5 ka. Conclusions/Significance Our analysis suggests two plausible explanations for the morphology sampled at Longlin Cave and Maludong. First, it may represent a late-surviving archaic population, perhaps paralleling the situation seen in North Africa as indicated by remains from Dar-es-Soltane and Temara, and maybe also in southern China at Zhirendong. Alternatively, East Asia may have been colonised during multiple waves during the Pleistocene, with the Longlin-Maludong morphology possibly reflecting deep population substructure in Africa prior to modern humans dispersing into Eurasia. PMID:22431968

  16. Megadontia, striae periodicity and patterns of enamel secretion in Plio-Pleistocene fossil hominins.

    Science.gov (United States)

    Lacruz, Rodrigo S; Dean, M Christopher; Ramirez-Rozzi, Fernando; Bromage, Timothy G

    2008-08-01

    Early hominins formed large and thick-enamelled cheek-teeth within relatively short growth periods as compared with modern humans. To understand better the developmental basis of this process, we measured daily enamel increments, or cross striations, in 17 molars of Plio-Pleistocene hominins representing seven different species, including specimens attributed to early Homo. Our results show considerable variation across species, although all specimens conformed to the known pattern characterised by greater values in outer than inner enamel, and greater cuspal than cervical values. We then compared our results with the megadontia index, which represents tooth size in relation to body mass, for each species to assess the effect of daily growth rates on tooth size. Our results indicate that larger toothed (megadont) taxa display higher rates or faster forming enamel than smaller toothed hominins. By forming enamel quickly, large tooth crowns were able to develop within the constraints of shorter growth periods. Besides daily increments, many animals express long-period markings (striae of Retzius) in their enamel. We report periodicity values (number of cross striations between adjacent striae) in 14 new specimens of Australopithecus afarensis, Paranthropus aethiopicus, Paranthropus boisei, Homo habilis, Homo rudolfensis and Homo erectus, and show that long-period striae express a strong association with male and average male-female body mass. Our results for Plio-Pleistocene hominins show that the biological rhythms that give rise to long-period striae are encompassed within the range of variation known for modern humans, but show a lower mean and modal value of 7 days in australopithecines. In our sample of early Homo, mean and modal periodicity values were 8 days, and therefore similar to modern humans. These new data on daily rates of enamel formation and periodicity provide a better framework to interpret surface manifestations of internal growth markings on

  17. Geomorphic and sedimentary responses of the Bull Creek Valley (Southern High Plains, USA) to Pleistocene and Holocene environmental change

    Science.gov (United States)

    Arauza, Hanna M.; Simms, Alexander R.; Bement, Leland C.; Carter, Brian J.; Conley, Travis; Woldergauy, Ammanuel; Johnson, William C.; Jaiswal, Priyank

    2016-01-01

    Fluvial geomorphology and stratigraphy often reflect past environmental and climate conditions. This study examines the response of Bull Creek, a small ephemeral creek in the Oklahoma panhandle, to environmental conditions through the late Pleistocene and Holocene. Fluvial terraces were mapped and their stratigraphy and sedimentology documented throughout the course of the main valley. Based on their elevations, terraces were broadly grouped into a late-Pleistocene fill terrace (T3) and two Holocene fill-cut terrace sets (T2 and T1). Terrace systems are marked by similar stratigraphies recording the general environmental conditions of the time. Sedimentary sequences preserved in terrace fills record the transition from a perennial fluvial system during the late glacial period and the Younger Dryas to a semiarid environment dominated by loess accumulation and punctuated by flood events during the middle to late Holocene. The highest rates of aeolian accumulation within the valley occurred during the early to middle Holocene. Our data provide significant new information regarding the late-Pleistocene and Holocene environmental history for this region, located between the well-studied Southern and Central High Plains of North America.

  18. Environment and Climate of Early Human Evolution

    Science.gov (United States)

    Levin, Naomi E.

    2015-05-01

    Evaluating the relationships between climate, the environment, and human traits is a key part of human origins research because changes in Earth's atmosphere, oceans, landscapes, and ecosystems over the past 10 Myr shaped the selection pressures experienced by early humans. In Africa, these relationships have been influenced by a combination of high-latitude ice distributions, sea surface temperatures, and low-latitude orbital forcing that resulted in large oscillations in vegetation and moisture availability that were modulated by local basin dynamics. The importance of both climate and tectonics in shaping African landscapes means that integrated views of the ecological, environmental, and tectonic histories of a region are necessary in order to understand the relationships between climate and human evolution.

  19. Late Pliocene Quaternary tectonics in the frontal part of the SE Carpathians: Insights from tectonic geomorphology

    Science.gov (United States)

    Necea, Diana; Fielitz, W.; Matenco, L.

    2005-12-01

    The Romanian East Carpathians display large-scale heterogeneities along the mountain belt, unusual foredeep geometries, significant post-collisional and neotectonic activity, and major variations in topography, mostly developed in the aftermath of late Miocene (Sarmatian; ˜11 Ma) subduction/underthrusting and continental collision between the East European/Scythian/Moesian foreland and the inner Carpathians Tisza-Dacia unit. In particular, the SE corner of the arcuate orogenic belt represents the place of still active large-scale differential vertical movements between the uplifting mountain chain and the subsiding Focşani foredeep basin. In this key area, we have analysed the configuration of the present day landforms and the drainage patterns in order to quantify the amplitude, timing and kinematics of these post-collisional late Pliocene-Quaternary vertical movements. A river network is incising in the upstream a high topography consisting of the external Carpathians nappes and the Pliocene-Lower Pleistocene sediments of the foreland. Further eastwards in the downstream, this network is cross-cutting a low topography consisting of the Middle Pleistocene-Holocene sediments of the foreland. Geological observations and well-preserved geomorphic features demonstrate a complex succession of geological structures. The late Pliocene-Holocene tectonic evolution is generally characterised by coeval uplift in the mountain chain and subsidence in the foreland. At a more detailed scale, these vertical movements took place in pulses of accelerated motion, with laterally variable amplitude both in space and in time. After a first late Pliocene uplifting period, subsidence took place during the Earliest Pleistocene resulting in a basal Quaternary unconformity. This was followed by two, quantifiable periods of increased uplift, which affected the studied area at the transition between the Carpathians orogen and the Focşani foreland basin in the late Early Pleistocene and the

  20. Early Pleistocene occurrence of Acheulian technology in North China

    NARCIS (Netherlands)

    Li, Xingwen; Ao, Hong; Dekkers, Mark J.; Roberts, Andrew P.; Zhang, Peng; Lin, Shan; Huang, Weiwen; Hou, Yamei; Zhang, Weihua; An, Zhisheng

    2017-01-01

    Acheulian tools with their associated level of cognizance heralded a major threshold in the evolution of hominin technology, culture and behavior. Thus, unraveling occurrence ages of Acheulian technology across different regions worldwide constitutes a key aspect of understanding the archeology of

  1. Osmoregulatory physiology and rapid evolution of salinity tolerance in threespine stickleback recently introduced to fresh water

    Science.gov (United States)

    Divino, Jeffrey N; Monette, Michelle Y.; McCormick, Stephen; Yancey, Paul H.; Flannery, Kyle G.; Bell, Michael A.; Rollins, Jennifer L.; von Hippel, Frank A.; Schultz, Eric T.

    2016-01-01

    Background: Post-Pleistocene diversification of threespine stickleback in fresh water offers a valuable opportunity to study how changes in environmental salinity shape physiological evolution in fish. In Alaska, the presence of both ancestral oceanic populations and derived landlocked populations, including recent lake introductions, allows us to examine rates and direction of evolution of osmoregulation following halohabitat transition.

  2. Pleistocene Brawley and Ocotillo Formations: Evidence for initial strike-slip deformation along the San Felipe and San Jacinto fault zonez, Southern California

    Science.gov (United States)

    Kirby, S.M.; Janecke, S.U.; Dorsey, R.J.; Housen, B.A.; Langenheim, V.E.; McDougall, K.A.; Steeley, A.N.

    2007-01-01

    We examine the Pleistocene tectonic reorganization of the Pacific-North American plate boundary in the Salton Trough of southern California with an integrated approach that includes basin analysis, magnetostratigraphy, and geologic mapping of upper Pliocene to Pleistocene sedimentary rocks in the San Felipe Hills. These deposits preserve the earliest sedimentary record of movement on the San Felipe and San Jacinto fault zones that replaced and deactivated the late Cenozoic West Salton detachment fault. Sandstone and mudstone of the Brawley Formation accumulated between ???1.1 and ???0.6-0.5 Ma in a delta on the margin of an arid Pleistocene lake, which received sediment from alluvial fans of the Ocotillo Formation to the west-southwest. Our analysis indicates that the Ocotillo and Brawley formations prograded abruptly to the east-northeast across a former mud-dominated perennial lake (Borrego Formation) at ???1.1 Ma in response to initiation of the dextral-oblique San Felipe fault zone. The ???25-km-long San Felipe anticline initiated at about the same time and produced an intrabasinal basement-cored high within the San Felipe-Borrego basin that is recorded by progressive unconformities on its north and south limbs. A disconformity at the base of the Brawley Formation in the eastern San Felipe Hills probably records initiation and early blind slip at the southeast tip of the Clark strand of the San Jacinto fault zone. Our data are consistent with abrupt and nearly synchronous inception of the San Jacinto and San Felipe fault zones southwest of the southern San Andreas fault in the early Pleistocene during a pronounced southwestward broadening of the San Andreas fault zone. The current contractional geometry of the San Jacinto fault zone developed after ???0.5-0.6 Ma during a second, less significant change in structural style. ?? 2007 by The University of Chicago. All rights reserved.

  3. The early-stage structural evolution of the Barmer Basin rift, Rajasthan, northwest India

    OpenAIRE

    Bladon, Andrew John

    2015-01-01

    The structural evolution of the Barmer Basin and the context of the rift within the northwest Indian region are poorly understood, despite being a prolific hydrocarbon province. In this work an integrated basin analysis is presented covering the outcrop-, seismic-, and lithosphere-scales. The early-stage structural evolution and the origin of poorly understood structural complications in the Barmer Basin subsurface are assessed. Subsequently, the findings are placed within the wider context o...

  4. Occasional, obligatory, and habitual stone tool use in hominin evolution.

    Science.gov (United States)

    Shea, John J

    2017-09-01

    Archeologists have long assumed that earlier hominins were obligatory stone tool users. This assumption is deeply embedded in traditional ways of describing the lithic record. This paper argues that lithic evidence dating before 1.7 Ma reflects occasional stone tool use, much like that practiced by nonhuman primates except that it involved flaked-stone cutting tools. Evidence younger than 0.3 Ma is more congruent with obligatory stone tool use, like that among recent humans. The onset of habitual stone tool use at about 1.7 Ma appears correlated with increased hominin logistical mobility (carrying things). The onset of obligatory stone tool use after 0.3 Ma may be linked to the evolution of spoken language. Viewing the lithic evidence dating between 0.3-1.7 Ma as habitual stone tool use explains previously inexplicable aspects of the Early-Middle Pleistocene lithic record. © 2017 Wiley Periodicals, Inc.

  5. Shaped by uneven Pleistocene climate

    DEFF Research Database (Denmark)

    Li, Xinlei; Dong, Feng; Lei, Fumin

    2016-01-01

    had different impacts on different populations: clade N expanded after the last glacial maximum (LGM), whereas milder Pleistocene climate of east Asia allowed clade SE a longer expansion time (since MIS 5); clade SW expanded over a similarly long time as clade SE, which is untypical for European...

  6. Plio-Pleistocene phylogeography of the Southeast Asian Blue Panchax killifish, Aplocheilus panchax

    Science.gov (United States)

    Carvalho, Gary R.; Barlow, Axel; Rüber, Lukas; Hui Tan, Heok; Nugroho, Estu; Wowor, Daisy; Mohd Nor, Siti Azizah; Herder, Fabian; Muchlisin, Zainal A.; de Bruyn, Mark

    2017-01-01

    The complex climatic and geological history of Southeast Asia has shaped this region’s high biodiversity. In particular, sea level fluctuations associated with repeated glacial cycles during the Pleistocene both facilitated, and limited, connectivity between populations. In this study, we used data from two mitochondrial and three anonymous nuclear markers to determine whether a fresh/brackish water killifish, Aplocheilus panchax, Hamilton, 1822, could be used to further understand how climatic oscillations and associated sea level fluctuations have shaped the distribution of biota within this region, and whether such patterns show evidence of isolation within palaeodrainage basins. Our analyses revealed three major mitochondrial clades within A. panchax. The basal divergence of A. panchax mitochondrial lineages was approximately 3.5 Ma, whilst the subsequent divergence timings of these clades occurred early Pleistocene (~2.6 Ma), proceeding through the Pleistocene. Continuous phylogeographic analysis showed a clear west-east dispersal followed by rapid radiation across Southeast Asia. Individuals from Krabi, just north of the Isthmus of Kra, were more closely related to the Indian lineages, providing further evidence for a freshwater faunal disjunction at the Isthmus of Kra biogeographic barrier. Our results suggest that Sulawesi, across the Wallace Line, was colonised relatively recently (~30 ka). Nuclear DNA is less geographically structured, although Mantel tests indicated that nuclear genetic distances were correlated with geographic proximity. Overall, these results imply that recent gene flow, as opposed to historical isolation, has been the key factor determining patterns of nuclear genetic variation in A. panchax, however, some evidence of historical isolation is retained within the mitochondrial genome. Our study further validates the existence of a major biogeographic boundary at the Kra Isthmus, and also demonstrates the use of widely distributed

  7. Stardust in Laboratory & Evolution of Early Solar System f y S Sy

    Indian Academy of Sciences (India)

    kkmarhas

    2008-09-13

    Sep 13, 2008 ... Picture book of presolar grains! Graphite grains. Silicon carbide. Corundum. 500nm. Spinel grains. Silicate grain. Silicon Nitride. Spinel grains. Silicate grain. Silicon Nitride. Presolar Grains &. Evolution of Early Solar System. Kuljeet K. Marhas. 13th September 2008. Physical Research Laboratory ...

  8. Numerical modeling of hydration process and temperature evolution in early age concrete

    NARCIS (Netherlands)

    Caggiano, A.; Pepe, M.; Koenders, E.A.B.; Martinelli, E.; Etse, G.J.

    2012-01-01

    Heat production induced by the hydration reaction and the resulting temperature evolution in the early phases of setting and hardening processes are critical phenomena, often leading to premature cracking of concrete members. However, the interest for simulating such phenomena is also related to the

  9. MicroEcos: Micro-Scale Explorations of Large-Scale Late Pleistocene Ecosystems

    Science.gov (United States)

    Gellis, B. S.

    2017-12-01

    Pollen data can inform the reconstruction of early-floral environments by providing data for artistic representations of what early-terrestrial ecosystems looked like, and how existing terrestrial landscapes have evolved. For example, what did the Bighorn Basin look like when large ice sheets covered modern Canada, the Yellowstone Plateau had an ice cap, and the Bighorn Mountains were mantled with alpine glaciers? MicroEcos is an immersive, multimedia project that aims to strengthen human-nature connections through the understanding and appreciation of biological ecosystems. Collected pollen data elucidates flora that are visible in the fossil record - associated with the Late-Pleistocene - and have been illustrated and described in botanical literature. It aims to make scientific data accessible and interesting to all audiences through a series of interactive-digital sculptures, large-scale photography and field-based videography. While this project is driven by scientific data, it is rooted in deeply artistic and outreach-based practices, which include broad artistic practices, e.g.: digital design, illustration, photography, video and sound design. Using 3D modeling and printing technology MicroEcos centers around a series of 3D-printed models of the Last Canyon rock shelter on the Wyoming and Montana border, Little Windy Hill pond site in Wyoming's Medicine Bow National Forest, and Natural Trap Cave site in Wyoming's Big Horn Basin. These digital, interactive-3D sculpture provide audiences with glimpses of three-dimensional Late-Pleistocene environments, and helps create dialogue of how grass, sagebrush, and spruce based ecosystems form. To help audiences better contextualize how MicroEcos bridges notions of time, space, and place, modern photography and videography of the Last Canyon, Little Windy Hill and Natural Trap Cave sites surround these 3D-digital reconstructions.

  10. Discriminating Between Tectonic and Climatic Controls on Early Hominin Paleoenvironments From the Koobi Fora Region, Northeastern Turkana Basin, Kenya: Part II

    Science.gov (United States)

    Quinn, R. L.; Lepre, C. J.

    2004-12-01

    Global climate is often elected as a catalyst for environmental change and used to characterize selective pressures acting on Plio-Pleistocene African hominins. Vrba's Habitat Theory (1992) and Pott's Variability Selection (1998) credit mammalian evolutionary pattern and process to global climate regulated by orbital forcing. Feibel (1999: 276) argues the need for a middle ground, tethering the "global-scale climatic phenomena" to "environmental change, habitat shift, and biotic evolution" and offers the basin as a scale for analysis. Feibel suggests that all basins are not created equal, and will respond to climate change with different sensitivities and thresholds. As such, interpretations of climate proxies must account for differences in basin size, climatic regime(s), topography, geology, and water availability when drawing relationships to global phenomena. Here we examine pedogenic carbonate isotopes (d13C, d18O) from the Plio-Pleistocene Koobi Fora Region to elucidate the differential influences of climate, tectonics, and deposition on ecological factors of early hominin evolution in the northeastern Turkana Basin of Kenya. One of the richest Plio-Pleistocene fossil localities in Africa, Koobi Fora has served as a setting for hominin evolution between 4.0 and 1.0 Ma. Numerous paleosols, stratigraphically controlled by tuffaceous marker beds, are preserved in the Plio-Pleistocene sediments of the Koobi Fora Formation. Cerling and others (1988) and Wynn (2000) conducted isotopic studies of pedogenic carbonates from the Plio-Pleistocene Omo Group deposits of the Turkana Basin. With these data Wynn (2004) demonstrates stepwise d13C shifts over the last 4.0 Ma, with marked events at 2.5 and 1.8 Ma, and interprets increased aridity on a basin scale due to comparable records on the east and west side of present Lake Turkana. In this study, we increased the sample size of the current database and conducted widespread sampling of synchronous lateral horizons in the

  11. The Late Pleistocene distribution of vicuñas (Vicugna vicugna) and the “extinction” of the gracile llama (“Lama gracilis”): New molecular data

    Science.gov (United States)

    Weinstock, Jaco; Shapiro, Beth; Prieto, Alfredo; Marín, Juan Carlos; González, Benito A.; Gilbert, M. Thomas P.; Willerslev, Eske

    2009-07-01

    We present the results of a palaeogenetic analysis of two Late Pleistocene camelids originating in southern Chile. Our analysis of two mitochondrial DNA fragments (control region and cytochrome b gene) reveals that these specimens do not belong to an extinct taxon, but rather to extant vicuña ( Vicugna vicugna), whose modern distribution is restricted to the extreme elevations of the Andes, more than 3500 km to the north of where these specimens originated. Our results also suggest fossil specimens from Patagonia that are currently assigned to the extinct taxon Lama gracilis, may actually belong to V. vicugna, implying a continuous distribution of the latter from the southern tip of South America to the Andes during the Final Pleistocene. The haplotypes of both specimens are not present in modern populations, suggesting a loss of genetic diversity concomitant with the contraction of the vicuña geographical distribution during the Final Pleistocene or early Holocene.

  12. The Dramatic Size and Kinematic Evolution of Massive Early-type Galaxies

    Science.gov (United States)

    Lapi, A.; Pantoni, L.; Zanisi, L.; Shi, J.; Mancuso, C.; Massardi, M.; Shankar, F.; Bressan, A.; Danese, L.

    2018-04-01

    We aim to provide a holistic view on the typical size and kinematic evolution of massive early-type galaxies (ETGs) that encompasses their high-z star-forming progenitors, their high-z quiescent counterparts, and their configurations in the local Universe. Our investigation covers the main processes playing a relevant role in the cosmic evolution of ETGs. Specifically, their early fast evolution comprises biased collapse of the low angular momentum gaseous baryons located in the inner regions of the host dark matter halo; cooling, fragmentation, and infall of the gas down to the radius set by the centrifugal barrier; further rapid compaction via clump/gas migration toward the galaxy center, where strong heavily dust-enshrouded star formation takes place and most of the stellar mass is accumulated; and ejection of substantial gas amount from the inner regions by feedback processes, which causes a dramatic puffing-up of the stellar component. In the late slow evolution, passive aging of stellar populations and mass additions by dry merger events occur. We describe these processes relying on prescriptions inspired by basic physical arguments and by numerical simulations to derive new analytical estimates of the relevant sizes, timescales, and kinematic properties for individual galaxies along their evolution. Then we obtain quantitative results as a function of galaxy mass and redshift, and compare them to recent observational constraints on half-light size R e , on the ratio v/σ between rotation velocity and velocity dispersion (for gas and stars) and on the specific angular momentum j ⋆ of the stellar component; we find good consistency with the available multiband data in average values and dispersion, both for local ETGs and for their z ∼ 1–2 star-forming and quiescent progenitors. The outcomes of our analysis can provide hints to gauge sub-grid recipes implemented in simulations, to tune numerical experiments focused on specific processes, and to plan

  13. Orbital- to Sub-Orbital-Scale Cyclicity in Seismic Reflections and Sediment Character in Early to Middle Pleistocene Mudstone, Santa Barbara Basin, California

    Science.gov (United States)

    Peterson, C. D.; Behl, R. J.; Nicholson, C.; Lisiecki, L. E.; Sorlien, C. C.

    2009-12-01

    High-resolution seismic reflection records and well logs from the Santa Barbara Channel suggest that large parts of the Pleistocene succession records climate variability on orbital to sub-orbital scales with remarkable sensitivity, much like the well-studied sediments of the last glacial cycle (ODP Site 893). Spectral analysis of seismic reflection data and gamma ray logs from stratigraphically similar Pleistocene sections finds similar cyclic character and shifts through the section. This correlation suggests that acoustic impedance and physical properties of sediment are linked by basin-scale, likely climatically-driven, oscillations in lithologic composition and fabric during deposition, and that seismic profiling can provide a method for remote identification and correlation of orbital- and sub-orbital-scale sedimentary cyclicity. Where it crops out along the northern shelf of the central Santa Barbara Channel, the early to middle Pleistocene succession (~1.8-1.2 Ma) is a bathyal hemipelagic mudstone with remarkably rhythmic planar bedding, finely laminated fabric, and well-preserved foraminifera, none of which have been significantly altered, or obscured by post-depositional diagenesis or tectonic deformation. Unlike the coarser, turbiditic successions in the central Ventura and Los Angeles basins, this sequence has the potential to record Quaternary global climate change at high resolution. Seismic reflection data (towed chirp) collected on the R/V Melville 2008 Cruise (MV08) penetrate 10's of meters below seafloor into a ~1 km-long sequence of south-dipping seismic reflectors. Sampling parallel to the seafloor permits acquisition of consistent signal amplitude for similar reflectors without spreading loss. Based on established age ranges for this section, sedimentation rates may range from 0.4 to 1.4 meters/kyr, therefore suggesting that the most powerful cycles are orbital- to sub-orbital-scale. Discrete sets of cycles with high power show an abrupt shift

  14. Direct U-series analysis of the Lezetxiki humerus reveals a Middle Pleistocene age for human remains in the Basque Country (northern Iberia).

    Science.gov (United States)

    de-la-Rúa, Concepción; Altuna, Jesús; Hervella, Monserrat; Kinsley, Leslie; Grün, Rainer

    2016-04-01

    In 1964, a human humerus was found in a sedimentary deposit in Lezetxiki Cave (Basque Country, northern Iberia). The first studies on the stratigraphy, associated mammal faunal remains and lithic implements placed the deposits containing the humerus into the Riss glacial stage. Direct chronometric evidence has so far been missing, and the previous chronostratigraphic framework and faunal dating gave inconsistent results. Here we report laser ablation U-series analyses on the humerus yielding a minimum age of 164 ± 9 ka, corresponding to MIS 6. This is the only direct dating analysis of the Lezetxiki humerus and confirms a Middle Pleistocene age for this hominin fossil. Morphometric analyses suggest that the Lezetxiki humerus has close affinities to other Middle Pleistocene archaic hominins, such as those from La Sima de los Huesos at Atapuerca. This emphasizes the significance of the Lezetxiki fossil within the populations that predate the Neanderthals in south-western Europe. It is thus an important key fossil for the understanding of human evolution in Europe during the Middle Pleistocene, a time period when a great morphological diversity is observed but whose phylogenetic meaning is not yet fully understood. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Origin and evolution of the atmospheres of early Venus, Earth and Mars

    Science.gov (United States)

    Lammer, Helmut; Zerkle, Aubrey L.; Gebauer, Stefanie; Tosi, Nicola; Noack, Lena; Scherf, Manuel; Pilat-Lohinger, Elke; Güdel, Manuel; Grenfell, John Lee; Godolt, Mareike; Nikolaou, Athanasia

    2018-05-01

    We review the origin and evolution of the atmospheres of Earth, Venus and Mars from the time when their accreting bodies were released from the protoplanetary disk a few million years after the origin of the Sun. If the accreting planetary cores reached masses ≥ 0.5 M_Earth before the gas in the disk disappeared, primordial atmospheres consisting mainly of H_2 form around the young planetary body, contrary to late-stage planet formation, where terrestrial planets accrete material after the nebula phase of the disk. The differences between these two scenarios are explored by investigating non-radiogenic atmospheric noble gas isotope anomalies observed on the three terrestrial planets. The role of the young Sun's more efficient EUV radiation and of the plasma environment into the escape of early atmospheres is also addressed. We discuss the catastrophic outgassing of volatiles and the formation and cooling of steam atmospheres after the solidification of magma oceans and we describe the geochemical evidence for additional delivery of volatile-rich chondritic materials during the main stages of terrestrial planet formation. The evolution scenario of early Earth is then compared with the atmospheric evolution of planets where no active plate tectonics emerged like on Venus and Mars. We look at the diversity between early Earth, Venus and Mars, which is found to be related to their differing geochemical, geodynamical and geophysical conditions, including plate tectonics, crust and mantle oxidation processes and their involvement in degassing processes of secondary N_2 atmospheres. The buildup of atmospheric N_2, O_2, and the role of greenhouse gases such as CO_2 and CH_4 to counter the Faint Young Sun Paradox (FYSP), when the earliest life forms on Earth originated until the Great Oxidation Event ≈ 2.3 Gyr ago, are addressed. This review concludes with a discussion on the implications of understanding Earth's geophysical and related atmospheric evolution in relation

  16. Symbiosis in cell evolution: Life and its environment on the early earth

    Science.gov (United States)

    Margulis, L.

    1981-01-01

    The book treats cell evolution from the viewpoint of the serial endosymbiosis theory of the origin of organelles. Following a brief outline of the symbiotic theory, which holds that eukaryotes evolved by the association of free-living bacteria with a host prokaryote, the diversity of life is considered, and five kingdoms of organisms are distinguished: the prokaryotic Monera and the eukaryotic Protoctista, Animalia, Fungi and Plantae. Symbiotic and traditional direct filiation theories of cell evolution are compared. Recent observations of cell structure and biochemistry are reviewed in relation to early cell evolution, with attention given to the geological context for the origin of eukaryotic cells, the origin of major bacterial anaerobic pathways, the relationship between aerobic metabolism and atmospheric oxygen, criteria for distinguishing symbiotic organelles from those that originated by differentiation, and the major classes of eukaryotic organelles: mitochondria, cilia, microtubules, the mitotic and meiotic apparatuses, and pastids. Cell evolution during the Phanerozoic is also discussed with emphasis on the effects of life on the biosphere

  17. Holocene Evolution of Qing'ao Embayment, Southern China

    Science.gov (United States)

    Switzer, A. D.; Yu, F.; Chen, B.; Zheng, Z.; Wang, D.

    2012-12-01

    The Holocene evolution of the Qing'ao embayment, Nan'ao Island, southern China, is primarily the result of the interaction of tectonic activity, climate variation and changes in relative sea level. Characterizing the evolutionary history of the relatively small Qing'ao embayment during the Holocene will help improve our understanding of the driving mechanisms of coastal evolution in the area. To reconstruct the Holocene evolution history we analyzed the grain size, loss on ignition (LOI) and carbonate content of modern and core samples. Modern environmental analogs were examined in surface samples ranging from the coastal sand dunes through to offshore. The results of these modern samples suggest that dune sand (mean size of ~2.33Phi) are slightly finer than beach sand (mean size of 2.13Phi), and nearshore sediment is much coarser than offshore sediment (mean size of 5.90Phi). This modern analogs were then applied to 8 percussion cores from the Qing'ao embayment. A chronological framework obtained from 11 radiocarbon samples suggests that the embayment started to accept deposition since early Holocene, ~8500 cal. yr. BP. Three main phases of Holocene evolution were identified. A basin wide shell-rich sand sheet forms the basal Holocene facies and overlies clay rich presumably Pleistocene sediments or bedrock. This facies records an initial sedimentation phase associated with the early Holocene transgression into the embayment (~8500-6000 cal. yr. BP). The basal facies grades upward to a mixed sandy-mud facies which includes lagoonal clayey-silts, flood tide delta sands and records an estuarine phase lasting from ~6000-1000 cal. yr. BP that appears coincident with falling regional sea levels. Coincident with the estuarine phase is a period of coastal dune building recorded as yet undated massive sands that are found in the upper fill. Toward the end of the estuarine phase it is apparent that dune migration has restricted the lagoon entrance and that this was

  18. Virtual reconstruction of the Early Pleistocene mandible ATD6-96 from Gran Dolina-TD6-2 (Sierra De Atapuerca, Spain).

    Science.gov (United States)

    Bermúdez de Castro, José María; Martín-Francés, Laura; Modesto-Mata, Mario; Martínez de Pinillos, Marina; Martinón-Torres, María; García-Campos, Cecilia; Carretero, José Miguel

    2016-04-01

    In this report, we present a further study of the late Early Pleistocene ATD6-96 human mandible, recovered from the TD6-2 level of the Gran Dolina cave site (Sierra de Atapuerca, northern Spain) and attributed to Homo antecessor. ATD6-96 consists of a left half of a gracile mandible of an adult individual with the premolars and molars in place that is broken at the level of the lateral incisor-canine septum. The present analysis is based on a virtual reconstruction of the whole mandible by means of computed tomography (CT). We have reconstructed the symphysis using information from a modern human sample, as well as from a wide sample composed of several Homo specimens. This research has allowed us to record new variables with taxonomic and phylogenetic interest. We have estimated the length/width index of the alveolar arcade, as well as the percentage of the arcade length with regard to the total length. The latter confirms that ATD6-96 shares with all African and Asian Homo species a primitive structural pattern, as it was established in previous studies. In constrast, the length/width index of the alveolar arcade in the H. antecessor specimen is close to the mean values of Neandertals and the Atapuerca-Sima de los Huesos hominins. H. antecessor is derived regarding the shape of the mandibular alveolar arcade within the genus Homo and points to an early divergence from contemporaneous African populations. Our results also ratify the affinities of H. antecessor with Neanderthals, although the precise relationship with this lineage needs further research. © 2015 Wiley Periodicals, Inc.

  19. (Plio-)Pleistocene alluvial-lacustrine basin infill evolution in a strike-slip active zone (Northern Andes, Western-Central Cordilleras, Colombia)

    OpenAIRE

    SUTER, F.; NEUWERTH, R.; GORIN, G.; GUZMÁN, C.

    2009-01-01

    The (Plio)-Pleistocene Zarzal Formation was deposited in the Cauca Depression and Quindío-Risaralda Basin between the Western and Central Cordilleras (Northern Andes). This area is structurally located on the transcurrent Romeral Fault System (RFS). Because of the interaction between the Nazca plate and the Chocó-Panamá block (an active indenter), the RFS strike-slip component changes direction around the study zone (dextral in the south, senestral in the north). Zarzal sediments are the olde...

  20. High-latitude steppe vegetation and the mineral nutrition of Pleistocene herbivores

    Science.gov (United States)

    Davydov, S. P.; Davydova, A.; Makarevich, R.; Loranty, M. M.; Boeskorov, G.

    2014-12-01

    High-latitude steppes were widespread and zonal in the Late Pleistocene and formed a landscape basis for the Mammoth Biome. Now the patches of these steppes survived on steep slopes under southern aspects. These steppes serve as unique information sources about the Late Pleistocene "Mammoth" steppe. Numerous data obtained by palynological, carpological, and DNA analysis of plant remains from feces and stomach contents of Pleistocene herbivore mummies, as well as from buried soils and enclosing deposits show that they are similar to modern steppe plant assemblage in taxa composition. Plant's nutrient concentrations are of fundamental importance across Pleistocene grass-rich ecosystems because of their role in the support of large herbivores. The average weight of an adult mammoth skeleton (about 0.5 tons) and of a woolly rhinoceros (about 0.2 tons) clearly suggests this. Detailed studies on fossil bone remains showed mineral deficiency in large Pleistocene herbivores. A three-year study of ash and mineral contents of two types of relict steppe vegetation at the Kolyma Lowland, Arctic Siberia has been carried out. Nowadays refugia of similar vegetation are located not far (1 - 15km) from the Yedoma permafrost outcrops were abundant fossil remains are found. Dominant species of the steppe vegetation were sampled. Preliminary studies indicate that the ash-content varied 1.5-2 times in speceies of steppe herbs. The Ca, P, Mg, K element contents was higher for most steppe species than in the local herbaceous vegetation, especially in Ca and P. One of the most important elements of the mineral nutrition, the phosphorus, was always found in higher concentrations in the steppe vegetation than in plants of recently dominant landscapes of the study area. It should be noted that the mineral nutrient content of the modern steppe vegetation of Siberian Arctic is comparable to that of the recent zonal steppe of Transbaikal Region. This study supports the hypothesis that

  1. Late Middle Pleistocene hominin teeth from Panxian Dadong, South China.

    Science.gov (United States)

    Liu, Wu; Schepartz, Lynne A; Xing, Song; Miller-Antonio, Sari; Wu, Xiujie; Trinkaus, Erik; Martinón-Torres, María

    2013-05-01

    The hominin teeth and evidence of hominin activities recovered from 1991 to 2005 at the Panxian Dadong site in South China are dated to the late Middle Pleistocene (MIS 8-6 or ca. 130-300 ka), a period for which very little is known about the morphology of Asian populations. The present study provides the first detailed morphometric description and comparisons of four hominin teeth (I(1), C1, P(3) and P3) from this site. Our study shows that the Panxian Dadong teeth combine archaic and derived features that align them with Middle and Upper Pleistocene fossils from East and West Asia and Europe. These teeth do not display any typical Neanderthal features and they are generally more derived than other contemporaneous populations from Asia and Africa. However, the derived traits are not diagnostic enough to specifically link the Panxian Dadong teeth to Homo sapiens, a common problem when analyzing the Middle Pleistocene dental record from Africa and Asia. These findings are contextualized in the discussion of the evolutionary course of Asian Middle Pleistocene hominins, and they highlight the necessity of incorporating the Asian fossil record in the still open debate about the origin of H. sapiens. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Evolution of Golpazari-Huyuk karst system (Bilecik-Turkey: indications of morpho-tectonic controls

    Directory of Open Access Journals (Sweden)

    Ekmekci Mehmet

    2004-12-01

    Full Text Available The Golpazari-Huyuk karst system is located in the Central Sakarya Basin whose geomorphologic evolution is mainly controlled by the Post-Miocene epirogenic continental rise. Drastic change in the drainage pattern and dissection of the carbonate platform were the major consequences of this tectonic movement. Rapid incision of the Sakarya river changed the position of the erosion base which consequently distorted the direction of surface and subsurface flow. The Golpazari and Huyuk plains are two topographically distinct, flat bottomed geomorphic features separated by a carbonate rock relief. The difference in elevation between these 10 km distant plains is 350 m. Morphological, geological and hydrological behavior of the plains suggests that the both have functioned as closed basins connected to each other through subsurface flow paths. Drainage has changed from subsurface to surface after the emplacement of the Sakarya river into its modern course. In this study, the authors suggest a conceptual model to reconstruct the hydrological-geomorphological processes that have been effective in the evolution of this karst area. The methodology is based on the records preserved in the morphological and sedimentological archives as well as the hydrogeological setting in the study area. According to the suggested model, the present landscape which exhibits a late stage of karstification has evolved in three main phases, after an initial stage attributed to Lower Miocene. The first phase represents karstification of carbonate rocks of Jurassic age at the Huyuk area and the limestone of Paleocene age at the Golpazari area. This region must have been significantly elevated from the karstification (erosion base. The geomorphologic and drainage setting reveal that the karstification was controlled mainly by major drainage elements in Late Miocene-Early Pliocene.The second phase is characterized by the uplift of the region and the subsequent rapid incision of

  3. The Tetramerium lineage (Acanthaceae: Justicieae) does not support the Pleistocene Arc hypothesis for South American seasonally dry forests.

    Science.gov (United States)

    Côrtes, Ana Luiza A; Rapini, Alessandro; Daniel, Thomas F

    2015-06-01

    The Tetramerium lineage (Acanthaceae) presents a striking ecological structuring in South America, with groups concentrated in moist forests or in seasonally dry forests. In this study, we investigate the circumscription and relationships of the South American genera as a basis for better understanding historic interactions between dry and moist biomes in the Neotropics. We dated the ancestral distribution of the Tetramerium lineage based on one nuclear and four plastid DNA regions. Maximum parsimony, maximum likelihood, and Bayesian inference analyses were performed for this study using 104 terminals. Phylogenetic divergences were dated using a relaxed molecular clock approach and ancestral distributions obtained from dispersal-vicariance analyses. The genera Pachystachys, Schaueria, and Thyrsacanthus are nonmonophyletic. A dry forest lineage dispersed from North America to South America and reached the southwestern part of the continent between the end of the Miocene and beginning of the Pleistocene. This period coincides with the segregation between Amazonian and Atlantic moist forests that established the geographic structure currently found in the group. The South American genera Pachystachys, Schaueria, and Thyrsacanthus need to be recircumscribed. The congruence among biogeographical events found for the Tetramerium lineage suggests that the dry forest centers currently dispersed throughout South America are relatively old remnants, probably isolated since the Neogene, much earlier than the Last Glacial Maximum postulated by the Pleistocene Arc hypothesis. In addition to exploring the Pleistocene Arc hypothesis, this research also informs evolution in a lineage with numerous geographically restricted and threatened species. © 2015 Botanical Society of America, Inc.

  4. The Watinglo mandible: a second terminal Pleistocene Homo sapiens fossil from tropical Sahul with a test on existing models for the human settlement of the region.

    Science.gov (United States)

    Bulbeck, D; O'Connor, S

    2011-02-01

    This paper analyses a fossil human mandible, dated to circa 10ka, from Watinglo rockshelter on the north coast of Papua New Guinea. The fossil is metrically and morphologically similar to male mandibles of recent Melanesians and Australian Aborigines. It is distinguished from Kow Swamp and Coobool Creek male mandibles (Murray Valley, terminal Pleistocene) by being smaller and having different shape characteristics, as well as smaller teeth and a slower rate of tooth wear. It pairs with the Liang Lemdubu female (Late Glacial Maximum, Aru Islands) in suggesting that the morphology of the terminal Pleistocene inhabitants of tropical Sahul was gracile compared to their contemporaries within the southern Murray drainage. An explanatory scenario for this morphological contrast is developed in the context of the Homo sapiens early fossil record, Australasian mtDNA evidence, terminal Pleistocene climatic variation, and the possibility of multiple entry points into Sahul. Copyright © 2010 Elsevier GmbH. All rights reserved.

  5. Late Pleistocene fishes of the Tennessee River Basin: an analysis of a late Pleistocene freshwater fish fauna from Bell Cave (site ACb-2) in Colbert County, Alabama, USA.

    Science.gov (United States)

    Jacquemin, Stephen J; Ebersole, Jun A; Dickinson, William C; Ciampaglio, Charles N

    2016-01-01

    The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (∼10,000 to 30,000 years B.P.) leading to modern Holocene fish diversity patterns. The objective of this study was to describe the fish assemblages of the Tennessee River Basin from the late Pleistocene using a series of faunas from locales throughout the basin documented from published literature, unpublished reports, and an undocumented fauna from Bell Cave (site ACb-2, Colbert County, AL). Herein we discuss 41 unequivocal taxa from 10 late Pleistocene localities within the basin and include a systematic discussion of 11 families, 19 genera, and 24 identifiable species (28 unequivocal taxa) specific to the Bell Cave locality. Among the described fauna are several extirpated (e.g., Northern Pike Esox lucius, Northern Madtom Noturus stigmosus) and a single extinct (Harelip Sucker Moxostoma lacerum) taxa that suggest a combination of late Pleistocene displacement events coupled with more recent changes in habitat that have resulted in modern basin diversity patterns. The Bell Cave locality represents one of the most intact Pleistocene freshwater fish deposits anywhere in North America. Significant preservational, taphonomic, sampling, and identification biases preclude the identification of additional taxa. Overall, this study provides a detailed look into paleo-river ecology, as well as freshwater fish diversity and distribution leading up to the contemporary biodiversity patterns of the Tennessee River Basin and Mississippi River Basin as a whole.

  6. Late Pleistocene fishes of the Tennessee River Basin: an analysis of a late Pleistocene freshwater fish fauna from Bell Cave (site ACb-2 in Colbert County, Alabama, USA

    Directory of Open Access Journals (Sweden)

    Stephen J. Jacquemin

    2016-02-01

    Full Text Available The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (∼10,000 to 30,000 years B.P. leading to modern Holocene fish diversity patterns. The objective of this study was to describe the fish assemblages of the Tennessee River Basin from the late Pleistocene using a series of faunas from locales throughout the basin documented from published literature, unpublished reports, and an undocumented fauna from Bell Cave (site ACb-2, Colbert County, AL. Herein we discuss 41 unequivocal taxa from 10 late Pleistocene localities within the basin and include a systematic discussion of 11 families, 19 genera, and 24 identifiable species (28 unequivocal taxa specific to the Bell Cave locality. Among the described fauna are several extirpated (e.g., Northern Pike Esox lucius, Northern Madtom Noturus stigmosus and a single extinct (Harelip Sucker Moxostoma lacerum taxa that suggest a combination of late Pleistocene displacement events coupled with more recent changes in habitat that have resulted in modern basin diversity patterns. The Bell Cave locality represents one of the most intact Pleistocene freshwater fish deposits anywhere in North America. Significant preservational, taphonomic, sampling, and identification biases preclude the identification of additional taxa. Overall, this study provides a detailed look into paleo-river ecology, as well as freshwater fish diversity and distribution leading up to the contemporary biodiversity patterns of the Tennessee River Basin and Mississippi River Basin as a whole.

  7. Late-Pleistocene evolution of the East Mediterranean shallow continental shelf of north-central Israel

    Science.gov (United States)

    Shtienberg, Gilad; Dix, Justin; Waldmann, Nicolas; Makovsky, Yizhaq; Bookman, Revital; Roskin, Joel; Bialik, Or; Golan, Arik; Sivan, Dorit

    2016-04-01

    . This approach allowed us to investigate the relationship between the lithological units and sea-level change and thus enable the reconstruction of the coastal evolution over the last ˜130 ka. This reconstruction suggests that the stratigraphy is dominated by a sea level lowstand during which aeolian, fluvial and paleosol sediments were deposited in a terrestrial environment. The coastal-terrestrial landscape was flooded by the early to middle Holocene transgression. The results of this study provide a valuable framework for future national strategic shallow-water infrastructure construction and also for the possible locations of past human settlements in relation to coastal evolution through time.

  8. The early evolution of Jean Piaget's clinical method.

    Science.gov (United States)

    Mayer, Susan Jean

    2005-11-01

    This article analyzes the early evolution of Jean Piaget's renowned "clinical method" in order to investigate the method's strikingly original and generative character. Throughout his 1st decade in the field, Piaget frequently discussed and justified the many different approaches to data collection he used. Analysis of his methodological progression during this period reveals that Piaget's determination to access the genuine convictions of children eventually led him to combine 3 distinct traditions in which he had been trained-naturalistic observation, psychometrics, and the psychiatric clinical examination. It was in this amalgam, first evident in his 4th text, that Piaget discovered the clinical dynamic that would drive the classic experiments for which he is most well known.

  9. Early-stage evolution of particle size distribution with Johnson's SB function due to Brownian coagulation

    International Nuclear Information System (INIS)

    Tang Hong; Lin Jianzhong

    2013-01-01

    The moment method can be used to determine the time evolution of particle size distribution due to Brownian coagulation based on the general dynamic equation (GDE). But the function form of the initial particle size distribution must be determined beforehand for the moment method. If the assumed function type of the initial particle size distribution has an obvious deviation from the true particle population, the evolution of particle size distribution may be different from the real evolution tendency. Thus, a simple and general method is proposed based on the moment method. In this method, the Johnson's S B function is chosen as a general distribution function to fit the initial distributions including the log normal (L-N), Rosin–Rammler (R-R), normal (N-N) and gamma distribution functions, respectively. Meanwhile, using the modified beta function to fit the L-N, R-R, N-N and gamma functions is also conducted as a comparison in order to present the advantage of the Johnson's S B function as the general distribution function. And then, the time evolution of particle size distributions using the Johnson's S B function as the initial distribution can be obtained by several lower order moment equations of the Johnson's S B function in conjunction with the GDE during the Brownian coagulation process. Simulation experiments indicate that fairly reasonable results of the time evolution of particle size distribution can be obtained with this proposed method in the free molecule regime, transition regime and continuum plus near continuum regime, respectively, at the early time stage of evolution. The Johnson's S B function has the ability of describing the early time evolution of different initial particle size distributions. (paper)

  10. Reconstruction of Late Pleistocene Paleoenvironments using bulk geochemistry of paleosols from the Lake Victoria Region

    Science.gov (United States)

    Beverly, Emily J.; Peppe, Daniel J.; Driese, Steven G.; Blegen, Nick; Faith, J. Tyler; Tryon, Christian A.; Stinchcomb, Gary E.

    2017-11-01

    The impact of changing environments on the evolution and dispersal of Homo sapiens is highly debated, but few data are available from equatorial Africa. Lake Victoria is the largest freshwater lake in the tropics and is currently a biogeographic barrier between the eastern and western branches of the East African Rift. The lake has previously desiccated at 17 ka and again at 15 ka, but little is known from this region prior to the Last Glacial Maximum. The Pleistocene terrestrial deposits on the northeast coast of Lake Victoria (94 to 36 ka) are ideal for paleoenvironmental reconstructions where volcaniclastic deposits (tuffs), fluvial deposits, tufa, and paleosols are exposed, which can be used to reconstruct Critical Zones (CZ) of the past (paleo-CZs). The paleo-CZ is a holistic concept that reconstructs the entire landscape using geologic records of the atmosphere, hydrosphere, lithosphere, biosphere, and pedosphere (the focus of this study). New paleosol-based mean annual precipitation (MAP) proxies from Karungu, Rusinga Island, and Mfangano Island indicate an average MAP of 750108 mm yr-1 (CALMAG), 800182 mm yr-1 (CIA-K), and 1010228 mm yr-1 (PPM1.0) with no statistical difference throughout the 11 m thick sequence. This corresponds to between 54 and 72% of modern precipitation. Tephras bracketing these paleosols have been correlated across seven sites, and sample a regional paleo-CZ across a 55 km transect along the eastern shoreline of the modern lake. Given the sensitivity of Lake Victoria to precipitation, it is likely that the lake was significantly smaller than modern between 94 ka and 36 ka. This would have removed a major barrier for the movement of fauna (including early modern humans) and provided a dispersal corridor across the equator and between the rifts. It is also consistent with the associated fossil faunal assemblage indicative of semi-arid grasslands. During the Late Pleistocene, the combined geologic and paleontological evidence suggests a

  11. Reconstruction of Late Pleistocene Paleoenvironments Using Bulk Geochemistry of Paleosols from the Lake Victoria Region

    Directory of Open Access Journals (Sweden)

    Emily J. Beverly

    2017-11-01

    Full Text Available The impact of changing environments on the evolution and dispersal of Homo sapiens is highly debated, but few data are available from equatorial Africa. Lake Victoria is the largest freshwater lake in the tropics and is currently a biogeographic barrier between the eastern and western branches of the East African Rift. The lake has previously desiccated at ~17 ka and again at ~15 ka, but little is known from this region prior to the Last Glacial Maximum. The Pleistocene terrestrial deposits on the northeast coast of Lake Victoria (94–36 ka are ideal for paleoenvironmental reconstructions where volcaniclastic deposits (tuffs, fluvial deposits, tufa, and paleosols are exposed, which can be used to reconstruct Critical Zones (CZ of the past (paleo-CZs. The paleo-CZ is a holistic concept that reconstructs the entire landscape using geologic records of the atmosphere, hydrosphere, lithosphere, biosphere, and pedosphere (the focus of this study. New paleosol-based mean annual precipitation (MAP proxies from Karungu, Rusinga Island, and Mfangano Island indicate an average MAP of 750 ± 108 mm year−1 (CALMAG, 800 ± 182 mm year−1 (CIA-K, and 1,010 ± 228 mm year−1 (PPM1.0 with no statistical difference throughout the 11 m thick sequence. This corresponds to between 54 and 72% of modern precipitation. Tephras bracketing these paleosols have been correlated across seven sites, and sample a regional paleo-CZ across a ~55 km transect along the eastern shoreline of the modern lake. Given the sensitivity of Lake Victoria to precipitation, it is likely that the lake was significantly smaller than modern between 94 and 36 ka. This would have removed a major barrier for the movement of fauna (including early modern humans and provided a dispersal corridor across the equator and between the rifts. It is also consistent with the associated fossil faunal assemblage indicative of semi-arid grasslands. During the Late Pleistocene, the combined geologic and

  12. Pleistocene Thermocline Reconstruction and Oxygen Minimum Zone Evolution in the Maldives

    Science.gov (United States)

    Yu, S. M.; Wright, J.

    2017-12-01

    Drift deposits of the southern flank the Kardiva Channel in the eastern Inner Sea of the Maldives provide a complete record of Pleistocene water column changes in conjunction with monsoon cyclicity and fluctuations in the current system. We sampled IODP Site 359-U1467 to reconstruct water column using foraminiferal stable isotope records. This unlithified lithostratigraphic unit is rich in well-preserved microfossils and has an average sedimentation rate of 3.4 cm/yr. Marine Isotope Stages 1-6 were identified and show higher sedimentation rates during the interglacial sections approaching 6 cm/kyr. We present the δ13C and δ18O record of planktonic and benthic foraminiferal species taken at intervals of 3 cm. Globigerinoides ruber was used to constrain surface conditions. The thermocline dwelling species, Globorotalia menardii, was chosen to monitor fluctuations in the thermocline compared to the mixed layer. Lastly, the δ13C of the benthic species, Cibicidoides subhaidingerii and Planulina renzi, reveal changes to the bottom water ventilation and expansion of oxygen minimum zones over time. All three taxa recorded similar changes in δ18O over the glacial/interglacial cycles which is remarkable given the large sea level change ( 120 m) and the relatively shallow water depth ( 450 m). There is a small increase in the δ13C gradient during the glacial intervals which might reflect less ventilated bottom waters in the Inner Sea. This multispecies approach allows us to better constrain the thermocline hydrography and suggests that changes in the OMZ thickness are driven by the intensification of the monsoon cycles while painting a more cohesive picture to the changes in the water column structure.

  13. Sedimentary architecture of a Plio-Pleistocene proto-back-arc basin: Wanganui Basin, New Zealand

    Science.gov (United States)

    Proust, Jean-Noël; Lamarche, Geoffroy; Nodder, Scott; Kamp, Peter J. J.

    2005-11-01

    The sedimentary architecture of active margin basins, including back-arc basins, is known only from a few end-members that barely illustrate the natural diversity of such basins. Documenting more of these basins types is the key to refining our understanding of the tectonic evolution of continental margins. This paper documents the sedimentary architecture of an incipient back-arc basin 200 km behind the active Hikurangi subduction margin, North Island, New Zealand. The Wanganui Basin (WB) is a rapidly subsiding, Plio-Pleistocene sedimentary basin located at the southern termination of the extensional back-arc basin of the active Central Volcanic Region (TVZ). The WB is asymmetric with a steep, thrust-faulted, outer (arc-ward) margin and a gentle inner (craton-ward) margin. It contains a 4-km-thick succession of Plio-Pleistocene sediments, mostly lying offshore, composed of shelf platform sediments. It lacks the late molasse-like deposits derived from erosion of a subaerial volcanic arc and basement observed in classical back-arc basins. Detailed seismic stratigraphic interpretations from an extensive offshore seismic reflection data grid show that the sediment fill comprises two basin-scale mega-sequences: (1) a Pliocene (3.8 to 1.35 Ma), sub-parallel, regressive "pre-growth" sequence that overtops the uplifted craton-ward margin above the reverse Taranaki Fault, and (2) a Pleistocene (1.35 Ma to present), divergent, transgressive, "syn-growth" sequence that onlaps: (i) the craton-ward high to the west, and (ii) uplifted basement blocks associated with the high-angle reverse faults of the arc-ward margin to the east. Along strike, the sediments offlap first progressively southward (mega-sequence 1) and then southeastward (mega-sequence 2), with sediment transport funnelled between the craton- and arc-ward highs, towards the Hikurangi Trough through the Cook Strait. The change in offlap direction corresponds to the onset of arc-ward thrust faulting and the rise of

  14. Mio-Pliocene to Pleistocene paleotopographic evolution of Brittany (France) from a sequence stratigraphic analysis: relative influence of tectonics and climate

    Science.gov (United States)

    Brault, N.; Bourquin, S.; Guillocheau, F.; Dabard, M.-P.; Bonnet, S.; Courville, P.; Estéoule-Choux, J.; Stepanoff, F.

    2004-01-01

    The Mio-Pliocene in Western Europe is a period of major climatic and tectonic change with important topographic consequences. The aim of this paper is to reconstruct these topographic changes (based on sedimentological analysis and sequence stratigraphy) for the Armorican Massif (western France) and to discuss their significance. The Mio-Pliocene sands of the Armorican Massif (Red Sands) are mainly preserved in paleovalleys and are characterized by extensive fluvial sheetflood deposits with low-preservation and by-pass facies. This sedimentological study shows that the Red Sands correspond to three main sedimentary environments: fluvial (alluvial fan, low-sinuosity rivers and braided rivers), estuarine and some rare open marine deposits (marine bioclastic sands: "faluns" of French authors). Two orders of sequences have been correlated across Brittany with one or two minor A/ S cycles comprised within the retrogradational trend of a major cycle. The unconformity at the base of the lower cycle is more marked than the unconformity observed at the top, which corresponds to a re-incision of the paleovalley network. A comparison of the results of the sequence stratigraphy analysis with eustatic variations and tectonic events during the Mio-Pliocene allows (1) to discuss their influence on the evolution of the Armorican Massif and (2) to compare the stratigraphic record with other west-European basins. The unconformity observed at the base of the first minor cycle may be attributed to Serravallian-Tortonian tectonic activity and/or eustatic fall, and the unconformity of the second minor cycle may be attributed to Late Tortonian-Early Messinian tectonic activity. The earlier unconformity is coeval with the development of a "smooth" paleovalley network compared to the jagged present-day relief. A single episode of Mio-Pliocene deformation recorded in Brittany may be dated as Zanclean, thus explaining the lack of the maximum flooding surface except in isolated areas. From

  15. Adaptation and convergent evolution within the Jamesonia-Eriosorus complex in high-elevation biodiverse Andean hotspots.

    Science.gov (United States)

    Sánchez-Baracaldo, Patricia; Thomas, Gavin H

    2014-01-01

    The recent uplift of the tropical Andes (since the late Pliocene or early Pleistocene) provided extensive ecological opportunity for evolutionary radiations. We test for phylogenetic and morphological evidence of adaptive radiation and convergent evolution to novel habitats (exposed, high-altitude páramo habitats) in the Andean fern genera Jamesonia and Eriosorus. We construct time-calibrated phylogenies for the Jamesonia-Eriosorus clade. We then use recent phylogenetic comparative methods to test for evolutionary transitions among habitats, associations between habitat and leaf morphology, and ecologically driven variation in the rate of morphological evolution. Páramo species (Jamesonia) display morphological adaptations consistent with convergent evolution in response to the demands of a highly exposed environment but these adaptations are associated with microhabitat use rather than the páramo per se. Species that are associated with exposed microhabitats (including Jamesonia and Eriorsorus) are characterized by many but short pinnae per frond whereas species occupying sheltered microhabitats (primarily Eriosorus) have few but long pinnae per frond. Pinnae length declines more rapidly with altitude in sheltered species. Rates of speciation are significantly higher among páramo than non-páramo lineages supporting the hypothesis of adaptation and divergence in the unique Páramo biodiversity hotspot.

  16. Microbes, Mineral Evolution, and the Rise of Microcontinents-Origin and Coevolution of Life with Early Earth.

    Science.gov (United States)

    Grosch, Eugene G; Hazen, Robert M

    2015-10-01

    Earth is the most mineralogically diverse planet in our solar system, the direct consequence of a coevolving geosphere and biosphere. We consider the possibility that a microbial biosphere originated and thrived in the early Hadean-Archean Earth subseafloor environment, with fundamental consequences for the complex evolution and habitability of our planet. In this hypothesis paper, we explore possible venues for the origin of life and the direct consequences of microbially mediated, low-temperature hydrothermal alteration of the early oceanic lithosphere. We hypothesize that subsurface fluid-rock-microbe interactions resulted in more efficient hydration of the early oceanic crust, which in turn promoted bulk melting to produce the first evolved fragments of felsic crust. These evolved magmas most likely included sialic or tonalitic sheets, felsic volcaniclastics, and minor rhyolitic intrusions emplaced in an Iceland-type extensional setting as the earliest microcontinents. With the further development of proto-tectonic processes, these buoyant felsic crustal fragments formed the nucleus of intra-oceanic tonalite-trondhjemite-granitoid (TTG) island arcs. Thus microbes, by facilitating extensive hydrothermal alteration of the earliest oceanic crust through bioalteration, promoted mineral diversification and may have been early architects of surface environments and microcontinents on young Earth. We explore how the possible onset of subseafloor fluid-rock-microbe interactions on early Earth accelerated metavolcanic clay mineral formation, crustal melting, and subsequent metamorphic mineral evolution. We also consider environmental factors supporting this earliest step in geosphere-biosphere coevolution and the implications for habitability and mineral evolution on other rocky planets, such as Mars.

  17. The Importance of Dietary Carbohydrate in Human Evolution

    OpenAIRE

    Hardy, K.; Brand-Miller, J.; Brown, K. D.; Thomas, M. G.; Copeland, L.

    2015-01-01

    We propose that plant foods containing high quantities of starch were essential for the evolution of the human phenotype during the Pleistocene. Although previous studies have highlighted a stone tool-mediated shift from primarily plant-based to primarily meat-based diets as critical in the development of the brain and other human traits, we argue that digestible carbohydrates were also necessary to accommodate the increased metabolic demands of a growing brain. Furthermore, we acknowledge th...

  18. Limestone percussion tools from the late Early Pleistocene sites of Barranco León and Fuente Nueva 3 (Orce, Spain).

    Science.gov (United States)

    Barsky, Deborah; Vergès, Josep-María; Sala, Robert; Menéndez, Leticia; Toro-Moyano, Isidro

    2015-11-19

    In recent years, there is growing interest in the study of percussion scars and breakage patterns on hammerstones, cores and tools from Oldowan African and Eurasian lithic assemblages. Oldowan stone toolkits generally contain abundant small-sized flakes and their corresponding cores, and are characterized by their structural dichotomy of heavy- and light-duty tools. This paper explores the significance of the lesser known heavy-duty tool component, providing data from the late Lower Pleistocene sites of Barranco León and Fuente Nueva 3 (Orce, Spain), dated 1.4-1.2 Myr. Using quantitative and qualitative data from the large-sized limestone industries from these two major sites, we present a new methodology highlighting their morpho-technological features. In the light of the results, we discuss the shortfalls of extant classificatory methods for interpreting the role of percussive technology in early toolkits. This work is rooted in an experimental program designed to reproduce the wide range of percussion marks observed on the limestone artefacts from these two sites. A visual and descriptive reference is provided as an interpretative aid for future comparative research. Further experiments using a variety of materials and gestures are still needed before the elusive traces yield the secrets of the kinds of percussive activities carried out by hominins at these, and other, Oldowan sites. © 2015 The Author(s).

  19. Size evolution in Goodwin’s small-eared shrew, Cryptotis goodwini

    Science.gov (United States)

    Woodman, N.; Merritt, J.F.; Churchfield, S.; Hutterer, R.; Sheftel, B.A.

    2005-01-01

    Fossils of Cryptotis goodwini from Honduras indicate that body sizes of modern individuals average at least 18% larger than among members of the late Pleistocene population of this species. Palynological and other paleoenvironmental studies provide evidence that the Neotropical montane environments that these shrews inhabit were cooler and drier in the late Pleistocene than at present and supported communities of plants without modern analog. Therefore, the most likely cause of this change in size ultimately was related to climatic change at the end of the Pleistocene?but to what specific factors did the species respond? I examined the possibilities that this species changed in size: to accommodate a change in temperature regime; to escape from predators; as a response to a change in intensity of interspecific competition; to take advantage of a newly abundant food resource. Based on evidence from studies of modern communities of shrews and niche partitioning, I hypothesized that size evolution in C. goodwini was directly related to changes in the community of soil and soil-surface invertebrates upon which the species depends, specifically an increase in the availability of earthworms (Annelida).

  20. Root evolution at the base of the lycophyte clade: insights from an Early Devonian lycophyte

    Science.gov (United States)

    Matsunaga, Kelly K. S.; Tomescu, Alexandru M. F.

    2016-01-01

    Background and Aims The evolution of complex rooting systems during the Devonian had significant impacts on global terrestrial ecosystems and the evolution of plant body plans. However, detailed understanding of the pathways of root evolution and the architecture of early rooting systems is currently lacking. We describe the architecture and resolve the structural homology of the rooting system of an Early Devonian basal lycophyte. Insights gained from these fossils are used to address lycophyte root evolution and homology. Methods Plant fossils are preserved as carbonaceous compressions at Cottonwood Canyon (Wyoming), in the Lochkovian–Pragian (∼411 Ma; Early Devonian) Beartooth Butte Formation. We analysed 177 rock specimens and documented morphology, cuticular anatomy and structural relationships, as well as stratigraphic position and taphonomic conditions. Key Results The rooting system of the Cottonwood Canyon lycophyte is composed of modified stems that bear fine, dichotomously branching lateral roots. These modified stems, referred to as root-bearing axes, are produced at branching points of the above-ground shoot system. Root-bearing axes preserved in growth position exhibit evidence of positive gravitropism, whereas the lateral roots extend horizontally. Consistent recurrence of these features in successive populations of the plant preserved in situ demonstrates that they represent constitutive structural traits and not opportunistic responses of a flexible developmental programme. Conclusions This is the oldest direct evidence for a rooting system preserved in growth position. These rooting systems, which can be traced to a parent plant, include some of the earliest roots known to date and demonstrate that substantial plant–substrate interactions were under way by Early Devonian time. The morphological relationships between stems, root-bearing axes and roots corroborate evidence that positive gravitropism and root identity were evolutionarily

  1. Hydrogen, metals, bifurcating electrons, and proton gradients: the early evolution of biological energy conservation.

    Science.gov (United States)

    Martin, William F

    2012-03-09

    Life is a persistent, self-specified set of far from equilibrium chemical reactions. In modern microbes, core carbon and energy metabolism are what keep cells alive. In very early chemical evolution, the forerunners of carbon and energy metabolism were the processes of generating reduced carbon compounds from CO(2) and the mechanisms of harnessing energy as compounds capable of doing some chemical work. The process of serpentinization at alkaline hydrothermal vents holds promise as a model for the origin of early reducing power, because Fe(2+) in the Earth's crust reduces water to H(2) and inorganic carbon to methane. The overall geochemical process of serpentinization is similar to the biochemical process of methanogenesis, and methanogenesis is similar to acetogenesis in that both physiologies allow energy conservation from the reduction of CO(2) with electrons from H(2). Electron bifurcation is a newly recognized cytosolic process that anaerobes use generate low potential electrons, it plays an important role in some forms of methanogenesis and, via speculation, possibly in acetogenesis. Electron bifurcation likely figures into the early evolution of biological energy conservation. Copyright © 2011. Published by Elsevier B.V.

  2. The TIM Barrel Architecture Facilitated the Early Evolution of Protein-Mediated Metabolism.

    Science.gov (United States)

    Goldman, Aaron David; Beatty, Joshua T; Landweber, Laura F

    2016-01-01

    The triosephosphate isomerase (TIM) barrel protein fold is a structurally repetitive architecture that is present in approximately 10% of all enzymes. It is generally assumed that this ubiquity in modern proteomes reflects an essential historical role in early protein-mediated metabolism. Here, we provide quantitative and comparative analyses to support several hypotheses about the early importance of the TIM barrel architecture. An information theoretical analysis of protein structures supports the hypothesis that the TIM barrel architecture could arise more easily by duplication and recombination compared to other mixed α/β structures. We show that TIM barrel enzymes corresponding to the most taxonomically broad superfamilies also have the broadest range of functions, often aided by metal and nucleotide-derived cofactors that are thought to reflect an earlier stage of metabolic evolution. By comparison to other putatively ancient protein architectures, we find that the functional diversity of TIM barrel proteins cannot be explained simply by their antiquity. Instead, the breadth of TIM barrel functions can be explained, in part, by the incorporation of a broad range of cofactors, a trend that does not appear to be shared by proteins in general. These results support the hypothesis that the simple and functionally general TIM barrel architecture may have arisen early in the evolution of protein biosynthesis and provided an ideal scaffold to facilitate the metabolic transition from ribozymes, peptides, and geochemical catalysts to modern protein enzymes.

  3. Plio-Pleistocene extinctions and immigration credit reflected in the size-frequency distribution of Mediterranean marine bivalves

    Science.gov (United States)

    Nawrot, Rafal; Zuschin, Martin; Chattopadhyay, Devapriya

    2015-04-01

    Following the opening of the Suez Canal hundreds of Red Sea species have entered the Mediterranean Sea making it a global hot spot of marine bioinvasion. With the ongoing influx of the subtropical and tropical alien species and increasing sea surface temperatures, the Mediterranean biota is currently gaining a more tropical character and increasingly becoming a mixture of faunal stocks with different evolutionary histories. This susceptibility to invasion was suggested to reflect the presence of an empty ecological space left after decimation of incumbent warm-water fauna during Plio-Pleistocene climate fluctuations. As molluscs are among the most prolific immigrants, we test this hypothesis using data on taxonomic composition and body size of Pliocene Mediterranean bivalves derived from the literature sources and museum collections. The Pliocene inter-specific size-frequency distribution (SFD) is strikingly similar to the SFDs of the Recent Red Sea bivalve fauna, in spite of different biogeographic provenance and the absence of true reef ecosystems in the Pliocene of the Mediterranean region. In contrast, body-size patterns in both assemblages are significantly different from the present-day Mediterranean fauna characterized by smaller median and modal size. Our preliminary results suggest that the distinct shape of the modern Mediterranean SFD may reflect the selective nature of the late Piacenzian - Galesian (Late Pliocene - Early Pleistocene) extinctions pulses related to the onset of the Northern Hemisphere glaciations. These extinctions affected almost 40% of Pliocene species and were biased towards large-bodied taxa. They were not followed by re-immigration of warm-water species owing to the isolation from the tropical Atlantic biota by the cold upwelling along the NW coasts of Africa. The resulting invasion credit (sensu Jackson & Sax, 2010) is currently being paid by the Red Sea bivalves colonizing the Mediterranean Sea through the Suez Canal. Successful

  4. A geometric morphometric analysis of hominin upper second and third molars, with particular emphasis on European Pleistocene populations.

    Science.gov (United States)

    Gómez-Robles, Aida; Bermúdez de Castro, José María; Martinón-Torres, María; Prado-Simón, Leyre; Arsuaga, Juan Luis

    2012-09-01

    The study of dental morphology by means of geometric morphometric methods allows for a detailed and quantitative comparison of hominin species that is useful for taxonomic assignment and phylogenetic reconstruction. Upper second and third molars have been studied in a comprehensive sample of Plio- and Pleistocene hominins from African, Asian and European sites in order to complete our analysis of the upper postcanine dentition. Intraspecific variation in these two molars is high, but some interspecific trends can be identified. Both molars exhibit a strong reduction of the distal cusps in recent hominin species, namely European Homo heidelbergensis, Homo neanderthalensis and Homo sapiens, but this reduction shows specific patterns and proportions in the three groups. Second molars tend to show four well developed cusps in earlier hominin species and their morphology is only marginally affected by allometric effects. Third molars can be incipiently reduced in earlier species and they evince a significant allometric component, identified both inter- and intraspecifically. European Middle Pleistocene fossils from Sima de los Huesos (SH) show a very strong reduction of these two molars, even more marked than the reduction observed in Neanderthals and in modern human populations. The highly derived shape of SH molars points to an early acquisition of typical Neanderthal dental traits by pre-Neanderthal populations and to a deviation of this population from mean morphologies of other European Middle Pleistocene groups. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States

    Science.gov (United States)

    Van Gosen, Bradley S.; Hall, Susan M.

    2017-12-18

    This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments.In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U3O8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U3O8.The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age.Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234U/238U activity ratios indicate two separate, distinct fluid sources.

  6. FOSSIL REPTILES FROM THE PLEISTOCENE HOMO-BEARING LOCALITY OF BUIA (ERITREA, NORTHERN DANAKIL DEPRESSION

    Directory of Open Access Journals (Sweden)

    MASSIMO DELFINO

    2004-12-01

    Full Text Available The early to early-Middle Pleistocene fossil assemblage form the Buia area (Northern Danakil Depression, Eritrea hosts, along with Homo and several other large mammal taxa, the following reptiles: Nile Crocodile, Crocodylus niloticus, Serrated Hinged Terrapin, Pelusios cf. P. sinuatus, Nile Monitor, Varanus niloticus and African Rock Python, Python gr. sebae. All the identified taxa belong to living species. At present, these taxa do not occur in the Northern Danakil depression since it is an arid area. P. sinuatus is not a member of the Eritrean herpetofauna. Although the marked preponderance of the crocodile remains is probably connected to the taphonomy of the sites and the collecting methods used, the ecological value of the reptile fauna corroborates that of the mammals, in indicating a lacustrine or fluvio-deltaic palaeoenvironment and a tropical/subtropical or even sub-Sahelic climate. The Buia remains represent the first reported Eritrean palaeoherpetofauna. 

  7. Stone tools associated with middle pleistocene fauna in the Toca da Esperanca, central region, Bahia state, Brazil

    International Nuclear Information System (INIS)

    Lumley, H. de; Lumley, M.A. de; Beltrao, M.C.M.C.

    1987-01-01

    Excavations (1 ) organized on a 12 m 2 surface have exhumed quaternary deposits under a 50 cm carbonate crust (layer I). These deposits were composed of angular broken stones compacted into breccia (layer II), yellowish sand (layer III) and reddish clayey sand (leyer IV), containing fossilized bones. These bones belong to extinct quaternary species, in particular Equidae. The uranium-thorium method was used to date several bone samples found in situ which gave these faunas an age of about 300,000 years. Several quartzite stone tools as well as fragments of quartzite and quartz pebbles were discovered among the fossil bones. In particular, the fragment of a pebble, broken by violent percussion and a chopper were found. The raw materials, quartzite and quartz, naturally absent from the cave could only have been brought there by prehistoric man. The Toca da Esperanca is, therefore, the most ancient site known on the American continent which contains evidence of early man. It provides evidence of human presence from the Middle Pleistocene period, about 300,000 years ago, well before the Calico sites in California (about 200,000 years) and the Santa Raimundo Nonato sites (about 30,000 years). In the light of these new discoveries, it is possible to surmise that Homo Erectus came from Asia very early during the Middle Pleistocene, passing the Behring Strait, during one of the big recessions in ocean levels which took place in the cold quaternary periods. (author) [pt

  8. Pleistocene Palaeoart of Africa

    Directory of Open Access Journals (Sweden)

    Robert G. Bednarik

    2013-02-01

    Full Text Available This comprehensive review of all currently known Pleistocene rock art of Africa shows that the majority of sites are located in the continent’s south, but that the petroglyphs at some of them are of exceptionally great antiquity. Much the same applies to portable palaeoart of Africa. The current record is clearly one of paucity of evidence, in contrast to some other continents. Nevertheless, an initial synthesis is attempted, and some preliminary comparisons with the other continents are attempted. Certain parallels with the existing record of southern Asia are defined.

  9. MAGNETOSTRATIGRAPHY OF THE HOMO-BEARING PLEISTOCENE DANDIERO BASIN (DANAKIL DEPRESSION, ERITREA

    Directory of Open Access Journals (Sweden)

    ANDREA ALBIANELLI

    2004-12-01

    Full Text Available Four magnetozones have been found in the 530 m thick profile of the Dandiero Group. The lower unit, the Bukra Sand and Gravel, extends in the R1 reversed magnetozone from 150 m below the tephra level which was used as the reference marker between the sampled sections. The normal magnetozone N1 is almost completely covered by the lacustrine and deltaic sediments of the Alat Formation, while the following reversed magnetozone contains both the Wara Sand and Gravel and the lacustrine Goreya Fm. The N2 polarity zone is completely occupied by the Aro Sand. This polarity sequence has been calibrated to the geomagnetic time scale using the Early to Middle Pleistocene age of the associated vertebrate fauna and fission-track dating. The four magnetozones were thus regarded as representing the chrons by which the Pleistocene is correlated with magnetochronology. Their three reversal boundaries provided the dates of 1.07, 0.99 and 0.78 Ma, allowing to determine average sedimentation rates close to 1 m/ky. Cyclostratigraphy of the magnetic signal, analysed by the spectral analysis of the time series across the Jaramillo and late Matuyama chrons, confirmed that value. The evidenced cyclicities were directly related to the alternating lithofacies, and both to the astronomical parameters driving the climate changes during the deposition of the Dandiero group (some five hundred thousand years. The section with the Homo site covers the Jaramillo/Matuyama boundary, and the Homo bed located 2 m below this limit is dated 0.992 Ma. 

  10. Cranial discrete traits in the middle pleistocene humans from Sima de los Huesos (Sierra de Atapuerca, Spain). Does hypostosis represent any increase in "ontogenetic stress" along the Neanderthal lineage?

    Science.gov (United States)

    Manzi, G; Gracia, A; Arsuaga, J L

    2000-03-01

    Cranial discrete traits may be regarded as markers of dynamic responses to general and local perturbations of the morphogenetic pattern, particularly when they are viewed and examined in terms of hypostosis vs. hyperostosis. There are indications, in fact, that the variation between these two opposite conditions relates to mechanical stress suffered by the bony structures during early stages of growth and development. In a previous comparison between Neanderthals and modern humans, variable degrees and contrasting distribution patterns of hypostosis were found [Manzi et al. (1996), JHE30: 511-527]. In the present paper, the occurrence, expression and cranial distribution of 20 hypo-hyperostotic traits are examined in the Middle Pleistocene sample from Atapuerca - Sima de los Huesos (Spain), with the principal aim being to test whether or not the degree of cranial hypostosis increases during the evolution of the Neanderthals. Other Middle Pleistocene representatives of the genus Homo (Kabwe and Petralona), the Italian Neanderthals, and a large recent European sample are also considered. A general consistency between the gradual appearance and stabilization of the Neanderthal cranial features and the results of the present analysis is found and is interpreted as an indication that hypostosis does mark the occurrence of "ontogenetic stress". As suggested more than half a century ago by S. Sergi, an increase in "ontogenetic stress" in the Neanderthal lineage could result from the relationship between intracranial pressures and other (heterochronic) effects produced by the growth of a large brain (encephalization) and the ossification of an archaic (platycephalic) cranial vault. Copyright 2000 Academic Press.

  11. Origins and Early Evolution of the tRNA Molecule

    Directory of Open Access Journals (Sweden)

    Koji Tamura

    2015-12-01

    Full Text Available Modern transfer RNAs (tRNAs are composed of ~76 nucleotides and play an important role as “adaptor” molecules that mediate the translation of information from messenger RNAs (mRNAs. Many studies suggest that the contemporary full-length tRNA was formed by the ligation of half-sized hairpin-like RNAs. A minihelix (a coaxial stack of the acceptor stem on the T-stem of tRNA can function both in aminoacylation by aminoacyl tRNA synthetases and in peptide bond formation on the ribosome, indicating that it may be a vestige of the ancestral tRNA. The universal CCA-3′ terminus of tRNA is also a typical characteristic of the molecule. “Why CCA?” is the fundamental unanswered question, but several findings give a comprehensive picture of its origin. Here, the origins and early evolution of tRNA are discussed in terms of various perspectives, including nucleotide ligation, chiral selectivity of amino acids, genetic code evolution, and the organization of the ribosomal peptidyl transferase center (PTC. The proto-tRNA molecules may have evolved not only as adaptors but also as contributors to the composition of the ribosome.

  12. Aspect of the early human occupation in Uruguay

    International Nuclear Information System (INIS)

    Castineira, C.

    2012-01-01

    This work is about the studies carried out in the geological sedimentary formation called So pa which is located in the basaltic basin in the north of Uruguay. The results obtained allow to recognize characteristics of the late pleistocene - early holocene as well as geometric morpho metrics aspects

  13. Pleistocene lake level changes in Western Mongolia

    Science.gov (United States)

    Borodavko, P. S.

    2009-04-01

    Global cooling in the Early Pleistocene caused extensive continental glaciation in the northern hemisphere including the arid areas of Central Asia. The reduction of temperatures (particularly summer temperatures) reduced evaporation and strengthened the importance of precipitation. The simultaneity of "lakes periods" (pluvials) and stages of glaciation is established experience confirmed by investigations in the west of North America and Russia. In the Mongolian Great Lakes Depression new evidence for similar conditions is found. The Great Lakes Depression is one of the largest in Central Asia, and is divided into 2 main Lakes basins: Hyargas Lake Basin and Uvs Lake Basin. The basin is 600-650 km in length with a width of 200-250 km in the north and 60-100 km in the south. Total catchment area is about 186600 km2. The elevation of the basin floor is from 1700 m a.s.l. to 760 m a.s.l., decreasing to the north and south-east. The depression extends south-north and is bounded by mountains: Tannu-Ola to the north, Hangai to the east; Gobi Altai to the south and Mongolian Altay to the west. The maximum elevation of the mountains is 4000 m a.s.l. There are some mountains with an elevation between 2000 and 3000 m a.s.l in the lake catchment. These mountains are not glaciated today. The geological record [1] suggests the Great Lakes Depression already existed in the Mesozoic, but assumed its modern form only during the Pliocene-Quaternary when tectonic movements caused the uplift of the surrounding mountains. A phase of tectonic stability occurred during the Late Quaternary. The depression is filled by Quaternary fluvial, aeolian and lacustrine deposits (e.g. sand, pebbles). The Neogene deposits are represented by coloured clay, marl, sand and sandstone [1]. Hyargas Lake is the end base level of erosion of the lake group consisting of the Hara-Us Nur, Dorgon, Hara Nur and Airag lakes. Hyargas is one of the largest lakes in Mongolia, with a water surface of 1,407 km2. The

  14. Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America

    OpenAIRE

    Mitchell, Kieren J.; Bray, Sarah C.; Bover, Pere; Soibelzon, Leopoldo; Schubert, Blaine W.; Prevosti, Francisco; Prieto, Alfredo; Martin, Fabiana; Austin, Jeremy J.; Cooper, Alan

    2016-01-01

    The Tremarctinae are a subfamily of bears endemic to the New World, including two of the largest terrestrial mammalian carnivores that have ever lived: the giant, short-faced bears Arctodus simus from North America and Arctotherium angustidens from South America (greater than or equal to 1000 kg). Arctotherium angustidens became extinct during the Early Pleistocene, whereas Arctodus simus went extinct at the very end of the Pleistocene. The only living tremarctine is the spectacled bear (Trem...

  15. Ice-rafting from the British-Irish ice sheet since the earliest Pleistocene (2.6 million years ago): implications for long-term mid-latitudinal ice-sheet growth in the North Atlantic region

    NARCIS (Netherlands)

    Thierens, M.; Pirlet, H.; Colin, C.; Latruwe, K.; Vanhaecke, F.; Lee, J.R.; Stuut, J.-B.; Titschaeck, J.; Titschack, J.; Huvenne, V.; Dorschel, B.; Wheeler, A.J.; Henriet, J.P.

    2012-01-01

    The Plio-Pleistocene intensification of Northern Hemisphere continental ice-sheet development is known to have profoundly affected the global climate system. Evidence for early continental glaciation is preserved in sediments throughout the North Atlantic Ocean, where ice-rafted detritus (IRD)

  16. Body size and premolar evolution in the early-middle eocene euprimates of Wyoming.

    Science.gov (United States)

    Jones, Katrina E; Rose, Kenneth D; Perry, Jonathan M G

    2014-01-01

    The earliest euprimates to arrive in North America were larger-bodied notharctids and smaller-bodied omomyids. Through the Eocene, notharctids generally continued to increase in body size, whereas omomyids generally radiated within small- and increasingly mid-sized niches in the middle Eocene. This study examines the influence of changing body size and diet on the evolution of the lower fourth premolar in Eocene euprimates. The P4 displays considerable morphological variability in these taxa. Despite the fact that most studies of primate dental morphology have focused on the molars, P4 can also provide important paleoecological insights. We analyzed the P4 from 177 euprimate specimens, representing 35 species (11 notharctids and 24 omomyids), in three time bins of approximately equal duration: early Wasatchian, late Wasatchian, and Bridgerian. Two-dimensional surface landmarks were collected from lingual photographs, capturing important variation in cusp position and tooth shape. Disparity metrics were calculated and compared for the three time bins. In the early Eocene, notharctids have a more molarized P4 than omomyids. During the Bridgerian, expanding body size range of omomyids was accompanied by a significant increase in P4 disparity and convergent evolution of the semimolariform condition in the largest omomyines. P4 morphology relates to diet in early euprimates, although patterns vary between families. Copyright © 2013 Wiley Periodicals, Inc.

  17. Cross-sectional properties of the lower limb long bones in the Middle Pleistocene Sima de los Huesos sample (Sierra de Atapuerca, Spain).

    Science.gov (United States)

    Rodríguez, Laura; Carretero, José Miguel; García-González, Rebeca; Arsuaga, Juan Luis

    2018-04-01

    The recovery to date of three complete and five partial femora, seven complete tibiae, and four complete fibulae from the Atapuerca Sima de los Huesos site provides an opportunity to analyze the biomechanical cross-sectional properties in this Middle Pleistocene population and to compare them with those of other fossil hominins and recent modern humans. We have performed direct comparisons of the cross-sectional geometric parameters and reduced major axis (RMA) regression lines among different samples. We have determined that Atapuerca Sima de los Huesos (SH) fossils have significantly thicker cortices than those of recent modern humans for the three leg bones at all diaphyseal levels, except that of the femur at 35% of biomechanical length. The SH bones are similar to those of Neandertals and Middle Pleistocene humans and different from Homo sapiens in their diaphyseal cross-sectional shape and strength parameters. When standardized by estimated body size, both the SH and Neandertal leg bones have in general greater strength than those of H. sapiens from the early modern (EMH), Upper Paleolithic (UP), and recent populations (RH). The Sima de los Huesos human leg bones have, in general terms, an ancestral pattern similar to that of Pleistocene humans and differing from H. sapiens. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Post-Palaeozoic evolution of weathered landsurfaces in Uganda by tectonically controlled deep weathering and stripping

    Science.gov (United States)

    Taylor, R. G.; Howard, K. W. F.

    1998-11-01

    A model for the evolution of weathered landsurfaces in Uganda is developed using available geotectonic, climatic, sedimentological and chronological data. The model demonstrates the pivotal role of tectonic uplift in inducing cycles of stripping, and tectonic quiescence for cycles of deep weathering. It is able to account for the development of key landforms, such as inselbergs and duricrust-capped plateaux, which previous hypotheses of landscape evolution that are based on climatic or eustatic controls are unable to explain. Development of the Ugandan landscape is traced back to the Permian. Following late Palaeozoic glaciation, a trend towards warmer and more humid climates through the Mesozoic enabled deep weathering of the Jurassic/mid-Cretaceous surface in Uganda during a period of prolonged tectonic quiescence. Uplift associated with the opening South Atlantic Ocean terminated this cycle and instigated a cycle of stripping between the mid-Cretaceous and early Miocene. Deep weathering on the succeeding Miocene to recent (African) surface has occurred from Miocene to present but has been interrupted in the areas adjacent to the western rift where development of a new drainage base level has prompted cycles of stripping in the Miocene and Pleistocene.

  19. Late Pleistocene fishes of the Tennessee River Basin: an analysis of a late Pleistocene freshwater fish fauna from Bell Cave (site ACb-2) in Colbert County, Alabama, USA

    OpenAIRE

    Stephen J. Jacquemin; Jun A. Ebersole; William C. Dickinson; Charles N. Ciampaglio

    2016-01-01

    The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (?10,000 to 30,000 years B.P.) lead...

  20. Early human speciation, brain expansion and dispersal influenced by African climate pulses.

    Directory of Open Access Journals (Sweden)

    Susanne Shultz

    Full Text Available Early human evolution is characterised by pulsed speciation and dispersal events that cannot be explained fully by global or continental paleoclimate records. We propose that the collated record of ephemeral East African Rift System (EARS lakes could be a proxy for the regional paleoclimate conditions experienced by early hominins. Here we show that the presence of these lakes is associated with low levels of dust deposition in both West African and Mediterranean records, but is not associated with long-term global cooling and aridification of East Africa. Hominin expansion and diversification seem to be associated with climate pulses characterized by the precession-forced appearance and disappearance of deep EARS lakes. The most profound period for hominin evolution occurs at about 1.9 Ma; with the highest recorded diversity of hominin species, the appearance of Homo (sensu stricto and major dispersal events out of East Africa into Eurasia. During this period, ephemeral deep-freshwater lakes appeared along the whole length of the EARS, fundamentally changing the local environment. The relationship between the local environment and hominin brain expansion is less clear. The major step-wise expansion in brain size around 1.9 Ma when Homo appeared was coeval with the occurrence of ephemeral deep lakes. Subsequent incremental increases in brain size are associated with dry periods with few if any lakes. Plio-Pleistocene East African climate pulses as evinced by the paleo-lake records seem, therefore, fundamental to hominin speciation, encephalisation and migration.

  1. Early human speciation, brain expansion and dispersal influenced by African climate pulses.

    Science.gov (United States)

    Shultz, Susanne; Maslin, Mark

    2013-01-01

    Early human evolution is characterised by pulsed speciation and dispersal events that cannot be explained fully by global or continental paleoclimate records. We propose that the collated record of ephemeral East African Rift System (EARS) lakes could be a proxy for the regional paleoclimate conditions experienced by early hominins. Here we show that the presence of these lakes is associated with low levels of dust deposition in both West African and Mediterranean records, but is not associated with long-term global cooling and aridification of East Africa. Hominin expansion and diversification seem to be associated with climate pulses characterized by the precession-forced appearance and disappearance of deep EARS lakes. The most profound period for hominin evolution occurs at about 1.9 Ma; with the highest recorded diversity of hominin species, the appearance of Homo (sensu stricto) and major dispersal events out of East Africa into Eurasia. During this period, ephemeral deep-freshwater lakes appeared along the whole length of the EARS, fundamentally changing the local environment. The relationship between the local environment and hominin brain expansion is less clear. The major step-wise expansion in brain size around 1.9 Ma when Homo appeared was coeval with the occurrence of ephemeral deep lakes. Subsequent incremental increases in brain size are associated with dry periods with few if any lakes. Plio-Pleistocene East African climate pulses as evinced by the paleo-lake records seem, therefore, fundamental to hominin speciation, encephalisation and migration.

  2. Fossils in Late Cretaceous to early Palaeocene flint nodules embedded in pleistocene glaciofluvial sediments near Fukov (Děčín District, Northern Bohemia)

    Czech Academy of Sciences Publication Activity Database

    Pokorný, R.; Kaše, J.; Kvaček, J.; Zágoršek, K.; Kočí, T.; Žítt, Jiří

    2012-01-01

    Roč. 68, 3/4 (2012), s. 119-131 ISSN 0036-5343 Institutional support: RVO:67985831 Keywords : Erratic boulders * Flint * Glaciofluvial sediments * Late Cretaceous * Northern Bohemia * Palaeocene * Pleistocene glaciation * Taphocoenosis Subject RIV: DB - Geology ; Mineralogy http://www.nm.cz/publikace/archiv.php?id=4&rok=68&kcislu=3-4&f_=Zobrazit

  3. Lucy's flat feet: the relationship between the ankle and rearfoot arching in early hominins.

    Directory of Open Access Journals (Sweden)

    Jeremy M DeSilva

    Full Text Available BACKGROUND: In the Plio-Pleistocene, the hominin foot evolved from a grasping appendage to a stiff, propulsive lever. Central to this transition was the development of the longitudinal arch, a structure that helps store elastic energy and stiffen the foot during bipedal locomotion. Direct evidence for arch evolution, however, has been somewhat elusive given the failure of soft-tissue to fossilize. Paleoanthropologists have relied on footprints and bony correlates of arch development, though little consensus has emerged as to when the arch evolved. METHODOLOGY/PRINCIPAL FINDINGS: Here, we present evidence from radiographs of modern humans (n = 261 that the set of the distal tibia in the sagittal plane, henceforth referred to as the tibial arch angle, is related to rearfoot arching. Non-human primates have a posteriorly directed tibial arch angle, while most humans have an anteriorly directed tibial arch angle. Those humans with a posteriorly directed tibial arch angle (8% have significantly lower talocalcaneal and talar declination angles, both measures of an asymptomatic flatfoot. Application of these results to the hominin fossil record reveals that a well developed rearfoot arch had evolved in Australopithecus afarensis. However, as in humans today, Australopithecus populations exhibited individual variation in foot morphology and arch development, and "Lucy" (A.L. 288-1, a 3.18 Myr-old female Australopithecus, likely possessed asymptomatic flat feet. Additional distal tibiae from the Plio-Pleistocene show variation in tibial arch angles, including two early Homo tibiae that also have slightly posteriorly directed tibial arch angles. CONCLUSIONS/SIGNIFICANCE: This study finds that the rearfoot arch was present in the genus Australopithecus. However, the female Australopithecus afarensis "Lucy" has an ankle morphology consistent with non-pathological flat-footedness. This study suggests that, as in humans today, there was variation in arch

  4. Early galactic evolution and the nature of the first stars

    International Nuclear Information System (INIS)

    Jones, J.E.

    1985-05-01

    In this paper, the observational data relating to the early evolution of the Galaxy are reviewed in order to assess the plausibility of a number of models that have been proposed for the first stars. On the basis of standard fragmentation models, it is argued that primordial stars were very similar to normal stars, but that in some circumstances the formation of low mass primordial stars may be suppressed through the dissociation of molecular hydrogen by UV radiation. The existence of these conditions at the time of formation of the Galaxy could explain the absence of zero-metal stars. (orig./WL)

  5. The early Miocene balaenid Morenocetus parvus from Patagonia (Argentina and the evolution of right whales

    Directory of Open Access Journals (Sweden)

    Mónica R. Buono

    2017-12-01

    Full Text Available Balaenidae (right and bowhead whales are a key group in understanding baleen whale evolution, because they are the oldest surviving lineage of crown Mysticeti, with a fossil record that dates back ∼20 million years. However, this record is mostly Pliocene and younger, with most of the Miocene history of the clade remaining practically unknown. The earliest recognized balaenid is the early Miocene Morenocetus parvus Cabrera, 1926 from Argentina. M. parvus was originally briefly described from two incomplete crania, a mandible and some cervical vertebrae collected from the lower Miocene Gaiman Formation of Patagonia. Since then it has not been revised, thus remaining a frequently cited yet enigmatic fossil cetacean with great potential for shedding light on the early history of crown Mysticeti. Here we provide a detailed morphological description of this taxon and revisit its phylogenetic position. The phylogenetic analysis recovered the middle Miocene Peripolocetus as the earliest diverging balaenid, and Morenocetus as the sister taxon of all other balaenids. The analysis of cranial and periotic morphology of Morenocetus suggest that some of the specialized morphological traits of modern balaenids were acquired by the early Miocene and have remained essentially unchanged up to the present. Throughout balaenid evolution, morphological changes in skull arching and ventral displacement of the orbits appear to be coupled and functionally linked to mitigating a reduction of the field of vision. The body length of Morenocetus and other extinct balaenids was estimated and the evolution of body size in Balaenidae was reconstructed. Optimization of body length on our phylogeny of Balaenidae suggests that the primitive condition was a relatively small body length represented by Morenocetus, and that gigantism has been acquired independently at least twice (in Balaena mysticetus and Eubalaena spp., with the earliest occurrence of this trait in the late

  6. The early Miocene balaenid Morenocetus parvus from Patagonia (Argentina) and the evolution of right whales

    Science.gov (United States)

    Cozzuol, Mario A.; Fitzgerald, Erich M.G.

    2017-01-01

    Balaenidae (right and bowhead whales) are a key group in understanding baleen whale evolution, because they are the oldest surviving lineage of crown Mysticeti, with a fossil record that dates back ∼20 million years. However, this record is mostly Pliocene and younger, with most of the Miocene history of the clade remaining practically unknown. The earliest recognized balaenid is the early Miocene Morenocetus parvus Cabrera, 1926 from Argentina. M. parvus was originally briefly described from two incomplete crania, a mandible and some cervical vertebrae collected from the lower Miocene Gaiman Formation of Patagonia. Since then it has not been revised, thus remaining a frequently cited yet enigmatic fossil cetacean with great potential for shedding light on the early history of crown Mysticeti. Here we provide a detailed morphological description of this taxon and revisit its phylogenetic position. The phylogenetic analysis recovered the middle Miocene Peripolocetus as the earliest diverging balaenid, and Morenocetus as the sister taxon of all other balaenids. The analysis of cranial and periotic morphology of Morenocetus suggest that some of the specialized morphological traits of modern balaenids were acquired by the early Miocene and have remained essentially unchanged up to the present. Throughout balaenid evolution, morphological changes in skull arching and ventral displacement of the orbits appear to be coupled and functionally linked to mitigating a reduction of the field of vision. The body length of Morenocetus and other extinct balaenids was estimated and the evolution of body size in Balaenidae was reconstructed. Optimization of body length on our phylogeny of Balaenidae suggests that the primitive condition was a relatively small body length represented by Morenocetus, and that gigantism has been acquired independently at least twice (in Balaena mysticetus and Eubalaena spp.), with the earliest occurrence of this trait in the late Miocene–early

  7. New insights on early evolution of spiny-rayed fishes (Teleostei: Acanthomorpha

    Directory of Open Access Journals (Sweden)

    Wei-Jen eChen

    2014-10-01

    Full Text Available The Acanthomorpha is the largest group of teleost fishes with about one third of extant vertebrate species. In the course of its evolution this lineage experienced several episodes of radiation, leading to a large number of descendant lineages differing profoundly in morphology, ecology, distribution and behavior. Although Acanthomorpha was recognized decades ago, we are only now beginning to decipher its large-scale, time-calibrated phylogeny, a prerequisite to test various evolutionary hypotheses explaining the tremendous diversity of this group. In this study, we provide new insights into the early evolution of the acanthomorphs and the euteleost allies based on the phylogenetic analysis of a newly developed dataset combining nine nuclear and mitochondrial gene markers. Our inferred tree is time-calibrated using 15 fossils, some of which have not been used before. While our phylogeny strongly supports a monophyletic Neoteleostei, Ctenosquamata (i.e., Acanthomorpha plus Myctophiformes, and Acanthopterygii, we find weak support (bootstrap value < 48% for the traditionally defined Acanthomorpha, as well as evidence of non-monophyly for the traditional Paracanthopterygii, Beryciformes, and Percomorpha. We corroborate the new Paracanthopterygii sensu Miya et al. (2005 including Polymixiiformes, Zeiformes, Gadiformes, Percopsiformes, and likely the enigmatic Stylephorus chordatus. Our timetree largely agrees with other recent studies based on nuclear loci in inferring an Early Cretaceous origin for the acanthomorphs followed by a Late Cretaceous/Early Paleogene radiation of major lineages. This is in contrast to mitogenomic studies mostly inferring Jurassic or even Triassic ages for the origin of the acanthomorphs. We compare our results to those of previous studies, and attempt to address some of the issues that may have led to incongruence between the fossil record and the molecular clock studies, as well as between the different molecular

  8. Origin and Evolution of The Early- Silurian Land Vascular Plants: Evidence From Biomarkers

    Science.gov (United States)

    Jin, R.

    2016-12-01

    Origin and early evolution of land vascular plants, is one of the most intriguing hotspots in the life science research. During the 1970s and 1980s,Pinnatiramosus qianensis was found in early-Silurian strata in guizhou of south China.43 years have passed. But so far, the biological characteristics and belonging of the age of this unique plant have been debated again and again, up in the air.Biomarkers have a good stability in the process of organic evolution, no more or less changed, so they have a special `function of mark'. While biomarkers can provide information about organic matter of hydrocarbon source rock (the source), the period of deposition and burial (diagenesis) environmental conditions, and many other aspects of information.This paper obtained the sedimentary environment, source of organic matter input and other relevant information, through extracting and analyzing biomarkers of the 26 samples in the late Ordovician to early Silurian strata in NorthGuizhou areas. According to the results, Pr/Ph of late Ordovician Meitan Fm-early Silurian Hanjiadian Fm is high.It manifests more pristane, characterized by reductive environment. At the bottom of the Hanjiadian Fm, Pr/Ph has a volatility.Some huge environmental changes may have taken place in the corresponding period. N-alkanes do not have parity advantage or has even carbon advantage slightly.The peak carbon is mainly in low carbon number.(C21 + C22)/(C28 + C29) is high.Aquatic organisms is a major source of organic matter during this period,C21-/C22+ is low.This may be caused by the relatively serious loss of light hydrocarbon during the separation of components. In the Hanjiadian Fm,information of C29/C27 sterane ratios and oleanane index showed a trend of rising at the same time, indicating that during this period, there was a gradual increase input in the number of higher plants.The stable carbon isotope of saturated hydrocarbon and aromatic hydrocarbon in the Hanjiadian Fm also gradually become

  9. Using provenance of terrigenous sediment to reconstruct the Agulhas Leakage during the Early and Late Pleistocene

    Science.gov (United States)

    Pearson, B.; Franzese, A. M.

    2017-12-01

    instance, for the Early Pleistocene ( 1.3 - 1.5 Ma), K-Ar model ages correlate with shipboard measurements of natural gamma radiation, which show approximate 41 kyr periodicity.

  10. Early Evolution of Earth's Geochemical Cycle and Biosphere: Implications for Mars Exobiology

    Science.gov (United States)

    DesMarais, David J.; Chang, Sherwood (Technical Monitor)

    1997-01-01

    Carbon (C) has played multiple key roles for life and its environment. C has formed organics, greenhouse gases, aquatic pH buffers, redox buffers, and magmatic constituents affecting plutonism and volcanism. These roles interacted across a network of reservoirs and processes known as the biogeochemical C cycle. Changes in the cycle over geologic time were driven by increasing solar luminosity, declining planetary heat flow, and continental and biological evolution. The early Archean C cycle was dominated by hydrothermal alteration of crustal rocks and by thermal emanations of CO2 and reduced species (eg., H2, Fe(2+) and sulfides). Bioorganic synthesis was achieved by nonphotosynthetic CO2-fixing bacteria (chemoautotrophs) and, possibly, bacteria (organotrophs) utilizing any available nonbiological organic C. Responding both to abundant solar energy and to a longterm decline in thermal sources of chemical energy and reducing power, the blaspheme first developed anoxygenic photosynthesis, then, ultimately, oxygenic photosynthesis. O2-photosynthesis played a central role in transforming the ancient environment and blaspheme to the modem world. The geochemical C cycles of early Earth and Mars were quite similar. The principal differences between the modem C cycles of these planets arose during the later evolution of their heat flows, crusts, atmospheres and, perhaps, their blasphemes.

  11. Plio-Pleistocene Hyracoidea from Swartkrans Cave, South Africa

    African Journals Online (AJOL)

    the decline in relative abundance and ultimate extinction of this species towards the end of the Pleistocene. Predators can ..... There is no reason to discount the possibility that leopards .... animal bones from archacologicaJ sites. Peabody Mus ...

  12. Chemical Evolution and the Formation of Dwarf Galaxies in the Early Universe

    Science.gov (United States)

    Cote, Benoit; JINA-CEE, NuGrid, ChETEC

    2018-06-01

    Stellar abundances in local dwarf galaxies offer a unique window into the nature and nucleosynthesis of the first stars. They also contain clues regarding how galaxies formed and assembled in the early stages of the universe. In this talk, I will present our effort to connect nuclear astrophysics with the field of galaxy formation in order to define what can be learned about galaxy evolution using stellar abundances. In particular, I will describe the current state of our numerical chemical evolution pipeline which accounts for the mass assembly history of galaxies, present how we use high-redshift cosmological hydrodynamic simulations to calibrate our models and to learn about the formation of dwarf galaxies, and address the challenge of identifying the dominant r-process site(s) using stellar abundances.

  13. Climatic implications of correlated upper Pleistocene glacial and fluvial deposits on the Cinca and Gallego rivers, NE Spain

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Claudia J [Los Alamos National Laboratory; Mcdonald, Eric [NON LANL; Sancho, Carlos [NON LANL; Pena, Jose- Luis [NON LANL

    2008-01-01

    We correlate Upper Pleistocene glacial and fluvial deposits of the Cinca and Gallego River valleys (south central Pyrenees and Ebro basin, Spain) using geomorphic position, luminescence dates, and time-related trends in soil development. The ages obtained from glacial deposits indicate glacial periods at 85 {+-} 5 ka, 64 {+-} 11 ka, and 36 {+-} 3 ka (from glacial till) and 20 {+-} 3 ka (from loess). The fluvial drainage system, fed by glaciers in the headwaters, developed extensive terrace systems in the Cinca River valley at 178 {+-} 21 ka, 97 {+-} 16 ka, 61 {+-} 4 ka, 47 {+-} 4 ka, and 11 {+-} 1 ka, and in the Gallego River valley at 151 {+-} 11 ka, 68 {+-} 7 ka, and 45 {+-} 3 ka. The times of maximum geomorphic activity related to cold phases coincide with Late Pleistocene marine isotope stages and heinrich events. The maximum extent of glaciers during the last glacial occurred at 64 {+-} 11 ka, and the terraces correlated with this glacial phase are the most extensive in both the Cinca (61 {+-} 4 ka) and Gallego (68 {+-} 7 ka) valleys, indicating a strong increase in fluvial discharge and availability of sediments related to the transition to deglaciation. The global Last Glacial Maximum is scarcely represented in the south central Pyrenees owing to dominantly dry conditions at that time. Precipitation must be controlled by the position of the Iberian Peninsula with respect to the North Atlantic atmospheric circulation system. The glacial systems and the associated fluvial dynamic seem sensitive to (1) global climate changes controlled by insolation, (2) North Atlantic thermohaline circulation influenced by freshwater pulses into the North Atlantic, and (3) anomalies in atmospheric circulation in the North Atlantic controlling precipitation on the Iberian peninsula. The model of glacial and fluvial evolution during the Late Pleistocene in northern Spain could be extrapolated to other glaciated mountainous areas in southern Europe.

  14. Galactic chemical evolution in hierarchical formation models - I. Early-type galaxies in the local Universe

    NARCIS (Netherlands)

    Arrigoni, Matías; Trager, Scott C.; Somerville, Rachel S.; Gibson, Brad K.

    We study the metallicities and abundance ratios of early-type galaxies in cosmological semi-analytic models (SAMs) within the hierarchical galaxy formation paradigm. To achieve this we implemented a detailed galactic chemical evolution model and can now predict abundances of individual elements for

  15. Galactic chemical evolution in hierarchical formation models : I. Early-type galaxies in the local Universe

    NARCIS (Netherlands)

    Arrigoni, Matias; Trager, Scott C.; Somerville, Rachel S.; Gibson, Brad K.

    2010-01-01

    We study the metallicities and abundance ratios of early-type galaxies in cosmological semi-analytic models (SAMs) within the hierarchical galaxy formation paradigm. To achieve this we implemented a detailed galactic chemical evolution model and can now predict abundances of individual elements for

  16. Out of Africa: modern human origins special feature: middle and later Pleistocene hominins in Africa and Southwest Asia.

    Science.gov (United States)

    Rightmire, G Philip

    2009-09-22

    Approximately 700,000 years ago, Homo erectus in Africa was giving way to populations with larger brains accompanied by structural adjustments to the vault, cranial base, and face. Such early Middle Pleistocene hominins were not anatomically modern. Their skulls display strong supraorbital tori above projecting faces, flattened frontals, and less parietal expansion than is the case for Homo sapiens. Postcranial remains seem also to have archaic features. Subsequently, some groups evolved advanced skeletal morphology, and by ca. 200,000 years ago, individuals more similar to recent humans are present in the African record. These fossils are associated with Middle Stone Age lithic assemblages and, in some cases, Acheulean tools. Crania from Herto in Ethiopia carry defleshing cutmarks and superficial scoring that may be indicative of mortuary practices. Despite these signs of behavioral innovation, neither the Herto hominins, nor others from Late Pleistocene sites such as Klasies River in southern Africa and Skhūl/Qafzeh in Israel, can be matched in living populations. Skulls are quite robust, and it is only after approximately 35,000 years ago that people with more gracile, fully modern morphology make their appearance. Not surprisingly, many questions concerning this evolutionary history have been raised. Attention has centered on systematics of the mid-Pleistocene hominins, their paleobiology, and the timing of dispersals that spread H. sapiens out of Africa and across the Old World. In this report, I discuss structural changes characterizing the skulls from different time periods, possible regional differences in morphology, and the bearing of this evidence on recognizing distinct species.

  17. A Late Pleistocene sea level stack

    OpenAIRE

    Spratt Rachel M; Lisiecki Lorraine E

    2016-01-01

    Late Pleistocene sea level has been reconstructed from ocean sediment core data using a wide variety of proxies and models. However, the accuracy of individual reconstructions is limited by measurement error, local variations in salinity and temperature, and assumptions particular to each technique. Here we present a sea level stack (average) which increases the signal-to-noise ratio of individual reconstructions. Specifically, we perform principal componen...

  18. High population connectivity and Pleistocene range expansion in ...

    African Journals Online (AJOL)

    Nuclear markers (ATPSα, ATPSβ, ANT, SRPS4, TBP, LTRS and ZMP) showed no sequence variation. Bullia rhodostoma exhibited shallow ... from these refugial regions. Keywords: cytochrome oxidase I, demographic history, Pleistocene climatic changes, population genetic structure, sandy beach ecosystems, sea level ...

  19. First early hominin from central Africa (Ishango, Democratic Republic of Congo.

    Directory of Open Access Journals (Sweden)

    Isabelle Crevecoeur

    Full Text Available Despite uncontested evidence for fossils belonging to the early hominin genus Australopithecus in East Africa from at least 4.2 million years ago (Ma, and from Chad by 3.5 Ma, thus far there has been no convincing evidence of Australopithecus, Paranthropus or early Homo from the western (Albertine branch of the Rift Valley. Here we report the discovery of an isolated upper molar (#Ish25 from the Western Rift Valley site of Ishango in Central Africa in a derived context, overlying beds dated to between ca. 2.6 to 2.0 Ma. We used µCT imaging to compare its external and internal macro-morphology to upper molars of australopiths, and fossil and recent Homo. We show that the size and shape of the enamel-dentine junction (EDJ surface discriminate between Plio-Pleistocene and post-Lower Pleistocene hominins, and that the Ishango molar clusters with australopiths and early Homo from East and southern Africa. A reassessment of the archaeological context of the specimen is consistent with the morphological evidence and suggest that early hominins were occupying this region by at least 2 Ma.

  20. First Early Hominin from Central Africa (Ishango, Democratic Republic of Congo)

    Science.gov (United States)

    Crevecoeur, Isabelle; Skinner, Matthew M.; Bailey, Shara E.; Gunz, Philipp; Bortoluzzi, Silvia; Brooks, Alison S.; Burlet, Christian; Cornelissen, Els; De Clerck, Nora; Maureille, Bruno; Semal, Patrick; Vanbrabant, Yves; Wood, Bernard

    2014-01-01

    Despite uncontested evidence for fossils belonging to the early hominin genus Australopithecus in East Africa from at least 4.2 million years ago (Ma), and from Chad by 3.5 Ma, thus far there has been no convincing evidence of Australopithecus, Paranthropus or early Homo from the western (Albertine) branch of the Rift Valley. Here we report the discovery of an isolated upper molar (#Ish25) from the Western Rift Valley site of Ishango in Central Africa in a derived context, overlying beds dated to between ca. 2.6 to 2.0 Ma. We used µCT imaging to compare its external and internal macro-morphology to upper molars of australopiths, and fossil and recent Homo. We show that the size and shape of the enamel-dentine junction (EDJ) surface discriminate between Plio-Pleistocene and post-Lower Pleistocene hominins, and that the Ishango molar clusters with australopiths and early Homo from East and southern Africa. A reassessment of the archaeological context of the specimen is consistent with the morphological evidence and suggest that early hominins were occupying this region by at least 2 Ma. PMID:24427292

  1. The cheetah Acinonyx pardinensis (Croizet et Jobert, 1828) s.l. at the hominin site of Dmanisi (Georgia) - A potential prime meat supplier in Early Pleistocene ecosystems

    Science.gov (United States)

    Hemmer, Helmut; Kahlke, Ralf-Dietrich; Vekua, Abesalom K.

    2011-09-01

    The fossil site of Dmanisi (southern Georgia) has yielded a significant amount of hominin remains dated to around 1.8 Ma, in addition to a rich contemporaneous faunal record. Based on topographic information combined with an updated list of the vertebrate faunal assemblage, the corresponding palaeo-landscape has been reconstructed. Over a distance of some kilometres the landscape pattern changed from that of a forested valley floor, to tree savannah and open grasslands, thus providing typical habitats for carnivores hunting in open spaces. Morphological analysis of the elements from a nearly complete cat's foreleg reveals the existence of a large and stoutly built cheetah, Acinonyx pardinensis (Croizet et Jobert, 1828) s.l., in the Dmanisi faunal assemblage. Body mass estimations based on the humerus and metacarpals point to a cat of around 100 kg. The amount of pure meat and associated leftovers produced by the cheetah's hunting activity available for other consumers has been estimated. Within Early Pleistocene ecosystems, the cheetah must be considered as a potential fresh prime meat supplier, above that of any other felid.

  2. Ancient DNA reveals that bowhead whale lineages survived Late Pleistocene climate change and habitat shifts

    DEFF Research Database (Denmark)

    Foote, Andrew David; Kaschner, Kristin; Schultze, Sebastian E.

    2013-01-01

    that a true Arctic species, the bowhead whale (Balaena mysticetus), shifted its range and tracked its core suitable habitat northwards during the rapid climate change of the Pleistocene-Holocene transition. Late Pleistocene lineages survived into the Holocene and effective female population size increased...

  3. The temporal bones from Sima de los Huesos Middle Pleistocene site (Sierra de Atapuerca, Spain). A phylogenetic approach.

    Science.gov (United States)

    Martínez, I; Arsuaga, J L

    1997-01-01

    Three well-preserved crania and 22 temporal bones were recovered from the Sima de los Huesos Middle Pleistocene site up to and including the 1994 field season. This is the largest sample of hominid temporal bones known from a single Middle Pleistocene site and it offers the chance to characterize the temporal bone morphology of an European Middle Pleistocene population and to study the phylogenetic relationships of the SH sample with other Upper and Middle Pleistocene hominids. We have carried out a cladistic analysis based on nine traits commonly used in phylogenetic analysis of Middle and Late Pleistocene hominids: shape of the temporal squama superior border, articular eminence morphology, contribution of the sphenoid bone to the median glenoid wall, postglenoid process projection, tympanic plate orientation, presence of the styloid process, mastoid process projection, digastric groove morphology and anterior mastoid tubercle. We have found two autapomorphies on the Home erectus temporal bone: strong reduction of the postglenoid process and absence of the styloid process. Modern humans, Neandertals and the Middle Pleistocene fossils from Europe and Africa constitute a clade characterized by a convex superior border of the temporal squama. The European Middle Pleistocene fossils from Sima de los Huesos, Petralona, Steinheim, Bilzingsleben and Castel di Guido share a Neandertal apomorphy: a relatively flat articular eminence. The fossils from Ehringsdorf, La Chaise Suardi and Biache-Saint-Vaast also display another Neandertal derived trait: an anteriorly obliterated digastric groove. Modern humans and the African Middle Pleistocene fossils share a synapomorphy: a sagittally orientated tympanic plate.

  4. Mass loss in early stages of stellar evolution

    International Nuclear Information System (INIS)

    Dearborn, D.S.P.; Kozlowski, M.; Schramm, D.

    1976-01-01

    It is known that stars lose mass between their birth on the main sequence and their death as white dwarfs, or as neutron stars or black holes for more massive stars. Solar wind considerations indicate that not all of the mass loss occurs in a 'last gasp' to form a planetary nebula. Mass loss has be observed in O-B stars and in red giants, but the mass loss observed in these stages do not appear sufficient to account for all the loss required for stars to become white dwarfs. The problem is at what stages and in what manner the excess mass is lost. Suggestions have tended to favour He flashes for stars with M < 2.25 M. and possibly double shell instability flashes for stars in the range from 2.25 M. to 8 M. Although is is possible that significant mass is lost during these stages, there appears to be no quantitative support for this suggestion, and in particular none for the He flash. It is shown here that there is increasing evidence for substantial mass loss during the immediate post main sequence stages when the star is moving from the main sequence to the giant branch. Mass loss at these early stages of evolution may have implications on the subsequent evolution of the star and the amount of nuclearly processed material that is ejected into the interstellar-medium. The behaviour of Arcturus is discussed in these connections. (U.K.)

  5. Sedimentology and Palynostratigraphy of a Pliocene-Pleistocene (Piacenzian to Gelasian) deposit in the lower Negro River: Implications for the establishment of large rivers in Central Amazonia

    Science.gov (United States)

    Soares, Emílio Alberto Amaral; D'Apolito, Carlos; Jaramillo, Carlos; Harrington, Guy; Caputo, Mario Vicente; Barbosa, Rogério Oliveira; Bonora dos Santos, Eneas; Dino, Rodolfo; Gonçalves, Alexandra Dias

    2017-11-01

    The Amazonas fluvial system originates in the Andes and runs ca. 6700 km to the Atlantic Ocean, having as the main affluent the Negro River (second largest in water volume). The Amazonas transcontinental system has been dated to the late Miocene, but the timing of origin and evolutionary processes of its tributaries are still poorly understood. Negro River alluvial deposits have been dated to the middle to late Pleistocene. Recently, we studied a number of boreholes drilled for the building of a bridge at the lower course of the Negro River. A thin (centimetric) sedimentary deposit was found, laterally continuous for about 1800 m, unconformably overlaying middle Miocene strata and unconformably overlain by younger Quaternary deposits. This deposit consists predominantly of brownish-gray sandstones cemented by siderite and with subordinate mudstone and conglomerate beds. Palynological, granulometric, textural and mineralogical data suggest that the initial Negro River aggradation took place in the deep incised valley under anoxic conditions and subsequently along the floodplain, with efficient transport of mixed origin particles (Andean and Amazonic). Angiosperm leaves, wood and pollen are indicative of a tropical continental palaeoenvironment. A well preserved palynoflora that includes Alnipollenites verus, Grimsdalea magnaclavata and Paleosantalaceaepites cingulatus suggests a late Pliocene to early Pleistocene (Piacenzian to Gelasian) age for this unit, which was an age yet unrecorded in the Amazon Basin. These results indicate that by the late Pliocene-early Pleistocene, large scale river activity was occurring in Central Amazonia linking this region with the Andean headwaters, and therefore incompatible with Central Amazonia barriers like the Purus arch.

  6. COSMIC EVOLUTION OF SIZE AND VELOCITY DISPERSION FOR EARLY-TYPE GALAXIES

    International Nuclear Information System (INIS)

    Fan, L.; Lapi, A.; Bressan, A.; De Zotti, G.; Danese, L.; Bernardi, M.

    2010-01-01

    Massive (stellar mass M * ∼> 3 x 10 10 M sun ), passively evolving galaxies at redshifts z ∼> 1 exhibit on average physical sizes smaller, by factors ∼3, than local early-type galaxies (ETGs) endowed with the same stellar mass. Small sizes are in fact expected on theoretical grounds, if dissipative collapse occurs. Recent results show that the size evolution at z ∼ 1, where both compact and already extended galaxies are observed and the scatter in size is remarkably larger than it is locally. The presence at high redshift of a significant number of ETGs with the same size as their local counterparts, as well as ETGs with quite small size (∼ H (z). We demonstrate that the projected mass of compact, high-redshift galaxies and that of local ETGs within the same physical radius, the nominal half-luminosity radius of high-redshift ETGs, differ substantially in that the high-redshift ETGs are on average significantly denser. This result suggests that the physical mechanism responsible for the size increase should also remove mass from central galaxy regions (r ∼ 1, we predict the local velocity dispersion distribution function. On comparing it to the observed one, we show that velocity dispersion evolution of massive ETGs is fully compatible with the observed average evolution in size at constant stellar mass. Less massive ETGs (with stellar masses M * ∼ 10 M sun ) are expected to evolve less both in size and in velocity dispersion, because their evolution is essentially determined by supernova feedback, which cannot yield winds as powerful as those triggered by quasars. The differential evolution is expected to leave imprints in the size versus luminosity/mass, velocity dispersion versus luminosity/mass, and central black hole mass versus velocity dispersion relationships, as observed in local ETGs.

  7. Pleistocene cave art from Sulawesi, Indonesia.

    Science.gov (United States)

    Aubert, M; Brumm, A; Ramli, M; Sutikna, T; Saptomo, E W; Hakim, B; Morwood, M J; van den Bergh, G D; Kinsley, L; Dosseto, A

    2014-10-09

    Archaeologists have long been puzzled by the appearance in Europe ∼40-35 thousand years (kyr) ago of a rich corpus of sophisticated artworks, including parietal art (that is, paintings, drawings and engravings on immobile rock surfaces) and portable art (for example, carved figurines), and the absence or scarcity of equivalent, well-dated evidence elsewhere, especially along early human migration routes in South Asia and the Far East, including Wallacea and Australia, where modern humans (Homo sapiens) were established by 50 kyr ago. Here, using uranium-series dating of coralloid speleothems directly associated with 12 human hand stencils and two figurative animal depictions from seven cave sites in the Maros karsts of Sulawesi, we show that rock art traditions on this Indonesian island are at least compatible in age with the oldest European art. The earliest dated image from Maros, with a minimum age of 39.9 kyr, is now the oldest known hand stencil in the world. In addition, a painting of a babirusa ('pig-deer') made at least 35.4 kyr ago is among the earliest dated figurative depictions worldwide, if not the earliest one. Among the implications, it can now be demonstrated that humans were producing rock art by ∼40 kyr ago at opposite ends of the Pleistocene Eurasian world.

  8. Using obsidian transfer distances to explore social network maintenance in late Pleistocene hunter-gatherers.

    Science.gov (United States)

    Pearce, Eiluned; Moutsiou, Theodora

    2014-12-01

    Social behaviour is notoriously difficult to study archaeologically and it is unclear how large the networks of prehistoric humans were, or how they remained connected. Maintaining social cohesion was crucial for early humans because social networks facilitate cooperation and are imperative for survival and reproduction. Recent hunter-gatherer social organisation typically comprises a number of nested layers, ranging from the nuclear family through to the ~1500-strong ethnolinguistic tribe. Here we compare maximum obsidian transfer distances from the late Pleistocene with ethnographic data on the size of the geographic areas associated with each of these social grouping layers in recent hunter-gatherers. The closest match between the two is taken to indicate the maximum social layer within which contact could be sustained by Pleistocene hominins. Within both the (sub)tropical African and Subarctic biomes, the maximum obsidian transfer distances for Pleistocene modern humans (~200km and ~400km respectively) correspond to the geographic ranges of the outermost tribal layer in recent hunter-gatherers. This suggests that modern humans could potentially sustain the cohesion of their entire tribe at all latitudes, even though networks are more dispersed nearer the poles. Neanderthal obsidian transfer distances (300km) indicate that although Neanderthal home ranges are larger than those of low latitude hominins, Neanderthals travelled shorter distances than modern humans living at the same high latitudes. We argue that, like modern humans, Neanderthals could have maintained tribal cohesion, but that their tribes were substantially smaller than those of contemporary modern humans living in similar environments. The greater time taken to traverse the larger modern human tribal ranges may have limited the frequency of their face-to-face interactions and thus necessitated additional mechanisms to ensure network connectivity, such as the exchange of symbolic artefacts

  9. Is the modern koala ( Phascolarctos cinereus) a derived dwarf of a Pleistocene giant? Implications for testing megafauna extinction hypotheses

    Science.gov (United States)

    Price, Gilbert J.

    2008-12-01

    The modern Australian koala ( Phascolarctos cinereus) is commonly regarded as a dwarf descendent of a Late Pleistocene giant koala ( Ph. stirtoni). The implication of that hypothesis is that the giant koala survived the Late Pleistocene megafaunal extinction "event", albeit as a smaller body-sized form. It is important to be able to constrain rates of Late Pleistocene faunal turnover, an aspect reliant on having accurate taxonomic information of extinct species. The koala dwarfing hypothesis is tested here by using a temporally-constrained biogeographical record of fossil koalas, and a morphological character analysis. The contemporary occurrence of both taxa in pre-Late Pleistocene deposits and significant differences in dental morphologies between those forms suggests that the modern koala is not a derived dwarf of the Pleistocene giant koala. Thus, the giant-form was among a number of other giant mammals, lizards and birds that suffered extinction sometime during the Late Pleistocene. The potential phenomenon of dwarfing of other Late Pleistocene and Recent faunas, such as grey kangaroos, is commonly used as a test for or against various megafaunal extinction hypotheses. However, the results of this study also demonstrate that the dwarfing hypothesis has not been adequately tested for a suite of other taxa. Thus, until the dwarfing hypothesis can be more fully tested, a clear understanding of the fate of Late Pleistocene faunas that apparently survived the extinction "event", and the origins of many extant forms will remain elusive.

  10. Lethal interpersonal violence in the Middle Pleistocene.

    Directory of Open Access Journals (Sweden)

    Nohemi Sala

    Full Text Available Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin.

  11. Lethal interpersonal violence in the Middle Pleistocene.

    Science.gov (United States)

    Sala, Nohemi; Arsuaga, Juan Luis; Pantoja-Pérez, Ana; Pablos, Adrián; Martínez, Ignacio; Quam, Rolf M; Gómez-Olivencia, Asier; Bermúdez de Castro, José María; Carbonell, Eudald

    2015-01-01

    Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin.

  12. Final Pleistocene and Early Holocene at Sitio do Meio, Piauí, Brazil: Stratigraphy and comparison with Pedra Furada

    Directory of Open Access Journals (Sweden)

    Giulia Aimola

    2014-09-01

    Full Text Available English: Sitio do Meio, in southern Piaui, Brazil, is the second rock shelter presenting fully Pleistocene dates and artefacts after Pedra Furada.  Despite the anthropogenic origin of Pedra Furada artefacts has been questioned, SDM has better chances to be accepted by the scientific community because of the absence of the most relevant stone breaking agents in this kind of site, i.e. waterfalls. This paper presents a critical revision of the history of excavations (1980-2000, stratigraphy, chronology, and the archaeological content of the site (sector 2. At least 98 stone tools have been identified and described, all of them being older than 12,500 BP, i.e. belonging to the Upper Pleistocenic phase of Pedra Furada 3, as defined in the close reference site. The lithic industry of Serra Talhada phase (lower Holocene is also presented and compared with paleoindian sites of North-Eastern and Central Brazil.French:Le Sitio do meio, dans le  Piaui méridional (Brésil est le deuxième abri sous roche de la région ayant livré des dates pléistocènes en dehors du site de la Pedra Furada. L'article présente une révision critique des fouilles (1980-2000, la chronostratigraphie et le contenu archéologique du secteur 2. Une centaine d'outils lithiques sont décrits, ils sont plus anciens de 12,5 ka BP  et correspondent à la phase Pléistocène Pedra Furada 3 définie dans le site éponyme de référence. On présente aussi l' industrie lithique de la phase Serra Talhada (Holocène  ancien en la comparant aux industries paléoindiennes du Nord-Est et du centre du Brésil.

  13. Water, plants, and early human habitats in eastern Africa.

    Science.gov (United States)

    Magill, Clayton R; Ashley, Gail M; Freeman, Katherine H

    2013-01-22

    Water and its influence on plants likely exerted strong adaptive pressures in human evolution. Understanding relationships among water, plants, and early humans is limited both by incomplete terrestrial records of environmental change and by indirect proxy data for water availability. Here we present a continuous record of stable hydrogen-isotope compositions (expressed as δD values) for lipid biomarkers preserved in lake sediments from an early Pleistocene archaeological site in eastern Africa--Olduvai Gorge. We convert sedimentary leaf- and algal-lipid δD values into estimates for ancient source-water δD values by accounting for biochemical, physiological, and environmental influences on isotopic fractionation via published water-lipid enrichment factors for living plants, algae, and recent sediments. Reconstructed precipitation and lake-water δD values, respectively, are consistent with modern isotopic hydrology and reveal that dramatic fluctuations in water availability accompanied ecosystem changes. Drier conditions, indicated by less negative δD values, occur in association with stable carbon-isotopic evidence for open, C(4)-dominated grassland ecosystems. Wetter conditions, indicated by lower δD values, are associated with expanded woody cover across the ancient landscape. Estimates for ancient precipitation amounts, based on reconstructed precipitation δD values, range between approximately 250 and 700 mm · y(-1) and are consistent with modern precipitation data for eastern Africa. We conclude that freshwater availability exerted a substantial influence on eastern African ecosystems and, by extension, was central to early human proliferation during periods of rapid climate change.

  14. Small mammal diversity loss in response to late-Pleistocene climatic change.

    Science.gov (United States)

    Blois, Jessica L; McGuire, Jenny L; Hadly, Elizabeth A

    2010-06-10

    Communities have been shaped in numerous ways by past climatic change; this process continues today. At the end of the Pleistocene epoch about 11,700 years ago, North American communities were substantially altered by the interplay of two events. The climate shifted from the cold, arid Last Glacial Maximum to the warm, mesic Holocene interglacial, causing many mammal species to shift their geographic distributions substantially. Populations were further stressed as humans arrived on the continent. The resulting megafaunal extinction event, in which 70 of the roughly 220 largest mammals in North America (32%) became extinct, has received much attention. However, responses of small mammals to events at the end of the Pleistocene have been much less studied, despite the sensitivity of these animals to current and future environmental change. Here we examine community changes in small mammals in northern California during the last 'natural' global warming event at the Pleistocene-Holocene transition and show that even though no small mammals in the local community became extinct, species losses and gains, combined with changes in abundance, caused declines in both the evenness and richness of communities. Modern mammalian communities are thus depauperate not only as a result of megafaunal extinctions at the end of the Pleistocene but also because of diversity loss among small mammals. Our results suggest that across future landscapes there will be some unanticipated effects of global change on diversity: restructuring of small mammal communities, significant loss of richness, and perhaps the rising dominance of native 'weedy' species.

  15. Contribution of the 40Ar/39Ar method to improve Middle-Pleistocene archaeological/palaeontological sites from the Italian Peninsula

    Science.gov (United States)

    Nomade, Sebastien, ,, Dr.; Pereira, MSc. Alison; voinchet, Pierre, ,, Dr.; Bahain, Jean-Jacques, ,, Dr.; Aureli, Daniele, ,, Dr.; Arzarello, Marta, ,, Dr.; Anzidei, Anna-Paola, ,, Dr.; Biddittu, Italo, ,, Dr.; Bulgarelli, Maria-Grazia, ,, Dr.; Falguères, Christophe, ,, Dr.; Giaccio, Biagio, ,, Dr.; Guillou, Hervé, ,, Dr.; Manzi, Gorgio, ,, Dr.; Moncel, Marie-Hélène, ,, Dr.; Nicoud, Elisa, ,, Dr.; Pagli, Maria, ,, Dr.; Parenti, Fabio, ,, Dr.; Peretto, Carlo, ,, Dr.; Piperno, Marcello, ,, Dr.; Rocca, Roxane, ,, Dr.

    2017-04-01

    European Middle-Pleistocene archaeological and/or paleontological sites lack a unified and precise chronological framework. Despite recent efforts mostly focused on methods such as OSL, ESR/U-series or cosmogenic nuclides, the age of numerous sites from this period fundamentally still relies on qualitative and speculative palaeoenvironmental and/or palaeontological/palaeoanthropological considerations. The lack of robust chronologies, along with the scarcity of human fossils, prevent coherent correlations between European sites which in turn limits our understanding of human diffusion dynamics, understand techno-cultural evolution or correlate archaeological sites with palaeoclimatic and environmental records. With the goal of providing an accurate and precise chronological framework based on a multi-method approach, a research network including geochronologists, archaeologist and paleoanthropologists from various French and Italian institutions launched in 2010 a wide study of Middle-Pleistocene archaeological sites of central and southern Italy. This study combining the 39Ar/40Ar method with palaeo-dosimetric methods applied to European sites in the age range of 700 ka to 300 ka is unprecedented. In parallel, a large effort has been done to improve the regional Middle-Pleistocene tephrostratigraphic database through a massive application of both high-precision 40Ar/39Ar geochronological and geochemical investigations. We illustrate our approach and results in addressing several key-sites such as Notarchirico, Valle Giumentina; Ceprano-Campogrande and La Polledrara di Cecanibbio. The accurate and precise chronological framework we built permits us to replace all the investigated archaeological and palaeontological records into a coherent climatic and environmental context. Furthermore, our work provides the opportunity to compare lithic industries from a technical and evolutionary point of view within a homogeneous temporal frame. These preliminary results border

  16. Early-state damage detection, characterization, and evolution using high-resolution computed tomography

    Science.gov (United States)

    Grandin, Robert John

    Safely using materials in high performance applications requires adequately understanding the mechanisms which control the nucleation and evolution of damage. Most of a material's operational life is spent in a state with noncritical damage, and, for example in metals only a small portion of its life falls within the classical Paris Law regime of crack growth. Developing proper structural health and prognosis models requires understanding the behavior of damage in these early stages within the material's life, and this early-stage damage occurs on length scales at which the material may be considered "granular'' in the sense that the discrete regions which comprise the whole are large enough to require special consideration. Material performance depends upon the characteristics of the granules themselves as well as the interfaces between granules. As a result, properly studying early-stage damage in complex, granular materials requires a means to characterize changes in the granules and interfaces. The granular-scale can range from tenths of microns in ceramics, to single microns in fiber-reinforced composites, to tens of millimeters in concrete. The difficulty of direct-study is often overcome by exhaustive testing of macro-scale damage caused by gross material loads and abuse. Such testing, for example optical or electron microscopy, destructive and further, is costly when used to study the evolution of damage within a material and often limits the study to a few snapshots. New developments in high-resolution computed tomography (HRCT) provide the necessary spatial resolution to directly image the granule length-scale of many materials. Successful application of HRCT with fiber-reinforced composites, however, requires extending the HRCT performance beyond current limits. This dissertation will discuss improvements made in the field of CT reconstruction which enable resolutions to be pushed to the point of being able to image the fiber-scale damage structures and

  17. Evolution of male coloration during a post-Pleistocene radiation of Bahamas mosquitofish (Gambusia hubbsi).

    Science.gov (United States)

    Martin, Ryan A; Riesch, Rüdiger; Heinen-Kay, Justa L; Langerhans, R Brian

    2014-02-01

    Sexual signal evolution can be complex because multiple factors influence the production, transmission, and reception of sexual signals, as well as receivers' responses to them. To grasp the relative importance of these factors in generating signal diversity, we must simultaneously investigate multiple selective agents and signaling traits within a natural system. We use the model system of the radiation of Bahamas mosquitofish (Gambusia hubbsi) inhabiting blue holes to test the effects of resource availability, male body size and other life-history traits, key aspects of the transmission environment, sex ratio, and predation risk on variation in multiple male color traits. Consistent with previous work examining other traits in this system, several color traits have repeatedly diverged between predation regimes, exhibiting greater elaboration in the absence of predators. However, other factors proved influential as well, with variation in resource levels, body size, relative testes size, and background water color being especially important for several color traits. For one prominent signaling trait, orange dorsal fins, we further confirmed a genetic basis underlying population differences using a laboratory common-garden experiment. We illustrate a promising approach for gaining a detailed understanding of the many contributing factors in the evolution of multivariate sexual signals. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  18. Environmental oxygen conditions during the origin and early evolution of life

    Science.gov (United States)

    Towe, Kenneth M.

    The well-known sensitivity of proteins and nucleic acids to UV-radiation requires that some internally consistent protection scenario be envisioned for the origin and early evolution of life on Earth. Although a variety of ozone-surrogates has been proposed, the available biochemical, geochemical and geological evidence best supports the conclusion that free oxygen was available at levels capable of providing at least a moderate ozone screen. Levels of oxygen near 1-2% of the present atmospheric level are consistent with such a screen, and with: (1) the biochemical needs of early procaryotes considered phylogenetically more primitive than the oxygen-producing Cyanobacteria; (2) the rare-earth element data from the oxide facies of the 3.8 Byr-old Isua banded-iron formations; (3) the nature and phylogenetic distribution of superoxide dismutases; (4) the need for aerobic recycling of early photosynthetic productivity dictated by the distribution of ancient sedimentary iron and organic carbon; (5) the incompatibility of dissolved reduced sulfur (to support anoxygenic photosynthesis) and ferrous iron (to support banded iron-formations) in the surface waters of the world oceans; and (6) the comparative oxygen and UV-sensitivities of modern procaryotes.

  19. Phylogeographic patterns of Hawaiian Megalagrion damselflies (Odonata: Coenagrionidae) correlate with Pleistocene island boundaries

    Science.gov (United States)

    Jordan, Stephen A.; Simon, C.; Foote, D.; Englund, R.A.

    2005-01-01

    The Pleistocene geological history of the Hawaiian Islands is becoming well understood. Numerous predictions about the influence of this history on the genetic diversity of Hawaiian organisms have been made, including the idea that changing sea levels would lead to the genetic differentiation of populations isolated on individual volcanoes during high sea stands. Here, we analyse DNA sequence data from two closely related, endemic Hawaiian damselfly species in order to test these predictions, and generate novel insights into the effects of Pleistocene glaciation and climate change on island organisms. Megalagrion xanthomelas and Megalagrion pacificum are currently restricted to five islands, including three islands of the Maui Nui super-island complex (Molokai, Lanai, and Maui) that were connected during periods of Pleistocene glaciation, and Hawaii island, which has never been subdivided. Maui Nui and Hawaii are effectively a controlled, natural experiment on the genetic effects of Pleistocene sea level change. We confirm well-defined morphological species boundaries using data from the nuclear EF-1?? gene and show that the species are reciprocally monophyletic. We perform phylogeographic analyses of 663 base pairs (bp) of cytochrome oxidase subunit II (COII) gene sequence data from 157 individuals representing 25 populations. Our results point to the importance of Pleistocene land bridges and historical island habitat availability in maintaining inter-island gene flow. We also propose that repeated bottlenecks on Maui Nui caused by sea level change and restricted habitat availability are likely responsible for low genetic diversity there. An island analogue to northern genetic purity and southern diversity is proposed, whereby islands with little suitable habitat exhibit genetic purity while islands with more exhibit genetic diversity. ?? 2005 Blackwell Publishing Ltd.

  20. New hominin fossils from Kanapoi, Kenya, and the mosaic evolution of canine teeth in early hominins

    Directory of Open Access Journals (Sweden)

    J. Michael Plavcan

    2012-03-01

    Full Text Available Whilst reduced size, altered shape and diminished sexual dimorphism of the canine–premolar complex are diagnostic features of the hominin clade, little is known about the rate and timing of changes in canine size and shape in early hominins. The earliest Australopithecus, Australopithecus anamensis, had canine crowns similar in size to those of its descendant Australopithecus afarensis, but a single large root alveolus has suggested that this species may have had larger and more dimorphic canines than previously recognised. Here we present three new associated dentitions attributed to A. anamensis, recently recovered from the type site of Kanapoi, Kenya, that provide evidence of canine evolution in early Australopithecus. These fossils include the largest mandibular canine root in the hominin fossil record. We demonstrate that, although canine crown height did not differ between these species, A. anamensis had larger and more dimorphic roots, more like those of extant great apes and Ardipithecus ramidus, than those of A. afarensis. The canine and premolar occlusal shapes of A. anamensis also resemble those of Ar. ramidus, and are intermediary between extant great apes and A. afarensis. A. afarensis achieved Homo-like maxillary crown basal proportions without a reduction in crown height. Thus, canine crown size and dimorphism remained stable during the early evolution of Australopithecus, but mandibular root dimensions changed only later within the A. anamensis–afarensis lineage, coincident with morphological changes in the canine–premolar complex. These observations suggest that selection on canine tooth crown height, shape and root dimensions was not coupled in early hominin evolution, and was not part of an integrated adaptive package.

  1. Chloroplast genome evolution in early diverged leptosporangiate ferns.

    Science.gov (United States)

    Kim, Hyoung Tae; Chung, Myong Gi; Kim, Ki-Joong

    2014-05-01

    In this study, the chloroplast (cp) genome sequences from three early diverged leptosporangiate ferns were completed and analyzed in order to understand the evolution of the genome of the fern lineages. The complete cp genome sequence of Osmunda cinnamomea (Osmundales) was 142,812 base pairs (bp). The cp genome structure was similar to that of eusporangiate ferns. The gene/intron losses that frequently occurred in the cp genome of leptosporangiate ferns were not found in the cp genome of O. cinnamomea. In addition, putative RNA editing sites in the cp genome were rare in O. cinnamomea, even though the sites were frequently predicted to be present in leptosporangiate ferns. The complete cp genome sequence of Diplopterygium glaucum (Gleicheniales) was 151,007 bp and has a 9.7 kb inversion between the trnL-CAA and trnVGCA genes when compared to O. cinnamomea. Several repeated sequences were detected around the inversion break points. The complete cp genome sequence of Lygodium japonicum (Schizaeales) was 157,142 bp and a deletion of the rpoC1 intron was detected. This intron loss was shared by all of the studied species of the genus Lygodium. The GC contents and the effective numbers of codons (ENCs) in ferns varied significantly when compared to seed plants. The ENC values of the early diverged leptosporangiate ferns showed intermediate levels between eusporangiate and core leptosporangiate ferns. However, our phylogenetic tree based on all of the cp gene sequences clearly indicated that the cp genome similarity between O. cinnamomea (Osmundales) and eusporangiate ferns are symplesiomorphies, rather than synapomorphies. Therefore, our data is in agreement with the view that Osmundales is a distinct early diverged lineage in the leptosporangiate ferns.

  2. The emergence and early evolution of biological carbon-fixation.

    Science.gov (United States)

    Braakman, Rogier; Smith, Eric

    2012-01-01

    The fixation of CO₂ into living matter sustains all life on Earth, and embeds the biosphere within geochemistry. The six known chemical pathways used by extant organisms for this function are recognized to have overlaps, but their evolution is incompletely understood. Here we reconstruct the complete early evolutionary history of biological carbon-fixation, relating all modern pathways to a single ancestral form. We find that innovations in carbon-fixation were the foundation for most major early divergences in the tree of life. These findings are based on a novel method that fully integrates metabolic and phylogenetic constraints. Comparing gene-profiles across the metabolic cores of deep-branching organisms and requiring that they are capable of synthesizing all their biomass components leads to the surprising conclusion that the most common form for deep-branching autotrophic carbon-fixation combines two disconnected sub-networks, each supplying carbon to distinct biomass components. One of these is a linear folate-based pathway of CO₂ reduction previously only recognized as a fixation route in the complete Wood-Ljungdahl pathway, but which more generally may exclude the final step of synthesizing acetyl-CoA. Using metabolic constraints we then reconstruct a "phylometabolic" tree with a high degree of parsimony that traces the evolution of complete carbon-fixation pathways, and has a clear structure down to the root. This tree requires few instances of lateral gene transfer or convergence, and instead suggests a simple evolutionary dynamic in which all divergences have primary environmental causes. Energy optimization and oxygen toxicity are the two strongest forces of selection. The root of this tree combines the reductive citric acid cycle and the Wood-Ljungdahl pathway into a single connected network. This linked network lacks the selective optimization of modern fixation pathways but its redundancy leads to a more robust topology, making it more

  3. The emergence and early evolution of biological carbon-fixation.

    Directory of Open Access Journals (Sweden)

    Rogier Braakman

    Full Text Available The fixation of CO₂ into living matter sustains all life on Earth, and embeds the biosphere within geochemistry. The six known chemical pathways used by extant organisms for this function are recognized to have overlaps, but their evolution is incompletely understood. Here we reconstruct the complete early evolutionary history of biological carbon-fixation, relating all modern pathways to a single ancestral form. We find that innovations in carbon-fixation were the foundation for most major early divergences in the tree of life. These findings are based on a novel method that fully integrates metabolic and phylogenetic constraints. Comparing gene-profiles across the metabolic cores of deep-branching organisms and requiring that they are capable of synthesizing all their biomass components leads to the surprising conclusion that the most common form for deep-branching autotrophic carbon-fixation combines two disconnected sub-networks, each supplying carbon to distinct biomass components. One of these is a linear folate-based pathway of CO₂ reduction previously only recognized as a fixation route in the complete Wood-Ljungdahl pathway, but which more generally may exclude the final step of synthesizing acetyl-CoA. Using metabolic constraints we then reconstruct a "phylometabolic" tree with a high degree of parsimony that traces the evolution of complete carbon-fixation pathways, and has a clear structure down to the root. This tree requires few instances of lateral gene transfer or convergence, and instead suggests a simple evolutionary dynamic in which all divergences have primary environmental causes. Energy optimization and oxygen toxicity are the two strongest forces of selection. The root of this tree combines the reductive citric acid cycle and the Wood-Ljungdahl pathway into a single connected network. This linked network lacks the selective optimization of modern fixation pathways but its redundancy leads to a more robust topology

  4. Drainage system inversion in the Guadalentin Depression during the Late Pleistocene-Holocene (Murcia, Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Calmel-Avila, M.; Silva, P. G.; Bardaji, T.; Goy, J. L.; Zazo, C.

    2009-07-01

    This article presents the results of studies conducted in the central sector of Guadalentin depression (Murcia) for the abnormal accumulation (more than 17 m) of Pleistocene and Holocene deposits upstream of Romeral tectonic threshold (Librilla). {sup 1}4C dating. ruins and archaeological sites, together with its stratigraphic analysis show that the three sequences that constitute the Holocene detrital filling of the Depression, prograded are superimposed on the upper Pleistocene travertine upstream from the confluence of the River Guadalentin the Rambla de Librilla. Between Librilla and threshold Romeral Holocene deposits only appear along the left bank (15-17m). By contrast the right side shows significant lifting of the Pleistocene travertine up area Romeral threshold, where the substrate allora Neogene. (Author) 11 refs.

  5. Thermoluminescence dating of pleistocene sediments

    International Nuclear Information System (INIS)

    Poupeau, G.; Souza, J.H.

    1984-01-01

    After a short introduction on recent trends in quaternary geochronology, this article focuses on the thermoluminescence (TL) dating of sediments, whose principles, present limits and prospects are discussed. Results are presented for TL behavior of sands from various geological contexts in Brazil. They show that the coarse (approx. 100-200 μm) quartz fraction of coastal and intracontinental, eolian and fluvial - type deposits, might be datable by TL from the upper Holocene to at least the base of the upper Pleistocene, with a precision of +- 10-15%. (Author) [pt

  6. Thermoluminescence dating of pleistocene sediments

    International Nuclear Information System (INIS)

    Poupeau, G.; Souza, J.H.; Rivera, A.

    1984-01-01

    After a short introduction on recent trends in quaternary geochronology, this article focuses on the thermoluminescence dating of sediments, whose principles and present limits and prospects are discussed. Results are presented for the TL behaviour of sands from various geological contexts in Brazil. They show that the coarse (approx. 100-200μm) quartz fraction of coastal and intra continental, eolian and fluvial-type deposits, might be datable by TL from the upper Holocene to at least the basis of the upper Pleistocene, with a precision of + - 10-15%. (Author) [pt

  7. Late Pleistocene - Holocene development of the Tista megafan (West Bengal, India): 10Be cosmogenic and IRSL age constraints

    Science.gov (United States)

    Abrahami, Rachel; Huyghe, Pascale; van der Beek, Peter; Lowick, Sally; Carcaillet, Julien; Chakraborty, Tapan

    2018-04-01

    The Himalayan proximal foreland is characterized by Quaternary megafans, of which the formational mechanisms remain debated. The Tista megafan spreads over more than 16,000 km2 from the mountain front, where it is strongly incised, to the confluence of the Tista River with the Jamuna/Brahmaputra River, and stores sediments produced in the Sikkim Himalaya. We propose a scenario for the late Pleistocene - Holocene development of the Tista megafan based on new 10Be cosmogenic and Infra-Red Stimulated Luminescence (IRSL) age constraints, and discuss the main potential controls on its evolution. We suggest that two distal lobes developed successively downstream from a common proximal lobe. Deposition in the proximal lobe took place since at least ∼135 ka and incision began at 3.7-0.7+1.0 ka. The western distal lobe of the megafan was deposited early in the history of the megafan, when the Sikkim Himalaya catchment was drained by a tributary of the Ganga River, and was abandoned in the early Holocene (10-11 ka). The eastern, recent (active. Approximately synchronous incision between terraces in the hinterland and megafan surfaces suggests that incision propagated rapidly through the system. Our data do not evidence a direct link between incicion and tectonic processes. Aggradation and incision episodes appear more compatible with a climatic control, through changes in monsoon intensity and associated sediment flux. Depositional episodes in the Tista megafan, as elsewhere in the Himalaya and its foreland, appear to correlate with periods of strong monsoon precipitation and associated high sediment flux toward the foreland. Abandonment and incision of megafan surfaces and hinterland terraces appear associated to both the onset and the ending of phases of strong monsoon precipitation, during which the balance between water and sediment discharge changes rapidly.

  8. Greigite formed in early Pleistocene lacustrine sediments from the Heqing Basin, southwest China, and its paleoenvironmental implications

    Science.gov (United States)

    Qiang, Xiaoke; Xu, Xinwen; Zhao, Hui; Fu, Chaofeng

    2018-05-01

    The ferrimagnetic iron sulfide greigite (Fe3S4) occurs widely in sulfidic lacustrine and marine sedimentary environments. Knowledge of its formation and persistence is important for both magnetostratigraphic and paleoenvironmental studies. Although the formation mechanism of greigite has been widely demonstrated, the sedimentary environments associated with greigite formation in lakes, especially on relatively long timescales, are poorly understood. A long and continuous sequence of Pleistocene lacustrine sediments was recovered in the Heqing drill core from southwestern China, which provides an outstanding record of continental climate and environment. Integrated magnetic, geochemical, and paleoclimatic analysis of the lacustrine sequence provides an opportunity to improve our understanding of the environmental controls on greigite formation. Rock magnetic and scanning electron microscope analyses of selected samples from the core reveal that greigite is present in the lower part of the core (part 1, 665.8-372.5 m). Greigite occurs throughout this interval and is the dominant magnetic mineral, irrespective of the climatic state. The magnetic susceptibility (χ) record, which is mainly controlled by the concentration of greigite, matches well with variations in the Indian Summer Monsoon (ISM) index and total organic carbon (TOC) content, with no significant time lag. This indicates that the greigite formed during early diagenesis. In greigite-bearing intervals, with the χ increase, Bc value increase and tends to be stable at about 50 mT. Therefore, we suggest that χ values could estimate the variation of greigite concentration approximately in the Heqing core. Greigite favored more abundant in terrigenous-rich and organic-poor layers associated with weak summer monsoon which are characterized by high χ values, high Fe content, high Rb/Sr ratio and low TOC content. Greigite enhancement can be explained by variations in terrigenous inputs. Our studies demonstrate

  9. Origin of late pleistocene formation water in Mexican oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Birkle, P. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    2004-07-01

    . For wellhead samples, a 20 liter-sampling-reagent was previously filled with N{sub 2}-gas for the collection and phase separation of the pressurized gas-water-crude oil mixture. No differences in {sup 14}C-concentrations were detected applying, both, conventional and AMS-techniques. In contradiction to the expected 'fossil age' of reservoir water as part of a stagnant hydraulic system, measured {sup 14}C-concentrations between 0.89 pmC and 31.86 pmC indicate a late Pleistocene-early Holocene, regional event for the infiltration of surface water into the reservoir. The variety in water mineralization from meteoric (TDS{sub max} = 0.5 g/l) to hyper-saline composition (TDS{sub max} = 338 g/l) is not caused by halite dissolution from adjacent salt domes, as shown by elevated Br/Cl ratios. In contrary, the linear correlation between {sup 18}O and Cl values reflect varying mixing proportions of two components - meteoric water and evaporated seawater. Instead of water/rock-interaction, evaporation of seawater at the surface prior to infiltration represents the principal process for fluid enrichment in {sup 18}O and chlorine, with maximum values of 17.2 %o and 228 g/l, respectively. The young residence time of formation water in Mexican oil reservoirs implies following: - The common assumption of 'hydraulically-frozen' reservoirs is not correct, as main descending fluid migration occurred during glacial period. Probably, major infiltration processes are related to periods with climatic changes and increased humidity - as observed for the adjacent Yucatan region in SE-Mexico during early-mid Holocene (6,000 yr BP) (Metcalfe et al. 2000) - with the probable transgression of Mexican Gulf seawater into the recent Mexican coastal plain. - The common hypothesis of hydrocarbon maturation within Jurassic organic-rich layers, and its subsequent expulsion and migration into Cretaceous/Tertiary sedimentary units must be expanded by a last-step-process: As glacial

  10. Oleistocene mammals in the late-early Holocene in Santa Lucia river basin (Uruguay southern)

    International Nuclear Information System (INIS)

    Ubilla, M.; Perea, D.; Corona, A.; Rinderknecht, A.; Sanchez, A.

    2012-01-01

    This work is about the fossileferous outcrops belongs to the late Pleistocene - early Holocene in Santa Lucia River. It enable to analyse the last records of megafauna vertebrate extinctions (olistecene mammals) with the climate conditions / environment

  11. Aminostratigraphic correlations and paleotemperature implications, Pliocene-Pleistocene high-sea-level deposits, northwestern Alaska

    Science.gov (United States)

    Kaufman, Darrell S.; Brigham-Grette, Julie

    Multiple periods of Late Pliocene and Pleistocene high sea level are recorded by surficial deposits along the coastal plains of northwestern Alaska. Analyses of the extent of amino acid epimerization in fossil molluscan shells from the Nome coastal plain of the northern Bering Sea coast, and from the Alaskan Arctic Coastal Plain of the Chukchi and Beaufort Sea coasts, allow recognition of at least five intervals of higher-than-present relative sea level. Three Late Pliocene transgressions are represented at Nome by the complex and protracted Beringian transgression, and on the Arctic Coastal Plain by the Colvillian, Bigbendian, and Fishcreekian transgressions. These were followed by a lengthy period of non-marine deposition during the Early Pleistocene when sea level did not reach above its present position. A Middle Pleistocene high-sea-level event is represented at Nome by the Anvilian transgression, and on the Arctic Coastal Plain by the Wainwrightian transgression. Anvilian deposits at the type locality are considerably younger than previously thought, perhaps as young as Oxygen-Isotope Stage 11 (˜410,000 BP). Finally, the last interglacial Pelukian transgression is represented discontinuously along the shores of northwestern Alaska. Amino acid epimerization data, together with previous paleomagnetic measurements, radiometric-age determinations, and paleontologic evidence provide geochronological constraints on the sequence of marine deposits. They form the basis of regional correlations and offer a means of evaluating the post-depositional thermal history of the high-sea-level deposits. Provisional correlations between marine units at Nome and the Artic Coastal Plain indicate that the temperature difference that separates the two sites today had existed by about 3.0 Ma. Since that time, the effective diagenetic temperature was lowered by about 3-4°C at both sites, and the mean annual temperature was lowered considerably more. This temperature decrease was

  12. Phylogeographic Structure of a Tethyan Relict Capparis spinosa (Capparaceae) Traces Pleistocene Geologic and Climatic Changes in the Western Himalayas, Tianshan Mountains, and Adjacent Desert Regions.

    Science.gov (United States)

    Wang, Qian; Zhang, Ming-Li; Yin, Lin-Ke

    2016-01-01

    Complex geological movements more or less affected or changed floristic structures, while the alternation of glacials and interglacials is presumed to have further shaped the present discontinuous genetic pattern of temperate plants. Here we consider Capparis spinosa, a xeromorphic Tethyan relict, to discuss its divergence pattern and explore how it responded in a stepwise fashion to Pleistocene geologic and climatic changes. 267 individuals from 31 populations were sampled and 24 haplotypes were identified, based on three cpDNA fragments (trnL-trnF, rps12-rpl20, and ndhF). SAMOVA clustered the 31 populations into 5 major clades. AMOVA suggests that gene flow between them might be restricted by vicariance. Molecular clock dating indicates that intraspecific divergence began in early Pleistocene, consistent with a time of intense uplift of the Himalaya and Tianshan Mountains, and intensified in mid-Pleistocene. Species distribution modeling suggests range reduction in the high mountains during the Last Glacial Maximum (LGM) as a result of cold climates when glacier advanced, while gorges at midelevations in Tianshan appear to have served as refugia. Populations of low-altitude desert regions, on the other hand, probably experienced only marginal impacts from glaciation, according to the high levels of genetic diversity.

  13. Phylogeographic Structure of a Tethyan Relict Capparis spinosa (Capparaceae Traces Pleistocene Geologic and Climatic Changes in the Western Himalayas, Tianshan Mountains, and Adjacent Desert Regions

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2016-01-01

    Full Text Available Complex geological movements more or less affected or changed floristic structures, while the alternation of glacials and interglacials is presumed to have further shaped the present discontinuous genetic pattern of temperate plants. Here we consider Capparis spinosa, a xeromorphic Tethyan relict, to discuss its divergence pattern and explore how it responded in a stepwise fashion to Pleistocene geologic and climatic changes. 267 individuals from 31 populations were sampled and 24 haplotypes were identified, based on three cpDNA fragments (trnL-trnF, rps12-rpl20, and ndhF. SAMOVA clustered the 31 populations into 5 major clades. AMOVA suggests that gene flow between them might be restricted by vicariance. Molecular clock dating indicates that intraspecific divergence began in early Pleistocene, consistent with a time of intense uplift of the Himalaya and Tianshan Mountains, and intensified in mid-Pleistocene. Species distribution modeling suggests range reduction in the high mountains during the Last Glacial Maximum (LGM as a result of cold climates when glacier advanced, while gorges at midelevations in Tianshan appear to have served as refugia. Populations of low-altitude desert regions, on the other hand, probably experienced only marginal impacts from glaciation, according to the high levels of genetic diversity.

  14. Cranial shape transformation in the evolution of the giant panda ( Ailuropoda melanoleuca)

    Science.gov (United States)

    Figueirido, Borja; Palmqvist, Paul; Pérez-Claros, Juan A.; Dong, Wei

    2011-02-01

    In this study, landmark-based methods of geometric morphometrics are used for investigating the main aspects of cranial shape transformation in the evolution of the giant panda, Ailuropoda melanoleuca. Specifically, we explore if the highly derived cranial adaptations for bamboo feeding of the living panda were developed early in the panda's lineage. Results obtained show that the overall cranial morphologies of the oldest known panda, the "pygmy" Ailuropoda microta, and the late Pleistocene Ailuropoda baconi are both very similar to that of their closest living relative, A. melanoleuca, which agrees with a previous proposal based on qualitative criteria. However, we also describe several differences between the crania of A. microta, A. baconi, and A. melanoleuca, including the development of the postorbital process, the orientation of the occipital region, and the expansion of the braincase. As a result, the cranial morphology of A. microta shows a less specialized morphology toward a fibrous and durophagous diet compared to the giant panda. These results are confirmed by a comparative analysis of the dimensions of the upper teeth in bears, which has revealed differences in relative tooth size between A. microta and A. melanoleuca, most probably as a result of mosaic evolution. Therefore, we conclude that cranial shape did not remain essentially uniform in the Ailuropoda lineage, as previously thought, but underwent a number of changes during more than 2 Myr.

  15. Timing of Pleistocene glaciations in the High Atlas, Morocco: New 10Be and 36Cl exposure ages

    Science.gov (United States)

    Hughes, Philip D.; Fink, David; Rodés, Ángel; Fenton, Cassandra R.; Fujioka, Toshiyuki

    2018-01-01

    This paper presents data from 42 new samples yielding Late Pleistocene cosmogenic 10Be and 36Cl exposure ages of moraine boulders across a series of glaciated valleys in the Toubkal Massif (4167 m a.s.l.), High Atlas, Morocco. This represents the first comprehensive Pleistocene glacial chronology in North Africa and one of the largest datasets from the Mediterranean region. The timing of these glacier advances has major implications for understanding the influence of Atlantic depressions on moisture supply to North Africa and the Mediterranean basin during the Pleistocene. The oldest and lowest moraines which span elevations from ∼1900 to 2400 m a.s.l. indicate that the maximum glacier advance occurred from MIS 5 to 3 with a combined mean 10Be and 36Cl age of 50.2 ± 19.5 ka (1 SD; n = 12, 7 outliers). The next moraine units up-valley at higher elevations (∼2200-2600 m a.s.l.) yielded exposure ages close to the global Last Glacial Maximum (LGM) with a combined mean 10Be and 36Cl age of 22.0 ± 4.9 ka (1 SD; n = 9, 7 outliers). The youngest exposure ages are from moraines that were emplaced during the Younger Dryas with a combined mean 10Be and 36Cl age of 12.3 ± 0.9 ka (1 SD; n = 7, no outliers) and are found in cirques at the highest elevations ranging from ∼2900 to 3300 m a.s.l. From moraines predating the Younger Dryas, a large number of young outliers are spread evenly between 6 and 13 ka suggesting a continuing process of exhumation or repositioning of boulders during the early to mid-Holocene. This attests to active seismic processes and possibly intense erosion during this period.

  16. The early quaternary sediments above the Gorleben salt dome

    International Nuclear Information System (INIS)

    Mueller, H.

    1986-01-01

    About 1500 borehole samples from the 90 m thick pre-Elsterian Pleistocene sediments above the Gorleben salt dome were studied to establish the palynostratigraphy of the main part of the still poorly known 'Cromerian Complex'. With the exception of two isolated sink holes above the gypsum cap rock, which developed during the early Bavelian, the investigated pre-Elsterian Pleistocene sediments were deposited in a very shallow lake, similar to the present-day Steinhuder Meer (NW Germany). Therefore, subrosion (subsurface erosion of salt) and sedimentation kept pace with each other during this time interval. Small discordances - similar to those in the Holocene sediments of the Steinhuder Meer - are frequent, but do not hamper the close correlation (to within 1 cm) between the different boreholes. (orig.) [de

  17. The early quaternary sediments above the Gorleben salt dome

    International Nuclear Information System (INIS)

    Mueller, H.

    1986-01-01

    About 1500 borehole samples from the 90 m thick pre-Elsterian Pleistocene sediments above the Gorleben salt dome were studied to establish the palynostratigraphy of the main part of the still poorly known 'Cromerian Complex'. With the exception of two isolated sink holes above the gypsum cap rock, which developed during the early Bavelian, the investigated pre-Elsterian Pleistocene sediments were deposited in a very shallow lake, similar to the present-day Steinhuder Meer (NW Germany). Therefore, subrosion (subsurface erosion of salt) and sedimentation kept pace with each other during this time interval. Small discordances - similar to those in the Holocene sediments of the Steinhuder Meer - are frequent, but do not hamper the close correlation (to within 1 cm) between the different boreholes. (orig./PW) [de

  18. Dental microwear and diets of African early Homo.

    Science.gov (United States)

    Ungar, Peter S; Grine, Frederick E; Teaford, Mark F; El Zaatari, Sireen

    2006-01-01

    Conventional wisdom ties the origin and early evolution of the genus Homo to environmental changes that occurred near the end of the Pliocene. The basic idea is that changing habitats led to new diets emphasizing savanna resources, such as herd mammals or underground storage organs. Fossil teeth provide the most direct evidence available for evaluating this theory. In this paper, we present a comprehensive study of dental microwear in Plio-Pleistocene Homo from Africa. We examined all available cheek teeth from Ethiopia, Kenya, Tanzania, Malawi, and South Africa and found 18 that preserved antemortem microwear. Microwear features were measured and compared for these specimens and a baseline series of five extant primate species (Cebus apella, Gorilla gorilla, Lophocebus albigena, Pan troglodytes, and Papio ursinus) and two protohistoric human foraging groups (Aleut and Arikara) with documented differences in diet and subsistence strategies. Results confirmed that dental microwear reflects diet, such that hard-object specialists tend to have more large microwear pits, whereas tough food eaters usually have more striations and smaller microwear features. Early Homo specimens clustered with baseline groups that do not prefer fracture resistant foods. Still, Homo erectus and individuals from Swartkrans Member 1 had more small pits than Homo habilis and specimens from Sterkfontein Member 5C. These results suggest that none of the early Homo groups specialized on very hard or tough foods, but that H. erectus and Swartkrans Member 1 individuals ate, at least occasionally, more brittle or tough items than other fossil hominins studied.

  19. Liquefaction along Late Pleistocene to early Holocene Faults as Revealed by Lidar in Northwest Tasmania, Australia

    Science.gov (United States)

    Webb, J.; Gardner, T.

    2016-12-01

    In northwest Tasmania well-preserved mid-Holocene beach ridges with maximum radiocarbon ages of 5.25 ka occur along the coast; inland are a parallel set of lower relief beach ridges of probable MIS 5e age. The latter are cut by northeast-striking faults clearly visible on LIDAR images, with a maximum vertical displacement (evident as difference in topographic elevation) of 3 m. Also distinct on the LIDAR images are large sand boils along the fault lines; they are up to 5 m in diameter and 2-3 m high and mostly occur on the hanging wall close to the fault traces. Without LIDAR it would have been almost impossible to distinguish either the fault scarps or the sand boils. Excavations through the sand boils show that they are massive, with no internal structure, suggesting that they formed in a single event. They are composed of well-sorted, very fine white sand, identical to the sand in the underlying beach ridges. The sand boils overlie a peaty paleosol; this formed in the tea-tree swamp that formerly covered the area, and has been offset along the faults. Radiocarbon dating of the buried organic-rich paleosol gave ages of 14.8-7.2 ka, suggesting that the faulting is latest Pleistocene to early Holocene in age; it occurred prior to deposition of the mid-Holocene beach ridges, which are not offset. The beach ridge sediments are up to 7 m thick and contain an iron-cemented hard pan 1-3 m below the surface. The water table is very shallow and close to the ground surface, so the sands of the beach ridges are mostly saturated. During faulting these sands experienced extensive liquefaction. The resulting sand boils rose to a substantial height of 2-3 m, probably possibly reflecting the elevation of the potentiometric surface within the confined part of the beach ridge sediments below the iron-cemented hard pan. Motion on the faults was predominantly dip slip (shown by an absence of horizontal offset) and probably reverse, which is consistent with the present-day northwest

  20. The Moon as a recorder of organic evolution in the early solar system: a lunar regolith analog study.

    Science.gov (United States)

    Matthewman, Richard; Court, Richard W; Crawford, Ian A; Jones, Adrian P; Joy, Katherine H; Sephton, Mark A

    2015-02-01

    The organic record of Earth older than ∼3.8 Ga has been effectively erased. Some insight is provided to us by meteorites as well as remote and direct observations of asteroids and comets left over from the formation of the Solar System. These primitive objects provide a record of early chemical evolution and a sample of material that has been delivered to Earth's surface throughout the past 4.5 billion years. Yet an effective chronicle of organic evolution on all Solar System objects, including that on planetary surfaces, is more difficult to find. Fortunately, early Earth would not have been the only recipient of organic matter-containing objects in the early Solar System. For example, a recently proposed model suggests the possibility that volatiles, including organic material, remain archived in buried paleoregolith deposits intercalated with lava flows on the Moon. Where asteroids and comets allow the study of processes before planet formation, the lunar record could extend that chronicle to early biological evolution on the planets. In this study, we use selected free and polymeric organic materials to assess the hypothesis that organic matter can survive the effects of heating in the lunar regolith by overlying lava flows. Results indicate that the presence of lunar regolith simulant appears to promote polymerization and, therefore, preservation of organic matter. Once polymerized, the mineral-hosted newly formed organic network is relatively protected from further thermal degradation. Our findings reveal the thermal conditions under which preservation of organic matter on the Moon is viable.

  1. Pattern of dental development in Hominid XVIII from the Middle Pleistocene Atapuerca-Sima de los Huesos site (Spain).

    Science.gov (United States)

    Bermudez De Castro, J M; Rosas, A

    2001-04-01

    . We describe the pattern of dental development of Hominid XVIII from the Middle Pleistocene Sima de los Huesos (SH) site of the Sierra de Atapuerca (Burgos, Spain). As expected, this pattern is similar to that of modern humans. A delay of development of the lower and upper canines was observed. In contrast, the relative advanced development of the lower second molars and, especially, the upper and lower third molars is noteworthy. This latter feature seems to be common in Pleistocene hominids, and suggests that the pattern of dental development evolved in the genus Homo during the Pleistocene. In European Middle Pleistocene hominids, this pattern probably was facilitated by the extra space available in the mandible and maxilla for developing teeth. Copyright 2001 Wiley-Liss, Inc.

  2. Upper Middle Pleistocene climate and landscape development of Northern Germany

    Science.gov (United States)

    Urban, B.

    2009-04-01

    The Pleistocene sequence of the Schöningen lignite mine contains a number of interglacial and interstadial limnic and peat deposits, travertine tuff, soils, tills and fluvioglacial sediments as well as loess deposits. The complex Quaternary sequence contains six major cycles with evidence of four interglacials younger than the Elsterian glaciation and preceding the Holocene. The sequence begins with Late Elsterian glacial and three interstadial deposits formed in shallow basins. Cycle I is assigned to late parts of the Holsteinian interglacial. A strong cooling is recorded by a significant increase of Artemisia and grasses during the following Buschhaus A Stadial, which is considered to mark the onset of the Saalian Complex sensu lato (penultimate glacial-complex). The lacustrine sediments of Cycle II, Reinsdorf interglacial sequence (Urban, 1995), have been found to occur at archaeological sites Schöningen 12 and 13 (Thieme,1997). Recent investigations give evidence for at least 13 Local Pollen Assemblage Zones showing a five-fold division of the interglacial and a sequence of five climatic oscillations following the interglacial (Urban, 2006). From the relative high values for grasses and herbs in the inferred forested periods of the interglacial, a warm dry forest steppe climate can be deduced. The stratigraphic position of throwing spears (Thieme, 1997), can clearly be allocated to Reinsdorf Interstadial B (level II-4) characterized by an open pine-birch forest. Uppermost parts (level II-5) represent the transition into a periglacial environment indicating the definite end of cycle II. The Schöningen Interglacial (Cycle III) represents the youngest of the pre-Drenthe (Early Saalian Stadial) interglacials (Urban, 1995). In summary, it can be concluded that the Middle Pleistocene terrestrial pollen record of the Schöningen sequence represents tentative correlatives of MIS 7, 9 and 11. North of Leck (North Friesland, Schleswig-Holstein) sediments of the centre

  3. Paleoenvironmental Evolution of Continental Carbonates in West-Central Brazil

    Directory of Open Access Journals (Sweden)

    EMILIANO C. OLIVEIRA

    Full Text Available ABSTRACT This paper presents a sedimentological and stratigraphical study of Quaternary (Middle to Late Pleistocene/Holocene continental carbonates outcrops inside Pantanal Basin and its surroundings, especially in Serra da Bodoquena, Pantanal do Miranda and Corumbá/Ladário plateau, in the state of Mato Grosso do Sul, as well as in Serra das Araras, in the state of Mato Grosso. The aim is to understand the depositional paleoenvironments and analyse climate and tectonic influences in their genesis and evolution. The results show that the deposition of these continental carbonates started in the Middle to Late Pleistocene and have continued, with some interruptions, until the present days. Sedimentary successions were identified in the different areas, without complete correlation. Two sedimentary successions separated by an erosional surface were described in Serra da Bodoquena and Serra das Araras. In Corumbá and Pantanal do Miranda, only one succession was described. These successions were deposited in elongated lakes parallel to fault planes; small lakes, related plains and plateaus; springs related to cliffs produced by faulting; rivers conditioned by topographic variation. The climatic interpretation, without proper temporal resolution, obtained by the stable-isotope composition and stratigraphic interpretation, indicates alternation of dry and wet periods. The Neoproterozoic faults with their neotectonics and the subsidence of the Pantanal Basin, are the major control for carbonated water flow and development of depositional areas, gradually turning plateaus into slight tilted areas, allowing the evolution of depositional systems from lakes to rivers.

  4. Novel scenarios of early animal evolution--is it time to rewrite textbooks?

    Science.gov (United States)

    Dohrmann, Martin; Wörheide, Gert

    2013-09-01

    Understanding how important phenotypic, developmental, and genomic features of animals originated and evolved is essential for many fields of biological research, but such understanding depends on robust hypotheses about the phylogenetic interrelationships of the higher taxa to which the studied species belong. Molecular approaches to phylogenetics have proven able to revolutionize our knowledge of organismal evolution. However, with respect to the deepest splits in the metazoan Tree of Life-the relationships between Bilateria and the four non-bilaterian phyla (Porifera, Placozoa, Ctenophora, and Cnidaria)-no consensus has been reached yet, since a number of different, often contradictory, hypotheses with sometimes spectacular implications have been proposed in recent years. Here, we review the recent literature on the topic and contrast it with more classical perceptions based on analyses of morphological characters. We conclude that the time is not yet ripe to rewrite zoological textbooks and advocate a conservative approach when it comes to developing scenarios of the early evolution of animals.

  5. Shedding light on the Early Pleistocene of TD6 (Gran Dolina, Atapuerca, Spain): The technological sequence and occupational inferences.

    Science.gov (United States)

    Mosquera, Marina; Ollé, Andreu; Rodríguez-Álvarez, Xose Pedro; Carbonell, Eudald

    2018-01-01

    This paper aims to update the information available on the lithic assemblage from the entire sequence of TD6 now that the most recent excavations have been completed, and to explore possible changes in both occupational patterns and technological strategies evidenced in the unit. This is the first study to analyse the entire TD6 sequence, including subunits TD6.3 and TD6.1, which have never been studied, along with the better-known TD6.2 Homo antecessor-bearing subunit. We also present an analysis of several lithic refits found in TD6, as well as certain technical features that may help characterise the hominin occupations. The archaeo-palaeontological record from TD6 consists of 9,452 faunal remains, 443 coprolites, 1,046 lithic pieces, 170 hominin remains and 91 Celtis seeds. The characteristics of this record seem to indicate two main stages of occupation. In the oldest subunit, TD6.3, the lithic assemblage points to the light and limited hominin occupation of the cave, which does, however, grow over the course of the level. In contrast, the lithic assemblages from TD6.2 and TD6.1 are rich and varied, which may reflect Gran Dolina cave's establishment as a landmark in the region. Despite the occupational differences between the lowermost subunit and the rest of the deposit, technologically the TD6 lithic assemblage is extremely homogeneous throughout. In addition, the composition and spatial distribution of the 12 groups of lithic refits found in unit TD6, as well as the in situ nature of the assemblage demonstrate the high degree of preservation at the site. This may help clarify the nature of the Early Pleistocene hominin occupations of TD6, and raise reasonable doubt about the latest interpretations that support the ex situ character of the assemblage as a whole.

  6. Kinematic evolution of the Romanian Carpathians

    Science.gov (United States)

    Linzer, Hans-Gert; Frisch, Wolfgang; Zweigel, Peter; Girbacea, Radu; Hann, Horst-Peter; Moser, Franz

    1998-11-01

    The regional pattern of contraction and extension directions and the evolution of the strain field from Paleogene to Neogene times enabled a reconstruction of the migration path of the Carpathian collision front. The Carpathian nappes were thrust around the Moesian Plate during Paleogene and Early Neogene times and protruded into a small oceanic embayment between the Moesian and European plates. The arc structure of the Carpathian fold-thrust belt was formed in Late Neogene times as a result of the eastward-escaping Tisza-Dacia block, due to N-directed convergence of the Adriatic plate and the retreating subduction of an oceanic slab. Brittle deformation structures in the Romanian Carpathians suggest three tectonic events related to major plate motions: (1) Paleogene to Middle Miocene NE to ENE contraction caused right-lateral curved strike-slip faults; (2) Middle Miocene to Pliocene fan-shaped orientations of contraction directions were caused by right-lateral oblique convergence in the Southern Carpathians, frontal convergence in the southern Eastern Carpathians and left-lateral convergence in the northern Eastern Carpathians; (3) Pleistocene to Holocene general E-W extension and N-S contraction in the Carpathian arc and local ESE-WNW contraction in the Vrancea area is related to the late roll back stage and break-off of the subducted slab in the bend area.

  7. Zonation of uplifted pleistocene coral reefs on barbados, west indies.

    Science.gov (United States)

    Mesolella, K J

    1967-05-05

    The coral species composition of uplifted Pleistocene reefs on Barbados is very similar to Recent West Indian reefs. Acropora palmata, Acropora cervicornis, and Montastrea annularis are qtuantitatively the most important of the coral species.

  8. Lunge feeding in early marine reptiles and fast evolution of marine tetrapod feeding guilds.

    Science.gov (United States)

    Motani, Ryosuke; Chen, Xiao-hong; Jiang, Da-yong; Cheng, Long; Tintori, Andrea; Rieppel, Olivier

    2015-03-10

    Traditional wisdom holds that biotic recovery from the end-Permian extinction was slow and gradual, and was not complete until the Middle Triassic. Here, we report that the evolution of marine predator feeding guilds, and their trophic structure, proceeded faster. Marine reptile lineages with unique feeding adaptations emerged during the Early Triassic (about 248 million years ago), including the enigmatic Hupehsuchus that possessed an unusually slender mandible. A new specimen of this genus reveals a well-preserved palate and mandible, which suggest that it was a rare lunge feeder as also occurs in rorqual whales and pelicans. The diversity of feeding strategies among Triassic marine tetrapods reached their peak in the Early Triassic, soon after their first appearance in the fossil record. The diet of these early marine tetrapods most likely included soft-bodied animals that are not preserved as fossils. Early marine tetrapods most likely introduced a new trophic mechanism to redistribute nutrients to the top 10 m of the sea, where the primary productivity is highest. Therefore, a simple recovery to a Permian-like trophic structure does not explain the biotic changes seen after the Early Triassic.

  9. Constrained pattern of viral evolution in acute and early HCV infection limits viral plasticity.

    Directory of Open Access Journals (Sweden)

    Katja Pfafferott

    2011-02-01

    Full Text Available Cellular immune responses during acute Hepatitis C virus (HCV and HIV infection are a known correlate of infection outcome. Viral adaptation to these responses via mutation(s within CD8+ T-cell epitopes allows these viruses to subvert host immune control. This study examined HCV evolution in 21 HCV genotype 1-infected subjects to characterise the level of viral adaptation during acute and early HCV infection. Of the total mutations observed 25% were within described CD8+ T-cell epitopes or at viral adaptation sites. Most mutations were maintained into the chronic phase of HCV infection (75%. The lack of reversion of adaptations and high proportion of silent substitutions suggests that HCV has structural and functional limitations that constrain evolution. These results were compared to the pattern of viral evolution observed in 98 subjects during a similar phase in HIV infection from a previous study. In contrast to HCV, evolution during acute HIV infection is marked by high levels of amino acid change relative to silent substitutions, including a higher proportion of adaptations, likely reflecting strong and continued CD8+ T-cell pressure combined with greater plasticity of the virus. Understanding viral escape dynamics for these two viruses is important for effective T cell vaccine design.

  10. Evolution of an Early Illness Warning System to Monitor Frail Elders in Independent Living

    Directory of Open Access Journals (Sweden)

    Gregory L. Alexander

    2011-01-01

    Full Text Available This paper describes the evolution of an early illness warning system used by an interdisciplinary team composed of clinicians and engineers in an independent living facility. The early illness warning system consists of algorithms which analyze resident activity patterns obtained from sensors embedded in residents' apartments. The engineers designed an automated reasoning system to generate clinically relevant alerts which are sent to clinicians when significant changes occur in the sensor data, for example declining activity levels. During January 2010 through July 2010, clinicians and engineers conducted weekly iterative review cycles of the early illness warning system to discuss concerns about the functionality of the warning system, to recommend solutions for the concerns, and to evaluate the implementation of the solutions. A total of 45 concerns were reviewed during this period. Iterative reviews resulted in greater efficiencies and satisfaction for clinician users who were monitoring elder activity patterns.

  11. Paleohydrology and paleoenvironments at Bir Sahara: Pleistocene lithostratigraphy and sedimentology in the southern Egyptian Sahara

    Science.gov (United States)

    Hill, Christopher L.; Schild, Romuald

    2017-12-01

    The Bir Sahara area contains a remarkable record of Middle and Late Pleistocene hydrologic and environmental conditions for Saharan North Africa, based on lithostratigraphic and sedimentologic evidence from basin-fill deposits. Some of the deposits contain Lower Paleolithic (Acheulean) or Middle Paleolithic artifacts that help to constrain their age, since Acheulian artifacts are assigned to the Middle Pleistocene, while Middle Paleolithic artifacts are limited to either the Middle or Late Pleistocene. Locality BS-14 is in the southern part of Bir Sahara, while localities E-88-15, E-88-2, BS-13, and BS-16 are situated in the south-central part of the deflational basin, closer to the present-day water-hole. Lowered groundwater conditions during arid intervals resulted in erosional topographic basins. These deflational basins were later filled with sediments associated with wetter hydrologic conditions. The oldest studied sedimentary sequence in the Bir Sahara depression (BS-14) contains in situ Acheulian artifacts. Acheulian handaxes are found in sands underlying carbonates that are interpreted as evidence of spring-fed pond and marsh environments during a Middle Pleistocene wet interval. At the E-88-15 locality, the stratigraphic sequence documents deposition in a possible perennial pond or small lake that varied in extent and depth and is associated with Middle Paleolithic artifacts. At E-88-12 and BS-13, lateral and vertical variations in the lithofacies of the basin-fill sediments provide additional records of changing hydrologic conditions during the Late Pleistocene. These hydrologic conditions appear to reflect variations in water-table levels related to groundwater recharge and, at times, local rains.

  12. Early to Middle Jurassic tectonic evolution of the Bogda Mountains, Northwest China: Evidence from sedimentology and detrital zircon geochronology

    Science.gov (United States)

    Ji, Hongjie; Tao, Huifei; Wang, Qi; Qiu, Zhen; Ma, Dongxu; Qiu, Junli; Liao, Peng

    2018-03-01

    The Bogda Mountains, as an important intracontinental orogenic belt, are situated in the southern part of the Central Asian Orogenic Belt (CAOB), and are a key area for understanding the Mesozoic evolution of the CAOB. However, the tectonic evolution of the Bogda Mountains remains controversial during the Mesozoic Era, especially the Early to Middle Jurassic Periods. The successive Lower to Middle Jurassic strata are well preserved and exposed along the northern flank of the Western Bogda Mountains and record the uplift processes of the Bogda Mountains. In this study, we analysed sedimentary facies combined with detrital zircon U-Pb geochronology at five sections of Lower to Middle Jurassic strata to detect the tectonic evolution and changes of provenance in the Bogda area. During Early to Middle Jurassic times, the fluvial, deltaic and lacustrine environments dominated in the western section of the Bogda area. The existence of Early Triassic peak age indicates that the Bogda Mountains did not experience uplift during the period of early Badaowan Formation deposition. The Early Triassic to Late Permian granitoid plutons and Carboniferous volcanic rocks from the Barkol and Santanghu areas were the main provenances. The significant change in the U-Pb age spectrum implies that the Eastern Bogda Mountains initiated uplift in the period of late Badaowan Formation deposition, and the Eastern Junggar Basin and the Turpan-Hami Basin were partially partitioned. The Eastern Bogda Mountains gradually became the major provenance. From the period of early Sangonghe to early Toutunhe Formations deposition, the provenance of the sediments and basin-range frame were similar to that of late Badaowan. However, the Eastern Bogda Mountains suffered intermittent uplift three times, and successive denudation. The uplifts respectively happened in early Sangonghe, late Sangonghe to early Xishanyao, and late Xishanyao to early Toutunhe. During the deposition stage of Toutunhe Formation, a

  13. Low Florida coral calcification rates in the Plio-Pleistocene

    Science.gov (United States)

    Brachert, Thomas C.; Reuter, Markus; Krüger, Stefan; Klaus, James S.; Helmle, Kevin; Lough, Janice M.

    2016-08-01

    In geological outcrops and drill cores from reef frameworks, the skeletons of scleractinian corals are usually leached and more or less completely transformed into sparry calcite because the highly porous skeletons formed of metastable aragonite (CaCO3) undergo rapid diagenetic alteration. Upon alteration, ghost structures of the distinct annual growth bands often allow for reconstructions of annual extension ( = growth) rates, but information on skeletal density needed for reconstructions of calcification rates is invariably lost. This report presents the bulk density, extension rates and calcification rates of fossil reef corals which underwent minor diagenetic alteration only. The corals derive from unlithified shallow water carbonates of the Florida platform (south-eastern USA), which formed during four interglacial sea level highstands dated approximately 3.2, 2.9, 1.8, and 1.2 Ma in the mid-Pliocene to early Pleistocene. With regard to the preservation, the coral skeletons display smooth growth surfaces with minor volumes of marine aragonite cement within intra-skeletal porosity. Within the skeletal structures, voids are commonly present along centres of calcification which lack secondary cements. Mean extension rates were 0.44 ± 0.19 cm yr-1 (range 0.16 to 0.86 cm yr-1), mean bulk density was 0.96 ± 0.36 g cm-3 (range 0.55 to 1.83 g cm-3) and calcification rates ranged from 0.18 to 0.82 g cm-2 yr-1 (mean 0.38 ± 0.16 g cm-2 yr-1), values which are 50 % of modern shallow-water reef corals. To understand the possible mechanisms behind these low calcification rates, we compared the fossil calcification rates with those of modern zooxanthellate corals (z corals) from the Western Atlantic (WA) and Indo-Pacific calibrated against sea surface temperature (SST). In the fossil data, we found a widely analogous relationship with SST in z corals from the WA, i.e. density increases and extension rate decreases with increasing SST, but over a significantly larger

  14. Pleistocene Park: the restoration of steppes as a tool to mitigate climate change through albedo effect

    Science.gov (United States)

    Zimov, N.; Loranty, M. M.; Edgar, C.; Kropp, H.; Zimov, S. A.

    2017-12-01

    In the late Pleistocene, the world largest ecosystem was the mammoth steppe. It stretched from the Iberian Peninsula to Canada and from the New Siberian Islands to China. It was a highly productive steppe ecosystem with numerous predators and herbivores that maintained the dominance of grasslands. With the end of the Pleistocene, the climate warmed and humans entered Siberia and the Americas. The introduction of humans as predators in these regions led to the extinction of most large animals, and the further degradation of the steppes. Mosses, shrubs and larch forest soon replaced grasses and herbs. Pleistocene Park is an experiment conducted in the far north of Siberia; its main goal is to revive the extinct steppe ecosystem in the Arctic. This would increase the richness of the northern ecosystems and, bioproductivity, and through a series of ecological mechanisms help to mitigate climate change. To conduct the experiment, was fenced 2000 hectares of land, and continue the ongoing process of introducing animals that either lived on this territory in the past or that can adapt to the modern northern environment. Through grazing, animals slowly transform the vegetation, replacing mosses, shrubs, and trees with grasses and herbs. Here we present the effects grazing animals have on the albedo of the landscape. Several years of year-round measurement of albedo and incoming and reflected radiation conducted in the grasslands in the park indicate substantially higher albedo compared with most modern ecosystems like larch forest and shrublands. Since grasses are lighter than forest, they reflect a higher portion of energy back to space. Results indicate the most dramatic difference in reflected solar radiation is in April and early May. Grasslands covered with snow reflect most of the sun's energy, while dark stems of forests and shrubs absorb that energy and promote warming. We argue that large-scale promotion of highly productive steppes in the Arctic will

  15. Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs

    Science.gov (United States)

    Green, Richard E; Braun, Edward L; Armstrong, Joel; Earl, Dent; Nguyen, Ngan; Hickey, Glenn; Vandewege, Michael W; St John, John A; Capella-Gutiérrez, Salvador; Castoe, Todd A; Kern, Colin; Fujita, Matthew K; Opazo, Juan C; Jurka, Jerzy; Kojima, Kenji K; Caballero, Juan; Hubley, Robert M; Smit, Arian F; Platt, Roy N; Lavoie, Christine A; Ramakodi, Meganathan P; Finger, John W; Suh, Alexander; Isberg, Sally R; Miles, Lee; Chong, Amanda Y; Jaratlerdsiri, Weerachai; Gongora, Jaime; Moran, Christopher; Iriarte, Andrés; McCormack, John; Burgess, Shane C; Edwards, Scott V; Lyons, Eric; Williams, Christina; Breen, Matthew; Howard, Jason T; Gresham, Cathy R; Peterson, Daniel G; Schmitz, Jürgen; Pollock, David D; Haussler, David; Triplett, Eric W; Zhang, Guojie; Irie, Naoki; Jarvis, Erich D; Brochu, Christopher A; Schmidt, Carl J; McCarthy, Fiona M; Faircloth, Brant C; Hoffmann, Federico G; Glenn, Travis C; Gabaldón, Toni; Paten, Benedict; Ray, David A

    2015-01-01

    To provide context for the diversifications of archosaurs, the group that includes crocodilians, dinosaurs and birds, we generated draft genomes of three crocodilians, Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial). We observed an exceptionally slow rate of genome evolution within crocodilians at all levels, including nucleotide substitutions, indels, transposable element content and movement, gene family evolution, and chromosomal synteny. When placed within the context of related taxa including birds and turtles, this suggests that the common ancestor of all of these taxa also exhibited slow genome evolution and that the relatively rapid evolution of bird genomes represents an autapomorphy within that clade. The data also provided the opportunity to analyze heterozygosity in crocodilians, which indicates a likely reduction in population size for all three taxa through the Pleistocene. Finally, these new data combined with newly published bird genomes allowed us to reconstruct the partial genome of the common ancestor of archosaurs providing a tool to investigate the genetic starting material of crocodilians, birds, and dinosaurs. PMID:25504731

  16. Fuxianhuiid ventral nerve cord and early nervous system evolution in Panarthropoda.

    Science.gov (United States)

    Yang, Jie; Ortega-Hernández, Javier; Butterfield, Nicholas J; Liu, Yu; Boyan, George S; Hou, Jin-Bo; Lan, Tian; Zhang, Xi-Guang

    2016-03-15

    Panarthropods are typified by disparate grades of neurological organization reflecting a complex evolutionary history. The fossil record offers a unique opportunity to reconstruct early character evolution of the nervous system via exceptional preservation in extinct representatives. Here we describe the neurological architecture of the ventral nerve cord (VNC) in the upper-stem group euarthropod Chengjiangocaris kunmingensis from the early Cambrian Xiaoshiba Lagerstätte (South China). The VNC of C. kunmingensis comprises a homonymous series of condensed ganglia that extend throughout the body, each associated with a pair of biramous limbs. Submillimetric preservation reveals numerous segmental and intersegmental nerve roots emerging from both sides of the VNC, which correspond topologically to the peripheral nerves of extant Priapulida and Onychophora. The fuxianhuiid VNC indicates that ancestral neurological features of Ecdysozoa persisted into derived members of stem-group Euarthropoda but were later lost in crown-group representatives. These findings illuminate the VNC ground pattern in Panarthropoda and suggest the independent secondary loss of cycloneuralian-like neurological characters in Tardigrada and Euarthropoda.

  17. Fluvial evolution of the Rhine during the last interglacial-glacial cycle in the southern North Sea basin : A review and look forward

    NARCIS (Netherlands)

    Peeters, Jan; Busschers, Freek S.; Stouthamer, Esther

    2015-01-01

    This paper presents the current state of knowledge on the evolution and depositional history of the River Rhine in the southern part of the North Sea basin during the upper Middle and Late Pleistocene, and its response to climate change, sea-level oscillation and glacio-isostasy. The study focuses

  18. Fluvial evolution of the Rhine during the last interglacial-glacial cycle in the southern North Sea basin: A review and look forward

    NARCIS (Netherlands)

    Peeters, J.; Busschers, F.S.; Stouthamer, E.

    2015-01-01

    This paper presents the current state of knowledge on the evolution and depositional history of the River Rhine in the southern part of the North Sea basin during the upper Middle and Late Pleistocene, and its response to climate change, sea-level oscillation and glacio-isostasy. The study focuses

  19. Spectral evolution of galaxies: current views

    International Nuclear Information System (INIS)

    Bruzual, A.G.

    1985-01-01

    A summary of current views on the interpretation of the various evolutionary tests aimed at detecting spectral evolution in galaxies is presented. It is concluded that the evolution taking place in known galaxy samples is a slow process (perhaps consistent with no evolution at all), and that the early phases of rapid spectral evolution in early-type galaxies have not yet been detected. (author)

  20. The Alleret Maar lacustrine sequence (French Massif Central): a 150 ka long early-middle Pleistocene continental paleoenvironmental record.

    Science.gov (United States)

    Nomade, S.; Pastre, J.; Guillou, H.; Gauthier, A.; Scaillet, S.

    2008-12-01

    Lacustrine maar sequences of the French Massif Central are of great interest for paleoclimatic and paleoenvironmental reconstructions of mid-latitudes Quaternary continental environments. In particular, the western Velay region yields exceptional sequences spanning the last 450 ka (Reille et al., J. Quat. Sci. 2000). However, older sequences remain largely unknown despite the presence of interbedded alkaline tephras allowing precise absolute radiochronological control of many lacustrine squences. The Alleret maar is a 1500 m wide phreatomagmatic crater that provides a long lacustrine sequence (41 m). The upper part of this sequence (AL2 core, 14.6 m) was studied between 2005 and 2006 (Pastre et al., C. R. Acad Sci, 2007). A 39Ar/40Ar date (557 ± 5ka) obtained from an interbedded tephra layer located at 7m as well as the associated pollen data attribute the beginning of this sequence to the MIS 15. Thanks to the AL3 core recovered in 2005 (40.6 m, CNRS Meudon) several new tephra layers were discovered in the bottom part of this lacustrine sequence. Three new 39Ar/40Ar ages (single crystal analyses) from trachytic tephra layers were obtained at the LSCE Argon Laboratory (France). These layers are located at -30.2, -36.2 and -39.2m. Ages obtained relative to the ACR-2 flux standard (1,201Ma, Kuiper et al., Science, 2008) range from 692 ± 6 ka (MSWD: 2.3, n=18) for the youngest (-30.2m) to 726 ± 9Ka Ka (MSWD: 2.2, n=12) for the lowest tephra located at -39.2m. These new dates indicate a relatively homogeneous deposition rate of 3.5cm/ka and that the last 10 meters cover the MIS 17-MIS18 period. According to these current radiochronological data the complete lacustrine sequence last more than 150ka. Ongoing sedimentary and pollen studies will allow to extend the paleoenvironmental and paleoclimatic records of the French Massif Central towards the beginning of the early middle Pleistocene.

  1. Quantifying the astronomical contribution to Pleistocene climate change: A non-linear, statistical approach

    Science.gov (United States)

    Crucifix, Michel; Wilkinson, Richard; Carson, Jake; Preston, Simon; Alemeida, Carlos; Rougier, Jonathan

    2013-04-01

    The existence of an action of astronomical forcing on the Pleistocene climate is almost undisputed. However, quantifying this action is not straightforward. In particular, the phenomenon of deglaciation is generally interpreted as a manifestation of instability, which is typical of non-linear systems. As a consequence, explaining the Pleistocene climate record as the addition of an astronomical contribution and noise-as often done using harmonic analysis tools-is potentially deceptive. Rather, we advocate a methodology in which non-linear stochastic dynamical systems are calibrated on the Pleistocene climate record. The exercise, though, requires careful statistical reasoning and state-of-the-art techniques. In fact, the problem has been judged to be mathematically 'intractable and unsolved' and some pragmatism is justified. In order to illustrate the methodology we consider one dynamical system that potentially captures four dynamical features of the Pleistocene climate : the existence of a saddle-node bifurcation in at least one of its slow components, a time-scale separation between a slow and a fast component, the action of astronomical forcing, and the existence a stochastic contribution to the system dynamics. This model is obviously not the only possible representation of Pleistocene dynamics, but it encapsulates well enough both our theoretical and empirical knowledge into a very simple form to constitute a valid starting point. The purpose of this poster is to outline the practical challenges in calibrating such a model on paleoclimate observations. Just as in time series analysis, there is no one single and universal test or criteria that would demonstrate the validity of an approach. Several methods exist to calibrate the model and judgement develops by the confrontation of the results of the different methods. In particular, we consider here the Kalman filter variants, the Particle Monte-Carlo Markov Chain, and two other variants of Sequential Monte

  2. High-resolution sequence stratigraphy and continental environmental evolution: An example from east-central Argentina

    Science.gov (United States)

    Beilinson, Elisa; Veiga, Gonzalo D.; Spalletti, Luis A.

    2013-10-01

    The aims of this contribution is to establish a high-resolution sequence stratigraphic scheme for the continental deposits that constitute the Punta San Andrés Alloformation (Plio-Pleistocene) in east-central Argentina, to analyze the basin fill evolution and to identify and assess the role that extrinsic factors such as climate and sea-level oscillations played during evolution of the unit. For the high-resolution sequence stratigraphical study of the Punta San Andrés Alloformation, high- and low-accommodation system tracts were defined mainly on the basis of the architectural elements present in the succession, also taking into account the relative degree of channel and floodplain deposits. Discontinuities and the nature of depositional systems generated during variations in accommodation helped identify two fourth-order high-accommodation system tracts and two fourth-order low-accommodation system tracts. At a third-order scale, the Punta San Andrés Alloformation may be interpreted as the progradation of continental depositional systems, characterized by a braided system in the proximal areas, and a low-sinuosity, single-channel system in the distal areas, defined by a high rate of sediment supply and discharge peaks which periodically flooded the plains and generated high aggradation rates during the late Pliocene and lower Pleistocene.

  3. Transformation and diversification in early mammal evolution.

    Science.gov (United States)

    Luo, Zhe-Xi

    2007-12-13

    Evolution of the earliest mammals shows successive episodes of diversification. Lineage-splitting in Mesozoic mammals is coupled with many independent evolutionary experiments and ecological specializations. Classic scenarios of mammalian morphological evolution tend to posit an orderly acquisition of key evolutionary innovations leading to adaptive diversification, but newly discovered fossils show that evolution of such key characters as the middle ear and the tribosphenic teeth is far more labile among Mesozoic mammals. Successive diversifications of Mesozoic mammal groups multiplied the opportunities for many dead-end lineages to iteratively evolve developmental homoplasies and convergent ecological specializations, parallel to those in modern mammal groups.

  4. Lunge feeding in early marine reptiles and fast evolution of marine tetrapod feeding guilds

    OpenAIRE

    Motani, R; Chen, XH; Jiang, DY; Cheng, L; Tintori, A; Rieppel, O

    2015-01-01

    Traditional wisdom holds that biotic recovery from the end-Permian extinction was slow and gradual, and was not complete until the Middle Triassic. Here, we report that the evolution of marine predator feeding guilds, and their trophic structure, proceeded faster. Marine reptile lineages with unique feeding adaptations emerged during the Early Triassic (about 248 million years ago), including the enigmatic Hupehsuchus that possessed an unusually slender mandible. A new specimen of this genus ...

  5. Revalidation of the genus Chiloguembelitria Hofker: Implications for the evolution of early Danian planktonic foraminifera

    Science.gov (United States)

    Arenillas, Ignacio; Arz, José A.; Gilabert, Vicente

    2017-10-01

    Guembelitria is the only planktonic foraminiferal genus whose survival from the mass extinction event of the Cretaceous/Paleogene (K/Pg) boundary has been clearly proven. The evolution of Guembelitria after the K/Pg boundary led to the appearance of two guembelitriid lineages in the early Danian: one biserial, represented by Woodringina and culminating in Chiloguembelina, and the other trochospiral, represented by Trochoguembelitria and culminating in Globoconusa. We have re-examined the genus Chiloguembelitria, another guembelitriid descended from Guembelitria and whose taxonomic validity had been questioned, it being considered a junior synonym of the latter. Nevertheless, Chiloguembelitria differs from Guembelitria mainly in the wall texture (pustulate to rugose vs. pore-mounded) and the position of the aperture (umbilical-extraumbilical to extraumbilical vs. umbilical). Chiloguembelitria shares its wall texture with Trochoguembelitria and some of the earliest specimens of Woodringina, suggesting that it played an important role in the evolution of early Danian guembelitriids, as it seems to be the most immediate ancestor of both trochospiral and biserial lineages. Morphological and morphostatistical analyses of Chiloguembelitria discriminate at least five species: Chg. danica, Chg. irregularis, and three new species: Chg. hofkeri, Chg. trilobata and Chg. biseriata.

  6. Oceanographic and climatic evolution of the southeastern subtropical Atlantic over the last 3.5 Ma

    Science.gov (United States)

    Petrick, Benjamin; McClymont, Erin L.; Littler, Kate; Rosell-Melé, Antoni; Clarkson, Matthew O.; Maslin, Mark; Röhl, Ursula; Shevenell, Amelia E.; Pancost, Richard D.

    2018-06-01

    The southeast Atlantic Ocean is dominated by two major oceanic systems: the Benguela Upwelling System, one of the world's most productive coastal upwelling cells and the Agulhas Leakage, which is important for transferring warm salty water from the Indian Ocean to the Atlantic Ocean. Here, we present a multi-proxy record of marine sediments from ODP Site 1087. We reconstruct sea surface temperatures (U37K‧ and TEX86 indices), marine primary productivity (total chlorin and alkenone mass accumulation rates), and terrestrial inputs derived from southern Africa (Ti/Al and Ca/Ti via XRF scanning) to understand the evolution of the Southeast Atlantic Ocean since the late Pliocene. In the late Pliocene and early Pleistocene, ODP Site 1087 was situated within the Benguela Upwelling System, which was displaced southwards relative to present. We recognize a series of events in the proxy records at 3.3, 3.0, 2.2, 1.5, 0.9 and 0.6 Ma, which are interpreted to reflect a combination of changes in the location of major global wind and oceanic systems and local variations in the strength and/or position of the winds, which influence nutrient availability. Although there is a temporary SST cooling observed around the initiation of Northern Hemisphere glaciation (iNHG), proxy records from ODP Site 1087 show no clear climatic transition around 2.7 Ma but instead most of the changes occur before this time. This observation is significant because it has been previously suggested that there should be a change in the location and/or strength of upwelling associated with this climate transition. Rather, the main shifts at ODP Site 1087 occur at ca. 0.9 Ma and 0.6 Ma, associated with the early mid-Pleistocene transition (EMPT), with a clear loss of the previous upwelling-dominated regime. This observation raises the possibility that reorganisation of southeast Atlantic Ocean circulation towards modern conditions was tightly linked to the EMPT, but not to earlier climate transitions.

  7. Early-type Galaxy Spin Evolution in the Horizon-AGN Simulation

    Science.gov (United States)

    Choi, Hoseung; Yi, Sukyoung K.; Dubois, Yohan; Kimm, Taysun; Devriendt, Julien. E. G.; Pichon, Christophe

    2018-04-01

    Using the Horizon-AGN simulation data, we study the relative role of mergers and environmental effects in shaping the spin of early-type galaxies (ETGs) after z ≃ 1. We follow the spin evolution of 10,037 color-selected ETGs more massive than {10}10 {M}ȯ that are divided into four groups: cluster centrals (3%), cluster satellites (33%), group centrals (5%), and field ETGs (59%). We find a strong mass dependence of the slow rotator fraction, f SR, and the mean spin of massive ETGs. Although we do not find a clear environmental dependence of f SR, a weak trend is seen in the mean value of the spin parameter driven by the satellite ETGs as they gradually lose their spin as their environment becomes denser. Galaxy mergers appear to be the main cause of total spin changes in 94% of the central ETGs of halos with {M}vir}> {10}12.5 {M}ȯ , but only 22% of satellite and field ETGs. We find that non-merger-induced tidal perturbations better correlate with the galaxy spin down in satellite ETGs than in mergers. Given that the majority of ETGs are not central in dense environments, we conclude that non-merger tidal perturbation effects played a key role in the spin evolution of ETGs observed in the local (z < 1) universe.

  8. THE SIZE EVOLUTION OF PASSIVE GALAXIES: OBSERVATIONS FROM THE WIDE-FIELD CAMERA 3 EARLY RELEASE SCIENCE PROGRAM

    International Nuclear Information System (INIS)

    Ryan, R. E. Jr.; McCarthy, P. J.; Cohen, S. H.; Rutkowski, M. J.; Mechtley, M. R.; Windhorst, R. A.; Yan, H.; Hathi, N. P.; Koekemoer, A. M.; Bond, H. E.; Bushouse, H.; O'Connell, R. W.; Balick, B.; Calzetti, D.; Crockett, R. M.; Disney, M.; Dopita, M. A.; Frogel, J. A.; Hall, D. N. B.; Holtzman, J. A.

    2012-01-01

    We present the size evolution of passively evolving galaxies at z ∼ 2 identified in Wide-Field Camera 3 imaging from the Early Release Science program. Our sample was constructed using an analog to the passive BzK galaxy selection criterion, which isolates galaxies with little or no ongoing star formation at z ∼> 1.5. We identify 30 galaxies in ∼40 arcmin 2 to H obs ∼ * ∼ 10 11 M ☉ ) undergo the strongest evolution from z ∼ 2 to the present. Parameterizing the size evolution as (1 + z) –α , we find a tentative scaling of α ≈ (– 0.6 ± 0.7) + (0.9 ± 0.4)log (M * /10 9 M ☉ ), where the relatively large uncertainties reflect the poor sampling in stellar mass due to the low numbers of high-redshift systems. We discuss the implications of this result for the redshift evolution of the M * -R e relation for red galaxies.

  9. Climate at the edge of human dispersal in the European Middle Pleistocene

    Science.gov (United States)

    Horne, David

    2014-05-01

    Pleistocene palaeoclimatic reconstructions based on fossils from sites containing archaeological evidence of human occupation can answer key questions about the climatic context of early human dispersal in Europe. Biological proxies including foraminifera, ostracods, diatoms, chironomid larvae, molluscs and pollen are widely used to estimate palaeoclimatic parameters, typically palaeotemperatures, using indicator species, Mutual Climatic Range (MCR), Modern Analogue Technique (MAT) and transfer function approaches. Any single proxy method will yield plausible results, but there is a need for multi-proxy testing; matching or overlapping results inspire confidence, whereas if independent proxies yield results that do not match or even overlap, one or more must be wrong. The Multi-Proxy Consensus (MPC) approach not only compares two or more proxy results in order to check for agreement, but also offers potential for more refined results to be obtained from the range of mutual agreement between two or more overlapping palaeotemperature ranges. Studies of MIS9 (late Middle Pleistocene) deposits in the Thames-Medway river system in SE England (some of which contain stone implements representing human occupation) have yielded palaeotemperature estimates based on ostracods, beetles, fish, herpetiles, pollen and plant macrofossils. The MPC approach demonstrates the consistency of the results and defines a more continental climate than today (mean July air temperatures similar or 1 degree warmer, mean January air temperatures at least 2 degrees colder). Two River Thames MIS11 sites (Ebbsfleet and Swanscombe) have yielded MPC results indicating summers up to 1.5 degrees warmer and winters at least 5 degrees colder than today. British early Middle Pleistocene sites record the earliest human presence in Europe North of the Alps. At Boxgrove (MIS13), well-known for its rich record of human activity (stone tools and butchered bones), combined ostracod and herpetile MCR results

  10. Climatic fluctuations as a significant contributing factor for volcanic collapses. Evidence from Mexico during the Late Pleistocene

    Science.gov (United States)

    Capra, L.; Bernal-Uruchurtu, J. P.; Carrasco, G.

    2013-05-01

    Climate oscillations have significantly contributed to the planet's evolution, including volcanic activity. Major glaciations have been considered not only as a triggering mechanism for large magmatic eruptions but also inducing volcano instability. Generally, volcano instability can be inferred from detailed volcanological and structural studies of a volcano and its associated depositional sequence, but the triggering mechanism has been always difficult to infer. In this paper, we present evidence of how climatic variations during the Late Pleistocene could have forced sector collapses of the main Mexican stratovolcanoes and enhanced the mobility of associated massive flows inducing the transformation of debris avalanche into debris flows. In particular, the climatic record based on atmospheric moisture content from robustly dated lake record from Guatemala and a U/Th dated speleothem from New Mexico are used here as indicators of summer and winter precipitation. Depositional sequences associated with Late Pleistocene sector collapses of Volcan de Colima, Nevado de Toluca, Citlaltepetl (Pico de Orizaba) and Cofre de Perote volcanoes are here analyzed. Comparing the timing of the event with the climatic record, a combination of summer and/or winter pluvial conditions could have forced and triggered the failure of already unstable volcanoes, even during glacier advances (as for the Citlaltepetl event). Independently of the main cause of the volcano instability (magmatic or tectonic) it is important to highlight that the climatic factor played an important role in enhancing the volcano instability and promoted the lateral transformation of debris avalanches, which under dry conditions would have affected more limited areas.

  11. Late Pleistocene and Holocene landscape formation in a gully catchment area in Northern Hesse, Germany

    DEFF Research Database (Denmark)

    Döhler, Susanne; Damm, Bodo; Terhorst, Birgit

    2015-01-01

    the differentiation between Pleistocene and Holocene landforms. Radiocarbon and optically stimulated luminescence dating are applied to add numerical data to the relative ages of the sediments and landforms. The gully channels are oriented along Pleistocene depressions that are built up of periglacial cover beds...... and intercalated reworked loess. As the gully channels cut through the periglacial cover beds, especially the upper layer, the gully system is of Holocene age. At least two phases of gully erosion are identified in the alluvial fan sediments. The initial gully erosion is dated to the time span between the Late......Permanent gully channels under forest are common geomorphological features in Central European low mountain areas. In the Rehgraben/Fuchslöchergraben gully catchment in Northern Hesse, Germany the Late Pleistocene landscape formation is reconstructed based on periglacial cover beds. In addition...

  12. Pliocene-Lower Pleistocene shallow-water mixed siliciclastics and carbonates (Yanigua and Los Haitises formations) in eastern Hispaniola (Dominican Republic)

    Science.gov (United States)

    Braga, Juan C.; Díaz de Neira, Alberto; Lasseur, Eric; Mediato, José; Aguirre, Julio; Abad, Manuel; Hernaiz-Huerta, Pedro P.; Monthel, Jacques; Pérez-Valera, Fernando; Lopera, Eusebio

    2012-07-01

    The virtually unfolded sedimentary cover of the Cordilleras Central and Oriental in the eastern Dominican Republic (eastern Hispaniola, tropical North Atlantic) largely consists of Pliocene to Early Pleistocene mixed siliciclastics and carbonates. These deposits have been grouped into two laterally interfingering mapping units, the Yanigua and Los Haitises formations. The former (mainly siliciclastics) comprises marl, marly limestone, and minor conglomerate, sandstone, lignite, and carbonaceous clay and crops out closest to the basement. The Los Haitises Formation mainly consists of limestone and intercalating beds of marly limestone and marl. Lithological mapping at the 1:50,000 scale and facies analysis of twelve measured sections and of additional fourteen outcrops suggest that these deposits mainly formed on a shallow-water marine platform fringing the precursor reliefs of the Cordillera Oriental and the southeastern end of the Cordillera Central. Only a limited proportion of sediment formed in floodplains and marshes. Marl and marly limestone dominated the inner platform sediments. Terrigenous mud decreased away from the emergent basement and carbonate sedimentation dominated the more external platform. Corals, molluscs, echinoids, foraminifers, bryozoans, coralline algae, and Halimeda are the main components with varying amounts of carbonate mud. The platform was generally a low-energy environment with seagrass patches. In the inner platform, corals grew as isolated colonies or as small patch reefs dominated by Porites in marly and bioclastic substrates. Branching corals (Stylophora and Acropora) grew in extensive carpets in more distal areas. At least in the last stage of its development (Early Pleistocene), the platform was rimmed by a reef barrier similar to the Holocene Caribbean barrier reefs, with Acropora gr. palmata, A. cervicornis, Porites, Montastrea, Siderastrea, and Diploria as the main reef builders.

  13. Canyon Creek: A late Pleistocene vertebrate locality in interior Alaska

    Science.gov (United States)

    Weber, Florence R.; Hamilton, Thomas D.; Hopkins, David M.; Repenning, Charles A.; Haas, Herbert

    1981-09-01

    The Canyon Creek vertebrate-fossil locality is an extensive road cut near Fairbanks that exposes sediments that range in age from early Wisconsin to late Holocene. Tanana River gravel at the base of the section evidently formed during the Delta Glaciation of the north-central Alaska Range. Younger layers and lenses of fluvial sand are interbedded with arkosic gravel from Canyon Creek that contains tephra as well as fossil bones of an interstadial fauna about 40,000 years old. Solifluction deposits containing ventifacts, wedge casts, and rodent burrows formed during a subsequent period of periglacial activity that took place during the maximum phase of Donnelly Glaciation about 25,000-17,000 years ago. Overlying sheets of eolian sand are separated by a 9500-year-old paleosol that may correlate with a phase of early Holocene spruce expansion through central Alaska. The Pleistocene fauna from Canyon Creek consists of rodents (indicated by burrows), Mammuthus primigenius (woolly mammoth), Equus lambei (Yukon wild ass), Camelops hesternus (western camel), Bison sp. cf. B. crassicornis (large-horned bison), Ovis sp. cf. O. dalli (mountain sheep), Canis sp. cf. C. lupus (wolf), Lepus sp. cf. L. othus or L. arcticus (tundra hare), and Rangifer sp. (caribou). This assemblage suggests an open landscape in which trees and tall shrubs were either absent or confined to sheltered and moist sites. Camelops evidently was present in eastern Beringia during the middle Wisconsin interstadial interval but may have disappeared during the following glacial episode. The stratigraphic section at Canyon Creek appears to demonstrate that the Delta Glaciation of the north-central Alaska Range is at least in part of early Wisconsin age and was separated from the succeeding Donnelly Glaciation by an interstadial rather than interglacial episode.

  14. Facies associations, depositional environments and stratigraphic framework of the Early Miocene-Pleistocene successions of the Mukah-Balingian Area, Sarawak, Malaysia

    Science.gov (United States)

    Murtaza, Muhammad; Rahman, Abdul Hadi Abdul; Sum, Chow Weng; Konjing, Zainey

    2018-02-01

    Thirty-five stratigraphic section exposed along the Mukah-Selangau road in the Mukah-Balingian area have been studied. Sedimentological and palynological data have been integrated to gain a better insight into the depositional architecture of the area. Broadly, the Mukah-Balingian area is dominated by fluvial, floodplain and estuarine related coal-bearing deposits. The Balingian, Begrih and Liang formations have been described and interpreted in terms of seven facies association. These are: FA1 - Fluvial-dominated channel facies association; FA2 - Tide-influenced channel facies association; FA3 - Tide-dominated channel facies association; FA4 - Floodplain facies association; FA5 - Estuarine central basin-mud flats facies association; FA6 - Tidal flat facies association and FA7 - Coastal swamps and marshes facies association. The Balingian Formation is characterised by the transgressive phase in the base, followed by a regressive phase in the upper part. On the basis of the occurrence of Florscheutzia trilobata with Florscheutzia levipoli, the Early to Middle Miocene age has been assigned to the Balingian Formation. The distinct facies pattern and foraminifera species found from the samples taken from the Begrih outcrop imply deposition in the intertidal flats having pronounced fluvio-tidal interactions along the paleo-margin. Foraminiferal data combined with the pronounced occurrence of Stenochlaena laurifolia suggest at least the Late Miocene age for the Begrih Formation. The internal stratigraphic architecture of the Liang Formation is a function of a combination of sea level, stable tectonic and autogenic control. Based on stratigraphic position, the Middle Pliocene to Pleistocene age for the Liang Formation is probable. The Balingian, Begrih and Liang formations display deposits of multiple regressive-transgressive cycles while the sediments were derived from the uplifted Penian high and Rajang group.

  15. Cyanobacterial evolution during the Precambrian

    Science.gov (United States)

    Schirrmeister, Bettina E.; Sanchez-Baracaldo, Patricia; Wacey, David

    2016-07-01

    Life on Earth has existed for at least 3.5 billion years. Yet, relatively little is known of its evolution during the first two billion years, due to the scarceness and generally poor preservation of fossilized biological material. Cyanobacteria, formerly known as blue green algae were among the first crown Eubacteria to evolve and for more than 2.5 billion years they have strongly influenced Earth's biosphere. Being the only organism where oxygenic photosynthesis has originated, they have oxygenated Earth's atmosphere and hydrosphere, triggered the evolution of plants -being ancestral to chloroplasts- and enabled the evolution of complex life based on aerobic respiration. Having such a strong impact on early life, one might expect that the evolutionary success of this group may also have triggered further biosphere changes during early Earth history. However, very little is known about the early evolution of this phylum and ongoing debates about cyanobacterial fossils, biomarkers and molecular clock analyses highlight the difficulties in this field of research. Although phylogenomic analyses have provided promising glimpses into the early evolution of cyanobacteria, estimated divergence ages are often very uncertain, because of vague and insufficient tree-calibrations. Results of molecular clock analyses are intrinsically tied to these prior calibration points, hence improving calibrations will enable more precise divergence time estimations. Here we provide a review of previously described Precambrian microfossils, biomarkers and geochemical markers that inform upon the early evolution of cyanobacteria. Future research in micropalaeontology will require novel analyses and imaging techniques to improve taxonomic affiliation of many Precambrian microfossils. Consequently, a better understanding of early cyanobacterial evolution will not only allow for a more specific calibration of cyanobacterial and eubacterial phylogenies, but also provide new dates for the tree

  16. Dinoflagellate cysts and the paleoenvironment of Late-Pliocene early-pleistocene deposits of Brittany, Northwest France

    Science.gov (United States)

    Morzadec-Kerfourn, Marie Thérèse

    The marine Pliocene facies of the Redon clay is widely distributed in the western part of Brittany. the decrease in the abundance of Tertiary pollen towards the top of the deposits, coupled with the increase of pollen of boreal forest taxa and the development of Ericaceae and Poaceae indicates a Late-Pliocene age. The occurrence of the transgression maximum is recorded in calcareous beds which contain the highest concentration of microforaminiferal linings and dinoflagellate cysts. Hystrichokolpoma rigaudae and Melitasphaeridium choanophorum, along with Achomosphaera andalousiensis and Operculodinium israelianum make up these aseemblages. The presence of dinoflagellate cyst assemblages with estuarine and neritic affinities but with an occasional oceanic form, indicates sedimentation in coastal waters with a neritic influence. The paleotopography exerts a control on the altitudinal distribution of the Redon clays in the western part of Brittany to the west of the Rennes Basin. The Pliocene-Pleistocene dinoflagelate cyst assemblages of southern England and northwestern france show a remarkable degree of homogeneity in their composition, chiefly expressed in the apparent contradictory association of A. andalousensis and O. israelianum that suggest sedimentation in an unusual type of environment which arose in the context of climatic change and sea-level variations at that time.

  17. Early evolution of the angiosperm clade Asteraceae in the Cretaceous of Antarctica.

    Science.gov (United States)

    Barreda, Viviana D; Palazzesi, Luis; Tellería, Maria C; Olivero, Eduardo B; Raine, J Ian; Forest, Félix

    2015-09-01

    The Asteraceae (sunflowers and daisies) are the most diverse family of flowering plants. Despite their prominent role in extant terrestrial ecosystems, the early evolutionary history of this family remains poorly understood. Here we report the discovery of a number of fossil pollen grains preserved in dinosaur-bearing deposits from the Late Cretaceous of Antarctica that drastically pushes back the timing of assumed origin of the family. Reliably dated to ∼76-66 Mya, these specimens are about 20 million years older than previously known records for the Asteraceae. Using a phylogenetic approach, we interpreted these fossil specimens as members of an extinct early diverging clade of the family, associated with subfamily Barnadesioideae. Based on a molecular phylogenetic tree calibrated using fossils, including the ones reported here, we estimated that the most recent common ancestor of the family lived at least 80 Mya in Gondwana, well before the thermal and biogeographical isolation of Antarctica. Most of the early diverging lineages of the family originated in a narrow time interval after the K/P boundary, 60-50 Mya, coinciding with a pronounced climatic warming during the Late Paleocene and Early Eocene, and the scene of a dramatic rise in flowering plant diversity. Our age estimates reduce earlier discrepancies between the age of the fossil record and previous molecular estimates for the origin of the family, bearing important implications in the evolution of flowering plants in general.

  18. HAZMAT. I. The evolution of far-UV and near-UV emission from early M stars

    International Nuclear Information System (INIS)

    Shkolnik, Evgenya L.; Barman, Travis S.

    2014-01-01

    The spectral energy distribution, variability, and evolution of the high-energy radiation from an M dwarf planet host is crucial in understanding the planet's atmospheric evolution and habitability and in interpreting the planet's spectrum. The star's extreme-UV (EUV), far-UV (FUV), and near-UV (NUV) emission can chemically modify, ionize, and erode the atmosphere over time. This makes determining the lifetime exposure of such planets to stellar UV radiation critical for both the evolution of a planet's atmosphere and our potential to characterize it. Using the early M star members of nearby young moving groups, which sample critical ages in planet formation and evolution, we measure the evolution of the GALEX NUV and FUV flux as a function of age. The median UV flux remains at a 'saturated' level for a few hundred million years, analogous to that observed for X-ray emission. By the age of the Hyades Cluster (650 Myr), we measure a drop in UV flux by a factor of 2-3 followed by a steep drop from old (several Gyrs) field stars. This decline in activity beyond 300 Myr follows roughly t –1 . Despite this clear evolution, there remains a wide range, of 1-2 orders of magnitude, in observed emission levels at every age. These UV data supply the much-needed constraints to M dwarf upper-atmosphere models, which will provide empirically motivated EUV predictions and more accurate age-dependent UV spectra as inputs to planetary photochemical models.

  19. HAZMAT. I. The evolution of far-UV and near-UV emission from early M stars

    Energy Technology Data Exchange (ETDEWEB)

    Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Barman, Travis S., E-mail: shkolnik@lowell.edu, E-mail: barman@lpl.arizona.edu [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2014-10-01

    The spectral energy distribution, variability, and evolution of the high-energy radiation from an M dwarf planet host is crucial in understanding the planet's atmospheric evolution and habitability and in interpreting the planet's spectrum. The star's extreme-UV (EUV), far-UV (FUV), and near-UV (NUV) emission can chemically modify, ionize, and erode the atmosphere over time. This makes determining the lifetime exposure of such planets to stellar UV radiation critical for both the evolution of a planet's atmosphere and our potential to characterize it. Using the early M star members of nearby young moving groups, which sample critical ages in planet formation and evolution, we measure the evolution of the GALEX NUV and FUV flux as a function of age. The median UV flux remains at a 'saturated' level for a few hundred million years, analogous to that observed for X-ray emission. By the age of the Hyades Cluster (650 Myr), we measure a drop in UV flux by a factor of 2-3 followed by a steep drop from old (several Gyrs) field stars. This decline in activity beyond 300 Myr follows roughly t {sup –1}. Despite this clear evolution, there remains a wide range, of 1-2 orders of magnitude, in observed emission levels at every age. These UV data supply the much-needed constraints to M dwarf upper-atmosphere models, which will provide empirically motivated EUV predictions and more accurate age-dependent UV spectra as inputs to planetary photochemical models.

  20. A new fossil peccary from the Pleistocene-Holocene boundary of the eastern Yucatán Peninsula, Mexico

    Science.gov (United States)

    Stinnesbeck, Sarah R.; Frey, Eberhard; Stinnesbeck, Wolfgang; Avíles Olguín, Jeronimo; Zell, Patrick; Terrazas Mata, Alejandro; Benavente Sanvicente, Martha; González González, Arturo; Rojas Sandoval, Carmen; Acevez Nuñez, Eugenio

    2017-08-01

    Here we describe the left mandibular ramus of a fossil peccary from the submerged karst cave system in the southeastern Mexican state of Quintana Roo. The specimen, which was discovered in the Muknal cave northwest of Tulúm, is a new genus and species of peccary termed Muknalia minima. The taxon likely dates from the latest Pleistocene and differs significantly from all extant peccaries and their Pleistocene relatives by a concave notch at the caudal edge of the mandibular ramus and prominent ventrally directed angular process. These diagnostic osteological differences suggest that the masticatory apparatus differed from all other peccaries, which may hint to an ecological isolation on the late Pleistocene Yucatán Peninsula.

  1. Plio-Pleistocene climate change and geographic heterogeneity in plant diversity-environment relationships

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Normand, Signe; Skov, Flemming

    2009-01-01

    Plio-Pleistocene climate change may have induced geographic heterogeneity in plant species richness-environment relationships in Europe due to greater in situ species survival and speciation rates in southern Europe. We formulate distinct hypotheses on how Plio-Pleistocene climate change may have...... affected richness-topographic heterogeneity and richness-water-energy availability relationships, causing steeper relationships in southern Europe. We investigated these hypotheses using data from Atlas Florae Europaeae on the distribution of 3069 species and geographically weighted regression (GWR). Our...... analyses showed that plant species richness generally increased with topographic heterogeneity (ln-transformed altitudinal range) and actual evapotranspiration (AET). We also found evidence for strong geographic heterogeneity in the species richness-environment relationship, with a greater increase...

  2. Lifestyle and Ice: The Relationship between Ecological Specialization and Response to Pleistocene Climate Change.

    Science.gov (United States)

    Kašparová, Eva; Van de Putte, Anton P; Marshall, Craig; Janko, Karel

    2015-01-01

    Major climatic changes in the Pleistocene had significant effects on marine organisms and the environments in which they lived. The presence of divergent patterns of demographic history even among phylogenetically closely-related species sharing climatic changes raises questions as to the respective influence of species-specific traits on population structure. In this work we tested whether the lifestyle of Antarctic notothenioid benthic and pelagic fish species from the Southern Ocean influenced the concerted population response to Pleistocene climatic fluctuations. This was done by a comparative analysis of sequence variation at the cyt b and S7 loci in nine newly sequenced and four re-analysed species. We found that all species underwent more or less intensive changes in population size but we also found consistent differences between demographic histories of pelagic and benthic species. Contemporary pelagic populations are significantly more genetically diverse and bear traces of older demographic expansions than less diverse benthic species that show evidence of more recent population expansions. Our findings suggest that the lifestyles of different species have strong influences on their responses to the same environmental events. Our data, in conjunction with previous studies showing a constant diversification tempo of these species during the Pleistocene, support the hypothesis that Pleistocene glaciations had a smaller effect on pelagic species than on benthic species whose survival may have relied upon ephemeral refugia in shallow shelf waters. These findings suggest that the interaction between lifestyle and environmental changes should be considered in genetic analyses.

  3. Early human-plant interactions based on palaeovegetation simulations of Africa over glacial-interglacial cycles

    Science.gov (United States)

    Cowling, S. A.; Cox, P. M.; Jones, C. D.; Maslin, M. A.; Spall, S. A.

    2003-04-01

    A greater understanding of African palaeovegetation environments over the Pleistocene (1.6 Mya) is important for evaluating potential catalysts underlying the anatomical, social and demographic changes observed in early human populations. We used a state-of-the-art fully-coupled earth system model (HADLEY-GCM3) to simulate typical glacial and interglacial environments likely encountered by late-Pleistocene humans. Our simulations indicate that tropical broadleaf forests of central Africa were not severely restricted by expanding grasslands during the last glacial maximum, although the carbon content of stem and density of leaf components were substantially reduced. We interpret a natural eastern migration corridor between southern Africa and the Rift Valley based on simulations of a no-analogue vegetation assemblage characterised by a unique combination of grass and low density forest. We postulate that early human populations in southern Africa were isolated from northern groups during warm interglacials, and that trans-African migration was facilitated during glacial cycles via a more openly forested eastern corridor.

  4. Nitrogen Isotope Evidence for a Shift in Eastern Beringian Nitrogen Cycle after the Terminal Pleistocene

    Science.gov (United States)

    Tahmasebi, F.; Longstaffe, F. J.; Zazula, G.

    2016-12-01

    The loess deposits of eastern Beringia, a region in North America between 60° and 70°N latitude and bounded by Chukchi Sea to the west and the Mackenzie River to the east, are a magnificent repository of Late Pleistocene megafauna fossils. The stable carbon and nitrogen isotope compositions of these fossils are measured to determine the paleodiet of these animals, and hence the paleoenvironment of this ecosystem during the Quaternary. For this approach to be most successful, however, requires consideration of possible changes in nutrient cycling and hence the carbon and nitrogen isotopic compositions of vegetation in this ecosystem. To test for such a shift following the terminal Pleistocene, we analyzed the stable carbon and nitrogen isotope compositions of modern plants and bone collagen of Arctic ground squirrels from Yukon Territory, and fossil plants and bones recovered from Late Pleistocene fossil Arctic ground squirrel nests. The data for modern samples provided a measure of the isotopic fractionation between ground squirrel bone collagen and their diet. The over-wintering isotopic effect of decay on typical forage grasses was also measured to evaluate its role in determining fossil plant isotopic compositions. The grasses showed only a minor change ( 0-1 ‰) in carbon isotope composition, but a major change ( 2-10 ‰) in nitrogen isotope composition over the 317-day experiment. Based on the modern carbon isotope fractionation between ground squirrel bone collagen and their diet, the modern vegetation carbon isotopic baseline provides a suitable proxy for the Late Pleistocene of eastern Beringia, after accounting for the Suess effect. However, the predicted nitrogen isotope composition of vegetation comprising the diet of fossil ground squirrels remains 2.5 ‰ higher than modern grasslands in this area, even after accounting for possible N-15 enrichment during decay. This result suggests a change in N cycling in this region since the Late Pleistocene.

  5. Evolutionary History of Atmospheric CO2 during the Late Cenozoic from Fossilized Metasequoia Needles.

    Directory of Open Access Journals (Sweden)

    Yuqing Wang

    Full Text Available The change in ancient atmospheric CO2 concentrations provides important clues for understanding the relationship between the atmospheric CO2 concentration and global temperature. However, the lack of CO2 evolution curves estimated from a single terrestrial proxy prevents the understanding of climatic and environmental impacts due to variations in data. Thus, based on the stomatal index of fossilized Metasequoia needles, we reconstructed a history of atmospheric CO2 concentrations from middle Miocene to late Early Pleistocene when the climate changed dramatically. According to this research, atmospheric CO2 concentration was stabile around 330-350 ppmv in the middle and late Miocene, then it decreased to 278-284 ppmv during the Late Pliocene and to 277-279 ppmv during the Early Pleistocene, which was almost the same range as in preindustrial time. According to former research, this is a time when global temperature decreased sharply. Our results also indicated that from middle Miocene to Pleistocene, global CO2 level decreased by more than 50 ppmv, which may suggest that CO2 decrease and temperature decrease are coupled.

  6. Evolutionary History of Atmospheric CO2 during the Late Cenozoic from Fossilized Metasequoia Needles.

    Science.gov (United States)

    Wang, Yuqing; Momohara, Arata; Wang, Li; Lebreton-Anberrée, Julie; Zhou, Zhekun

    2015-01-01

    The change in ancient atmospheric CO2 concentrations provides important clues for understanding the relationship between the atmospheric CO2 concentration and global temperature. However, the lack of CO2 evolution curves estimated from a single terrestrial proxy prevents the understanding of climatic and environmental impacts due to variations in data. Thus, based on the stomatal index of fossilized Metasequoia needles, we reconstructed a history of atmospheric CO2 concentrations from middle Miocene to late Early Pleistocene when the climate changed dramatically. According to this research, atmospheric CO2 concentration was stabile around 330-350 ppmv in the middle and late Miocene, then it decreased to 278-284 ppmv during the Late Pliocene and to 277-279 ppmv during the Early Pleistocene, which was almost the same range as in preindustrial time. According to former research, this is a time when global temperature decreased sharply. Our results also indicated that from middle Miocene to Pleistocene, global CO2 level decreased by more than 50 ppmv, which may suggest that CO2 decrease and temperature decrease are coupled.

  7. Core-Log-Seismic investigations of the Surveyor Fan and Channel system during the Pleistocene; IODP Exp. 341

    Science.gov (United States)

    Somchat, K.; Reece, R.; Gulick, S. P. S.

    2017-12-01

    The Chugach-St. Elias mountain range is the product of the ongoing subduction and collision of the Yakutat microplate with the North America Plate. The presence of this high topography close to the shoreline creates a unique source-to-sink system in which glacial eroded sediment is transported directly to the sea and preserved offshore in a deep sea fan without intervening storage. Surveyor Fan and Channel system is the product of this system. In this study we will focus on the four tributary channels that form at the head of the Surveyor Channel complex and merge into the main channel trunk 200 km from the shelf edge. We integrated drill core and 2D seismic reflection data to study the evolution of these tributaries in order to decipher glacial history along the southern Alaskan margin since the mid-Pleistocene (1.2 Ma). An age model from Integrated Ocean Drilling Program Expedition 341 Site U1418 provides a higher resolution chronology of sediment delivery to the Surveyor Fan than previous studies. We regionally mapped the seismic subunits previously identified by Exp. 341 scientists starting from Site U1418 and analyzed regional patterns of sediment deposition. Channel migrations are observable between 1.2-0.5 Ma which could be the result of increasing glacial ice volume onshore due to onset of the MPT. Two-way travel time (isopach) maps of the three subunits show that sediment depocenter began to move eastward since 1.2 Ma with a trend of overall sediment flux increase in all tributary channels. Changes in sediment flux in each system represent the changes in volume of glacial ice over successive glacial intervals. Additionally, seismic analysis of channel geomorphology shows that each system contains distinct geomorphological evolutions that respond to the glacially eroded sediment flux at different times. Since glacial erosional processes is the driver of this source-to-sink system, a history of glacial ice onshore since the Pleistocene can be inferred from

  8. Two Late Pleistocene climate-driven incision/aggradation rhythms in the middle Dnieper River basin, west-central Russian Plain

    DEFF Research Database (Denmark)

    Panin, Andrei; Adamiec, Grzegorz; Buylaert, Jan-Pieter

    2017-01-01

    Pleistocene - Holocene climate cycle. The following events were detected. (1) Late MIS 5 - early MIS 4: aggradation of Terrace T1 following the deep incision at the end of MIS 6. (2) Late MIS 4 (40-30 ka): incision into Terrace T1 below the present-day river, formation of the main scarp in the bottom...... of the valley between Terrace T1 and Terrace T0/Floodplain levels. (3) MIS 2: aggradation of Terrace T0, lateral migrations of a shallow braided channel located few meters above the present-day river since ∼25 ka through the LGM. (4) 18-13 ka: incision into Terrace T0 below the modern river. Multiple...

  9. Studies of Physcomitrella patens reveal that ethylene-mediated submergence responses arose relatively early in land-plant evolution

    KAUST Repository

    Yasumura, Yuki

    2012-10-18

    Colonization of the land by multicellular green plants was a fundamental step in the evolution of life on earth. Land plants evolved from fresh-water aquatic algae, and the transition to a terrestrial environment required the acquisition of developmental plasticity appropriate to the conditions of water availability, ranging from drought to flood. Here we show that extant bryophytes exhibit submergence-induced developmental plasticity, suggesting that submergence responses evolved relatively early in the evolution of land plants. We also show that a major component of the bryophyte submergence response is controlled by the phytohormone ethylene, using a perception mechanism that has subsequently been conserved throughout the evolution of land plants. Thus a plant environmental response mechanism with major ecological and agricultural importance probably had its origins in the very earliest stages of the colonization of the land. © 2012 Blackwell Publishing Ltd.

  10. Oxygen isotopic stratigraphy as a tool for chronology establishing of early and Middle Pleistocene speleothems - a case study from Gleboka Cave (Kraków-Czestochowa Upland, Poland

    Czech Academy of Sciences Publication Activity Database

    Blaszczyk, M.; Hercman, H.; Pawlak, J.; Gasiorowski, M.; Matoušková, Šárka; Aninowska, M.; Kicinska, D.; Tyc, A.

    2017-01-01

    Roč. 22, č. 2 (2017) ISSN 1335-213X. [Vedecká konferencia „Výskum, využívanie a ochrana jaskýň“ /11./. 25.09.2017-26.09.2017, Liptovský Mikuláš] Institutional support: RVO:67985831 Keywords : speleothems * Pleistocene * Gleboka Cave Subject RIV: DB - Geology ; Mineralogy

  11. Tectonic and sedimentary evolution of the late Miocene-Pleistocene Dali Basin in the southeast margin of the Tibetan Plateau : Evidences from anisotropy of magnetic susceptibility and rock magnetic data

    NARCIS (Netherlands)

    Li, Shihu; Deng, Chenglong; Paterson, Greig A.; Yao, Haitao; Huang, Sheng; Liu, Chengying; He, Huaiyu; Pan, Yongxin; Zhu, Rixiang

    2014-01-01

    The Cenozoic Dali Basin, located at the northeast of Diancang Shan and south of the first bend of Yangtze River, is tectonically controlled by the Dali fault system in the southeast margin of the Tibetan Plateau. The basin is filled with late Miocene to Pleistocene fluviolacustrine sediments, which

  12. Ocean circulation in the southern Benguela region from the Pliocene to the Pleistocene: tracking Agulhas leakage into the SE Atlantic

    Science.gov (United States)

    Petrick, Benjamin; McClymont, Erin; Felder, Sojna; Leng, Melanie

    2013-04-01

    The transition from the warmth of the middle Pliocene to the large amplitude, 100 kyr glacial-interglacial cycles of the late Pleistocene provides a way to understand the forcings and impacts of regional and global climate change. Here, we investigate changes in ocean circulation over the period from 3.5 Ma to present using a marine sediment core, ODP Site 1087 (31o28'S, 15o19'E, 1374m water depth). ODP 1087 is located in the South-east Atlantic Ocean, outside the Benguela upwelling region. Its location allows investigation of the history of the heat and salt transfer to the Atlantic Ocean from the Indian Ocean ("Agulhas leakage"), which plays an important part in the global thermohaline circulation. It is not known how this transfer reacted to generally warmer global temperatures during the mid-Pliocene, nor to the transition to a globally cooler climate in the early Pleistocene. Our approach is to apply several organic geochemistry proxies and foraminiferal analyses to reconstruct the history of ODP 1087. These include the U37K' index to reconstruct sea surface temperatures, pigment analysis for understanding productivity changes, and foraminifera assemblage analysis to detect the presence of different water masses at the site. We have identified changes in SSTs and biological productivity that we argue to reflect shifts in the position of the Benguela upwelling cells, and a changing influence of Agulhas leakage. Our new data reveal a different organization in the Southeast Atlantic. It shows that during the Pliocene ODP 1087 was dominated by Benguela upwelling which had shifted south. We find no evidence for Agulhas leakage during the mid Pliocene, which could mean that Agulhas Leakage was severely reduced during the mid Pliocene. The implications of these results for understanding Plio-Pleistocene climate changes will be explored here.

  13. Origin and tectonic evolution of early Paleozoic arc terranes abutting the northern margin of North China Craton

    Science.gov (United States)

    Zhou, Hao; Pei, Fu-Ping; Zhang, Ying; Zhou, Zhong-Biao; Xu, Wen-Liang; Wang, Zhi-Wei; Cao, Hua-Hua; Yang, Chuan

    2017-12-01

    The origin and tectonic evolution of the early Paleozoic arc terranes abutting the northern margin of the North China Craton (NCC) are widely debated. This paper presents detrital zircon U-Pb and Hf isotopic data of early Paleozoic strata in the Zhangjiatun arc terrane of central Jilin Province, northeast (NE) China, and compares them with the Bainaimiao and Jiangyu arc terranes abutting the northern margin of the NCC. Detrital zircons from early Paleozoic strata in three arc terranes exhibit comparable age groupings of 539-430, 1250-577, and 2800-1600 Ma. The Paleoproterozoic to Neoarchean ages and Hf isotopic composition of the detrital zircons imply the existence of the Precambrian fragments beneath the arc terranes. Given the evidences from geology, igneous rocks, and detrital zircons, we proposed that the early Paleozoic arc terranes abutting the northern margin of the NCC are a united arc terrane including the exotic Precambrian fragments, and these fragments shared a common evolutionary history from Neoproterozoic to early-middle Paleozoic.

  14. Paleomagnetism and geochronology of the Pliocene-Pleistocene lavas in Iceland

    NARCIS (Netherlands)

    McDougall, Ian; Wensink, H.

    Potassium-argon dates are reported on five basalt samples from the Pliocene-Pleistocene sequence of lavas in the Jökuldalur area, northeastern Iceland. These dates confirm the correlations previously made with the geological time scale by means of paleomagnetic stratigraphy. The R1 and N2 polarity

  15. The Formation and Early Evolution of Embedded Massive Star Clusters

    Science.gov (United States)

    Barnes, Peter

    We propose to combine Spitzer, WISE, Herschel, and other archival spacecraft data with an existing ground- and space-based mm-wave to near-IR survey of molecular clouds over a large portion of the Milky Way, in order to systematically study the formation and early evolution of massive stars and star clusters, and provide new observational calibrations for a theoretical paradigm of this key astrophysical problem. Central Objectives: The Galactic Census of High- and Medium-mass Protostars (CHaMP) is a large, unbiased, uniform, and panchromatic survey of massive star and cluster formation and early evolution, covering 20°x6° of the Galactic Plane. Its uniqueness lies in the comprehensive molecular spectroscopy of 303 massive dense clumps, which have also been included in several archival spacecraft surveys. Our objective is a systematic demographic analysis of massive star and cluster formation, one which has not been possible without knowledge of our CHaMP cloud sample, including all clouds with embedded clusters as well as those that have not yet formed massive stars. For proto-clusters deeply embedded within dense molecular clouds, analysis of these space-based data will: 1. Yield a complete census of Young Stellar Objects in each cluster. 2. Allow systematic measurements of embedded cluster properties: spectral energy distributions, luminosity functions, protostellar and disk fractions, and how these vary with cluster mass, age, and density. Combined with other, similarly complete and unbiased infrared and mm data, CHaMP's goals include: 3. A detailed comparison of the embedded stellar populations with their natal dense gas to derive extinction maps, star formation efficiencies and feedback effects, and the kinematics, physics, and chemistry of the gas in and around the clusters. 4. Tying the demographics, age spreads, and timescales of the clusters, based on pre-Main Sequence evolution, to that of the dense gas clumps and Giant Molecular Clouds. 5. A

  16. Complete mitochondrial genome and phylogeny of Pleistocene mammoth Mammuthus primigenius.

    Directory of Open Access Journals (Sweden)

    Evgeny I Rogaev

    2006-03-01

    Full Text Available Phylogenetic relationships between the extinct woolly mammoth (Mammuthus primigenius, and the Asian (Elephas maximus and African savanna (Loxodonta africana elephants remain unresolved. Here, we report the sequence of the complete mitochondrial genome (16,842 base pairs of a woolly mammoth extracted from permafrost-preserved remains from the Pleistocene epoch--the oldest mitochondrial genome sequence determined to date. We demonstrate that well-preserved mitochondrial genome fragments, as long as approximately 1,600-1700 base pairs, can be retrieved from pre-Holocene remains of an extinct species. Phylogenetic reconstruction of the Elephantinae clade suggests that M. primigenius and E. maximus are sister species that diverged soon after their common ancestor split from the L. africana lineage. Low nucleotide diversity found between independently determined mitochondrial genomic sequences of woolly mammoths separated geographically and in time suggests that north-eastern Siberia was occupied by a relatively homogeneous population of M. primigenius throughout the late Pleistocene.

  17. Discussion on the Regional Paleotemperature Evolution since the Late Pleistocene in the Loess Plateau with GDGT as an Index

    Science.gov (United States)

    Yingchun, S.

    2017-12-01

    It is an effective way to understand the modern climate and predict the future climate trend by using the geological substitute indicators to reconstruct the past climate. In recent years, scientists have begun to apply Glycerol dialkyl glycerol tetraethers (GDGTs) to reconstruct paleoclimate and many proxies about ancient air temperature based on GDGTs have been proposed, even the empirical formulas used for China have also been established. In this paper, five loess-paleosol sequences spanning the Late Pleistocene from the Loess Plateau have been used to examine the effectiveness of the formulas as well as to discuss the regional evolution of the ancient temperature of the plateau. The results are as follows: (1) The relative content of iGDGT is higher than that of bGDGT in all Loess sections, and that of each compound follows relatively fixed regularity. Seen from the geographical distribution, the relative content of GDGT in southernmost sections is the highest, which in the northernmost is the smallest. (2) In the last interglacial period, from the northern part to the southern part of the Loess Plateau, the mean annual air temperature (MAAT) of northern Jingbian was 14°, central Luochuan was up to 15°, and southern Weinan was nearly 18°. And at the end of the last glacial period the temperature, where LC and WN located, dropped to 13.5°. Along the east-west direction of the Plateau, in the last interglacial period, the MAAT of western Qin'an secion was 13°, and that of central Baoji and eastern Weinan was about 18°. To the end of the last glacial period, the MAAT decreased to the lowest, Weinan 13.5°, Baoji 14.5°, while Qin'an 10.8°. (3)In contrast to the magnetic susceptibility index, the curves of GDGT MAAT have great similarity with the magnetic susceptibility curve, but it is obvious that there are phase differences between them. That may be indicating that the temperature rise was before the onset of the East-Asian summer monsoon in the Plateau

  18. Paleoescatology in the sopas formation (Upper Pleistocene) form Uruguay, paleobilogic focus

    International Nuclear Information System (INIS)

    Verde, M.; Ubilla, M.; Soloviy, J.

    1998-01-01

    Continental tetrapod coprolites are reported for the first time for Uruguay, these remains come from the Sopas Formation (Upper Pleistocene). They are assigned to carnivore mammals based on morphology and inclusions of micrommmal remains besides of other attributes.(author)

  19. True single-molecule DNA sequencing of a pleistocene horse bone

    DEFF Research Database (Denmark)

    Orlando, Ludovic Antoine Alexandre; Ginolhac, Aurélien; Raghavan, Maanasa

    2011-01-01

    -preserved Pleistocene horse bone using the Helicos HeliScope and Illumina GAIIx platforms, respectively. We find that the percentage of endogenous DNA sequences derived from the horse is higher among the Helicos data than Illumina data. This result indicates that the molecular biology tools used to generate sequencing...

  20. The late Pleistocene to Holocene palaeogeographic evolution of the Porto Conte area: Clues for a better understanding of human colonization of Sardinia and faunal dynamics during the last 30 ka

    NARCIS (Netherlands)

    Palombo, M.R.; Antonioli, F.; Lo Presti, V.; Mannino, M.A.; Melis, R.T.; Orru, P.; Stocchi, P.; Talamo, S.; Quarta, G.; Calcagnile, L.; Deiana, G.; Altamura, S.

    2017-01-01

    The timing of the colonization of Sardinia by mammalian fauna and anatomically modern humans (AMH) is currently under debate. The understanding of the geological and palaeoclimatological conditions that characterized the Late Pleistocene and the Holocene is essential to investigate colonization

  1. Vertebrates from the Middle Pleistocene locality Lysa Gora 1 in Ukraine

    Czech Academy of Sciences Publication Activity Database

    Rekovets, L.; Čermák, Stanislav; Kovalchuk, O.; Prisyazhniuk, V.; Nowakowski, D.

    326/327, 1 April (2014), s. 481-491 ISSN 1040-6182 Institutional research plan: CEZ:AV0Z30130516 Institutional support: RVO:67985831 Keywords : Vertebrates * Pleistocene * paleoecology * taxonomy * phylogeny Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.062, year: 2014

  2. Attempt at ESR dating of tooth enamel of French middle pleistocene sites

    International Nuclear Information System (INIS)

    Bahain, J.J.; Sarcia, M.N.; Falgueres, C.; Yokoyama, Y.

    1993-01-01

    Tooth enamel samples from four important French middle Pleistocene sites are analyzed by the ESR method. ESR ages were calculated using uranium uptake mathematical models and compared with U-series results. (author)

  3. Late Pleistocene leopards across Europe - northernmost European German population, highest elevated records in the Swiss Alps, complete skeletons in the Bosnia Herzegowina Dinarids and comparison to the Ice Age cave art

    Science.gov (United States)

    Diedrich, Cajus G.

    2013-09-01

    European leopard sites in Europe demonstrate Early/Middle Pleistocene out of Africa lowland, and Late Pleistocene Asian alpine migrations being driven by climatic changes. Four different European Pleistocene subspecies are known. The final European Late Pleistocene “Ice Age leopard” Panthera pardus spelaea (Bächler, 1936) is validated taxonomically. The skull shows heavy signs of sexual dimorphism with closest cranial characters to the Caucasian Panthera pardus ciscaucasica (Persian leopard). Late Pleistocene leopards were distributed northernmost, up to S-England with the youngest stratigraphic records by skeletons and cave art in the MIS 2/3 (about 32,000-26,000 BP). The oldest leopard painting left by Late Palaeolithics (Aurignacians/Gravettians) in the Chauvet Cave (S-France) allows the reconstruction of the Ice Age leopard fur spot pattern being close to the snow or Caucasian leopards. The last Ice Age glacial leopard habitat was the mountain/alpine boreal forest (not mammoth steppe lowland), where those hunted even larger prey such as alpine game (Ibex, Chamois). Into some lairs, those imported their prey by short-term cave dwelling (e.g. Baumann's Cave, Harz Mountains, Germany). Only Eurasian Ice Age leopards specialized, similar as other Late Pleistocene large felids (steppe lions), on cave bear predation/scavenging partly very deep in caves. In Vjetrenica Cave (Dinarid Mountains, Bosnia Herzegovina), four adult leopards (two males/two females) of the MIS 3 were found about two km deep from the entrance in a cave bear den, near to one cave bear skeleton, that remained articulated in its nest. Leopards died there, partly being trapped by raising water levels of an active ponor stream, but seem to have been killed possibly either, similar as for lions known, in battles with cave bears in several cave bear den sites of Europe (e.g. Baumann's Cave, Wildkirchli Cave, Vjetrenica Cave). At other large cave sites, with overlap of hyena, wolf and dhole dens at

  4. Paleobiology of Pleistocene Proboscideans

    Science.gov (United States)

    Fisher, Daniel C.

    2018-05-01

    The paleobiology of Pleistocene proboscideans plays a pivotal role in understanding their history and in answering fundamental questions involving their interactions with other taxa, including humans. Much of our view of proboscidean paleobiology is influenced by analogies with extant elephants. However, a wealth of information is available for reconstructing the paleobiology of ancient proboscideans using data from fossil specimens and preservational settings. Remarkable opportunities include permafrost-derived specimens with preserved soft tissue, intestinal contents with direct evidence of diet, and compositional and structural profiles with subannual temporal resolution archived in appositional systems such as proboscidean tusks. New information on diets and local climates puts our understanding of proboscidean paleoecology on a firmer foundation, but the greatest prospects for new insight spring from life history data now being retrieved from accelerator mass spectrometry–dated fossil material. Interaction between humans and proboscideans has been a critical factor in the history of both groups.

  5. Mandibular molar root morphology in Neanderthals and Late Pleistocene and recent Homo sapiens.

    Science.gov (United States)

    Kupczik, Kornelius; Hublin, Jean-Jacques

    2010-11-01

    Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n=127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M(1) and M(2) is small. In contrast, Aterian H. sapiens root surface areas peak at M(2). Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. End-Devonian extinction and a bottleneck in the early evolution of modern jawed vertebrates.

    Science.gov (United States)

    Sallan, Lauren Cole; Coates, Michael I

    2010-06-01

    The Devonian marks a critical stage in the early evolution of vertebrates: It opens with an unprecedented diversity of fishes and closes with the earliest evidence of limbed tetrapods. However, the latter part of the Devonian has also been characterized as a period of global biotic crisis marked by two large extinction pulses: a "Big Five" mass extinction event at the Frasnian-Famennian stage boundary (374 Ma) and the less well-documented Hangenberg event some 15 million years later at the Devonian-Carboniferous boundary (359 Ma). Here, we report the results of a wide-ranging analysis of the impact of these events on early vertebrate evolution, which was obtained from a database of vertebrate occurrences sampling over 1,250 taxa from 66 localities spanning Givetian to Serpukhovian stages (391 to 318 Ma). We show that major vertebrate clades suffered acute and systematic effects centered on the Hangenberg extinction involving long-term losses of over 50% of diversity and the restructuring of vertebrate ecosystems worldwide. Marine and nonmarine faunas were equally affected, precluding the existence of environmental refugia. The subsequent recovery of previously diverse groups (including placoderms, sarcopterygian fish, and acanthodians) was minimal. Tetrapods, actinopterygians, and chondrichthyans, all scarce within the Devonian, undergo large diversification events in the aftermath of the extinction, dominating all subsequent faunas. The Hangenberg event represents a previously unrecognized bottleneck in the evolutionary history of vertebrates as a whole and a historical contingency that shaped the roots of modern biodiversity.

  7. A bizarre new toothed mysticete (Cetacea) from Australia and the early evolution of baleen whales

    OpenAIRE

    Fitzgerald, Erich M.G

    2006-01-01

    Extant baleen whales (Cetacea, Mysticeti) are all large filter-feeding marine mammals that lack teeth as adults, instead possessing baleen, and feed on small marine animals in bulk. The early evolution of these superlative mammals, and their unique feeding method, has hitherto remained enigmatic. Here, I report a new toothed mysticete from the Late Oligocene of Australia that is more archaic than any previously described. Unlike all other mysticetes, this new whale was small, had enormous eye...

  8. Sedimentologic and paleontologic study of the southeast coast of Buenos Aires province, Argentina: A late Pleistocene Holocene paleoenvironmental reconstruction

    Science.gov (United States)

    Aramayo, S. A.; Téllez, B. Gutiérrez; Schillizzi, R. A.

    2005-10-01

    A paleoenvironmental reconstruction of the southeast coast of Buenos Aires province, Argentina, is made mainly on the basis of paleontological and paleoichnological studies, supported by sedimentological analyses and radiocarbon dating. Continental late Pleistocene and continental, transitional, and marine Holocene stratigraphic units are identified. The former comprises fossil mammals and ichnites of 16000-12,000 BP. The continental early Holocene time, ca. 8100 BP, is represented by an interdune paleoenvironment in which shallow brackish ponds were colonized by diatoms, fish, rodents, and birds. A transitional paleoenvironment in the middle Holocene—6930-6570 BP—is recorded by deposits formed by estuarine crabs. During the late Holocene, between 5000 and 4800 BP, a marine transgression was recorded by a rich mollusc fauna.

  9. Earth's earliest biosphere: Its origin and evolution

    International Nuclear Information System (INIS)

    Schopf, J.W.

    1983-01-01

    Some of the subjects discussed are related to the early biogeologic history, the nature of the earth prior to the oldest known rock record, the early earth and the Archean rock record, the prebiotic organic syntheses and the origin of life, Precambrian organic geochemistry, the biochemical evolution of anaerobic energy conversion, the isotopic inferences of ancient biochemistries, Archean stromatolites providing evidence of the earth's earliest benthos, Archean microfossils, the geologic evolution of the Archean-Early Proterozoic earth, and the environmental evolution of the Archean-Early Proterozoic earth. Other topics examined are concerned with geochemical evidence bearing on the origin of aerobiosis, biological and biochemical effects of the development of an aerobic environment, Early Proterozoic microfossils, the evolution of earth's earliest ecosystems, and geographic and geologic data for processed rock samples. Attention is given to a processing procedure for abiotic samples and calculation of model atmospheric compositions, and procedures of organic geochemical analysis

  10. Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse

    DEFF Research Database (Denmark)

    Orlando, Ludovic Antoine Alexandre; Ginolhac, Aurélien; Zhang, Guojie

    2013-01-01

    The rich fossil record of equids has made them a model for evolutionary processes. Here we present a 1.12-times coverage draft genome from a horse bone recovered from permafrost dated to approximately 560-780 thousand years before present (kyr bp). Our data represent the oldest full genome sequen...

  11. Deciphering Late-Pleistocence landscape evolution: linking proxies by combining pedo-stratigraphy and luminescence dating

    Science.gov (United States)

    Kreutzer, Sebastian; Meszner, Sascha; Faust, Dominik; Fuchs, Markus

    2014-05-01

    Interpreting former landscape evolution asks for understanding the processes that sculpt such landforms by means of deciphering complex systems. For reconstructing terrestrial Quaternary environments based on loess archives this might be considered, at least, as a three step process: (1) Identifying valuable records in appropriate morphological positions in a previously defined research area, (2) analysing the profiles by field work and laboratory methods and finally (3) linking the previously considered pseudo-isolated systems to set up a comprehensive picture. Especially the first and the last step might bring some pitfalls, as it is tempting to specify single records as pseudo-isolated, closed systems. They might be, with regard to their preservation in their specific morphological position, but in fact they are part of a complex, open system. Between 2008 and 2013, Late-Pleistocene loess archives in Saxony have been intensively investigated by field and laboratory methods. Linking pedo- and luminescence dating based chronostratigraphies, a composite profile for the entire Saxonian Loess Region has been established. With this, at least, two-fold approach we tried to avoid misinterpretations that might appear when focussing on one standard profile in an open morphological system. Our contribution focuses on this multi-proxy approach to decipher the Late-Pleistocene landscape evolution in the Saxonian Loess Region. Highlighting the challenges and advantages of combining different methods, we believe that (1) this multi-proxy approach is without alternative, (2) the combination of different profiles may simplify the more complex reality, but it may be a useful generalisation to understand and reveal the stratigraphical significance of the landscape evolution in this region.

  12. Complete plastome sequences of Equisetum arvense and Isoetes flaccida: implications for phylogeny and plastid genome evolution of early land plant lineages

    OpenAIRE

    Karol, Kenneth G; Arumuganathan, Kathiravetpillai; Boore, Jeffrey L; Duffy, Aaron M; Everett, Karin DE; Hall, John D; Hansen, S Kellon; Kuehl, Jennifer V; Mandoli, Dina F; Mishler, Brent D; Olmstead, Richard G; Renzaglia, Karen S; Wolf, Paul G

    2010-01-01

    Abstract Background Despite considerable progress in our understanding of land plant phylogeny, several nodes in the green tree of life remain poorly resolved. Furthermore, the bulk of currently available data come from only a subset of major land plant clades. Here we examine early land plant evolution using complete plastome sequences including two previously unexamined and phylogenetically critical lineages. To better understand the evolution of land plants and their plastomes, we examined...

  13. Toward a better understanding of nearshore meteotsunami evolution, and effective meteotsunami early-warning systems

    Science.gov (United States)

    Sheremet, A.; Li, C.; Shrira, V. I.

    2017-12-01

    We present high-resolution observations collected in 2008 on the Atcahfalaya shelf that capture the shoaling evolution of a meteotsunami (MT), including the disintegration into the train of solitons (solibore). One of the intriguing elements of this process is a spectacular 1.5-m solitary-wave (soliton), that precedes the arrival of the MT solibore by approximately 5 min, reaching the observation site propagating through a background of nearly-calm waters (20-cm height wind waves). Solitons, products of the MT disintegration process, are observed at all experiment sites, covering approx. 200 km shoreline. We interpret observations employing numerical simulations of a simplified hydrodynamic model based on the variable coefficient KdV equation. The analysis shows that observed wide-spread soliton presence and the soliton/solibore formation are the result of a complicated evolution process involving refraction, collision, and nonlinear interaction of multiple meteotsunami waves.Our results highlight the substantial lack of detail of the current picture of the nonlinear transformation of a MT from generation to its shoreline manifestation. A realistic reconstruction of MT evolution is at present almost impossible based on the current poor spatial and temporal resolution MT observations, overwhelmingly confined to the shoreline. Since the MTs tend to disintegrate into very short (down to 10s) pulses, even modern tidal gauges (1 min resolution) fail to capture essential features of its evolution. We also briefly discuss an ongoing field experiment that carries further the effort to collect high-resolution MT measurements, and that will investigate and test methodologies for early warning systems.

  14. Late Pleistocene - Holocene surface processes and landscape evolution in the central Swiss Alps

    Science.gov (United States)

    Boxleitner, Max; Musso, Alessandra; Waroszewski, Jarosław; Malkiewicz, Małgorzata; Maisch, Max; Dahms, Dennis; Brandová, Dagmar; Christl, Marcus; de Castro Portes, Raquel; Egli, Markus

    2017-10-01

    The European Alps are a geomorphologically active region and experience a number of gravity-driven hillslope processes. Soil and landscape formation in the Alps has consequently undergone several minor and major traceable changes of developmental trajectories during the Holocene. Soil development is hypothesised to be often non-linear with time and characterised by stages of progressive and regressive evolution caused by upbuilding (formation, profile deepening) and erosion (profile shallowing). Several cold and warm climate phases are identified during the Holocene but it is largely unknown which effects these might have had on slope processes. By using datable moraines (10Be) and mires (14C), we have constructed a temporal framework for these processes. Using the geochemical imprint of mires in the Alpine setting of the Göschener-valley of the Central Swiss Alps, we reconstructed general (mostly erosional) landscape processes for the last ca. 10 ka. As this is the type locality for the Göschener cold phase, we assumed that this phase (Göschener cold phase I and II 1.5 and 2.5 ka BP) should have left easily recognizable traits. After deglaciation (11-12 ka BP), soil evolution was progressive. Beginning around 8 ka BP, we detect a distinct increase in erosion here, together with a vegetation change (towards tundra vegetation) and the highest measured rates of carbon sequestration. Other phases of high geomorphic activity were recognised ca. 5-6 ka BP, 4 ka BP and, to a lesser extent, 1-3 ka ago. The cold phase at 5-6 ka BP corresponds to a less distinct change in vegetation and lessened erosion. Human impact is increasingly obvious since about 2.4 ka BP which overlaps with the Göschener cold phase. Nonetheless, erosion processes were not extraordinarily high during this period and a climate effect cannot be distinguished. We detect evidence of increasing human disturbance (regressive soil evolution) for about the last 1 ka. We also detect an increase in dust

  15. Dietary variation and overlap in Central and Northwest European Stephanorhinus kirchbergensis and S. hemitoechus (Rhinocerotidae, Mammalia) influenced by habitat diversity. "You'll have to take pot luck!" (proverb)

    Science.gov (United States)

    van Asperen, Eline N.; Kahlke, Ralf-Dietrich

    2015-01-01

    To trace the dietary evolution of the two abundant Middle to Late Pleistocene rhinoceros species Stephanorhinus kirchbergensis and Stephanorhinus hemitoechus in Europe over several climatic cycles, we examined comprehensive material of stratigraphically well-defined palaeopopulations from different regions and interglacials. Using morphometrics and mesowear analysis, these reconstructions of Stephanorhinus diets indicate that habitat diversity and interspecific competition with closely related rhinoceros species induced variation in feeding behaviour. Although anatomical features of both species suggest significantly higher dietary specializations compared to the Early to early Middle Pleistocene Stephanorhinus hundsheimensis, their mesowear signals are characteristic of a mixed feeder diet, similar to that of extant mammal species in relatively open habitats. Both species retained a degree of dietary flexibility, enabling them to survive in a range of environments. Although each of these rhinoceroses preferred different habitats, species identity alone is not sufficient to establish the real dietary traits of a Stephanorhinus palaeopopulation. As a consequence, their occurrence in a faunal assemblage alone cannot be taken to indicate a specific habitat. S. kirchbergensis and S. hemitoechus were embedded in a dynamic process of temporo-spatial replacements and interspecific differentiation of rhinoceroses in the western Palaearctic. However, dietary specialization in these Middle to Late Pleistocene European rhinoceroses was not the result of a directed time-transgressive evolution. Rather, within the range of each species' ecological tolerance, it was controlled by environmental parameters, with habitat variability as the main factor.

  16. Early evolution of an X-ray emitting solar active region

    International Nuclear Information System (INIS)

    Wolfson, C.J.; Acton, L.W.; Leibacher, J.W.; Roethig, D.T.

    1977-01-01

    The birth and early evolution of a solar active region has been investigated using X-ray observations from the Lockheed Mapping X-Ray Heliometer on board the OSO-8 spacecraft. X-ray emission is observed within three hours of the first detection of Hα plage. At that time, a plasma temperature of 4 x 10 6 K in a region having a density of the order of 10 10 cm -3 is inferred. During the fifty hours following birth almost continuous flares or flare-like X-ray bursts are superimposed on a monotonically increasing base level of X-ray emission produced by plasma with a temperature of the order 3 x 10 6 K. If it is assumed that the X-rays result from heating due to dissipation of current systems or magnetic field reconnection, it can be concluded that flare-like X-ray emission soon after active region birth implies that the magnetic field probably emerges in a stressed or complex configuration. (Auth.)

  17. How Far into Europe Did Pikas (Lagomorpha: Ochotonidae) Go during the Pleistocene? New Evidence from Central Iberia

    Science.gov (United States)

    Laplana, César; Sevilla, Paloma; Arsuaga, Juan Luis; Arriaza, Mari Carmen; Baquedano, Enrique; Pérez-González, Alfredo

    2015-01-01

    This paper reports the first find of pika remains in the Iberian Peninsula, at a site in central Spain. A fragmented mandible of Ochotona cf. pusilla was unearthed from Layer 3 (deposited some 63.4±5.5 ka ago as determined by thermoluminescence) of the Buena Pinta Cave. This record establishes new limits for the genus geographic distribution during the Pleistocene, shifting the previous edge of its known range southwest by some 500 km. It also supports the idea that, even though Europe’s alpine mountain ranges represented a barrier that prevented the dispersal into the south to this and other taxa of small mammals from central and eastern Europe, they were crossed or circumvented at the coldest time intervals of the end of the Middle Pleistocene and of the Late Pleistocene. During those periods both the reduction of the forest cover and the emersion of large areas of the continental shelf due to the drop of the sea level probably provided these species a way to surpass this barrier. The pika mandible was found accompanying the remains of other small mammals adapted to cold climates, indicating the presence of steppe environments in central Iberia during the Late Pleistocene. PMID:26535576

  18. Forests of the tropical eastern Andean flank during the middle Pleistocene

    NARCIS (Netherlands)

    Cárdenas, M.L.; Gosling, W.D.; Pennington, R.T.; Poole, I.; Sherlock, S.C.; Mothes, P.

    2014-01-01

    Inter-bedded volcanic and organic sediments from Erazo (Ecuador) indicate the presence of four different forest assemblages on the eastern Andean flank during the middle Pleistocene. Radiometric dates (40Ar-39Ar) obtained from the volcanic ash indicate that deposition occurred between 620,000 and

  19. Terminal Pleistocene Alaskan genome reveals first founding population of Native Americans

    DEFF Research Database (Denmark)

    Moreno-Mayar, J Víctor; Potter, Ben A; Vinner, Lasse

    2017-01-01

    Despite broad agreement that the Americas were initially populated via Beringia, the land bridge that connected far northeast Asia with northwestern North America during the Pleistocene epoch, when and how the peopling of the Americas occurred remains unresolved. Analyses of human remains from La...

  20. Isotopic feature and uranium dating of the volcanic rocks in the Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Volcanic rocks from the northern and middle Okinawa Trough were dated by uranium-series dating method. Differential fractions using magnetic procedure were designed to separate samples. New report on the ages and isotopic data of rocks in the northern trough (especially black pumice) was discussed. Based on the uranium dates and Sr-Nd isotopic ratio, magmatic evolution process of the Okinawa Trough was noted. Firstly, there have been wide silicic volcanic activities in the Okinawa Trough from late Pleistocene to present, and the volcanic rocks can be divided into three subgroups. Secondly, magma generally came from PREMA source area under the Okinawa Trough. Magmatic evolution in the northern trough was similar to the middle, but different to the south. Finally, volcanic activities indicated that opening of the southern Okinawa Trough did not happen due to the collision between Luson Arc and Eurasian Plate until the early Pleistocene.

  1. Brief communication: Plio-Pleistocene eagle predation on fossil cercopithecids from the Humpata Plateau, southern Angola.

    Science.gov (United States)

    Gilbert, Christopher C; McGraw, W Scott; Delson, Eric

    2009-07-01

    Recent studies suggest a large raptor such as the crowned eagle (Stephanaoetus coronatus) was responsible for collecting at least a portion of the primate fauna from the South African fossil site of Taung, including its lone hominin specimen. This taphonomic signature at Taung is currently regarded as a unique and, most likely, isolated case in primate and human evolution. However, the activities of large, carnivorous birds should also be detectable at other primate fossil localities in Africa if raptors have been a strong selective force throughout primate evolution. Over the last 60 years, a collection of extinct cercopithecids has been assembled from several cave breccias on the Humpata Plateau in southern Angola. The material, dated near the Plio-Pleistocene boundary, includes an assortment of craniodental and postcranial remains variably assigned to Papio (Dinopithecus) cf. quadratirostris, Parapapio, Cercopithecoides, and Theropithecus. We compare the Angolan and Taung material to remains of extant primates killed by crowned eagles in the Ivory Coast's Tai National Park. Our analysis indicates that the size distribution and composition of fauna from the localities is quite similar and that there are striking consistencies in damage to the crania from each site. The absence of large bodied (>20 kg) primates and other mammalian taxa at the Taung hominin locality and Tai, and their rarity in Angola, combined with the strong likelihood that raptor nests were positioned near fissure openings at both fossil localities, provides additional support for eagle involvement. On the basis of this evidence, we conclude that at least some of the Angolan cercopithecids were most likely raptor prey and hypothesize that raptor predation has been a strong and perhaps underappreciated selective force during the course of primate evolution.

  2. Three neuropeptide Y receptor genes in the spiny dogfish, Squalus acanthias, support en bloc duplications in early vertebrate evolution.

    Science.gov (United States)

    Salaneck, Erik; Ardell, David H; Larson, Earl T; Larhammar, Dan

    2003-08-01

    It has been debated whether the increase in gene number during early vertebrate evolution was due to multiple independent gene duplications or synchronous duplications of many genes. We describe here the cloning of three neuropeptide Y (NPY) receptor genes belonging to the Y1 subfamily in the spiny dogfish, Squalus acanthias, a cartilaginous fish. The three genes are orthologs of the mammalian subtypes Y1, Y4, and Y6, which are located in paralogous gene regions on different chromosomes in mammals. Thus, these genes arose by duplications of a chromosome region before the radiation of gnathostomes (jawed vertebrates). Estimates of duplication times from linearized trees together with evidence from other gene families supports two rounds of chromosome duplications or tetraploidizations early in vertebrate evolution. The anatomical distribution of mRNA was determined by reverse-transcriptase PCR and was found to differ from mammals, suggesting differential functional diversification of the new gene copies during the radiation of the vertebrate classes.

  3. Human talus bones from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca, Burgos, Spain).

    Science.gov (United States)

    Pablos, Adrián; Martínez, Ignacio; Lorenzo, Carlos; Gracia, Ana; Sala, Nohemi; Arsuaga, Juan Luis

    2013-07-01

    Here we present and describe comparatively 25 talus bones from the Middle Pleistocene site of the Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain). These tali belong to 14 individuals (11 adult and three immature). Although variation among Middle and Late Pleistocene tali tends to be subtle, this study has identified unique morphological characteristics of the SH tali. They are vertically shorter than those of Late Pleistocene Homo sapiens, and show a shorter head and a broader lateral malleolar facet than all of the samples. Moreover, a few shared characters with Neanderthals are consistent with the hypothesis that the SH population and Neanderthals are sister groups. These shared characters are a broad lateral malleolar facet, a trochlear height intermediate between modern humans and Late Pleistocene H. sapiens, and a short middle calcaneal facet. It has been possible to propose sex assignment for the SH tali based on their size. Stature estimates based on these fossils give a mean stature of 174.4 cm for males and 161.9 cm for females, similar to that obtained based on the long bones from this same site. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo.

    Science.gov (United States)

    Leakey, Meave G; Spoor, Fred; Dean, M Christopher; Feibel, Craig S; Antón, Susan C; Kiarie, Christopher; Leakey, Louise N

    2012-08-09

    Since its discovery in 1972 (ref. 1), the cranium KNM-ER 1470 has been at the centre of the debate over the number of species of early Homo present in the early Pleistocene epoch of eastern Africa. KNM-ER 1470 stands out among other specimens attributed to early Homo because of its larger size, and its flat and subnasally orthognathic face with anteriorly placed maxillary zygomatic roots. This singular morphology and the incomplete preservation of the fossil have led to different views as to whether KNM-ER 1470 can be accommodated within a single species of early Homo that is highly variable because of sexual, geographical and temporal factors, or whether it provides evidence of species diversity marked by differences in cranial size and facial or masticatory adaptation. Here we report on three newly discovered fossils, aged between 1.78 and 1.95 million years (Myr) old, that clarify the anatomy and taxonomic status of KNM-ER 1470. KNM-ER 62000, a well-preserved face of a late juvenile hominin, closely resembles KNM-ER 1470 but is notably smaller. It preserves previously unknown morphology, including moderately sized, mesiodistally long postcanine teeth. The nearly complete mandible KNM-ER 60000 and mandibular fragment KNM-ER 62003 have a dental arcade that is short anteroposteriorly and flat across the front, with small incisors; these features are consistent with the arcade morphology of KNM-ER 1470 and KNM-ER 62000. The new fossils confirm the presence of two contemporary species of early Homo, in addition to Homo erectus, in the early Pleistocene of eastern Africa.

  5. Early human communication helps in understanding language evolution.

    Science.gov (United States)

    Lenti Boero, Daniela

    2014-12-01

    Building a theory on extant species, as Ackermann et al. do, is a useful contribution to the field of language evolution. Here, I add another living model that might be of interest: human language ontogeny in the first year of life. A better knowledge of this phase might help in understanding two more topics among the "several building blocks of a comprehensive theory of the evolution of spoken language" indicated in their conclusion by Ackermann et al., that is, the foundation of the co-evolution of linguistic motor skills with the auditory skills underlying speech perception, and the possible phylogenetic interactions of protospeech production with referential capabilities.

  6. Sequence stratigraphy of the Nukumaruan stratotype (Pliocene-Pleistocene, c. 2.08-1.63 Ma), Wanganui Basin, New Zealand

    International Nuclear Information System (INIS)

    Abbott, S.T.; Naish, T.R.; Carter, R.M.; Pillans, B.J.

    2005-01-01

    Late Pliocene to Early Pleistocene (c. 2.08-1.63 Ma) strata exposed in coastal cliffs along Nukumaru and Ototoka beaches near Wanganui, between the top of the Nukumaru Limestone and the base of the Butlers Shell Conglomerate, comprise 11 depositional sequences of a total thickness of c. 86 m. The sequences consist predominantly of siliciclastic shoreline facies. Non-marine facies (including palaeosols), and a variety of shallow-marine shellbed facies, are also represented. Patterns in facies composition and sequence architecture reveal three sequence motifs (Maxwell, Nukumaru, and Birdgrove) that represent progressively increasing maximum palaeowater depths within a broadly basin-margin palaeogeographic setting. The sequence motif changes systematically up section and records a lower order tectonic influence on accommodation that has modulated the stacking patterns of individual sequences. Correlation of the sequences with oxygen isotope stages 77-57 is achieved using the basin-wide Ototoka tephra, and indicates that the sequences accumulated in response to obliquity driven (41 k.y. duration) glacio-eustatic sea-level oscillations. Correlation of the Nukumaru coast sequences with other sections along basin strike, and the global oxygen isotope record indicates that (i) 500 k.y. (δ 18 O stages MIS 56-34) is missing at the unconformity between the Nukumaruan and overlying Castlecliffian stratotypes on the Wanganui coast, and (ii) the Pliocene-Pleistocene boundary lies within sequence NC7 at the base of the Lower Maxwell Formation. (author). 52 refs., 15 figs., 2 tabs

  7. Topographic evolution of a continental indenter: The eastern Southern Alps

    Science.gov (United States)

    Robl, Jörg; Heberer, Bianca; Prasicek, Günther; Neubauer, Franz; Hergarten, Stefan

    2017-04-01

    The topographic evolution of the eastern Southern Alps (ESA) is controlled by the Late Oligocene - Early Miocene indentation of the Adriatic microplate into an overthickened orogenic wedge emplaced on top of the European plate. Rivers follow topographic gradients that evolve during continental collision and in turn incise into bedrock counteracting the formation of topography. In principle, erosional surface processes tend to establish a topographic steady state so that an interpretation of topographic metrics in terms of the latest tectonic history should be straightforward. However, a series of complications impede deciphering the topographic record of the ESA. The Pleistocene glaciations locally excavated alpine valleys and perturbed fluvial drainages. The Late Miocene desiccation of the Mediterranean Sea and the uplift of the northern Molasse Basin led to significant base level changes in the far field of the ESA and the Eastern Alps (EA), respectively. Among this multitude of mechanisms, the processes that dominate the current topographic evolution of the ESA and the ESA-EA drainage divide have not been identified and a number of questions regarding the interaction of crustal deformation, erosion and climate in shaping the present-day topography remain. We demonstrate the expected topographic effects of each mechanism in a 1-dimensional model and compare them with observed channel metrics. Modern uplift rates are largely consistent with long-term exhumation in the ESA and with variations in the normalized steepness index (ksn) indicating a stable uplift and erosion pattern since Miocene times. We find that ksn increases with uplift rate and declines from the indenter tip in the northwest to the foreland basin in the southeast. The number and magnitude of knickpoints and the distortion in longitudinal channel profiles similarly decrease towards the east. Most knickpoints probably evolved during Pleistocene glaciation cycles, but may represent the incrementally

  8. Direct radiocarbon dates for Vindija G1 and Velika Pećina Late Pleistocene hominid remains

    Science.gov (United States)

    Smith, Fred H.; Trinkaus, Erik; Pettitt, Paul B.; Karavanić, Ivor; Paunović, Maja

    1999-01-01

    New accelerator mass spectrometry radiocarbon dates taken directly on human remains from the Late Pleistocene sites of Vindija and Velika Pećina in the Hrvatsko Zagorje of Croatia are presented. Hominid specimens from both sites have played critical roles in the development of current perspectives on modern human evolutionary emergence in Europe. Dates of ≈28 thousand years (ka) before the present (B.P.) and ≈29 ka B.P. for two specimens from Vindija G1 establish them as the most recent dated Neandertals in the Eurasian range of these archaic humans. The human frontal bone from Velika Pećina, generally considered one of the earliest representatives of modern humans in Europe, dated to ≈5 ka B.P., rendering it no longer pertinent to discussions of modern human origins. Apart from invalidating the only radiometrically based example of temporal overlap between late Neandertal and early modern human fossil remains from within any region of Europe, these dates raise the question of when early modern humans first dispersed into Europe and have implications for the nature and geographic patterning of biological and cultural interactions between these populations and the Neandertals. PMID:10535913

  9. A revision of Sanpasaurus yaoi Young, 1944 from the Early Jurassic of China, and its relevance to the early evolution of Sauropoda (Dinosauria

    Directory of Open Access Journals (Sweden)

    Blair W. McPhee

    2016-10-01

    Full Text Available The Early Jurassic of China has long been recognized for its diverse array of sauropodomorph dinosaurs. However, the contribution of this record to our understanding of early sauropod evolution is complicated by a dearth of information on important transitional taxa. We present a revision of the poorly known taxon Sanpasaurus yaoi Young, 1944 from the late Early Jurassic Ziliujing Formation of Sichuan Province, southwest China. Initially described as the remains of an ornithopod ornithischian, we demonstrate that the material catalogued as IVPP V156 is unambiguously referable to Sauropoda. Although represented by multiple individuals of equivocal association, Sanpasaurus is nonetheless diagnosable with respect to an autapomorphic feature of the holotypic dorsal vertebral series. Additional material thought to be collected from the type locality is tentatively referred to Sanpasaurus. If correctly attributed, a second autapomorphy is present in a referred humerus. The presence of a dorsoventrally compressed pedal ungual in Sanpasaurus is of particular interest, with taxa possessing this typically ‘vulcanodontid’ character exhibiting a much broader geographic distribution than previously thought. Furthermore, the association of this trait with other features of Sanpasaurus that are broadly characteristic of basal eusauropods underscores the mosaic nature of the early sauropod–eusauropod transition. Our revision of Sanpasaurus has palaeobiogeographic implications for Early Jurassic sauropods, with evidence that the group maintained a cosmopolitan Pangaean distribution.

  10. New foot remains from the Gran Dolina-TD6 Early Pleistocene site (Sierra de Atapuerca, Burgos, Spain).

    Science.gov (United States)

    Pablos, Adrián; Lorenzo, Carlos; Martínez, Ignacio; Bermúdez de Castro, José María; Martinón-Torres, María; Carbonell, Eudald; Arsuaga, Juan Luis

    2012-10-01

    This paper presents and describes new foot fossils from the species Homo antecessor, found in level TD6 of the site of Gran Dolina (Sierra de Atapuerca, Burgos, Spain). These new fossils consist of an almost complete left talus (ATD6-95) and the proximal three-quarters of a right fourth metatarsal (ATD6-124). The talus ATD6-95 is tentatively assigned to Hominin 10 of the TD6 sample, an adult male specimen with which the second metatarsal ATD6-70+107 (already published) is also tentatively associated. Analysis of these fossils and other postcranial remains has made possible to estimate a stature similar to those of the specimens from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca, Burgos, Spain). The morphology of the TD6 metatarsals does not differ significantly from that of modern humans, Neanderthals and the specimens from Sima de los Huesos. Talus ATD6-95, however, differs from the rest of the comparative samples in being long and high, having a long and wide trochlea, and displaying a proportionally short neck. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Constraints on the Miocene landscape evolution of the Eastern Alps from the Kalkspitze region, Niedere Tauern (Austria)

    Science.gov (United States)

    Dertnig, Florian; Stüwe, Kurt; Woodhead, Jon; Stuart, Finlay M.; Spötl, Christoph

    2017-12-01

    In order to unravel aspects of the Miocene landscape evolution of the eastern European Alps, we present geomorphic and isotopic data from the western Niedere Tauern region (Austria). The region is critical for such interpretations, because it is one of the few regions along the topographic axis of the Eastern Alps where the highest peaks (up to 2500 m a.s.l.) are dominated by limestone. As such, the region contains a record of Miocene landscape-forming events that survived the Pleistocene glaciations, not preserved elsewhere in the central Eastern Alps. This record includes karst caves, karstified planation surfaces and crystalline fluvial pebbles (Augenstein Formation) preserved on planation surfaces and in karst caves. Caves in the region occur in three distinct levels that correlate with well-known cave levels in the Northern Calcareous Alps, although they are somewhat higher in the Niedere Tauern. In part, these cave elevations also correlate with three planation surfaces and knickpoints of major streams draining the region, testifying their pre-glacial origin. We report details of a karst cave (Durchgangshöhle) from the highest cave level located at 2340 m a.s.l. In this cave, allochthonous fluvial gravels are present, overgrown by speleothems. One speleothem yielded an early middle Pleistocene U-Pb age (682 ± 17 ka). We regard this as a minimum age for the erosion of the fluvial cave deposits during Marine Isotope Stages 17 or 16. Carbon and oxygen isotope data of these speleothems imply a climate that is consistent with this interpretation. Cosmogenic 21Ne data of fluvial quartz clasts collected from the surface on plateaus of the Northern Calcareous Alps suggest minimum exposure durations of 115 and 262 ka. They probably reflect successive exposure since removal of the sediment cover of the Oligocene Augenstein Formation during the Pleistocene. While our geochronological data fail to record aspects of the earlier Miocene uplift history, they are

  12. Size variation in early human mandibles and molars from Klasies River, South Africa: comparison with other middle and late Pleistocene assemblages and with modern humans.

    Science.gov (United States)

    Royer, Danielle F; Lockwood, Charles A; Scott, Jeremiah E; Grine, Frederick E

    2009-10-01

    Previous studies of the Middle Stone Age human remains from Klasies River have concluded that they exhibited more sexual dimorphism than extant populations, but these claims have not been assessed statistically. We evaluate these claims by comparing size variation in the best-represented elements at the site, namely the mandibular corpora and M(2)s, to that in samples from three recent human populations using resampling methods. We also examine size variation in these same elements from seven additional middle and late Pleistocene sites: Skhūl, Dolní Vestonice, Sima de los Huesos, Arago, Krapina, Shanidar, and Vindija. Our results demonstrate that size variation in the Klasies assemblage was greater than in recent humans, consistent with arguments that the Klasies people were more dimorphic than living humans. Variation in the Skhūl, Dolní Vestonice, and Sima de los Huesos mandibular samples is also higher than in the recent human samples, indicating that the Klasies sample was not unusual among middle and late Pleistocene hominins. In contrast, the Neandertal samples (Krapina, Shanidar, and Vindija) do not evince relatively high mandibular and molar variation, which may indicate that the level of dimorphism in Neandertals was similar to that observed in extant humans. These results suggest that the reduced levels of dimorphism in Neandertals and living humans may have developed independently, though larger fossil samples are needed to test this hypothesis.

  13. THE POTENTIAL IMPORTANCE OF BINARY EVOLUTION IN ULTRAVIOLET-OPTICAL SPECTRAL FITTING OF EARLY-TYPE GALAXIES

    International Nuclear Information System (INIS)

    Li, Zhongmu; Mao, Caiyan; Chen, Li; Zhang, Qian; Li, Maocai

    2013-01-01

    Most galaxies possibly contain some binaries, and more than half of Galactic hot subdwarf stars, which are thought to be a possible origin of the UV-upturn of old stellar populations, are found in binaries. However, the effect of binary evolution has not been taken into account in most works on the spectral fitting of galaxies. This paper studies the role of binary evolution in the spectral fitting of early-type galaxies, via a stellar population synthesis model including both single and binary star populations. Spectra from ultraviolet to optical bands are fitted to determine a few galaxy parameters. The results show that the inclusion of binaries in stellar population models may lead to obvious change in the determination of some parameters of early-type galaxies and therefore it is potentially important for spectral studies. In particular, the ages of young components of composite stellar populations become much older when using binary star population models instead of single star population models. This implies that binary star population models will measure significantly different star formation histories for early-type galaxies compared to single star population models. In addition, stellar population models with binary interactions on average measure larger dust extinctions than single star population models. This suggests that when binary star population models are used, negative extinctions are possibly no longer necessary in the spectral fitting of galaxies (see previous works, e.g., Cid Fernandes et al. for comparison). Furthermore, it is shown that optical spectra have strong constraints on stellar age while UV spectra have strong constraints on binary fraction. Finally, our results suggest that binary star population models can provide new insight into the stellar properties of globular clusters

  14. Evolution of Late-type Galaxies in a Cluster Environment: Effects of High-speed Multiple Encounters with Early-type Galaxies

    Science.gov (United States)

    Hwang, Jeong-Sun; Park, Changbom; Banerjee, Arunima; Hwang, Ho Seong

    2018-04-01

    Late-type galaxies falling into a cluster would evolve being influenced by the interactions with both the cluster and the nearby cluster member galaxies. Most numerical studies, however, tend to focus on the effects of the former with little work done on those of the latter. We thus perform a numerical study on the evolution of a late-type galaxy interacting with neighboring early-type galaxies at high speed using hydrodynamic simulations. Based on the information obtained from the Coma cluster, we set up the simulations for the case where a Milky Way–like late-type galaxy experiences six consecutive collisions with twice as massive early-type galaxies having hot gas in their halos at the closest approach distances of 15–65 h ‑1 kpc at the relative velocities of 1500–1600 km s‑1. Our simulations show that the evolution of the late-type galaxy can be significantly affected by the accumulated effects of the high-speed multiple collisions with the early-type galaxies, such as on cold gas content and star formation activity of the late-type galaxy, particularly through the hydrodynamic interactions between cold disk and hot gas halos. We find that the late-type galaxy can lose most of its cold gas after the six collisions and have more star formation activity during the collisions. By comparing our simulation results with those of galaxy–cluster interactions, we claim that the role of the galaxy–galaxy interactions on the evolution of late-type galaxies in clusters could be comparable with that of the galaxy–cluster interactions, depending on the dynamical history.

  15. A critical evaluation of the evidence for multiple Late Pleistocene eruptions of Laacher See Volcano

    DEFF Research Database (Denmark)

    Zernack, Anke Verena; Hoggard, Christian Steven; Sauer, Florian Rudolf

    The c. 12,900 BP Plinian eruption of Laacher See Volcano is one of the largest known volcanic events of the Late Pleistocene in the Northern Hemisphere. It buried proximal areas under tens of meters of pyroclastic flow, surge and fallout deposits and deposited a widespread tephra layer across much...... of dispersal of the products from varying eruptive stages and some sites even report two distinct Laacher See Tephra layers that have been interpreted as evidence of a precursor eruption. In order to assess the potential for multiple Late Pleistocene eruptions of Laacher See Volcano, we have compiled...

  16. Zoogdieren uit de Onderst-Pleistocene kuststreken van Nederland (with English summary)

    NARCIS (Netherlands)

    Schreuder, A.

    1949-01-01

    Lower-Villafranchian landmammals lived in the South of the Netherlands when the coastline of the North Sea retired in northern direction during the Plio-Pleistocene transition period. In the province of Zealand their black remains have been fished out of the waters of the Scheldt in the depth of

  17. Phylogeography, hybridization and Pleistocene refugia of the kob antelope (Kobus kob)

    DEFF Research Database (Denmark)

    Lorenzen, Eline Deidre; De Neergaard, Rikke; Arctander, Peter

    2007-01-01

    that the divergent phenotype and life-history adaptations of K. k. leucotis reflect the isolation of kob populations in refugia in west and east Africa during the Pleistocene. Subsequent dispersal has led to secondary contact and hybridization in northern Uganda between lineages, which was supported by high levels...

  18. Pleistocene vertebrates from Celebes : XIV. Additions to the Archidiskodon-Celebochoerus fauna

    NARCIS (Netherlands)

    Hooijer, D.A.

    1972-01-01

    A joint Dutch-Indonesian expedition to Celebes in 1970 worked especially in the Beru area whence the first described Pleistocene Celebes vertebrate remains came. In the present contribution I shall describe the most important specimens that have been brought to light. My thanks are due to Mr. R. P.

  19. Long-term changes in composition and distribution patterns in the Iberian herpetofaunal communities since the latest Pleistocene

    Science.gov (United States)

    Bisbal-Chinesta, Josep Francesc; Blain, Hugues-Alexandre

    2018-03-01

    The climate has undergone significant changes since the end of the Last Glacial Maximum and in the course of the Holocene, parallel to important cultural transformations and migrations in the human communities. The faunal record has also suffered the effects of climate change. Amphibians and reptiles in particular have been shown to be highly sensitive because they are very susceptible to temperature alterations due to their ectothermy. This research presents the first approach to the Iberian paleobiogeography of the different species of amphibians and reptiles from the Late Pleistocene (MIS3) to present times, based on a comparative synthesis of the latest research published in recent years and the fossil record of the 58 archaeo-paleontological sites with significant assemblages. The paleoherpetofaunal associations make it possible to establish two major biotic regions during the Late Pleistocene. The first biotic region was located in the center and south of the Iberian Peninsula, with thermophilic species as the most representative taxa. The second biotic region was formed by the Atlantic-Cantabrian facade and the northeast Iberian area, dominated by hygrophilous and Euro-Siberian species, with an absence of Mediterranean species. After the Last Glacial Maximum there was an unprecedented concurrence in the northern Iberian Peninsula of autochthonous taxa from that area with thermophilic species. In the early Holocene, new species with no previous record in the Iberian Peninsula entered northern Iberia from eastern Mediterranean refugia. Finally, the introduction of North African species was the last significant biogeographical change during the Middle-Late Holocene.

  20. Early vertebrate chromosome duplications and the evolution of the neuropeptide Y receptor gene regions

    Directory of Open Access Journals (Sweden)

    Brenner Sydney

    2008-06-01

    Full Text Available Abstract Background One of the many gene families that expanded in early vertebrate evolution is the neuropeptide (NPY receptor family of G-protein coupled receptors. Earlier work by our lab suggested that several of the NPY receptor genes found in extant vertebrates resulted from two genome duplications before the origin of jawed vertebrates (gnathostomes and one additional genome duplication in the actinopterygian lineage, based on their location on chromosomes sharing several gene families. In this study we have investigated, in five vertebrate genomes, 45 gene families with members close to the NPY receptor genes in the compact genomes of the teleost fishes Tetraodon nigroviridis and Takifugu rubripes. These correspond to Homo sapiens chromosomes 4, 5, 8 and 10. Results Chromosome regions with conserved synteny were identified and confirmed by phylogenetic analyses in H. sapiens, M. musculus, D. rerio, T. rubripes and T. nigroviridis. 26 gene families, including the NPY receptor genes, (plus 3 described recently by other labs showed a tree topology consistent with duplications in early vertebrate evolution and in the actinopterygian lineage, thereby supporting expansion through block duplications. Eight gene families had complications that precluded analysis (such as short sequence length or variable number of repeated domains and another eight families did not support block duplications (because the paralogs in these families seem to have originated in another time window than the proposed genome duplication events. RT-PCR carried out with several tissues in T. rubripes revealed that all five NPY receptors were expressed in the brain and subtypes Y2, Y4 and Y8 were also expressed in peripheral organs. Conclusion We conclude that the phylogenetic analyses and chromosomal locations of these gene families support duplications of large blocks of genes or even entire chromosomes. Thus, these results are consistent with two early vertebrate

  1. Late Carboniferous to early Permian sedimentary–tectonic evolution of the north of Alxa, Inner Mongolia, China: Evidence from the Amushan Formation

    Directory of Open Access Journals (Sweden)

    Haiquan Yin

    2016-09-01

    Full Text Available The late Paleozoic evolution of the Wulijishanhen (WSH-Shangdan (SD area near to the Chaganchulu Ophiolite belt is reinterpreted. Analysis of the upper Carboniferous to lower Permian sedimentary sequence, biological associations, detrital materials, sandstone geochemistry and volcanic rocks indicates that the SD area was an epicontinental sea and rift during the late Paleozoic rather than a large-scale ocean undergoing spreading and closure. This study reveals that the actual evolution of the study area is from the late Carboniferous to the early Permian. The fusulinids Triticites sp. and Pseudoschwagerina sp. in the limestones demonstrate that the Amushan Formation develops during the late Carboniferous to the early Permian. The limestones at the base of the SD section indicate that it is a stable carbonate platform environment, the volcanic rocks in the middle of the sequence support a rift tectonic background, and the overlying conglomerates and sandstones are characteristic of an epicontinental sea or marine molasse setting. The rift volcanism made the differences in the fossil content of the SD and WSH sections and led to two sections expose different levels within the Amushan Formation and different process of tectonic evolution. Moreover, the geochemical characteristics and detrital materials of the sandstones show that the provenance and formation of the sandstones were related to the setting of active continental margin. The quartz-feldspar-lithic fragments distribution diagram indicates that the material source for the sandstones was a recycled orogenic belt. Thus, the source area of the sandstones may have been an active continental margin before the late Carboniferous–early Permian. The characteristics of the regional tectonic evolution of the area indicate that the region may form a small part of the Gobi–Tianshan rift of southern Mongolia.

  2. Looking Back to the Future: Insight on Anthropocene beaches from Holocene and Pleistocene barriers

    Science.gov (United States)

    Dougherty, A. J.; Choi, J. H.; Turney, C. S.; Dosseto, A.

    2017-12-01

    `Super' storms and accelerated rates of sea-level rise are forecast in the Anthropocene, but how coasts will respond (or even if they have started to be impacted) remain uncertain. The onset of this new anthropogenic age is considered mid-1900s when multiple indices including sea level exceed previous Holocene measurements. Centuries of sea surface elevation data, used to project an increase of up to 2m by 2100, show that the current rise started 200 years ago. Similar records of storms or shoreline evolution over these centennial time-scales do not exist. With empirical studies of coastal morphodynamics concentrated during decades of accelerated sea-level rise, present-day beaches can be considered Anthropocene features. To determine the future of vulnerable sandy shorelines, climate change scenarios of increased sea level and storm intensity have been combined with computer models integrating short-term process data with large-scale coastal evolution. The uncertainty in these models can be reduced with longer sea level and storm records as well as filling the gap between detailed beach profile/wave buoy data and generalized barrier stratigraphy. High-resolution chronostratigraphic models necessary to achieve this can be constructed using Light Detection And Ranging (LiDAR), Ground Penetrating Radar (GPR), and Optically Stimulated Luminescence (OSL). Combined GPR, OSL and LiDAR (GOaL) on prograded barriers enables analysis of shorelines back through time, by comparing behaviour since the onset of anthropogenic global warming to that in the preceding millennia. Extracting a record of coastal evolution prior to and since seas began to rise two centuries ago offers the opportunity to detect any difference indicating if/how shorelines have responded. In double barrier systems with composite Holocene and Pleistocene components GOaL can extend the Anthropocene record back to when seas were known to have been higher than today. To demonstrate the potential of GOaL, data

  3. The development of plant food processing in the Levant: insights from use-wear analysis of Early Epipalaeolithic ground stone tools.

    Science.gov (United States)

    Dubreuil, Laure; Nadel, Dani

    2015-11-19

    In recent years, the study of percussive, pounding and grinding tools has provided new insights into human evolution, more particularly regarding the development of technology enabling the processing and exploitation of plant resources. Some of these studies focus on early evidence for flour production, an activity frequently perceived as an important step in the evolution of plant exploitation. The present paper investigates plant food preparation in mobile hunter-gatherer societies from the Southern Levant. The analysis consists of a use-wear study of 18 tools recovered from Ohalo II, a 23 000-year-old site in Israel showing an exceptional level of preservation. Our sample includes a slab previously interpreted as a lower implement used for producing flour, based on the presence of cereal starch residues. The use-wear data we have obtained provide crucial information about the function of this and other percussive tools at Ohalo II, as well as on investment in tool manufacture, discard strategies and evidence for plant processing in the Late Pleistocene. The use-wear analysis indicates that the production of flour was a sporadic activity at Ohalo II, predating by thousands of years the onset of routine processing of plant foods. © 2015 The Author(s).

  4. New Views on the Early Evolution of Oxygen in the Galaxy

    Science.gov (United States)

    Rebolo, R.; Israelian, G.; García López, R. J.

    We have performed a detailed oxygen abundance analysis of 23 metal-poor (-3.0 Abia & Rebolo 1989; Tomkin et al. 1992; Cavallo, Pilachowski, & Rebolo 1997). Contrary to the previously accepted picture, our oxygen abundances, derived from low-excitation OH lines, agree well with those derived from high-excitation lines of the triplet. For nine stars in common with Tomkin et al. we obtain a mean difference of 0.00 plus or minus 0.11dex with respect to the abundances determined from the triplet using the same stellar parameters and model photospheres. Our new results show a smooth extension of the Edvardsson et al.'s (1993) [O/Fe] versus metallicity curve to much lower abundances. The oxygen abundances of unevolved stars when compared with values in the literature for giants of similar metallicity imply that the latter may have suffered a process of oxygen depletion. It appears that unevolved metal-poor stars are better tracers of the early chemical evolution of the Galaxy. The extrapolation of our results to very low metallicities indicates that the ratio of oxygen to iron emerging from the first Type II SNe in the early Galaxy was indeed close to unity. The higher [O/Fe] ratios we find in dwarfs has an impact on the age determination of globular clusters, and suggest that current age estimates have to be reduced by about 1-2 Gyr.

  5. The eastern migratory caribou: the role of genetic introgression in ecotype evolution.

    Science.gov (United States)

    Klütsch, Cornelya F C; Manseau, Micheline; Trim, Vicki; Polfus, Jean; Wilson, Paul J

    2016-02-01

    Understanding the evolutionary history of contemporary animal groups is essential for conservation and management of endangered species like caribou (Rangifer tarandus). In central Canada, the ranges of two caribou subspecies (barren-ground/woodland caribou) and two woodland caribou ecotypes (boreal/eastern migratory) overlap. Our objectives were to reconstruct the evolutionary history of the eastern migratory ecotype and to assess the potential role of introgression in ecotype evolution. STRUCTURE analyses identified five higher order groups (i.e. three boreal caribou populations, eastern migratory ecotype and barren-ground). The evolutionary history of the eastern migratory ecotype was best explained by an early genetic introgression from barren-ground into a woodland caribou lineage during the Late Pleistocene and subsequent divergence of the eastern migratory ecotype during the Holocene. These results are consistent with the retreat of the Laurentide ice sheet and the colonization of the Hudson Bay coastal areas subsequent to the establishment of forest tundra vegetation approximately 7000 years ago. This historical reconstruction of the eastern migratory ecotype further supports its current classification as a conservation unit, specifically a Designatable Unit, under Canada's Species at Risk Act. These findings have implications for other sub-specific contact zones for caribou and other North American species in conservation unit delineation.

  6. Trophic interactions between larger crocodylians and giant tortoises on Aldabra Atoll, Western Indian Ocean, during the Late Pleistocene.

    Science.gov (United States)

    Scheyer, Torsten M; Delfino, Massimo; Klein, Nicole; Bunbury, Nancy; Fleischer-Dogley, Frauke; Hansen, Dennis M

    2018-01-01

    Today, the UNESCO World Heritage Site of Aldabra Atoll is home to about 100 000 giant tortoises, Aldabrachelys gigantea , whose fossil record goes back to the Late Pleistocene. New Late Pleistocene fossils (age ca . 90-125 000 years) from the atoll revealed some appendicular bones and numerous shell fragments of giant tortoises and cranial and postcranial elements of crocodylians. Several tortoise bones show circular holes, pits and scratch marks that are interpreted as bite marks of crocodylians. The presence of a Late Pleistocene crocodylian species, Aldabrachampsus dilophus , has been known for some time, but the recently found crocodylian remains presented herein are distinctly larger than those previously described. This indicates the presence of at least some larger crocodylians, either of the same or of a different species, on the atoll. These larger crocodylians, likely the apex predators in the Aldabra ecosystem at the time, were well capable of inflicting damage on even very large giant tortoises. We thus propose an extinct predator-prey interaction between crocodylians and giant tortoises during the Late Pleistocene, when both groups were living sympatrically on Aldabra, and we discuss scenarios for the crocodylians directly attacking the tortoises or scavenging on recently deceased animals.

  7. Biogeography in deep time - What do phylogenetics, geology, and paleoclimate tell us about early platyrrhine evolution?

    Science.gov (United States)

    Kay, Richard F

    2015-01-01

    Molecular data have converged on a consensus about the genus-level phylogeny of extant platyrrhine monkeys, but for most extinct taxa and certainly for those older than the Pleistocene we must rely upon morphological evidence from fossils. This raises the question as to how well anatomical data mirror molecular phylogenies and how best to deal with discrepancies between the molecular and morphological data as we seek to extend our phylogenies to the placement of fossil taxa. Here I present parsimony-based phylogenetic analyses of extant and fossil platyrrhines based on an anatomical dataset of 399 dental characters and osteological features of the cranium and postcranium. I sample 16 extant taxa (one from each platyrrhine genus) and 20 extinct taxa of platyrrhines. The tree structure is constrained with a "molecular scaffold" of extant species as implemented in maximum parsimony using PAUP with the molecular-based 'backbone' approach. The data set encompasses most of the known extinct species of platyrrhines, ranging in age from latest Oligocene (∼26 Ma) to the Recent. The tree is rooted with extant catarrhines, and Late Eocene and Early Oligocene African anthropoids. Among the more interesting patterns to emerge are: (1) known early platyrrhines from the Late Oligocene through Early Miocene (26-16.5Ma) represent only stem platyrrhine taxa; (2) representatives of the three living platyrrhine families first occur between 15.7 Ma and 13.5 Ma; and (3) recently extinct primates from the Greater Antilles (Cuba, Jamaica, Hispaniola) are sister to the clade of extant platyrrhines and may have diverged in the Early Miocene. It is probable that the crown platyrrhine clade did not originate before about 20-24 Ma, a conclusion consistent with the phylogenetic analysis of fossil taxa presented here and with recent molecular clock estimates. The following biogeographic scenario is consistent with the phylogenetic findings and climatic and geologic evidence: Tropical South

  8. A Pleistocene coastal alluvial fan complex produced by Middle Pleistocene glacio-fluvial processes

    Science.gov (United States)

    Adamson, Kathryn; Woodward, Jamie; Hughes, Philip; Giglio, Federico; Del Bianco, Fabrizio

    2014-05-01

    A coarse-grained alluvial fan sequence at Lipci, Kotor Bay, in western Montenegro, provides a sedimentary record of meltwater streams draining from the Orjen Massif (1,894 m a.s.l.) to the coastal zone. At Lipci sedimentary evidence and U-series ages have been used alongside offshore bathymetric imagery and seismic profiles to establish the size of the fan and constrain the nature and timing of its formation. Establishing the depositional history of such coastal fans is important for our understanding of cold stage sediment flux from glaciated uplands to the offshore zone, and for exploring the impact of sea level change on fan reworking. There is evidence of at least four phases of Pleistocene glaciation on the Orjen massif, which have been U-series dated and correlated to MIS 12, MIS 6, MIS 5d-2 and the Younger Dryas. A series of meltwater channels delivered large volumes of coarse- and fine-grained limestone sediment from the glaciated uplands into the Bay of Kotor. At the southern margin of the Orjen massif, a series of large (>700 m long) alluvial fans has developed. Some of these extend offshore for up to 600 m. Lipci fan lies downstream of end moraines in the valley immediately above, which were formed by an extensive outlet glacier of the Orjen ice cap during MIS 12. The terrestrial deposits are part of the fan apex (50 m a.s.l.) that lies at the foot of a steep bedrock channel, but the majority of the fan is now more than 25 m below sea level. The terrestrial fan sediments are strongly cemented by multiple generations of calcite precipitates: the oldest U-series ages are infinite indicating that the fan is >350 ka in age. These ages are in agreement with alluvial sedimentary evidence and U-series ages from other fluvial units on Mount Orjen. The terrestrial portion of the Lipci fan surface contains several channels. These are well preserved due to cementation with calcium carbonate. Submarine imagery indicates that the now submerged portion of the fan also

  9. Biologist Edwin Grant Conklin and the idea of the religious direction of human evolution in the early 1920s.

    Science.gov (United States)

    Pavuk, Alexander

    2017-01-01

    Edwin Grant Conklin, renowned US embryologist and evolutionary popularizer, publicly advocated a social vision of evolution that intertwined science and modernist Protestant theology in the early 1920s. The moral prestige of professional science in American culture - along with Conklin's own elite scientific status - diverted attention from the frequency with which his work crossed boundaries between natural science, religion and philosophy. Writing for broad audiences, Conklin was one of the most significant of the religious and modernist biological scientists whose rhetoric went well beyond simply claiming that certain kinds of religion were amenable to evolutionary science; he instead incorporated religion itself into evolution's broadest workings. A sampling of Conklin's widely-resonant discourse suggests that there was substantially more to the religion-evolution story in the 1920s US than many creationist-centred narratives of the era imply.

  10. Effects of Pleistocene sea-level fluctuations on mangrove population dynamics: a lesson from Sonneratia alba.

    Science.gov (United States)

    Yang, Yuchen; Li, Jianfang; Yang, Shuhuan; Li, Xinnian; Fang, Lu; Zhong, Cairong; Duke, Norman C; Zhou, Renchao; Shi, Suhua

    2017-01-18

    A large-scale systematical investigation of the influence of Pleistocene climate oscillation on mangrove population dynamics could enrich our knowledge about the evolutionary history during times of historical climate change, which in turn may provide important information for their conservation. In this study, phylogeography of a mangrove tree Sonneratia alba was studied by sequencing three chloroplast fragments and seven nuclear genes. A low level of genetic diversity at the population level was detected across its range, especially at the range margins, which was mainly attributed to the steep sea-level drop and associated climate fluctuations during the Pleistocene glacial periods. Extremely small effective population size (Ne) was inferred in populations from both eastern and western Malay Peninsula (44 and 396, respectively), mirroring the fragility of mangrove plants and their paucity of robustness against future climate perturbations and human activity. Two major genetic lineages of high divergence were identified in the two mangrove biodiversity centres: the Indo-Malesia and Australasia regions. The estimated splitting time between these two lineages was 3.153 million year ago (MYA), suggesting a role for pre-Pleistocene events in shaping the major diversity patterns of mangrove species. Within the Indo-Malesia region, a subdivision was implicated between the South China Sea (SCS) and the remaining area with a divergence time of 1.874 MYA, corresponding to glacial vicariance when the emerged Sunda Shelf halted genetic exchange between the western and eastern coasts of the Malay Peninsula during Pleistocene sea-level drops. Notably, genetic admixture was observed in populations at the boundary regions, especially in the two populations near the Malacca Strait, indicating secondary contact between divergent lineages during interglacial periods. These interregional genetic exchanges provided ample opportunity for the re-use of standing genetic variation

  11. The Gradual Evolution of Language

    Directory of Open Access Journals (Sweden)

    Michael C. Corballis

    2014-12-01

    Full Text Available Language is commonly held to be unique to humans, and to have emerged suddenly in a single “great leap forward” within the past 100,000 years. The view is profoundly anti-Darwinian, and I propose instead a framework for understanding how language might have evolved incrementally from our primate heritage. One major proposition is that language evolved from manual action, with vocalization emerging as the dominant mode late in hominin evolution. The second proposition has to do with the role of language as a means of communicating about events displaced in space and time from the present. Some have argued that mental time travel itself is unique to human, which might explain why language itself is uniquely human. I argue instead that mental time travel has ancient evolutionary origins, and gradually assumed narrative-like properties during the Pleistocene, when language itself began to take shape.

  12. A first-principles model of early evolution: emergence of gene families, species, and preferred protein folds.

    Directory of Open Access Journals (Sweden)

    Konstantin B Zeldovich

    2007-07-01

    Full Text Available In this work we develop a microscopic physical model of early evolution where phenotype--organism life expectancy--is directly related to genotype--the stability of its proteins in their native conformations-which can be determined exactly in the model. Simulating the model on a computer, we consistently observe the "Big Bang" scenario whereby exponential population growth ensues as soon as favorable sequence-structure combinations (precursors of stable proteins are discovered. Upon that, random diversity of the structural space abruptly collapses into a small set of preferred proteins. We observe that protein folds remain stable and abundant in the population at timescales much greater than mutation or organism lifetime, and the distribution of the lifetimes of dominant folds in a population approximately follows a power law. The separation of evolutionary timescales between discovery of new folds and generation of new sequences gives rise to emergence of protein families and superfamilies whose sizes are power-law distributed, closely matching the same distributions for real proteins. On the population level we observe emergence of species--subpopulations that carry similar genomes. Further, we present a simple theory that relates stability of evolving proteins to the sizes of emerging genomes. Together, these results provide a microscopic first-principles picture of how first-gene families developed in the course of early evolution.

  13. The first finding of Asian black bear (Carnivora, Ursidae, Ursus (Euarctos) thibetanus G. Cuvier, 1823) in the Late Pleistocene of northern Eurasia.

    Science.gov (United States)

    Kosintsev, P A; Tiunov, M P; Gimranov, D O; Panov, V S

    2016-11-01

    An M1 tooth of Asian black bear (Ursus (Euarctos) thibetanus G. Cuvier, 1823) was found in deposits of the Tetyukhinskaya cave (Middle Sikhote-Alin, 44°35'N, 135°36'E). This finding is the first reliable evidence of Asian black bear's presence in Pleistocene of Primorye. Its morphological and morphometric descriptions are given. The period of inhabitation of U. (E.) thibetanus determined based on the radiocarbon date obtained during the study of the tooth, is 39 874 ± 133 BP (NSK-850, UGAMS-21786), which corresponds to the middle of Marine Isotope Stage 3 (MIS 3) of Late Pleistocene. The composition of ancient theriofauna indicates the existence of wide variety of landscapes in Primorye in the middle of Late Pleistocene. A refugium of forest fauna, in which species of taiga, nemoral, and Central Asian mountain-forest theriocomplexes were present, was located in southern Primorye in Late Pleistocene.

  14. Adaptability and evolution.

    Science.gov (United States)

    Bateson, Patrick

    2017-10-06

    The capacity of organisms to respond in their own lifetimes to new challenges in their environments probably appeared early in biological evolution. At present few studies have shown how such adaptability could influence the inherited characteristics of an organism's descendants. In part, this has been because organisms have been treated as passive in evolution. Nevertheless, their effects on biological evolution are likely to have been important and, when they occurred, accelerated the pace of evolution. Ways in which this might have happened have been suggested many times since the 1870s. I review these proposals and discuss their relevance to modern thought.

  15. Post-early cretaceous landform evolution along the western margin of the banca~nnia trough, western nsw

    Science.gov (United States)

    Gibson, D.L.

    2000-01-01

    Previously undated post-Devonian sediments outcropping north of Fowlers Gap station near the western margin of the Bancannia Trough are shown by plant macro- and microfossil determinations to be of Early Cretaceous (most likely Neocomian and/or Aptian) age, and thus part of the Eromanga Basin. They are assigned to the previously defined Telephone Creek Formation. Study of the structural configuration of this unit and the unconformably underlying Devonian rocks suggests that the gross landscape architecture of the area results from post-Early Cretaceous monoclinal folding along blind faults at the western margin of the trough, combined with the effects of differential erosion. This study shows that, while landscape evolution in the area has been dynamic, the major changes that have occurred are on a geological rather than human timescale.

  16. Mid-Pliocene to Early Pleistocene land and sea surface temperature history of NW Australia based on organic geochemical proxies

    Science.gov (United States)

    Smith, R. A.; Castañeda, I. S.; Henderiks, J.; Christensen, B. A.; De Vleeschouwer, D.; Renema, W.; Groeneveld, J.; Bogus, K.; Gallagher, S. J.; Fulthorpe, C.; Expedition 356 Scientists, I.

    2017-12-01

    IODP Expedition 356 Site U1463 is located off the coast of NW Australia, and is sensitive to Indonesian Throughflow (ITF) variability. The ITF is a critical ocean gateway that affects global thermohaline circulation, and regulates the movement of water from the Pacific Ocean into the Indian Ocean. However, despite its importance to the global climate system, few SST reconstructions exist for this region that span the Plio-Pleistocene. Here we investigate both the land and sea-surface temperature (SST) history of NW Australia to constrain ITF variability across the Plio-Pleistocene interval. We apply multiple organic geochemical proxies to this site from 3.4-2.6 Ma, which includes the mid-Pliocene warm period, characterized by slightly higher (2-3°C) global temperatures and similar CO2 concentrations to modern values (e.g. Badger et al. 2013; Bartoli et al., 2011; Dowsett et al., 2009; Hönisch et al., 2009; Pagani et al. 2009; Raymo et al., 1996). SST was reconstructed using TEX86, based on isoprenoid glycerol dialkyl glycerol tetraethers (iGDGTs), and the long-chain diol index (LDI), based on the ratio of diols produced by marine diatoms (Rampen et al., 2012). The Uk'37 index, based on long-chain ketones, was analyzed but cannot be applied as a SST proxy at this site due to the influence of coastal alkenone producers. Additionally, a continental air temperature record was developed using the MBT'5ME proxy, based on branched GDGTs (De Jonge et al., 2014; Weijers et al., 2007). We find that TEX86, LDI and MBT'5Me exhibit similar trends and show relatively warm and stable temperatures from 3.5-2.4 Ma followed by a gradual cooling of 3-4°C from 2.4-1.5 Ma. This cooling corresponds with an arid interval previously identified on the same core by Christensen et al. (2017). Furthermore, we find that the TEX86 record agrees closely with the LR04 global benthic δ18O stack (Lisiecki and Raymo, 2005) and captures glacial/interglacial periods including Marine Isotope Stage

  17. Shoreline deposits and diagenesis resulting from two Late Pleistocene highstands near +5 and +6 metres, Durban, South Africa

    Science.gov (United States)

    Cooper, J.A.G.; Flores, R.M.

    1991-01-01

    In exposures of Pleistocene rocks on the east coast of South Africa, eight sedimentary facies were distinguished on the basis of petrology, grain size, internal structures and field relationships. These are interpreted as deposits of surf zone, breaker zone, swash zone, backbeach, boulder beach and dune environments. Three phases of deposition and diagenesis are recognized. As a result of the stabilising effect of pre-existing coastal facies, the deposits from successive sea level stands are stacked vertically in a narrow coast-normal strip. Early cementation prevented erosion of the deposits during subsequent transgressions. Deposition of subsequent facies took place on an existing coastal dune (Facies 1). A terrace was cut into this dune at a sea level 4.5 to 5 m above present. At this sea level, clastic shoreline sediments were deposited which make up the main sedimentary sequence exposed (Facies 2-7). The steep swash zone, coarse grain size, and comparison with modern conditions in the study area indicate clastic deposition on a high-energy, wave-dominated, microtidal coastline. Vertical stacking of progressively shallower water facies indicates progradation associated with slightly regressive conditions, prior to stranding of the succession above sea level. During a subsequent transgression to 5.5 or 6 m above present sea level, a second terrace was cut across the existing facies, which by then were partly lithified. A boulder beach (Facies 8) deposited on this terrace is indicative of high wave energy and a rocky coastline, formed by existing cemented coastal facies. Comparison with dated deposits from other parts of the South African coast suggest a Late Pleistocene age for Facies 2-8. Deposition was terminated by subsequent regression and continuing low sea levels during the remainder of the Pleistocene. Cementation of the facies took place almost entirely by carbonate precipitation. The presence of isopachous fibrous cements suggests early cementation of

  18. Five-year evolution of reperfusion strategies and early mortality in patients with ST-segment elevation myocardial infarction in France.

    Science.gov (United States)

    El Khoury, Carlos; Bochaton, Thomas; Flocard, Elodie; Serre, Patrice; Tomasevic, Danka; Mewton, Nathan; Bonnefoy-Cudraz, Eric

    2017-10-01

    To assess 5-year evolutions in reperfusion strategies and early mortality in patients with ST-segment elevation myocardial infarction. Using data from the French RESCUe network, we studied patients with ST-segment elevation myocardial infarction treated in mobile intensive care units between 2009 and 2013. Among 2418 patients (median age 62 years; 78.5% male), 2119 (87.6%) underwent primary percutaneous coronary intervention and 299 (12.4%) pre-hospital thrombolysis (94.0% of whom went on to undergo percutaneous coronary intervention). Use of primary percutaneous coronary intervention increased from 78.4% in 2009 to 95.9% in 2013 ( P trend 90 minutes delay group (83.0% in 2009 to 97.7% in 2013; P trend <0.001 versus 34.1% in 2009 to 79.2% in 2013; P trend <0.001). In-hospital (4-6%) and 30-day (6-8%) mortalities remained stable from 2009 to 2013. In the RESCUe network, the use of primary percutaneous coronary intervention increased from 2009 to 2013, in line with guidelines, but there was no evolution in early mortality.

  19. Virtual endocasts of Eocene Paramys (Paramyinae): oldest endocranial record for Rodentia and early brain evolution in Euarchontoglires.

    Science.gov (United States)

    Bertrand, Ornella C; Amador-Mughal, Farrah; Silcox, Mary T

    2016-01-27

    Understanding the pattern of brain evolution in early rodents is central to reconstructing the ancestral condition for Glires, and for other members of Euarchontoglires including Primates. We describe the oldest virtual endocasts known for fossil rodents, which pertain to Paramys copei (Early Eocene) and Paramys delicatus (Middle Eocene). Both specimens of Paramys have larger olfactory bulbs and smaller paraflocculi relative to total endocranial volume than later occurring rodents, which may be primitive traits for Rodentia. The encephalization quotients (EQs) of Pa. copei and Pa. delicatus are higher than that of later occurring (Oligocene) Ischyromys typus, which contradicts the hypothesis that EQ increases through time in all mammalian orders. However, both species of Paramys have a lower relative neocortical surface area than later rodents, suggesting neocorticalization occurred through time in this Order, although to a lesser degree than in Primates. Paramys has a higher EQ but a lower neocortical ratio than any stem primate. This result contrasts with the idea that primates were always exceptional in their degree of overall encephalization and shows that relative brain size and neocortical surface area do not necessarily covary through time. As such, these data contradict assumptions made about the pattern of brain evolution in Euarchontoglires. © 2016 The Author(s).

  20. Pliocene and pleistocene hominid-bearing sites from west of lake turkana, kenya.

    Science.gov (United States)

    Harris, J M; Brown, F H; Leakey, M G; Walker, A C; Leakey, R E

    1988-01-01

    Pliocene and Pleistocene fossil localities near the western shoreline of Lake Turkana, ranging in age between 1 million and 3.5 million years in age, have produced important new hominid specimens including most of a Homo erectus skeleton and a relatively complete early robust australopithecine cranium. The lacustrine, fluviatile, and terrestrial strata are designated the Nachukui Formation, which is subdivided into eight members. The distribution of sedimentary facies within the Nachukui Formation suggests that, as today, the Labur and Murua Rith ranges formed the western margin of the basin and were drained by eastward-flowing rivers that fed into the forerunner of the present lake or a major river system. There is also stratigraphic evidence for tectonic movement during the deposition of these sediments. Twenty-three of the tuffs observed in the succession occur also in the Koobi Fora Formation east of the lake and in the Shungura Formation of the lower Omo Valley and permit precise correlation among these three localities. Fortyseven fossiliferous sites from West Turkana have yielded more than 1000 specimens of 93 mammalian species. The mammalian fossils represent nine sequential assemblages that augment information about faunal and environmental change from elsewhere in the basin.

  1. The Valle di Manche section (Calabria, Southern Italy): A high resolution record of the Early-Middle Pleistocene transition (MIS 21-MIS 19) in the Central Mediterranean

    Science.gov (United States)

    Capraro, Luca; Ferretti, Patrizia; Macrì, Patrizia; Scarponi, Daniele; Tateo, Fabio; Fornaciari, Eliana; Bellini, Giulia; Dalan, Giorgia

    2017-06-01

    The on-land marine Valle di Manche section (Crotone Basin, Calabria, Southern Italy), one of the candidates to host the GSSP of the Middle Pleistocene (;Ionian;) Stage, preserves a manifold record of independent chronological, paleoclimatic and stratigraphic proxies that permit a straightforward correlation with marine and terrestrial reference records at the global scale. In particular, the section holds an excellent record of the Matuyama-Brunhes magnetic reversal, which occurs in the midst of Marine Isotope Stage (MIS) 19. We report on a complete revision of the section that improves dramatically the available dataset, especially in the stratigraphic interval straddling the Lower-Middle Pleistocene boundary. Our benthic δ18O record provides evidence that the Matuyama-Brunhes transition, the stratigraphic position of which is marked by a prominent tephra (the ;Pitagora ash;), occurred during full MIS 19, in agreement with many records worldwide. We obtained an age of 786.9 ± 5 ka for the Matuyama-Brunhes magnetic reversal and pinpointed the paleomagnetic transition of to a 3 cm-thick interval, indicating that the event was very fast. Since the section fulfills all the requirements to host the GSSP of the Ionian Stage, we propose that the boundary should be placed at the base of the ;Pitagora ash;, ca. 12.5 cm below the midpoint of the Matuyama-Brunhes reversal.

  2. Hybrid Differential Evolution Optimisation for Earth Observation Satellite Scheduling with Time-Dependent Earliness-Tardiness Penalties

    Directory of Open Access Journals (Sweden)

    Guoliang Li

    2017-01-01

    Full Text Available We study the order acceptance and scheduling (OAS problem with time-dependent earliness-tardiness penalties in a single agile earth observation satellite environment where orders are defined by their release dates, available processing time windows ranging from earliest start date to deadline, processing times, due dates, sequence-dependent setup times, and revenues. The objective is to maximise total revenue, where the revenue from an order is a piecewise linear function of its earliness and tardiness with reference to its due date. We formulate this problem as a mixed integer linear programming model and develop a novel hybrid differential evolution (DE algorithm under self-adaptation framework to solve this problem. Compared with classical DE, hybrid DE employs two mutation operations, scaling factor adaptation and crossover probability adaptation. Computational tests indicate that the proposed algorithm outperforms classical DE in addition to two other variants of DE.

  3. Changes of 2H and 18O enrichment of meteoric water and Pleistocene glaciation

    International Nuclear Information System (INIS)

    Harmon, R.S.; Schwarcz, H.P.

    1981-01-01

    Isotopic data on fluid inclusions and host speleothems are presented which support the hypothesis that the deltaD-delta 18 O relationship for modern meteoric waters may have changed during the Pleistocene glacial periods in response to increased ocean surface air humidity. Palaeotemperatures for five areas of east-central North America and Bermuda, calculated assuming the present deltaDdelta 18 O meteoric water relationship for fluid inclusion waters, are observed to be too low during late Pleistocene glacial periods (in some instances falling below O 0 C) while interglacial palaeotemperatures are largely equivalent to those in the areas at present. As speleothem deposition cannot occur at subzero temperatures, a possible solution to this dilemma is a shift in the intercept of the meteoric water relationship. (U.K.)

  4. Cheek tooth morphology and ancient mitochondrial DNA of late Pleistocene horses from the western interior of North America: Implications for the taxonomy of North American Late Pleistocene Equus.

    Directory of Open Access Journals (Sweden)

    Christina I Barrón-Ortiz

    Full Text Available Horses were a dominant component of North American Pleistocene land mammal communities and their remains are well represented in the fossil record. Despite the abundant material available for study, there is still considerable disagreement over the number of species of Equus that inhabited the different regions of the continent and on their taxonomic nomenclature. In this study, we investigated cheek tooth morphology and ancient mtDNA of late Pleistocene Equus specimens from the Western Interior of North America, with the objective of clarifying the species that lived in this region prior to the end-Pleistocene extinction. Based on the morphological and molecular data analyzed, a caballine (Equus ferus and a non-caballine (E. conversidens species were identified from different localities across most of the Western Interior. A second non-caballine species (E. cedralensis was recognized from southern localities based exclusively on the morphological analyses of the cheek teeth. Notably the separation into caballine and non-caballine species was observed in the Bayesian phylogenetic analysis of ancient mtDNA as well as in the geometric morphometric analyses of the upper and lower premolars. Teeth morphologically identified as E. conversidens that yielded ancient mtDNA fall within the New World stilt-legged clade recognized in previous studies and this is the name we apply to this group. Geographic variation in morphology in the caballine species is indicated by statistically different occlusal enamel patterns in the specimens from Bluefish Caves, Yukon Territory, relative to the specimens from the other geographic regions. Whether this represents ecomorphological variation and/or a certain degree of geographic and genetic isolation of these Arctic populations requires further study.

  5. Nitrogen isotopes suggest a change in nitrogen dynamics between the Late Pleistocene and modern time in Yukon, Canada

    Science.gov (United States)

    Longstaffe, Fred J.; Zazula, Grant

    2018-01-01

    A magnificent repository of Late Pleistocene terrestrial megafauna fossils is contained in ice-rich loess deposits of Alaska and Yukon, collectively eastern Beringia. The stable carbon (δ13C) and nitrogen (δ15N) isotope compositions of bone collagen from these fossils are routinely used to determine paleodiet and reconstruct the paleoecosystem. This approach requires consideration of changes in C- and N-isotope dynamics over time and their effects on the terrestrial vegetation isotopic baseline. To test for such changes between the Late Pleistocene and modern time, we compared δ13C and δ15N for vegetation and bone collagen and structural carbonate of some modern, Yukon, arctic ground squirrels with vegetation and bones from Late Pleistocene fossil arctic ground squirrel nests preserved in Yukon loess deposits. The isotopic discrimination between arctic ground squirrel bone collagen and their diet was measured using modern samples, as were isotopic changes during plant decomposition; Over-wintering decomposition of typical vegetation following senescence resulted in a minor change (~0–1 ‰) in δ13C of modern Yukon grasses. A major change (~2–10 ‰) in δ15N was measured for decomposing Yukon grasses thinly covered by loess. As expected, the collagen-diet C-isotope discrimination measured for modern samples confirms that modern vegetation δ13C is a suitable proxy for the Late Pleistocene vegetation in Yukon Territory, after correction for the Suess effect. The N-isotope composition of vegetation from the fossil arctic ground squirrel nests, however, is determined to be ~2.8 ‰ higher than modern grasslands in the region, after correction for decomposition effects. This result suggests a change in N dynamics in this region between the Late Pleistocene and modern time. PMID:29447202

  6. Preliminary Facies Reconstruction of a Late Pleistocene Cypress Forest Discovered on the Northern Gulf of Mexico Continental Shelf

    Science.gov (United States)

    Gonzalez Rodriguez, S. M.; Bentley, S. J.; DeLong, K. L.; Xu, K.; Caporaso, A.; Obelcz, J. B.; Harley, G. L.; Reese, C. A.; Truong, J. T.

    2016-12-01

    We are investigating the origin and preservation of an ancient bald cypress forest (Taxodium distichum) discovered on the continental shelf seafloor, offshore of Gulf Shores, Alabama, USA, in 20 m water depth. The forest was likely buried in the late Pleistocene, possibly exhumed by Hurricane Ivan in 2004, and is now exposed as stumps in life position with little evidence of decay before recent marine exposure. Radiocarbon analyses show that the forest age is near (and in some cases beyond) the limits of 14C dating, at least 41-45 ky BP. In August 2015 and July 2016, submersible vibracores (up to 5 m in length) were collected. Ongoing core analyses include: organic content (loss on ignition), granulometry, and core logging using a Geotek Multi Sensor Core Logger to generate imagery, bulk density, and x-ray fluorescence data. To bolster 14C analyses, cores collected in 2016 are presently being dated using optically stimulated luminescence. Local stratigraphy consists of a surface facies of Holocene transgressive sands, underlain by possible estuarine sediments of interbedded sand and mud (potentially Holocene or Pleistocene), overlying a swamp or delta plain facies (likely Pleistocene) containing woody debris and mud. Deeper woody facies are thought to include the soil horizons of the ancient cypress forest. Cores collected in 2016 revealed a Pleistocene paleosol beneath Holocene sands in a nearby trough. Elevation differences between swamp and paleosol horizons will be evaluated from bathymetric and subbottom data, to help characterize the preserved ancient landscape. Initial interpretation based on close proximity of Pleistocene swamp and oxidized paleosol sediments, and regional geomorphic gradients suggest that this relatively diverse assemblage of facies developed up to tens of km from the glacial-age coastline, and relatively rapid burial prevented erosion by coastal processes during the Holocene transgression thus preserving the tree stumps and wood debris.

  7. The III working days of the Cenozoic

    International Nuclear Information System (INIS)

    2012-06-01

    The third working days in geology were organized by the Uruguayan Society of geology and took place in DINAMIGE in June - 2012. The lectures were given by national and foreign professionals and included important topics such as mineral raw materials used in the archaeological artifacts in Guayacas - Dayman - Paysandu . The Holocene in the coastal zone of Uruguay. Aspect of the early human occupation in Uruguay. Change effects in the land use about the mineral clay (eucalyptus forestation, illite). Paleoclimatic and paleoenvironmental reconstruction for middle and late holocene (Rocha). Gas hydrate resource quantification in Uruguay. Application of the geophysical techniques in the environmental pollution in Montevideo - Piriapolis. Environmental evolution and builders of small hills in India Muerta zone. Human or natural forcing in the geomorphological processes in Pocitos and Ramirez beaches (80 years of aerophotographic records).Tipology and nomenclature proposal for technological soil. Quarries reconditioning methodology. Hydraulic conductivity in sugar cane cultivated in soils previous vinaza application. Paleosoils and pedogenic calcretes formations in Fray Bentos (Oligocene - early miocene) Raigon (late pliocene and Middle pleistocene) and Libertad (early - middle pleistocene). Tectonics and sedimentary process in the continental talud in Uruguay. Rio de la Plata as paleoenvironmental focus using diatomos as proxies. Oleistocene mammals in the late-early Holocene in Santa Lucia river basin (Uruguay southern). Anthropization in Montevideo Bay during the Holocene. Paleocene stratigraphic plays in Uruguay offshore. Continental Influence versus marine transition in Rio de la Plata zone - internal continental shelf of the South Atlantic - a multiproxy study. Macrofossils vegetable in Palmar formation (later pleistocene) in Entre Rios - Argentina. Phytolith analysis in quaternary fluvial sediment (plio-pleistocene) in San Salvador and Palmar formation - Uruguay

  8. Evolution of allosteric regulation in chorismate mutases from early plants

    Energy Technology Data Exchange (ETDEWEB)

    Kroll, Kourtney; Holland, Cynthia K.; Starks, Courtney M.; Jez, Joseph M.

    2017-09-28

    Plants, fungi, and bacteria synthesize the aromatic amino acids: l-phenylalanine, l-tyrosine, and l-tryptophan. Chorismate mutase catalyzes the branch point reaction of phenylalanine and tyrosine biosynthesis to generate prephenate. In Arabidopsis thaliana, there are two plastid-localized chorismate mutases that are allosterically regulated (AtCM1 and AtCM3) and one cytosolic isoform (AtCM2) that is unregulated. Previous analysis of plant chorismate mutases suggested that the enzymes from early plants (i.e. bryophytes/moss, lycophytes, and basal angiosperms) formed a clade distinct from the isoforms found in flowering plants; however, no biochemical information on these enzymes is available. To understand the evolution of allosteric regulation in plant chorismate mutases, we analyzed a basal lineage of plant enzymes homologous to AtCM1 based on sequence similarity. The chorismate mutases from the moss/bryophyte Physcomitrella patens (PpCM1 and PpCM2), the lycophyte Selaginella moellendorffii (SmCM), and the basal angiosperm Amborella trichopoda (AmtCM1 and AmtCM2) were characterized biochemically. Tryptophan was a positive effector for each of the five enzymes examined. Histidine was a weak positive effector for PpCM1 and AmtCM1. Neither tyrosine nor phenylalanine altered the activity of SmCM; however, tyrosine was a negative regulator of the other four enzymes. Phenylalanine down-regulates both moss enzymes and AmtCM2. The 2.0 Å X-ray crystal structure of PpCM1 in complex with the tryptophan identified the allosteric effector site and reveals structural differences between the R- (more active) and T-state (less active) forms of plant chorismate mutases. Molecular insight into the basal plant chorismate mutases guides our understanding of the evolution of allosteric regulation in these enzymes.

  9. Fossils mollusc asemblage found at Zagarzazu, marine Pleistocene, Uruguay

    International Nuclear Information System (INIS)

    Rojas, A. . E mail: alejandra@fcien.edu.uy

    2004-01-01

    There are presented the results of the paleoecological analysis of the mollusc assemblage found at Zagarzazu, Colonia department. The fossils are well preserved, arranged in thin shell-beds with some specimens in life position. The assemblage is indicative of higher temperatures than present, and a strong marine influence. It is important to stress that new thermophilic molluscs for the marine Quaternary were found and that this locality represents a new Pleistocene marine record in Uruguay [es

  10. Rates and modes of body size evolution in early carnivores and herbivores: a case study from Captorhinidae

    Directory of Open Access Journals (Sweden)

    Neil Brocklehurst

    2016-01-01

    Full Text Available Body size is an extremely important characteristic, impacting on a variety of ecological and life-history traits. It is therefore important to understand the factors which may affect its evolution, and diet has attracted much interest in this context. A recent study which examined the evolution of the earliest terrestrial herbivores in the Late Carboniferous and Early Permian concluded that in the four herbivorous clades examined there was a trend towards increased body size, and that this increase was more substantial than that observed in closely related carnivorous clades. However, this hypothesis was not based on quantitative examination, and phylogenetic comparative methods provide a more robust means of testing such hypotheses. Here, the evolution of body size within different dietary regimes is examined in Captorhinidae, the most diverse and longest lived of these earliest high fibre herbivores. Evolutionary models were fit to their phylogeny to test for variation in rate and mode of evolution between the carnivorous and herbivorous members of this clade, and an analysis of rate variation throughout the tree was carried out. Estimates of ancestral body sizes were calculated in order to compare the rates and direction of evolution of lineages with different dietary regimes. Support for the idea that the high fibre herbivores within captorhinids are being drawn to a higher adaptive peak in body size than the carnivorous members of this clade is weak. A shift in rates of body size evolution is identified, but this does not coincide with the evolution of high-fibre herbivory, instead occurring earlier in time and at a more basal node. Herbivorous lineages which show an increase in size are not found to evolve at a faster rate than those which show a decrease; in fact, it is those which experience a size decrease which evolve at higher rates. It is possible the shift in rates of evolution is related to the improved food processing ability of

  11. Macro fossils vegetable in Palmar formation (later pleistocene) in Entre Rios - Argentina

    International Nuclear Information System (INIS)

    Ramos, R.; Brea, M.; Krohling, D.

    2012-01-01

    This work is about the macro fossil knowledge preserved like wood fossils in the El Palmar Formation (Late Pleistocene) from a systematic - anatomical as well as paleoecological and paleoclimate point of view.The paleo Flora comes from various fossil located in the province of Entre Rios - Argentina

  12. Pleistocene fossil woods from the Okote Member, site FwJj 14 in the Ileret region, Koobi Fora Formation, northern Kenya.

    Science.gov (United States)

    Bamford, Marion K

    2017-11-01

    On the eastern side of Lake Turkana in northern Kenya are extensive Plio-Pleistocene deposits containing a rich diversity of fossil mammals, hominins and flora within the radiometrically dated tuffaceous, lacustrine and fluvial sequence. Reconstruction of this landscape and paleoenvironment are part of an ongoing multinational and multidisciplinary human evolution project in the eastern Turkana Basin. Today there is a huge lake in the Rift Valley but it has fluctuated since the early Pliocene. Silicified wood is fairly common in some areas of the Koobi Fora Formation. One such site is FwJj 14E, alongside one of the tributaries of the Ileret River. Hominin hand and arm bones have been excavated from here in the Okote Member and dated at 1.56-1.36 Ma. The fossils are associated with hominin and bovid footprints. Sixty of the over 100 wood specimens collected have been sectioned and studied. In general the woods have large vessels and an average vulnerability index of 40, which implies a mesic megathermal environment with no water stress. Taxonomically the woods belong to large African families: Caesalpiniaceae (Didelotia idae), Combretaceae (Anogeissus sp.), Putranjivaceae (Euphorbiaceae; Drypetes sp.), Lamiaceae (cf Premna sp.), Malvaceae (Heritiera sp.) and Sapindaceae (Sapindoxylon sp.). Most of these taxa do not occur in the area today because now it is much drier and the local vegetation is predominantly Acacia-Commiphora-Salvadora shrubland. The reconstruction of the paleovegetation supports the interpretation from the fauna, namely, a tall riverine forest with shady refuge trees, possibly some edible fruits, and wooded grassland and more open bushland in the vicinity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. First record of Smilodon fatalis Leidy, 1868 (Felidae, Machairodontinae) in the extra-Andean region of South America (late Pleistocene, Sopas Formation), Uruguay: Taxonomic and paleobiogeographic implications

    Science.gov (United States)

    Manzuetti, Aldo; Perea, Daniel; Ubilla, Martín; Rinderknecht, Andrés

    2018-01-01

    The Felidae are known in South America from the Ensenadan Stage/Age onwards. Among them, machairodonts of the genus Smilodon stand out. Three species are recognized, and all three are present on the continent: S. gracilis from the early-middle Pleistocene in north-east Venezuela; S. fatalis, found only in Lujanian sediments on the west side of the Andes (north-west of Peru and south-west of Ecuador); and S. populator, which inhabited the eastern part of the Andes during the Ensenadan and Lujanian. This distribution has led to the suggestion that the last two felids were allopatric during the Lujanian. Here, we report the first evidence of S. fatalis in the eastern part of the continent (Sopas Formation, late Pleistocene of Uruguay), based on an almost complete skull. This finding not only enlarges its distribution in South America but questions the idea of allopatric distribution. It also adds a new component to the mammalian predator trophic level of Uruguay, with the capacity to predate large South American herbivores and megaherbivores. A revision of materials previously assigned to S. populator in the extra-Andean zone of South America will be required.

  14. Prey preferences of the jaguar Panthera onca reflect the post-Pleistocene demise of large prey.

    Directory of Open Access Journals (Sweden)

    Matt W Hayward

    2016-01-01

    Full Text Available Documenting the impacts of the Pleistocene megafaunal extinctions on predator-prey interactions is a challenge because of the incomplete fossil record and depauperate extant community structure. We used a comparative ecological approach to investigate whether the existing prey preference patterns of jaguars Panthera onca were potentially affected by the Pleistocene extinctions in the Americas compared with large felids in Africa and Asia. We reviewed the literature and found 25 studies reporting 3214 jaguar kills recorded throughout the species’ distribution. We found that jaguars significantly preferred capybara Hydrochaeris hydrochaeris and giant anteater Myrmecophaga tridactyla, and avoided agoutis, carnivorans, primates, black-eared opossum Didelphis marsupialis and tapirs. Generalised linear models showed that jaguars select prey primarily based on socio-ecological and behavioural traits (abundance and herd size, rather than morphological characteristics (body size. Nonetheless, their accessible prey weight range was 6-60 kg, preferred prey weight range was 45-85 kg, and mean mass of significantly preferred prey was 32 ± 13 kg leading to a predator to prey body mass ratio of 1:0.53, which is much less than that of other solitary felids. Compared with other large, solitary felids, jaguars have an unusual predator to prey body mass ratio, show limited effect of prey morphology as a driver of prey selection, lack evidence of optimal foraging beyond their preferred prey, and an absence of preferentially hunting on Cetartiodactyla herbivores. These features, coupled with the reduction in jaguar body mass since the Pleistocene, suggest that the loss of larger potential prey items within the preferred and accessible weight ranges at the end-Pleistocene still affects jaguar predatory behaviour. It may be that jaguars survived this mass extinction event by preferentially preying on relatively small species.

  15. Upper pliocene-lower pleistocene 40Ar/39Ar ages of Pudahuel ignimbrite (Diamante-Maipo volcanic complex), Central Chile (33.50S)

    International Nuclear Information System (INIS)

    Wall, R.M.; Lara, L.E.; Perez de Arce, C

    2001-01-01

    brittle deformation, the age of N-S compressive event recognized by Lavenu and Cembrano (1999) toward the south in the Central Depression is constrained. Thus, the Pudahuel Ignimbrite (Diamante-Maipo Volcanic Complex) is part of a Plio-Quaternary silicic magmatic belt formed by the NNW alignment of volcanic centres and complexes like the Calabozos Caldera (35.5 o S ), with pleistocene pyroclastic flow deposits (Hildreth et al., 1984; Grunder and Mahood, 1988); the Puelche Volcanic Field (35.7 o S ), with rhyolitic lavas of Early Pleistocene age (Hildreth et al., 1999); the Laguna del Maule Volcanic Field (36 o S ) with plio-pleistocene lavas and ignimbrites (Hildreth et al., 1999) and Domuyo volcano (36.7 o S ) in Argentina. This belt is superimposed on rocks which are deformed by the Tertiary Malargue fold and thrust belt. To the south of 38 o S , and with the same orientation, another coeval magmatic belt is formed by alkaline basaltic centres (Munoz y Stern, 1989) (au)

  16. The Evolution of Reproduction within Testudinata as Evidenced by the Fossil Record

    Science.gov (United States)

    Lawver, Daniel Ryan

    Although known from every continent except Antarctica and having a fossil record ranging from the Middle Jurassic to the Pleistocene, fossil turtle eggs are relatively understudied. In this dissertation I describe four fossil specimens, interpret paleoecology and conduct cladistic analyses in order to investigate the evolution of turtle reproduction. Fossil eggshell descriptions primarily involve analysis by scanning electron and polarized light microscopy, as well as cathodoluminescence to determine the degree of diagenetic alteration. Carapace lengths and gas conductance are estimated in order to investigate the ecology of the adults that produced fossil turtle eggs and clutches, as well as their incubation environments, respectively. Cladistic analyses of turtle egg and reproductive characters permit assessment of the usefulness of these characters for determining phylogenetic relationships of fossil specimens and the evolution of reproduction in turtles. Specimens described here include 1) Testudoolithus oosp. from the Late Cretaceous of Madagascar, 2) a clutch of eggs (some containing late stage embryos and at least one exhibiting multilayer eggshell) from the Late Cretaceous Judith River Formation of Montana and named Testudoolithus zelenitskyae oosp. nov., 3) an egg contained within an adult Basilemys nobilis from the Late Cretaceous Kaiparowits Formation of Utah, and 4) a clutch of Meiolania platyceps eggs from the Pleistocene of Lord Howe Island, Australia. Meiolania platyceps eggs are named Testudoolithus lordhowensis oosp. nov. and provide valuable information on the origin of aragonite eggshell composition and nesting behaviors. Cladistic analyses utilizing egg and reproductive characters are rarely performed on taxa outside of Dinosauria. My analyses demonstrate that morphological data produces poorly resolved trees in which only the clades Adocia and Trionychia are resolved and all other turtles form a large polytomy. However, when combined with

  17. Human influence on distribution and extinctions of the late Pleistocene Eurasian megafauna.

    Science.gov (United States)

    Pushkina, Diana; Raia, Pasquale

    2008-06-01

    Late Pleistocene extinctions are of interest to paleontological and anthropological research. In North America and Australia, human occupation occurred during a short period of time and overexploitation may have led to the extinction of mammalian megafauna. In northern Eurasia megafaunal extinctions are believed to have occurred over a relatively longer period of time, perhaps as a result of changing environmental conditions, but the picture is much less clear. To consider megafaunal extinction in Eurasia, we compare differences in the geographical distribution and commonness of extinct and extant species between paleontological and archaeological localities from the late middle Pleistocene to Holocene. Purely paleontological localities, as well as most extinct species, were distributed north of archaeological sites and of the extant species, suggesting that apart from possible differences in adaptations between humans and other species, humans could also have a detrimental effect on large mammal distribution. However, evidence for human overexploitation applies only to the extinct steppe bison Bison priscus. Other human-preferred species survive into the Holocene, including Rangifer tarandus, Equus ferus, Capreolus capreolus, Cervus elaphus, Equus hemionus, Saiga tatarica, and Sus scrofa. Mammuthus primigenius and Megaloceros giganteus were rare in archaeological sites. Carnivores appear little influenced by human presence, although they become rarer in Holocene archaeological sites. Overall, the data are consistent with the conclusion that humans acted as efficient hunters selecting for the most abundant species. Our study supports the idea that the late Pleistocene extinctions were environmentally driven by climatic changes that triggered habitat fragmentation, species range reduction, and population decrease, after which human interference either by direct hunting or via indirect activities probably became critical.

  18. Geochemistry of great Salt Lake, Utah II: Pleistocene-Holocene evolution

    Science.gov (United States)

    Spencer, R.J.; Eugster, H.P.; Jones, B.F.

    1985-01-01

    Sedimentologic and biostratigraphic evidence is used to develop a geochemical model for Great Salt Lake, Utah, extending back some 30,000 yrs. B.P. Hydrologie conditions as defined by the water budget equation are characterized by a lake initially at a low, saline stage, rising by about 17,000 yrs. B.P. to fresh water basin-full conditions (Bonneville level) and then, after about 15,000 yrs. B.P., dropping rapidly to a saline stage again, as exemplified by the present situation. Inflow composition has changed through time in response to the hydrologie history. During fresh-water periods high discharge inflow is dominated by calcium bicarbonate-type river waters; during saline stages, low discharge, NaCl-rich hydrothermal springs are significant solute sources. This evolution in lake composition to NaCl domination is illustrated by the massive mirabilite deposition, free of halite, following the rapid drawdown until about 8,000 years ago, while historic droughts have yielded principally halite. Hydrologic history can be combined with inferred inflow composition to derive concentration curves with time for each major solute in the lake. Calcium concentrations before the drawdown were controlled by calcite solubility, and afterwards by aragonite. Significant amounts of solutes are removed from the lake by diffusion into the sediments. Na+, Cl- and SO42- are also involved in salt precipitation. By including pore fluid data, a surprisingly good fit has been obtained between solute input over the time period considered and the amounts actually found in lake brines, pore fluids, salt beds and sediments. Excess amounts are present for calcium, carbonate and silica, indicating detrital input. ?? 1985.

  19. Magnetostratigraphy, paleomagnetic correlation, and deformation of pleistocene deposits in the south central Puget Lowland, Washington

    Science.gov (United States)

    Hagstrum, J.T.; Booth, D.B.; Troost, K.G.; Blakely, R.J.

    2002-01-01

    Paleomagnetic results from Pleistocene sedimentary deposits in the central Puget Lowland indicate that the region has experienced widespread deformation within the last 780 kyr. Three oriented samples were collected from unaltered fine-grained sediments mostly at sea level to determine the magnetostratigraphy at 83 sites. Of these, 47 have normal, 18 have reversed, and 18 have transitional (8 localities) polarities. Records of reversed- to normal-polarity transitions of the geomagnetic field were found in thick sections of silt near the eastern end of the Tacoma Narrows Bridge, and again at Wingehaven Park near the northern tip of Vashon Island. The transitional horizons, probably related to the Bruhnes-Matuyama reversal, apparently fall between previously dated Pleistocene sediments at the Puyallup Valley type section (all reversed-polarity) to the south and the Whidbey Island type section (all normal-polarity) to the north. The samples, in general, are of sufficient quality to record paleosecular variation (PSV) of the geomagnetic field, and a statistical technique is used to correlate horizons with significant agreement in their paleomagnetic directions. Our data are consistent with the broad structures of the Seattle uplift inferred at depth from seismic reflection, gravity, and aeromagnetic profiles, but the magnitude of vertical adjustments is greatly subdued in the Pleistocene deposits.

  20. Frequency of fault occurrence at shallow depths during Plio-Pleistocene and estimation of the incident of new faults

    International Nuclear Information System (INIS)

    Shiratsuchi, H.; Yoshida, S.

    2009-01-01

    It is required that buried high-level radioactive wastes should not be broken directly by faulting in the future. Although a disposal site will be selected in an area where no active faults are present, the possibility of new fault occurrence in the site has to be evaluated. The probability of new fault occurrence is estimated from the frequency of faults which exist in Pliocene and Pleistocene strata distributed beneath 3 large plains in Japan, where a large number of seismic profiles and borehole data are obtained. Estimation of the frequency of faults having occurred and/or reached at shallow depth during Plio-Pleistocene time. The frequency of fault occurrence was estimated by counting the number of faults that exist in Plio-Pleistocene strata that are widely distributed in large plains in Japan. Three plains, Kanto, Nobi and Osaka Plains are selected for this purpose because highly precise geological profiles, which were prepared from numerous geological drillings and geophysical investigations, are available in them. (authors)

  1. Climate and evolution: implications of some extinction patterns in African and European Machairodontine Cats of the Plio-Pleistocene

    Directory of Open Access Journals (Sweden)

    Antón, M.

    1998-12-01

    Full Text Available Estudios recientes sobre las correlaciones entre cambios climáticos globales y la evolución de la biota del Plio-Pleistoceno Africano han revelado aparentes discrepancias entre las fechas y la significación de eventos registrados en distintas fuentes. Las diferencias mas notables se refieren a un importante cambio en la proporción de isótopos de oxígeno marinas hace 2,5 millones de años, y a la posibilidad de una transición biótica relacionada causalmente con dicho cambio. Cambios en la vegetación detectados a través de los valores de isótopos estables en los paleosuelos sugieren que el principal cambio hacia una vegetación mas abierta ocurrió mas tarde, hace ∼1,7 millones de años. Nosotros estudiamos el problema refiriendonos en particular a los eventos de hace 1,7 millones de años, y a la extinción en Africa de los félidos con dientes de sable que se produce poco después, puesto que las extinciones de taxones euritópicos como estos probablemente señala cambios significativos en las condiciones ambientales. Nosotros comparamos el patrón de dichas extinciones con los de taxones semejantes 0 idénticos, en Eurasia y América, y sugerimos que en cada caso hay claros indicios de importantes cambios ambientales. Es probable que los cambios en la vegetación de Africa registrados hace ∼1,7 millones de años representen una respuesta en el medio terrestre alas cambios climáticos globales reflejados en el registro marino hace ∼1,9 millones de años.Recent discussions of correlations between global climatic change and evolution of the African Plio-Pleistocene biota have revealed apparent discrepancies between the timing and significance of events recorded in different data sets. The most notable differences have occurred in relation to a major shift in the ratio of marine oxygen isotopes by 2.5 myr and claims for a causally related transition in the biota. Vegetational changes recorded in palaeosol stable isotope

  2. Latest Pleistocene and Holocene Glacier Fluctuations in southernmost Patagonia

    Science.gov (United States)

    Menounos, B.; Maurer, M.; Clague, J. J.; osborn, G.; Ponce, F.; Davis, P. T.; Rabassa, J.; Coronato, A.; Marr, R.

    2011-12-01

    Summer insolation has been proposed to explain long-term glacier fluctuations during the Holocene. If correct, the record of glacier fluctuations at high latitudes in the Southern Hemisphere should differ from that in the Northern Hemisphere. Testing this insolation hypothesis has been hampered by dating uncertainties of many Holocene glacier chronologies from Patagonia. We report on our ongoing research aimed at developing a regional glacier chronology at the southern end of the Andes north and west of Ushuaia, Argentina. We have found evidence for an advance of cirque glaciers at the end of the Pleistocene; one or locally two closely spaced moraines extend up to 2 km beyond Little Ice Age moraines. Radiocarbon dating of terrestrial macrofossils recovered from basal sediments behind two of these moraines yielded ages of 10,320 ± 25 and 10,330 ± 30 14C yr BP. These moraines may record glacier advances coeval with the Antarctic Cold Reversal; surface exposure dating of these moraines is currently in progress to test this hypothesis. We find no evidence of Holocene moraines older than 6800 14C yr BP, based on the distribution of Hudson tephra of that age. At some sites, there is evidence for an early Neoglacial advance of glaciers slightly beyond (Peru. We have documented multiple wood mats with stumps in growth position separated by till units in a 100 m section of the northeast lateral moraine at Stoppani Glacier (54.78 S, 68.98 W), 50 km west of Ushuaia. Ten radiocarbon ages on these wood mats range in age from 3510 ± 15 to 135 ± 15 14C yr BP. The mats decrease in age up-section; many overlap with published age ranges for Neoglacial advances in western Canada. Taken together, these data: a) do not support the summer insolation hypothesis for Holocene glacier fluctuations in southernmost Patagonia; b) confirm paleobotanical evidence for a warm, dry early Holocene; and c) suggest that many Neoglacial advances in southernmost Patagonia and western North America

  3. Paleoclimatological revision of climate evolution in Spain since the middle pleistocene from travertine and speleothems studies; Aportaciones al conociiento de la evolucion paleoclimatica y paleoambiental en la pensinsula iberica durante los dos ultimos millones de anos a partir del estudio de travertinos y espeleotemas

    Energy Technology Data Exchange (ETDEWEB)

    Torres, T; Barettino, D; Canoira, L; Cobo, R; Garcia-Cortes, A; Grun, R; Hoyos, M; Julia, R; Llamas, R

    1996-10-01

    This paper deals on the main results of the Project: ``Paleoclimatological revision since the Middle Pleistocene from geochronological and isotope analysis of spanish travertine`` (CEC-F12W-CT91-0075 ``Paleoclimatological revision of climate evolution in the Western Mediterranean Region, evaluation of altered scenarios). Four travertine deposition areas and a karstic zone were selected according to their geographical signification. Travertine deposits areas were: Priego and Rio Blanco: fluvial travertine; Banyoles and Rio Blanco: lacustrine deposits; Tolox: Alluvial fan deposits. The Cueva del Reguerillo was the karstic area selected. In spite of travertine and speleothems are warm climate indicators, important paleoenvironmental and palaeoclimatological data were obtained, which are in short: Through geomorphology and dating (palaeomagnetism, U/Th, Electro spin resonance and amino acid racemization analysis) the fluvial history of Priego, Rio Blanco and el Reguerillo cave, where a neotectonic and palaeosismicity phenomena were also dated. The oldest ESR dating method age obtained was of 950ka; and the oldest Priego deposits AARD dated were 750 ka old. Through dating, sedimentology, stable isotope analysis and palinology some aspects of climatic evolution of the Iberian Peninsula were determined. A net correlation found between palinology and stable isotope ratios in the Banyoles lake drill hole, allowed to validate the results. Some cualitative data on fluvial and karstic systems water input were determined also.

  4. Geology and Volcanology of Kima'Kho Mountain, Northern British Columbia: A Pleistocene Glaciovolcanic Edifice

    Science.gov (United States)

    Turnbull, M.; Porritt, L. A.; Edwards, B. R.; Russell, K.

    2014-12-01

    Kima'Kho Mountain is a 1.8 Ma (40Ar/39Ar of 1.82 +/- 40 ka) Pleistocene an alkali-olivine basaltic tuya situated in northern British Columbia. The volcanic edifice rises 460 m from its base and comprises a central vent, dominated by lapilli-tuff and minor pillow lava and dykes; and a surrounding plateau underlain by a sequence of dipping beds of basaltic tuff-breccia and capped by a series of flat-lying, subaerial lava flows. We present a 1:10,000 geological map for Kima'Kho Mountain building on the preliminary work of Ryane et al. (2010). We use the volcanic stratigraphy to explore the implications of three unique features. (1) The central cone comprises massive to crudely-bedded lapilli tuffs containing abundant armoured lapilli - cores of highly-vesicular pyroclasts coated with blocky to cuspate vitric ash. These units suggest an explosive origin from within an ice-enclosed lake, and deposited by wet, dilute pyroclastic surge events. (2) The entire stratigraphic sequence hosts at least two "passage zones" (cf. Jones, 1969); the presence and geometry of these passage zones constrain ice thicknersses at the time of eruption and inform on the englacial lake dynamics. (3) Lastly, our field-based stratigraphic relationships are at odds with the classic tuya model (i.e. an effusive onset to the eruption, forming pillow basalts, followed by explosive activity). Our field mapping suggests an alternative model of tuya architecture, involving a highly-energetic, sustained explosive onset creating a tephra cone that become emergent followed by effusive eruption to create lavas and a subaqueous lava-fed delta. Jones, J. G. Intraglacial volcanoes of the Laugarvatn region, south-west Iceland-I. Geological Society of London Quarterly Journal 124, 197-211 (1969). Ryane, C., Edwards, B. R. & Russell, J. K. The volcanic stratigraphy of Kima'Kho Mountain: A Pleistocene tuya, northwestern British Columbia. Geological Survey of Canada, Current Research 2011-104, 12p, doi:10

  5. Constraining Middle Pleistocene Glaciations in Birmingham, England; Using Optical Stimulated Luminescence (OSL) Dating.

    Science.gov (United States)

    Gibson, S. M.; Gibbard, P. L.; Bateman, M. D.; Boreham, S.

    2014-12-01

    Birmingham is built on a complex sequence of Middle Pleistocene sediments, representing at least three lowland glaciations (MIS12, MIS6, and MIS2). British Geological Survey mapping accounts 75% of the land mass as Quaternary deposits; predominantly glacial-sandy tills, glacial-fluvial sands, clays and organic silts and peats. Understanding the age of fluvial-glacial outwash, related to specific glaciations, is critical in establishing a Geochronology of Birmingham. Shotton (1953) found a series of Middle Pleistocene glacial sediments, termed the Wolstonian, intermediate in age between MIS11 and MIS5e Interglacial's. Uncertainty surrounding the relation to East Anglian sequences developed by Rose (1987) implies Birmingham sequences should be referred to MIS12. Despite this, younger Middle Pleistocene glacial sequences occur in Birmingham, yet uncertainty has deepened over our understanding of the complex, inaccessible sediments, especially as deposits have similar extent with MIS2 sequences. Five Optical Stimulated Luminescence (OSL) dates from three sites around Birmingham have been sampled. East of Birmingham, ice advanced from the Irish Sea and later the North East. In Wolston, a sample of outwash sand, associated with the Thurssington Till, is dated. In Meriden, two samples of outwash sands, associated with a distal Oadby Till, are dated. West of Birmingham, ice advanced from the Welsh Ice Sheet. In Seisdon, two samples of an Esker and outwash sand, associated with a Ridgeacre Till, are dated. Correlation of OSL dates provide an important constraint on understanding the history of Birmingham. Using GSI3D modeling to correlate geochronology and sedimentology, the significance of OSL dating can be understood within the complex sequences (and regional stratigraphy), complimented by Cosmogenic and Palynology dates taken in South West and North East. OSL dating on Birmingham's outwash sands, deposited by extensive repeated Middle Pleistocene glaciations, asserts the

  6. Contemporary evolution strategies

    CERN Document Server

    Bäck, Thomas; Krause, Peter

    2013-01-01

    Evolution strategies have more than 50 years of history in the field of evolutionary computation. Since the early 1990s, many algorithmic variations of evolution strategies have been developed, characterized by the fact that they use the so-called derandomization concept for strategy parameter adaptation. Most importantly, the covariance matrix adaptation strategy (CMA-ES) and its successors are the key representatives of this group of contemporary evolution strategies. This book provides an overview of the key algorithm developments between 1990 and 2012, including brief descriptions of the a

  7. Early Stages of Microstructure and Texture Evolution during Beta Annealing of Ti-6Al-4V

    Science.gov (United States)

    Pilchak, A. L.; Sargent, G. A.; Semiatin, S. L.

    2018-03-01

    The early stages of microstructure evolution during annealing of Ti-6Al-4V in the beta phase field were established. For this purpose, a series of short-time heat treatments was performed using sheet samples that had a noticeable degree of alpha-phase microtexture in the as-received condition. Reconstruction of the beta-grain structure from electron-backscatter-diffraction measurements of the room-temperature alpha-phase texture revealed that microstructure evolution at short times was controlled not by general grain growth, but rather by nucleation-and-growth events analogous to discontinuous recrystallization. The nuclei comprised a small subset of beta grains that were highly misoriented relative to those comprising the principal texture component of the beta matrix. From a quantitative standpoint, the transformation kinetics were characterized by an Avrami exponent of approximately unity, thus suggestive of metadynamic recrystallization. The recrystallization process led to the weakening and eventual elimination of the initial beta texture through the growth of a population of highly misoriented grains.

  8. Pegylated interferon and ribavirin promote early evolution of nonstructural 5A protein in individuals with hepatitis C who demonstrate a response to treatment.

    Science.gov (United States)

    Jain, Mamta K; Yuan, He-Jun; Adams-Huet, Beverley; Reeck, Amanda; Shelton, Janel; Attar, Nahid; Zhang, Song; Neumann, Avidan U; Carney, David S; Gale, Michael; Lee, William M

    2009-09-15

    Hepatitis C virus (HCV) quasispecies diversity is more likely to affect early viral decline during treatment of hepatitis C than is having human immunodeficiency virus (HIV) infection. We evaluated the influence of HCV therapy on changes in the nonstructural 5A (NS5A) protein. Fifteen patients with HCV genotype 1 infection with or without HIV infection were recruited for the present study, and the decrease in the HCV RNA level was measured at early time points. The evolution of HCV NS5A quasispecies within the first week was analyzed by comparing the clones observed at later times in the study with the baseline consensus sequence of individual patients. The response to therapy was defined as an early response (ER; ie, an HCV RNA level <615 IU/mL at week 4) or a slow response (SR; ie, a detectable HCV RNA level at week 4). HIV infection did not affect early viral kinetics. At baseline, lower diversity was seen in NS5A and in the amino and carboxyl termini of patients with an ER, compared with those with an SR. Rapid evolution of the NS5A genetic region occurred in patients with an ER (P = .01) but not in those with an SR (P = .73). The evolution was the result of an increase in the number of amino acid substitutions in the carboxyl region (P = .02) in patients with an ER. Selective pressure appears to result in more-marked changes in individuals with an ER than in those with an SR. The carboxyl terminus was subject to the most change and may be an important determinant of phenotypic resistance to interferon-based therapy.

  9. Late Pleistocene and Holocene activity of the Atacazo-Ninahuilca Volcanic Complex (Ecuador)

    NARCIS (Netherlands)

    Hidalgo, Silvana; Monzier, Michel; Almeida, Eduardo; Chazot, Gilles; Eissen, Jean-Philippe; van der Plicht, Johannes; Hall, Minard L.

    2008-01-01

    The Atacazo-Ninahuilca Volcanic Complex (ANVC) is located in the Western Cordillera of Ecuador, 10 km southwest of Quito. At least six periods of Pleistocene to Holocene activity (N1 to N6) have been preserved in the geologic record as tephra fallouts and pyroclastic flow deposits. New field data,

  10. Earthquake-induced soft-sediment deformation structures in Late Pleistocene lacustrine deposits of Issyk-Kul lake (Kyrgyzstan)

    Science.gov (United States)

    Gladkov, A. S.; Lobova, E. U.; Deev, E. V.; Korzhenkov, A. M.; Mazeika, J. V.; Abdieva, S. V.; Rogozhin, E. A.; Rodkin, M. V.; Fortuna, A. B.; Charimov, T. A.; Yudakhin, A. S.

    2016-10-01

    This paper discusses the composition and distribution of soft-sediment deformation structures induced by liquefaction in Late Pleistocene lacustrine terrace deposits on the southern shore of Issyk-Kul Lake in the northern Tien Shan mountains of Kyrgyzstan. The section contains seven deformed beds grouped in two intervals. Five deformed beds in the upper interval contain load structures (load casts and flame structures), convolute lamination, ball-and-pillow structures, folds and slumps. Deformation patterns indicate that a seismic trigger generated a multiple slump on a gentle slope. The dating of overlying subaerial deposits suggests correlation between the deformation features and strong earthquakes in the Late Pleistocene.

  11. Paleolimnological reconstruction of environmental variability during the Late Pleistocene and Holocene in the south-east Baltic region

    Science.gov (United States)

    Kublitskiy, Iurii; Subetto, Dmitriy; Druzhinina, Olga; Kulkova, Marianna; Arslanov, Khikmatula

    2016-04-01

    Kamyshovoe Lake : history of vegetation during late Pleistocene and early Holocene (Kaliningrad District, Russia). Baltica, 28 (2). (in press). Kublitskiy, I., Subetto, D., Kulkova, M., Druzhinina, O., Arslanov, Kh., 2015. Analysis of the climatic changes at the Late Pleistocene and the Holocene based on palaeolimnological studies of the Kamyshovoe Lake (Kaliningrad Region). Proceeding of the IX Russian conference on Quaternary Research (Irkutsk, 15-20 September 2015) [In Russian].

  12. Microfaunal evidence of age and depositional environments of the Cerro Prieto section (Plio-Pleistocene), Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ingle, J.C. Jr.

    1982-01-01

    Microfossils including benthic and planktic foraminifera, ostracodes, calcareous algae, fish skeletal material, and fragments of pelecypods were found in 14 core samples from depths of 185 to 1952 m in the Cerro Prieto geothermal field, providing evidence of both the age and depositional history of sediments comprising the 3000-m-thick Pliocene and Pleistocene section in this area. Ostracodes of brackish water and marine origin constitute the most common microfossils present in this sequence occurring in 8 samples; in situ littoral and neritic species of benthic foraminifera occur in 5 samples with planktic species present in 2 samples. Distributional patterns of ostracodes and foraminifera together with previously analyzed lithofacies (Lyons and van de Kamp, 1980) indicate that the Cerro Prieto section represents an intertonguing complex of alluvial, deltaic, estuarine, and shallow marine environments deposited along the front of the Colorado River delta as it prograded across the Salton Trough during Pliocene and Pleistocene time. Foraminiferal evidence indicates that a sand and shale unit commonly present at depths between 700 and 1100 m represents a significant mid-Pleistocene marine incursion in the Cerro Prieto area. Tentative correlation of the Cerro Prieto section with the well dated Palm Springs Formation of the Imperial Valley, California area suggests that the Pliocene/Pleistocene boundary occurs at a depth of approximately 2000 m in the area of well M-93. Reworked specimens of Cretaceous foraminifera and fragments of the Cretaceous pelecypod Inoceramus were found in five samples further substantiating the Colorado Plateau provenance of a significant portion of the Colorado River deltaic sediments in the Cerro Prieto area.

  13. Early evolution and dynamics of Earth from a molten initial stage

    Science.gov (United States)

    Louro Lourenço, Diogo; Tackley, Paul J.

    2016-04-01

    It is now well established that most of the terrestrial planets underwent a magma ocean stage during their accretion. On Earth, it is probable that at the end of accretion, giant impacts like the hypothesised Moon-forming impact, together with other sources of heat, melted a substantial part of the mantle. The thermal and chemical evolution of the resulting magma ocean most certainly had dramatic consequences on the history of the planet. Considerable research has been done on magma oceans using simple 1-D models (e.g.: Abe, PEPI 1997; Solomatov, Treat. Geophys. 2007; Elkins-Tanton EPSL 2008). However, some aspects of the dynamics may not be adequately addressed in 1-D and require the use of 2-D or 3-D models. Moreover, new developments in mineral physics that indicate that melt can be denser than solid at high pressures (e.g.: de Koker et al., EPSL 2013) can have very important impacts on the classical views of the solidification of magma oceans (Labrosse et al., Nature 2007). The goal of our study is to understand and characterize the influence of melting on the long-term thermo-chemical evolution of rocky planet interiors, starting from an initial molten state (magma ocean). Our approach is to model viscous creep of the solid mantle, while parameterizing processes that involve melt as previously done in 1-D models, including melt-solid separation at all melt fractions, the use of an effective diffusivity to parameterize turbulent mixing, coupling to a parameterized core heat balance and a radiative surface boundary condition. These enhancements have been made to the numerical code StagYY (Tackley, PEPI 2008). We present results for the evolution of an Earth-like planet from a molten initial state to present day, while testing the effect of uncertainties in parameters such as melt-solid density differences, surface heat loss and efficiency of turbulent mixing. Our results show rapid cooling and crystallization until the rheological transition then much slower

  14. Architecture and sedimentary processes on the mid-Norwegian continental slope: A 2.7 Myr record from extensive seismic evidence

    Science.gov (United States)

    Montelli, A.; Dowdeswell, J. A.; Ottesen, D.; Johansen, S. E.

    2018-07-01

    Quaternary architectural evolution and sedimentary processes on the mid-Norwegian continental slope are investigated using margin-wide three- and two-dimensional seismic datasets. Of ∼100,000 km3 sediments delivered to the mid-Norwegian shelf and slope over the Quaternary, ∼75,000 km3 comprise the slope succession. The structural high of the Vøring Plateau, characterised by initially low (∼1-2°) slope gradients and reduced accommodation space, exerted a strong control over the long-term architectural evolution of the margin. Slope sediment fluxes were higher on the Vøring Plateau area, increasing up to ∼32 km3 ka-1 during the middle Pleistocene, when fast-flowing ice streams advanced to the palaeo-shelf edge. Resulted in a more rapid slope progradation on the Vøring Plateau, these rates of sediment delivery are high compared to the maximum of ∼7 km3 ka-1 in the adjacent sectors of the slope, characterised by steeper slope (∼3-5°), more available accommodation space and smaller or no palaeo-ice streams on the adjacent shelves. In addition to the broad-scale architectural evolution, identification of more than 300 buried slope landforms provides an unprecedented level of detailed, process-based palaeoenvironmental reconstruction. Channels dominate the Early Pleistocene record (∼2.7-0.8 Ma), during which glacimarine sedimentation on the slope was influenced by dense bottom-water flow and turbidity currents. Morphologic signature of glacigenic debris-flows appear within the Middle-Late Pleistocene (∼0.8-0 Ma) succession. Their abundance increases towards Late Pleistocene, marking a decreasing role for channelized turbidity currents and dense water flows. This broad-scale palaeo-environmental shift coincides with the intensification of Northern Hemispheric glaciations, highlighting first-order climate control on the sedimentary processes in high-latitude continental slopes.

  15. Reconstruction of a semi-arid late Pleistocene paleocatena from the Lake Victoria region, Kenya

    Science.gov (United States)

    Beverly, Emily J.; Driese, Steven G.; Peppe, Daniel J.; Arellano, L. Nicole; Blegen, Nick; Faith, J. Tyler; Tryon, Christian A.

    2015-11-01

    The effect of changing environment on the evolution of Homo sapiens is heavily debated, but few data are available from equatorial Africa prior to the last glacial maximum. The Karungu deposits on the northeast coast of Lake Victoria are ideal for paleoenvironmental reconstructions and are best studied at the Kisaaka site near Karunga in Kenya (94 to > 33 ka) where paleosols, fluvial deposits, tufa, and volcaniclastic deposits (tuffs) are exposed over a 2 km transect. Three well-exposed and laterally continuous paleosols with intercalated tuffs allow for reconstruction of a succession of paleocatenas. The oldest paleosol is a smectitic paleo-Vertisol with saline and sodic properties. Higher in the section, the paleosols are tuffaceous paleo-Inceptisols with Alfisol-like soil characteristics (illuviated clay). Mean annual precipitation (MAP) proxies indicate little change through time, with an average of 764 ± 108 mm yr- 1 for Vertisols (CALMAG) and 813 ± 182 to 963 ± 182 mm yr- 1 for all paleosols (CIA-K). Field observations and MAP proxies suggest that Karungu was significantly drier than today, consistent with the associated faunal assemblage, and likely resulted in a significantly smaller Lake Victoria during the late Pleistocene. Rainfall reduction and associated grassland expansion may have facilitated human and faunal dispersals across equatorial East Africa.

  16. A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya

    Science.gov (United States)

    Lupien, R. L.; Russell, J. M.; Feibel, C.; Beck, C.; Castañeda, I.; Deino, A.; Cohen, A. S.

    2018-04-01

    Climate is thought to play a critical role in human evolution; however, this hypothesis is difficult to test due to a lack of long, high-quality paleoclimate records from key hominin fossil locales. To address this issue, we analyzed organic geochemical indicators of climate in a drill core from West Turkana, Kenya that spans ∼1.9-1.4 Ma, an interval that includes several important hominin evolutionary transitions. We analyzed the hydrogen isotopic composition of terrestrial plant waxes (δDwax) to reconstruct orbital-timescale changes in regional hydrology and their relationship with global climate forcings and the hominin fossil record. Our data indicate little change in the long-term mean hydroclimate during this interval, in contrast to inferred changes in the level of Lake Turkana, suggesting that lake level may be responding dominantly to deltaic progradation or tectonically-driven changes in basin configuration as opposed to hydroclimate. Time-series spectral analyses of the isotopic data reveal strong precession-band (21 kyr) periodicity, indicating that regional hydroclimate was strongly affected by changes in insolation. We observe an interval of particularly high-amplitude hydrologic variation at ∼1.7 Ma, which occurs during a time of high orbital eccentricity hence large changes in processionally-driven insolation amplitude. This interval overlaps with multiple hominin species turnovers, the appearance of new stone tool technology, and hominin dispersal out of Africa, supporting the notion that climate variability played an important role in hominin evolution.

  17. Potentials and pitfalls of depth profile (10Be), burial isochron (26Al/10Be) and palaeomagnetic techniques for dating Early Pleistocene terrace deposits of the Moselle valley (Germany)

    Science.gov (United States)

    Rixhon, Gilles; Cordier, Stéphane; May, Simon Matthias; Kelterbaum, Daniel; Szemkus, Nina; Keulertz, Rebecca; Dunai, Tibor; Binnie, Steven; Hambach, Ulrich; Scheidt, Stephanie; Brueckner, Helmut

    2016-04-01

    Throughout the river network of the Rhenish Massif the so-called main terraces complex (MTC) forms the morphological transition between a wide upper palaeovalley and a deeply incised lower valley. The youngest level of this complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature; it is often used as a reference level to identify the beginning of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). Although the main terraces are particularly well preserved in the lower Moselle valley, a questionable age of ca. 800 ka is assumed for the YMT, mainly based on the uncertain extrapolation of controversially interpreted palaeomagnetic data obtained in the Rhine valley. In this study, we applied terrestrial cosmogenic nuclide (TCN) dating (10Be/26Al) and palaeomagnetic dating to Moselle fluvial sediments of the MTC. To unravel the spatio-temporal characteristics of the Pleistocene evolution of the valley, several sites along the lower Moselle were sampled following two distinct TCN dating strategies: depth profiles where the original terrace (palaeo-) surface is well preserved and did not experience a major post-depositional burial (e.g., loess cover); and the isochron technique, where the sediment thickness exceeds 4.5-5 m. One terrace deposit was sampled for both approaches (reference site). In addition, palaeomagnetic sampling was systematically performed in each terrace sampled for TCN measurements. The TCN dating techniques show contrasting results for our reference site. Three main issues are observed for the depth profile method: (i) an inability of the modeled profile to constrain the 10Be concentration of the uppermost sample; (ii) an overestimated density value as model output; and (iii) a probable concentration steady state of the terrace deposits. By contrast, the isochron method yields a burial age estimate of 1.26 +0.29/-0.25 Ma, although one sample showed a depleted 26Al/10Be ratio

  18. Pleistocene climate change and the origin of two desert plant species, Pugionium cornutum and Pugionium dolabratum (Brassicaceae), in northwest China.

    Science.gov (United States)

    Wang, Qian; Abbott, Richard J; Yu, Qiu-Shi; Lin, Kao; Liu, Jian-Quan

    2013-07-01

    Pleistocene climate change has had an important effect in shaping intraspecific genetic variation in many species; however, its role in driving speciation is less clear. We examined the possibility of a Pleistocene origin of the only two representatives of the genus Pugionium (Brassicaceae), Pugionium cornutum and Pugionium dolabratum, which occupy different desert habitats in northwest China. We surveyed sequence variation for internal transcribed spacer (ITS), three chloroplast (cp) DNA fragments, and eight low-copy nuclear genes among individuals sampled from 11 populations of each species across their geographic ranges. One ITS mutation distinguished the two species, whereas mutations in cpDNA and the eight low-copy nuclear gene sequences were not species-specific. Although interspecific divergence varied greatly among nuclear gene sequences, in each case divergence was estimated to have occurred within the Pleistocene when deserts expanded in northwest China. Our findings point to the importance of Pleistocene climate change, in this case an increase in aridity, as a cause of speciation in Pugionium as a result of divergence in different habitats that formed in association with the expansion of deserts in China. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  19. A lacustrine record from Lop Nur, Xinjiang, China: Implications for paleoclimate change during Late Pleistocene

    Science.gov (United States)

    Chao, L.; Zicheng, P.; Dong, Y.; Weiguo, L.; Zhaofeng, Z.; Jianfeng, H.; Chenlin, C.

    2009-01-01

    Climate variability during the Late Pleistocene is studied from the proxies in core CK-2 drilled from the Luobei Depression (91??03???E, 40??47???N), Lop Nur in the eastern Tarim Basin, Xinjiang, China. Geophysical and geochemical properties, including magnetic susceptibility, granularity, chroma, carbonate content, loss on ignition and trace elements, have been determined to reconstruct the environmental evolution of the area during 32-9 ka BP. The chronology is established by uranium-thorium disequilibrium dating techniques. Our data suggest four paleoclimate stages, indicating glacial variations between cold-humid and warm-arid environments. A period of extreme humidity occurred during 31,900-19,200 yr BP is attributed the last glacial maximum (LGM). The period was followed by a warm-arid episode during 19,200-13,500 yr BP. Then a cold-humid interval during 13,500-12,700 yr BP may correspond to another cooling phases at high latitudes of the Northern Hemisphere. The last stage from 12,700 to 9000 yr BP has a trend that the climate turned warm and arid. The Lop Nur region is characterized by particularly humid stadials and arid interstadials. The climate variability in Lop Nur was constrained by global climate change because it is correlated with Dansgaard-Oeschger and Heinrich events, which were observed at the northern high latitudes. The synchroneity of the palaeoclimatic events suggested that cold air activity at the northern high latitudes was the most important factor that influenced the climate evolution in the Lop Nur region. A probable mechanism that involves the migration of westerly winds is proposed to interpret this synchroneity. ?? 2008 Elsevier Ltd.

  20. The Palos Verdes Fault offshore southern California: late Pleistocene to present tectonic geomorphology, seascape evolution and slip rate estimate based on AUV and ROV surveys

    Science.gov (United States)

    Brothers, Daniel S.; Conrad, James E.; Maier, Katherine L.; Paull, Charles K.; McGann, Mary L.; Caress, David W.

    2015-01-01

    The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. To characterize the near-seafloor fault morphology, tectonic influences on continental slope sedimentary processes and late Pleistocene to present slip rate, a grid of high-resolution multibeam bathymetric data, and chirp subbottom profiles were acquired with an autonomous underwater vehicle (AUV) along the main trace of PVF in water depths between 250 and 600 m. Radiocarbon dates were obtained from vibracores collected using a remotely operated vehicle (ROV) and ship-based gravity cores. The PVF is expressed as a well-defined seafloor lineation marked by subtle along-strike bends. Right-stepping transtensional bends exert first-order control on sediment flow dynamics and the spatial distribution of Holocene depocenters; deformed strata within a small pull-apart basin record punctuated growth faulting associated with at least three Holocene surface ruptures. An upper (shallower) landslide scarp, a buried sedimentary mound, and a deeper scarp have been right-laterally offset across the PVF by 55 ± 5, 52 ± 4 , and 39 ± 8 m, respectively. The ages of the upper scarp and buried mound are approximately 31 ka; the age of the deeper scarp is bracketed to 17–24 ka. These three piercing points bracket the late Pleistocene to present slip rate to 1.3–2.8 mm/yr and provide a best estimate of 1.6–1.9 mm/yr. The deformation observed along the PVF is characteristic of strike-slip faulting and accounts for 20–30% of the total right-lateral slip budget accommodated offshore Southern California.