Radiolarians decreased silicification as an evolutionary response to reduced Cenozoic ocean silica availability.

Science.gov (United States)

Lazarus, David B; Kotrc, Benjamin; Wulf, Gerwin; Schmidt, Daniela N

2009-06-09

It has been hypothesized that increased water column stratification has been an abiotic "universal driver" affecting average cell size in Cenozoic marine plankton. Gradually decreasing Cenozoic radiolarian shell weight, by contrast, suggests that competition for dissolved silica, a shared nutrient, resulted in biologic coevolution between radiolaria and marine diatoms, which expanded dramatically in the Cenozoic. We present data on the 2 components of shell weight change--size and silicification--of Cenozoic radiolarians. In low latitudes, increasing Cenozoic export of silica to deep waters by diatoms and decreasing nutrient upwelling from increased water column stratification have created modern silica-poor surface waters. Here, radiolarian silicification decreases significantly (r = 0.91, P stratification and abundance of diatoms. In high southern latitudes, Southern Ocean circulation, present since the late Eocene, maintains significant surface water silica availability. Here, radiolarian silicification decreased insignificantly (r = 0.58, P = 0.1), from approximately 0.13 at 35 Ma to 0.11 today. Trends in shell size in both time series are statistically insignificant and are not correlated with each other. We conclude that there is no universal driver changing cell size in Cenozoic marine plankton. Furthermore, biologic and physical factors have, in concert, by reducing silica availability in surface waters, forced macroevolutionary changes in Cenozoic low-latitude radiolarians.

Cenozoic Tectonic Characteristics in the Adare Basin, West Ross Sea: Evidence From Seismic Profiles

Science.gov (United States)

Zhang, Q.; Gao, J.; Ding, W.

2017-12-01

Based on the geophysical data obtained from the Adare Basin and its adjacent areas, West Ross Sea, the authors employed the frequency wave-number filtering technique to recover the newly processed dataset with high signal noise ratio and complete seismic event which highly contributes to reveal more detailed deep-seated geological structures than previously thought. The structural features and magmatism of the study area in Cenozoic were classified and analyzed. Combined with glaciation, the associated sedimentary facies were summarized systematically. The authors' analysis revealed that, at 16 Ma, under the influence of the thermal effect caused by residual magmatism and asymmetric spreading of Adare Basin in the initial period, surrounding areas of two flanks of the Adare trough were characterized by uplift folds and tilted uplift zone, respectively. The small-scale uplift fold zone was characterized by nearly upright faults and folds and was located in the southern part of the eastern flank, whereas the tilted uplift zone dominated in the corresponding district of western flank that reached the continental margin. By utilizing the contact relationship between igneous rocks and surrounding rocks, igneous rocks can be divided into two periods: early-stage and late Cenozoic igneous rocks. The early-stage rocks are generally located dispersedly in the tilted uplift zone and the age is poorly known. It is suggested that they were related to the residual magmatism. On the other hand, the spatial distribution of Late Cenozoic igneous rocks, formed not earlier 5.5 Ma, was extensive and scattered, almost covering the whole study area, which indicates that they might be unrelated to the rifting in space and time, instead they were affected by decompression melting of the mantle because of the large-scale deglaciation since Pliocene.

Genesis of Cenozoic intraplate high Mg# andesites in Northeast China

Science.gov (United States)

Liu, J. Q.; Chen, L. H.; Zhong, Y.; Wang, X. J.

2017-12-01

High-Mg# andesites (HMAs) are usually generated in the converged plate boundary and have genetic relationships with slab subduction. However, it still remained controversial about the origin of those HMAs erupted in the intra-plate setting. Here we present major, trace element, and Sr-Nd-Pb-Hf isotopic compositions for the Cenozoic intra-plate HMAs from Northeast China to constrain their origin and formation process. Cenozoic Xunke volcanic rocks are located in the northern Lesser Khingan Range, covering an area of about 3, 000 km2. These volcanic rocks are mainly basaltic andesite and basaltic trachyandesite, with only several classified as trachyandesite and andesites. They have high SiO2 contents (54.3-57.4 wt%) and Mg# (49.6-57.8), falling into the scope of high Mg# andesites. The Xunke HMAs are enriched in large ion lithophile elements but depleted in high field strength elements, with positive Ba, K, Sr and negative Zr-Hf, and Ti anomalies. Their trace element absolute concentrations are between those of potassic basalts and Wuchagou HMAs. The Xunke HMAs have relatively enriched Sr-Nd-Hf isotopes (87Sr/86Sr = 0.705398-0.705764, ɛNd=-8.8-3.8, ɛHf=0.5-11.7), and low radiogenic Pb isotopes (206Pb/204Pb = 16.701-17.198), towards to the EM1 end-member, which indicates that they are ultimately derived from ancient, recycled crustal components. Primitive silica-rich melts were generated from higher degrees of partial melting of recycled crustal materials (relative to potassic basalts) and then interacted with the peridotite to produce the Xunke HMAs.

Fires in the Cenozoic: a late flowering of flammable ecosystems

Directory of Open Access Journals (Sweden)

William John Bond

2015-01-01

Full Text Available Modern flammable ecosystems include tropical and subtropical savannas, steppe grasslands, boreal forests and temperate sclerophyll shrublands. Despite the apparent fiery nature of much contemporary vegetation, terrestrial fossil evidence would suggest we live in a time of low fire activity relative to the deep past. The inertinite content of coal, fossil charcoal, is strikingly low from the Eocene to the Pleistocene and no charcoalified mesofossils have been reported for the Cenozoic. Marine cores have been analysed for charcoal in the North Pacific, the north and south Atlantic off Africa, and the south China sea. These tell a different story with the oldest records indicating low levels of fire activity from the Eocene but a surge of fire from the late Miocene (~7 Ma. Phylogenetic studies of woody plants adapted to frequent savanna fires show them beginning to appear from the Late Miocene with peak origins in the late Pliocene in both South American and African lineages. Phylogenetic studies indicate ancient origins (60 Ma+ for clades characteristic of flammable sclerophyll vegetation from Australia and the Cape region of South Africa. However, as for savannas, there was a surge of speciation from the Late Miocene associated with the retreat of closed fire-intolerant forests. The wide geographic spread of increased fire activity in the last few million years suggests a global cause. However none of the potential global factors (oxygen, rainfall seasonality, CO2 , novel flammable growth forms provides an adequate explanation as yet. The global patterns and processes of fire and flammable vegetation in the Cenozoic, especially since the Late Miocene, deserve much more attention to better understand fire in the earth system.

Fires in the Cenozoic: a late flowering of flammable ecosystems.

Science.gov (United States)

Bond, William J

2014-01-01

Modern flammable ecosystems include tropical and subtropical savannas, steppe grasslands, boreal forests, and temperate sclerophyll shrublands. Despite the apparent fiery nature of much contemporary vegetation, terrestrial fossil evidence would suggest we live in a time of low fire activity relative to the deep past. The inertinite content of coal, fossil charcoal, is strikingly low from the Eocene to the Pleistocene and no charcoalified mesofossils have been reported for the Cenozoic. Marine cores have been analyzed for charcoal in the North Pacific, the north and south Atlantic off Africa, and the south China sea. These tell a different story with the oldest records indicating low levels of fire activity from the Eocene but a surge of fire from the late Miocene (~7 Ma). Phylogenetic studies of woody plants adapted to frequent savanna fires show them beginning to appear from the Late Miocene with peak origins in the late Pliocene in both South American and African lineages. Phylogenetic studies indicate ancient origins (60 Ma+) for clades characteristic of flammable sclerophyll vegetation from Australia and the Cape region of South Africa. However, as for savannas, there was a surge of speciation from the Late Miocene associated with the retreat of closed fire-intolerant forests. The wide geographic spread of increased fire activity in the last few million years suggests a global cause. However, none of the potential global factors (oxygen, rainfall seasonality, CO2, novel flammable growth forms) provides an adequate explanation as yet. The global patterns and processes of fire and flammable vegetation in the Cenozoic, especially since the Late Miocene, deserve much more attention to better understand fire in the earth system.

Study on the relationships between the structural evolution and sandstone-type uranium mineralization in mesozoic era and cenozoic era in the northern of Chaidam basin

International Nuclear Information System (INIS)

Liu Lin; Song Zhe; Song Xiansheng; Feng Wei

2008-01-01

By detailed expounding the characteristics of the Mesozoic and Cenozoic structural evolution in northern of Chaidam basin, the author inquires into its relationships with the sandstone-type uranium mineralization, analyzes the prospect of forming uranium deposit, and thinks that the Mesozoic and Cenozoic strata are mainly controlled by the tectonic role of the later Yanshan movement and the later Cenozoic era. The north-west palaeo-structural slope belt is formed in the later Cretacous Epoch that is favorable for developing palaeo-interlayer oxidized zone. After the slightly extensional role of the oldest Tertiary and the early Plioeene, the middle and lower Jurassic were buried, and the block-imbricated slope belts are formed in the tectonic movement of the later Cenozoic, which are favorable for developing recent interlayer oxidized zone. According to drilling, it has the conditions for forming palaeo-recent interlayer oxidized zone sandstone-type uranium deposit at the northern of Chaidam basin. Finally, the author lays his finger on the prospecting of uranium. (authors)

A low-angle normal fault and basement structures within the Enping Sag, Pearl River Mouth Basin: Insights into late Mesozoic to early Cenozoic tectonic evolution of the South China Sea area

Science.gov (United States)

Ye, Qing; Mei, Lianfu; Shi, Hesheng; Shu, Yu; Camanni, Giovanni; Wu, Jing

2018-04-01

The basement structure of the Cenozoic Enping Sag, within the Pearl River Mouth Basin on the northern margin of South China Sea, is revealed by borehole-constrained high-quality 3D seismic reflection data. Such data suggest that the Enping Sag is bounded in the north by a low-angle normal fault. We interpret this low-angle normal fault to have developed as the result of the reactivation of a pre-existing thrust fault part of a pre-Cenozoic thrust system. This is demonstrated by the selective reactivation of the pre-existing thrust and by diffuse contractional deformation recognized from the accurate analysis of basement reflections. Another significant result of this study is the finding of some residual rift basins within the basement of the Enping Sag. Both the thrust system and the residual basins are interpreted to have developed after the emplacement of continental margin arc-related granitoids (J3-K1) that define the basement within the study area. Furthermore, seismic sections show that the pre-existing residual rift basins are offset by the main thrust fault and they are both truncated by the Tg unconformity. These structural relationships, interpreted in the frame of previous studies, help us to reconstruct a six-event structural evolution model for the Enping Sag from the late Mesozoic to the early Cenozoic. In particular, we interpret the residual rift basins to have formed as the result of back-arc extension due to the slab roll-back of the Paleo-Pacific Plate subduction in the early K2. The thrust system has recorded a compressional event in the late K2 that followed the back-arc extension in the SCS area. The mechanism of this compressional event is still to be clarified, and might be related to continuous subduction of the Paleo-Pacific Plate or to the continent-continent collision between a micro-continental block and the South China margin.

3-D thermal effect of late Cenozoic erosion and deposition within the Lofoten-Vesterålen segment of the Mid-Norwegian continental margin

Science.gov (United States)

Maystrenko, Yuriy Petrovich; Gernigon, Laurent; Olesen, Odleiv; Ottesen, Dag; Rise, Leif

2018-05-01

A 3-D subsurface temperature distribution within the Lofoten-Vesterålen segment of the Mid-Norwegian continental margin and adjacent areas has been studied to understand the thermal effect of late Cenozoic erosion of old sedimentary and crystalline rocks and subsequent deposition of glacial sediments during the Pleistocene. A lithosphere-scale 3-D structural model of the Lofoten-Vesterålen area has been used as a realistic approximation of the geometries of the sedimentary infill, underlying crystalline crust and lithospheric mantle during the 3-D thermal modelling. The influence of late Cenozoic erosion and sedimentation has been included during the 3-D thermal calculations. In addition, the 3-D thermal modelling has been carried out by taking also into account the influence of early Cenozoic continental breakup. The results of the 3-D thermal modelling demonstrate that the mainland is generally colder than the basin areas within the upper part of the 3-D model. The thermal influence of the early Cenozoic breakup is still clearly recognizable within the western and deep parts of the Lofoten-Vesterålen margin segment in terms of the increased temperatures. The thermal effects of the erosion and deposition within the study area also indicate that a positive thermal anomaly exists within the specific subareas where sedimentary and crystalline rocks were eroded. A negative thermal effect occurs in the subareas affected by subsidence and sedimentation. The erosion-related positive thermal anomaly reaches its maximum of more than +27 °C at depths of 17-22 km beneath the eastern part of the Vestfjorden Basin. The most pronounced deposition-related negative anomaly shows a minimum of around -70 °C at 17-20 km depth beneath the Lofoten Basin. The second negative anomaly is located within the northeastern part of the Vøring Basin and has minimal values of around -48 °C at 12-14 km depth. These prominent thermal anomalies are associated with the subareas where

Structural evolution of Cenozoic basins in northeastern Tunisia, in response to sinistral strike-slip movement on the El Alia-Teboursouk Fault

Science.gov (United States)

Bejaoui, Hamida; Aïfa, Tahar; Melki, Fetheddine; Zargouni, Fouad

2017-10-01

This paper resolves the structural complexity of Cenozoic sedimentary basins in northeastern Tunisia. These basins trend NE-SW to ∼ E-W, and are bordered by old fracture networks. Detailed descriptions of the structural features in outcrop and in subsurface data suggest that the El Alia-Teboursouk Fault zone in the Bizerte area evolved through a series of tectonic events. Cross sections, lithostratigraphic correlations, and interpretation of seismic profiles through the basins show evidence for: (i) a Triassic until Jurassic-Early Cretaceous rifting phase that induced lateral variations of facies and strata thicknesses; (ii) a set of faults oriented NE-SW, NW-SE, N-S, and E-W that guided sediment accumulation in pull-apart basins, which were subject to compressive and transpressive deformation during Eocene (Lutetian-Priabonian), Miocene (Tortonian), and Pliocene-Quaternary; and (iii) NNW-SSE to NS contractional events that occurred during the Late Pliocene. Part of the latest phase has been the formation of different synsedimentary folded structures with significant subsidence inversion. Such events have been responsible for the reactivation of inherited faults, and the intrusion of Triassic evaporites, ensuring the role of a slip layer. The combined effects of the different paleoconstraints and halokinetic movements are at the origin of the evolution of these pull-apart basins. The subsurface data suggest that an important fault displacement occurred during the Mesozoic-Cenozoic. The patterns of sediment accumulation in the different basins reflect a high activity of deep ancient faults.

Cenozoic structures and the tectonic evolution of the eastern North Sea

DEFF Research Database (Denmark)

Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

2011-01-01

Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...... influencede.g. Miocene deposition and controlled the generation of second order faults. The latter detached along the top Chalk Group due to the topography generated during faulting, i.e. they are second order detachment surfaces. We conclude that the regional tectonic significance of the Cenozoic structures...

New aero-gravity results from the Arctic: Linking the latest Cretaceous-early Cenozoic plate kinematics of the North Atlantic and Arctic Ocean

DEFF Research Database (Denmark)

Døssing, Arne; Hopper, J.R.; Olesen, Arne Vestergaard

2013-01-01

The tectonic history of the Arctic Ocean remains poorly resolved and highly controversial. Details regarding break up of the Lomonosov Ridge from the Barents-Kara shelf margins and the establishment of seafloor spreading in the Cenozoic Eurasia Basin are unresolved. Significantly, the plate...... tectonic evolution of the Mesozoic Amerasia Basin is essentially unknown. The Arctic Ocean north of Greenland is at a critical juncture that formed at the locus of a Mesozoic three-plate setting between the Lomonosov Ridge, Greenland, and North America. In addition, the area is close to the European plate...... plateau against an important fault zone north of Greenland. Our results provide new constraints for Cretaceous-Cenozoic plate reconstructions of the Arctic. Key Points Presentation of the largest aero-gravity survey acquired over the Arctic Ocean Plate tectonic link between Atlantic and Arctic spreading...

Evolution of Meso-Cenozoic lithospheric thermal-rheological structure in the Jiyang sub-basin, Bohai Bay Basin, eastern North China Craton

Science.gov (United States)

Xu, Wei; Qiu, Nansheng; Wang, Ye; Chang, Jian

2018-01-01

The Meso-Cenozoic lithospheric thermal-rheological structure and lithospheric strength evolution of the Jiyang sub-basin were modeled using thermal history, crustal structure, and rheological parameter data. Results indicate that the thermal-rheological structure of the Jiyang sub-basin has exhibited obvious rheological stratification and changes over time. During the Early Mesozoic, the uppermost portion of the upper crust, middle crust, and the top part of the upper mantle had a thick brittle layer. During the early Early Cretaceous, the top of the middle crust's brittle layer thinned because of lithosphere thinning and temperature increase, and the uppermost portion of the upper mantle was almost occupied by a ductile layer. During the late Early Cretaceous, the brittle layer of the middle crust and the upper mantle changed to a ductile one. Then, the uppermost portion of the middle crust changed to a thin brittle layer in the late Cretaceous. During the early Paleogene, the thin brittle layer of the middle crust became even thinner and shallower under the condition of crustal extension. Currently, with the decrease in lithospheric temperature, the top of the upper crust, middle crust, and the uppermost portion of the upper mantle are of a brittle layer. The total lithospheric strength and the effective elastic thickness ( T e) in Meso-Cenozoic indicate that the Jiyang sub-basin experienced two weakened stages: during the late Early Cretaceous and the early Paleogene. The total lithospheric strength (approximately 4-5 × 1013 N m-1) and T e (approximately 50-60 km) during the Early Mesozoic was larger than that after the Late Jurassic (2-7 × 1012 N m-1 and 19-39 km, respectively). The results also reflect the subduction, and rollback of Pacific plate is the geodynamic mechanism of the destruction of the eastern North China Craton.

Cenozoic volcanic rocks of Saudi Arabia

Science.gov (United States)

Coleman, R.G.; Gregory, R.T.; Brown, G.F.

2016-01-01

The Cenozoic volcanic rocks of Saudi Arabia cover about 90,000 km2, one of the largest areas of alkali olivine basalt in the world. These volcanic rocks are in 13 separate fields near the eastern coast of the Red Sea and in the western Arabian Peninsula highlands from Syria southward to the Yemen Arab Republic.

Feedbacks of lithosphere dynamics and environmental change of the Cenozoic West Antarctic Rift System.

NARCIS (Netherlands)

van der Wateren, F.M.; Cloetingh, S.A.P.L.

1999-01-01

This special issue of Global and Planetary Change contains 11 contributions dealing with various aspects of the Cenozoic West Antarctic Rift System. During the last two decades, investigations of the interplay of tectonics and climate greatly improved understanding of Cenozoic global change. Major

Cenozoic to Cretaceous paleomagnetic dataset from Egypt: New data, review and global analysis

Science.gov (United States)

Perrin, Mireille; Saleh, Ahmed

2018-04-01

Different phases of igneous activity took place in Egypt during the Mesozoic and the Cenozoic and oriented samples were collected from three Cenozoic localities (Baharya oasis in the Western Desert, Abu Had in the Eastern Desert and Quseir along the Red Sea coast), and four Cretaceous localities (Toshki & Abu Simbel south of Aswan, and Shalaten & Abu Shihat along the Red Sea coast). Rock magnetic properties of the samples indicate magnetite and titanomagnetite as the main carrier of the remanent magnetization. Following stepwise demagnetization, characteristic remanent directions were identified only for 62% of the samples, a fairly low rate for that type of samples, and 8 new paleomagnetic poles were calculated. All our Cenozoic poles fall clearly off Master Polar Wander Paths proposed for South Africa. Therefore, all paleomagnetic results, previously published for Egypt, were compiled from Cretaceous to Quaternary. The published poles largely overlap, blurring the Egyptian Apparent Polar Wander Path. A new analysis at the site level was then carried out. Only poles having a kappa larger than 50 were selected, and new pole positions were calculated by area and by epoch, when at least 3 sites were available. Even though the selection drastically reduced the number of considered poles, it allows definition of a reliable Cenozoic apparent polar wander trend for Egypt that differs from the South African Master Polar Wander Path by about 10-15 °. If the Cretaceous igneous poles are in good agreement with the rest of the African data, the sedimentary poles plot close to the Cenozoic portion of the South African Master Polar Wander Path, a discrepancy that could be related either to inclination flattening and/or error on age and/or remagnetization in the Cenozoic.

A nearly modern amphibious bird from the Early Cretaceous of northwestern China.

Science.gov (United States)

You, Hai-Lu; Lamanna, Matthew C; Harris, Jerald D; Chiappe, Luis M; O'connor, Jingmai; Ji, Shu-An; Lü, Jun-Chang; Yuan, Chong-Xi; Li, Da-Qing; Zhang, Xing; Lacovara, Kenneth J; Dodson, Peter; Ji, Qiang

2006-06-16

Three-dimensional specimens of the volant fossil bird Gansus yumenensis from the Early Cretaceous Xiagou Formation of northwestern China demonstrate that this taxon possesses advanced anatomical features previously known only in Late Cretaceous and Cenozoic ornithuran birds. Phylogenetic analysis recovers Gansus within the Ornithurae, making it the oldest known member of the clade. The Xiagou Formation preserves the oldest known ornithuromorph-dominated avian assemblage. The anatomy of Gansus, like that of other non-neornithean (nonmodern) ornithuran birds, indicates specialization for an amphibious life-style, supporting the hypothesis that modern birds originated in aquatic or littoral niches.

Age and provenance of Triassic to Cenozoic sediments of West and Central Sarawak, Malaysia

Science.gov (United States)

Breitfeld, H. Tim; Galin, Thomson; Hall, Robert

2015-04-01

Sarawak is located on the northern edge of Sundaland in NW Borneo. West and Central Sarawak include parts of the Kuching and Sibu Zones. These contain remnants of several sedimentary basins with ages from Triassic to Cenozoic. New light mineral, heavy mineral and U-Pb detrital zircon ages show differences in provenance reflecting the tectonic evolution of the region. The oldest clastic sediments are Triassic (Sadong Formation and its deep marine equivalent Kuching Formation). They were sourced by a Triassic (Carnian to Norian) volcanic arc and reworked Paleoproterozoic detritus derived from Cathaysialand. The Upper Jurassic to Cretaceous Pedawan Formation is interpreted as forearc basin fill with distinctive zircon populations indicating subduction beneath present-day West Sarawak which initiated in the Late Jurassic. Subsequent subduction until the early Late Cretaceous formed the Schwaner Mountains magmatic arc. After collision of SW Borneo and other microcontinental fragments with Sundaland in the early Late Cretaceous, deep marine sedimentation (Pedawan Formation) ceased, and there was uplift forming the regional Pedawan-Kayan unconformity. Two episodes of extension followed and were responsible for basin development on land in West Sarawak from the latest Cretaceous onwards, probably in a pull-apart setting. The first episode is associated with sediments of the Kayan Group, deposited in the Latest Cretaceous (Maastrichtian) to Eocene, and the second episode with Upper Eocene sediments of the Ketungau Basin. Zircon ages indicate volcanic activity throughout the Early Cenozoic in NW Borneo, and inherited zircon ages indicate reworking of Triassic and Cretaceous rocks. A large deep marine basin, the Rajang Basin, was north of the Lupar Line Fault in Central Sarawak (Sibu Zone) from the Late Cretaceous to the Late Eocene. Zircons from sediments of the Rajang Basin indicate they have similar ages and provenance to contemporaneous terrestrial sediments of the Kayan

On the origin and distribution of magnolias: Tectonics, DNA and climate change

Science.gov (United States)

Hebda, R. J.; Irving, E.

Extant magnolias have a classic disjunct distribution in southeast Asia and in the Americas between Canada and Brazil, and nowhere in between. Of the 17 sections (about 210 species) in two subgenera, only two, Tulipastrum and Rhytidospermum, are truly disjunct. Molecular analyses reveal that several North American species are basal forms suggesting that magnolias originated in North America, as indicated by their fossil record. We recognize four elements in their evolution. (1) Ancestral magnolias originated in the Late Cretaceous of North America in high mid-latitudes (45°-60°N) at low altitudes in a greenhouse climate. (2) During the exceptionally warm climate of the Eocene, magnolias spread eastwards, via the Disko Island and Thulean isthmuses, first to Europe, and then across Asia, still at low altitudes and high mid-latitudes. (3) With mid-Cenozoic global cooling, they shifted to lower mid-latitudes (30°-45°N), becoming extinct in Europe and southern Siberia, dividing a once continuous distribution into two, centred in eastern Asia and in North America. (4) In the late Cenozoic, as ice-house conditions developed, magnolias migrated southward from both centres into moist warm temperate upland sites in the newly uplifted mountains ranges of South and Central America, southeast Asia, and the High Archipelago, where they diversified. Thus the late Cenozoic evolution of magnolias is characterized by impoverishment of northern and diversification of southern species, the latter being driven by a combination of high relief and climate oscillations, and neither of the present centers of diversity is the center of origin. Disjunction at the generic level and within section Tulipastrum likely occurred as part of the general mid-Cenozoic southward displacement assisted by the development of north-south water barriers, especially the Turgai Strait across western Siberia. Disjunction in section Rhytidospermum could be Neogene.

Different nucleosomal architectures at early and late replicating origins in Saccharomyces cerevisiae.

Science.gov (United States)

Soriano, Ignacio; Morafraile, Esther C; Vázquez, Enrique; Antequera, Francisco; Segurado, Mónica

2014-09-13

Eukaryotic genomes are replicated during S phase according to a temporal program. Several determinants control the timing of origin firing, including the chromatin environment and epigenetic modifications. However, how chromatin structure influences the timing of the activation of specific origins is still poorly understood. By performing high-resolution analysis of genome-wide nucleosome positioning we have identified different chromatin architectures at early and late replication origins. These different patterns are already established in G1 and are tightly correlated with the organization of adjacent transcription units. Moreover, specific early and late nucleosomal patterns are fixed robustly, even in rpd3 mutants in which histone acetylation and origin timing have been significantly altered. Nevertheless, higher histone acetylation levels correlate with the local modulation of chromatin structure, leading to increased origin accessibility. In addition, we conducted parallel analyses of replication and nucleosome dynamics that revealed that chromatin structure at origins is modulated during origin activation. Our results show that early and late replication origins present distinctive nucleosomal configurations, which are preferentially associated to different genomic regions. Our data also reveal that origin structure is dynamic and can be locally modulated by histone deacetylation, as well as by origin activation. These data offer novel insight into the contribution of chromatin structure to origin selection and firing in budding yeast.

Mesozoic and Cenozoic structural evolution of North Oman: New insights from high-quality 3D seismic from the Lekhwair area

Science.gov (United States)

Bazalgette, Loïc; Salem, Hisham

2018-06-01

This paper highlights the role of Triassic-Jurassic extension and late Cretaceous compression in the Mesozoic-Cenozoic (Alpine) structuring of North Oman. The syn/post-Mesozoic regional structural evolution is usually documented as a succession of two stages of deformation. The Alpine 1 phase, late Cretaceous in age, occurred in association with two ophiolite obduction stages (Semail and Masirah ophiolites). It was characterised by strike slip to extensional deformation in the North Oman foreland basin sub-surface. The Alpine 2 phase, Miocene in age, was related to the continental collision responsible for both the Zagros orogen and the uplift of the Oman Mountains. The Alpine 2 deformation was transpressional to compressional. Observation and interpretation of good quality 3D seismic in the Lekhwair High area enabled the distinction of two earlier phases. Early Mesozoic extension occurred concomitantly with the regional Triassic to Jurassic rifting, developing Jurassic-age normal faults. Late Cretaceous compression occurred prior to the main Alpine 1 phase and triggered the inversion of Jurassic-seated normal faults as well as the initiation of compressional folds in the Cretaceous overburden. These early phases have been ignored or overlooked as part of the North Oman history although they are at the origin of structures hosting major local and regional hydrocarbon accumulations.

The role of Mesozoic sedimentary basin tapers on the formation of Cenozoic crustal shortening structures and foredeep in the western Sichuan Basin, China

Science.gov (United States)

Wang, M.

2017-12-01

The foreland basin records important clues of tectonic and sedimentary process of mountain-building, thus to explore its dynamic mechanism on the formation is an important issue of the mountain-basin interaction. The Longmen Shan fold-and-thrust belt and its adjacent Sichuan basin located in the eastern margin of Tibetan Plateau, are one of the most-concerned regions of studying modern mountain-building and seismic process, and are also a natural laboratory of studying the dynamics of the formation and development of foreland basin. However, it still need further explore on the mechanics of the development of the Cenozoic foreland basin and thrust-belts in the western Sichuan Basin. The Longmen Shan thrust belt has experienced multi-stages of tectonics evolution, foreland basin formation and topography growth since Late Triassic, and whether the early formed basin architecture and large Mesozoic sedimentary basin taper can influence the formation and development of the Cenozoic foreland basin and thrust belts? To solve these issues, this project aim to focus on the Cenozoic foreland basin and internal crustal shortening structures in the western Sichuan basin, on the basis of growth critical wedge taper theory. We will reconstruct the shape of multi-phases of sedimentary basin tapers, the temporal-spatial distribution of crustal shortening and thrusting sequences, and analyze the control mechanism of Mesozoic sedimentary basin taper on the formation of Cenozoic foreland basins, and final explore the interaction between the tectonics geomorphology, stress field and dynamic propagation of foreland basin.

Origin of the Blue Ridge escarpment along the passive margin of Eastern North America

Science.gov (United States)

Spotila, J.A.; Bank, G.C.; Reiners, P.W.; Naeser, C.W.; Naeser, N.D.; Henika, B.S.

2004-01-01

The Blue Ridge escarpment is a rugged landform situated within the ancient Appalachian orogen. While similar in some respects to the great escarpments along other passive margins, which have evolved by erosion following rifting, its youthful topographic expression has inspired proposals of Cenozoic tectonic rejuvenation in eastern North America. To better understand the post-orogenic and post-rift geomorphic evolution of passive margins, we have examined the origin of this landform using low-temperature thermochronometry and manipulation of topographic indices. Apatite (U-Th)/He and fission-track analyses along transects across the escarpment reveal a younging trend towards the coast. This pattern is consistent with other great escarpments and fits with an interpretation of having evolved by prolonged erosion, without the requirement of tectonic rejuvenation. Measured ages are also comparable specifically to those measured along other great escarpments that are as much as 100 Myr younger. This suggests that erosional mechanisms that maintain rugged escarpments in the early post-rift stages may remain active on ancient passive margins for prolonged periods. The precise erosional evolution of the escarpment is less clear, however, and several end-member models can explain the data. Our preferred model, which fits with all data, involves a significant degree of erosional escarpment retreat in the Cenozoic. Although this suggests that early onset of topographic stability is not required of passive margin evolution, more data are required to better constrain the details of the escarpment's development. ?? 2003 Blackwell Publishing Ltd.

Cenozoic deformation from the Yakutat-North American collision to the eastern margin of the Northern Canadian Cordillera

Science.gov (United States)

Enkelmann, E.

2017-12-01

The western margin of the Northern Cordillera of North America is dominated by transform motion of the Yakutat microplate along the Fairweather fault system. In southeast Alaska the transform boundary changes to convergence and the oblique collision of the buoyant Yakutat microplate formed the St. Elias Mountains. One of the outstanding questions in understanding the St. Elias orogeny is how stress from the plate boundary has been transferred inboard and distributed strain in the North American plate. The timing, amount, and spatial pattern of deformation and rock exhumation have been studied using multiple thermochronology methods. Together the data reveal that Late Cenozoic deformation inboard of the Fairweather Fault and the colliding Yakutat plate corner at the St. Elias syntaxis was spatially very limited, resulting in rock exhumation within a cooling associated with Cordilleran deformation, and Paleocene-Eocene cooling due to spreading-ridge subduction. In contrast, the region west of the St. Elias syntaxis is dominated by convergence, which resulted in significant Cenozoic deformation in southeastern and southern Alaska. In the St. Elias orogen itself, most of the Late Cenozoic deformation and exhumation occurs within the Yakutat microplate and its Cenozoic sedimentary cover that composes the fold-thrust belt. The efficient interaction between tectonic uplift and glacial erosion resulted in rapid exhumation (>1 km/Myr) and extreme rates (4 km/Myr) that are localized at the syntaxis region and have shifted southward over the past 10 Myr. Far-field deformation reaches more than 500 km to the northwest of the convergent margin and caused mountain building in south-central Alaska. Deformation to the northeast is unclear. New thermochronology data from the eastern margin of the Northern Canadian Cordillera (Northwest Territory) reveal exhumation during the Oligocene to early Miocene. At this time, transform motion was already dominating the plate margin in the

The Origin of Dust in the Early Universe

Science.gov (United States)

Dwek, Eli

2011-01-01

In this talk I will describe the origin of dust in the early universe. I will be presenting observations of the spectral energy distribution of the galaxy J1148+5251, and present estimates of the dust mass in this high redshift (z=6.4) object. I will then discuss the origin of this dust, and the role of SN and AGB stars as dust sources, and the effect of SNRs on the destruction of dust in the interstellar medium of this galaxy.

Evolutionary origins and early development of number processing

CERN Document Server

Geary, David C; Mann Koepke, Kathleen

2014-01-01

The first volume in this ground-breaking series focuses on the origins and early development of numerical cognition in non-human primates, lower vertebrates, human infants, and preschool children. The text will help readers understand the nature and complexity of these foundational quantitative concepts and skills along with evolutionary precursors and early developmental trajectories. Brings together and focuses the efforts and research of multiple disciplines working in math cognition.The contributors bring vast knowledge and experience to bear on resolving extant

Cenozoic uplift of the Tibetan Plateau: Evidence from the tectonic–sedimentary evolution of the western Qaidam Basin

Directory of Open Access Journals (Sweden)

Yadong Wang

2012-03-01

Full Text Available Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau. However, controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift. Geology has recorded this uplift well in the Qaidam Basin. This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments, faults growth index, sedimentary facies variations, and the migration of the depositional depressions. The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal. Tectonic movements controlled deposition in various depressions, and the depressions gradually shifted southeastward. In addition, the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into (a the southern fault terrace zone, (b a central Yingxiongling orogenic belt, and (c the northern fold-thrust belt; divided by the XI fault (Youshi fault and Youbei fault, respectively. The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India–Asia plate collision. Further, the Basin experienced two phases of intensive tectonic deformation. The first phase occurred during the Middle Eocene–Early Miocene (Xia Ganchaigou Fm. and Shang Ganchaigou Fm., 43.8–22 Ma, and peaked in the Early Oligocene (Upper Xia Ganchaigou Fm., 31.5 Ma. The second phase occurred between the Middle Miocene and the Present (Shang Youshashan Fm. and Qigequan Fm., 14.9–0 Ma, and was stronger than the first phase. The tectonic–sedimentary evolution and the orientation of surface structures in the western Qaidam Basin resulted from the Tibetan

Paleomagnetic constraints on the Cenozoic kinematic evolution of the Pamir plateau from the Western Kunlun Shan foreland

Science.gov (United States)

Li, Zhenyu; Ding, Lin; Lippert, Peter C.; Wei, Honghong

2013-09-01

Thick Cenozoic marine and terrestrial sediments are widely distributed along the perimeter of the Pamir plateau and provide valuable information on the kinematic evolution of the region. Here, we report new biostratigraphic and paleomagnetic results from the piedmont of the Western Kunlun Shan to constrain the magnitude and timing of vertical-axis rotations along the eastern margin of the Pamir. Sampling sites were selected by rock formations and ages, which are based on previous field mapping and on litholostratigraphic and biostratigraphic work presented here. Thermomagnetic analysis, step-wise thermal demagnetization behavior, and positive field tests all suggest that the characteristic remanent magnetization (ChRM) directions most probably have a primary detrital and chemical origin. Our results indicate variable, minor, but in some intervals significant vertical axis rotations with respect to a stable Asian reference frame. This pattern of rotations is similar to paleomagnetic data reported in previously published studies from the Eastern Pamir foreland. In contrast, published paleomagnetic data from the Western Pamir foreland consistently indicate significant CCW rotations within that region. Collectively, these results challenge simple oroclinal bending models for the origin of the Pamir salient, and instead are more consistent with an asymmetric "half-orocline" kinematic model in which the curvature of the Western Pamir is the product of a combination of lithospheric bending of an originally quasi-linear mountain belt and radial thrusting, and the subdued curvature of the eastern edge of the plateau is the result of lateral translation of the Pamir plateau northward past Tibet and Tarim along the Kashgar-Yecheng transfer system. Our results are consistent with activity on the Kashgar-Yecheng transfer system in the Early Miocene.

Patterns of Cenozoic sediment flux from western Scandinavia

DEFF Research Database (Denmark)

Gołędowski, Bartosz; Nielsen, S.B.; Clausen, O.R.

2012-01-01

deposits in the North Sea, the post-mid-Miocene Molo and Kai Formations of the Norwegian Shelf, the southern North Sea delta system and large volumes of the Late Pliocene-Holocene Naust Formation. The sediment flux from Scandinavia during the Cenozoic is in general agreement with the detrital flux...

Thermochronological Evidence for Cenozoic Segmentation of Transantarctic Mountains

Science.gov (United States)

Zattin, M.; Pace, D.; Andreucci, B.; Rossetti, F.; Talarico, F.

2013-12-01

The Transantarctic Mountains (TAM) represent the boundary between the cratonic East Antarctica and the West Antarctica and are thus related to formation of the Western Antarctic Rift system (WARS). However, temporal relationships between timing of TAM uplift and evolution of the WARS are not clear. The large amount of existing thermochronological data indicate that exhumation of the TAM occurred at different times and extents, with main cooling events in the Early Cretaceous, Late Cretaceous, and early Cenozoic. Uplift of the different segments of the TAM was not recorded according to regular trends along the mountain chain, but instead appears diachronous and without a recognizable spatial pattern. Here we present apatite fission-track (AFT) data from 20 samples, collected from metamorphic and intrusive rocks from the region comprised between the Blue Glacier and the Byrd Glacier. AFT data show a large variety of ages, ranging from 28.0 to 88.8 Ma and without a clear correlation between age and elevation. As a whole, spatial variations suggest a decrease of ages from S to the region of the Koettlitz Glacier, where ages suddenly raise up to Cretaceous values. A marked increase of ages has been detected also south of Darwin Glacier, that is in correspondence of the Britannia Range. Thermal modelling shows that cooling paths are usually composite, with a main cooling event followed by slower cooling to present day temperatures. Time of main cooling event is late Cretaceous for samples from the Britannia Range whereas it is Eocene-Oligocene for samples from Koettlitz and Mulock areas. In any case, cooling rates are always quite low also during periods of enhanced uplift, with values not exceeding 5°C/Ma. These data support the idea of tectonic block segmentation of the TAM during the last phases of exhumation. Most of vertical displacements occurred during the Oligocene across transverse fault zones such as the Discovery Accommodation Zone to the north and the

Dynamic topography and the Cenozoic carbonate compensation depth

Science.gov (United States)

Campbell, S. M.; Moucha, R.; Raymo, M. E.; Derry, L. A.

2015-12-01

The carbonate compensation depth (CCD), the ocean depth at which the calcium carbonate accumulation rate goes to zero, can provide valuable insight into climatic and weathering conditions over the Cenozoic. The paleoposition of the CCD can be inferred from sediment core data. As the carbonate accumulation rate decreases linearly with depth between the lysocline and CCD, the CCD can be calculated using a linear regression on multiple sediment cores with known carbonate accumulation rates and paleodepths. It is therefore vital to have well-constrained estimates of paleodepths. Paleodepths are typically calculated using models of thermal subsidence and sediment loading and compaction. However, viscous convection-related stresses in the mantle can warp the ocean floor by hundreds of meters over broad regions and can also vary significantly over millions of years. This contribution to paleobathymetry, termed dynamic topography, can be calculated by modeling mantle flow backwards in time. Herein, we demonstrate the effect dynamic topography has on the inference of the late Cenozoic CCD with an example from the equatorial Pacific, considering sites from IODP Expeditions 320/321. The equatorial Pacific, given its large size and high productivity, is closely tied to the global carbon cycle. Accordingly, long-term changes in the equatorial Pacific CCD can be considered to reflect global changes in weathering fluxes and the carbon cycle, in addition to more regional changes in productivity and thermohaline circulation. We find that, when the dynamic topography contribution to bathymetry is accounted for, the equatorial Pacific CCD is calculated to be appreciably shallower at 30 Ma than previous estimates would suggest, implying a greater deepening of the Pacific CCD over the late Cenozoic.

History of oceanic front development in the New Zealand sector of the Southern Ocean during the Cenozoic: a synthesis

International Nuclear Information System (INIS)

Nelson, C.S.; Cooke, P.J.

2001-01-01

The New Zealand sector of the Southern Ocean (NZSSO) has opened about the Indian-Pacific spreading ridge throughout the Cenozoic. Today the NZSSO is characterised by broad zonal belts of antarctic (cold), subantarctic (cool), and subtropical (warm) surface-water masses separated by prominent oceanic fronts: the Subtropical Front (STF) c. 43 degrees S, Subantarctic Front (SAF) c. 50 degrees S, and Antarctic Polar Front (AAPF) c. 60 degrees S. Despite a meagre database, the broad pattern of Cenozoic evolution of these fronts is reviewed from the results of Deep Sea Drilling Project-based studies of sediment facies, microfossil assemblages and diversity, and stable isotope records, as well as from evidence in onland New Zealand Cenozoic sequences. Results are depicted schematically on seven paleogeographic maps covering the NZSSO at 10 m.y. intervals through the Cenozoic. During the Paleocene and most of the Eocene (65-35 Ma), the entire NZSSO was under the influence of warm to cool subtropical waters, with no detectable oceanic fronts. In the latest Eocene (c. 35 Ma), a proto-STF is shown separating subantarctic and subtropical waters offshore from Antarctica, near 65 degrees S paleolatitude. During the earliest Oligocene, this front was displaced northwards by development of an AAPF following major global cooling and biotic turnover associated with ice sheet expansion to sea level on East Antarctica. Early Oligocene full opening (c. 31 Ma) of the Tasmanian gateway initiated vigorous proto-circum-Antarctic flow of cold/cool waters, possibly through a West Antarctic seaway linking the southern Pacific and Atlantic Oceans, including detached northwards 'jetting' onto the New Zealand plateau where condensation and unconformity development was widespread in cool-water carbonate facies. Since this time, a broad tripartite division of antarctic, subantarctic, and subtropical waters has existed in the NZSSO, including possible development of a proto-SAF within the

Upper mantle structure under western Saudi Arabia from Rayleigh wave tomography and the origin of Cenozoic uplift and volcanism on the Arabian Shield

Energy Technology Data Exchange (ETDEWEB)

Park, Y; Nyblade, A; Rodgers, A; Al-Amri, A

2007-11-09

The shear velocity structure of the shallow upper mantle beneath the Arabian Shield has been modeled by inverting new Rayleigh wave phase velocity measurements between 45 and 140 s together with previously published Rayleigh wave group velocity measurement between 10 and 45 s. For measuring phase velocities, we applied a modified array method that minimizes the distortion of raypaths by lateral heterogeneity. The new shear velocity model shows a broad low velocity region in the lithospheric mantle across the Shield and a low velocity region at depths {ge} 150 km localized along the Red Sea coast and Makkah-Madinah-Nafud (MMN) volcanic line. The velocity reduction in the upper mantle corresponds to a temperature anomaly of {approx}250-330 K. These finding, in particular the region of continuous low velocities along the Red Sea and MMN volcanic line, do not support interpretations for the origin of the Cenozoic plateau uplift and volcanism on the Shield invoking two separate plumes. When combined with images of the 410 and 660 km discontinuities beneath the southern part of the Arabian Shield, body wave tomographic models, a S-wave polarization analysis, and SKS splitting results, our new model supports an interpretation invoking a thermal upwelling of warm mantle rock originating in the lower mantle under Africa that crosses through the transition zone beneath Ethiopia and moves to the north and northwest under the eastern margin of the Red Sea and the Arabian Shield. In this interpretation, the difference in mean elevation between the Platform and Shield can be attributed to isostatic uplift caused by heating of the lithospheric mantle under the Shield, with significantly higher region along the Red Sea possibly resulting from a combination of lithosphere thinning and dynamic uplift.

A Paleocene penguin from New Zealand substantiates multiple origins of gigantism in fossil Sphenisciformes.

Science.gov (United States)

Mayr, Gerald; Scofield, R Paul; De Pietri, Vanesa L; Tennyson, Alan J D

2017-12-12

One of the notable features of penguin evolution is the occurrence of very large species in the early Cenozoic, whose body size greatly exceeded that of the largest extant penguins. Here we describe a new giant species from the late Paleocene of New Zealand that documents the very early evolution of large body size in penguins. Kumimanu biceae, n. gen. et sp. is larger than all other fossil penguins that have substantial skeletal portions preserved. Several plesiomorphic features place the new species outside a clade including all post-Paleocene giant penguins. It is phylogenetically separated from giant Eocene and Oligocene penguin species by various smaller taxa, which indicates multiple origins of giant size in penguin evolution. That a penguin rivaling the largest previously known species existed in the Paleocene suggests that gigantism in penguins arose shortly after these birds became flightless divers. Our study therefore strengthens previous suggestions that the absence of very large penguins today is likely due to the Oligo-Miocene radiation of marine mammals.

Early Eocene climatic optimum: Environmental impact on the North Iberian continental margin

NARCIS (Netherlands)

Payros, A.; Ortiz, S.; Millán, I.; Arostegi, J.; Orue-Etxebarria, X.; Apellaniz, E.

2015-01-01

The early Eocene climatic optimum, which constituted the peak of the long-term early Cenozoic global warming, had a significant impact on the environmental evolution of terrestrial and oceanic areas. Surprisingly, however, its influence on continental margins is poorly known. New insights are

A coccolithophore concept for constraining the Cenozoic carbon cycle

Science.gov (United States)

Henderiks, J.; Rickaby, R. E. M.

2007-06-01

An urgent question for future climate, in light of increased burning of fossil fuels, is the temperature sensitivity of the climate system to atmospheric carbon dioxide (pCO>sub>2). To date, no direct proxy for past levels of pCO2 exists beyond the reach of the polar ice core records. We propose a new methodology for placing a constraint on pCO2 over the Cenozoic based on the physiological plasticity of extant coccolithophores. Specifically, our premise is that the contrasting calcification tolerance of various extant species of coccolithophore to raised pCO2 reflects an "evolutionary memory" of past atmospheric composition. The different times of evolution of certain morphospecies allows an upper constraint of past pCO2 to be placed on Cenozoic timeslices. Further, our hypothesis has implications for the response of marine calcifiers to ocean acidification. Geologically "ancient" species, which have survived large changes in ocean chemistry, are likely more resilient to predicted acidification.

U-Pb zircon geochronology of the Paleogene - Neogene volcanism in the NW Anatolia: Its implications for the Late Mesozoic-Cenozoic geodynamic evolution of the Aegean

Science.gov (United States)

Ersoy, E. Yalçın; Akal, Cüneyt; Genç, Ş. Can; Candan, Osman; Palmer, Martin R.; Prelević, Dejan; Uysal, İbrahim; Mertz-Kraus, Regina

2017-10-01

The northern Aegean region was shaped by subduction, obduction, collision, and post-collisional extension processes. Two areas in this region, the Rhodope-Thrace-Biga Peninsula to the west and Armutlu-Almacık-Nallıhan (the Central Sakarya) to the east, are characterized by extensive Eocene to Miocene post-collisional magmatic associations. We suggest that comparison of the Cenozoic magmatic events of these two regions may provide insights into the Late Mesozoic to Cenozoic tectonic evolution of the Aegean. With this aim, we present an improved Cenozoic stratigraphy of the Biga Peninsula derived from a new comprehensive set of U-Pb zircon age data obtained from the Eocene to Miocene volcanic units in the region. The compiled radiometric age data show that calc-alkaline volcanic activity occurred at 43-15 Ma in the Biga Peninsula, 43-17 Ma in the Rhodope and Thrace regions, and 53-38 Ma in the Armutlu-Almacık-Nallıhan region, which are slightly overlapping. We discuss the possible cause for the distinct Cenozoic geodynamic evolution of the eastern and western parts of the region, and propose that the Rhodope, Thrace and Biga regions in the north Aegean share the same Late Mesozoic to Cenozoic geodynamic evolution, which is consistent with continuous subduction, crustal accretion, southwestward trench migration and accompanying extension; all preceded by the Late Cretaceous - Paleocene collision along the Vardar suture zone. In contrast, the Armutlu-Almacık-Nallıhan region was shaped by slab break-off and related processes following the Late Cretaceous - Paleocene collision along the İzmir-Ankara suture zone. The eastern and western parts of the region are presently separated by a northeast-southwest trending transfer zone that was likely originally present as a transform fault in the subducted Tethys oceanic crust, and demonstrates that the regional geodynamic evolution can be strongly influenced by the geographical distribution of geologic features on the

Evidence of Late Palaeocene-Early Eocene equatorial rain forest ...

Indian Academy of Sciences (India)

Prakash

2009-11-02

Nov 2, 2009 ... influx of CO2 during early Cenozoic times (Kent and Muttoni. 2008), besides ... Palaeocene – Eocene lignite and coal deposits of India. .... journey of the Indian subcontinent and massive outpouring ..... ice age (Plana 2004).

Formal and Informal Early Education of Turkish-Origin Children in Germany

Science.gov (United States)

Becker, Birgit; Boldin, Elena; Klein, Oliver

2016-01-01

A lack of adequate German language skills is often discussed as a major reason for the disadvantage of children of immigrants in the German educational system. This article analyses the access to formal and informal early education of Turkish-origin children in Germany and the influence of these early education contexts on the children's German…

Distribution of Cenozoic plant relicts in China explained by drought in dry season.

Science.gov (United States)

Huang, Yongjiang; Jacques, Frédéric M B; Su, Tao; Ferguson, David K; Tang, Hui; Chen, Wenyun; Zhou, Zhekun

2015-09-15

Cenozoic plant relicts are those groups that were once widespread in the Northern Hemisphere but are now restricted to some small isolated areas as a result of drastic climatic changes. They are good proxies to study how plants respond to climatic changes since their modern climatic requirements are known. Herein we look at the modern distribution of 65 palaeoendemic genera in China and compare it with the Chinese climatic pattern, in order to find a link between the plant distribution and climate. Central China and Taiwan Island are shown to be diversity centres of Cenozoic relict genera, consistent with the fact that these two regions have a shorter dry season with comparatively humid autumn and spring in China. Species distribution models indicate that the precipitation parameters are the most important variables to explain the distribution of relict genera. The Cenozoic wide-scale distribution of relict plants in the Northern Hemisphere is therefore considered to be linked to the widespread humid climate at that time, and the subsequent contraction of their distributional ranges was probably caused by the drying trend along with global cooling.

Stratigraphy and Folding in the Cenozoic Cover of a Fold-Thrust Belt in the Nallıhan Region (Ankara, Central Turkey)

Science.gov (United States)

Karaaǧaç, Serdal; Koral, Hayrettin

2017-04-01

This study investigates stratigraphy and structural features in the Cenozoic sedimentary sequence of the fold-thrust belt of the Nallıhan-Ankara region, located to the north of the İzmir-Ankara-Erzincan Suture Zone. Permian-Triassic age marble intercalated with schist-phyllites, the upper Jurassic-lower Cretaceous age limestone and the upper Cretaceous age sandstone-shale alternation compose the basement in the study area. These rocks are unconformably overlain by the Cenozoic age terrestrial sedimentary and volcanic units. The Cenozoic stratigraphy begins with the Paleocene-Eocene age coal-bearing, at times, volcanic intercalated conglomerate-sandstone-mudstone alternation of alluvial-fluvial origins (Aksaklar Formation) and the tuff intercalated with lacustrine limestone, bituminous limestone (Kabalar Formation). These units are conformably overlain by the Eocene age basalt-andesite and pyroclastic rocks (Meyildere volcanics). The Paleocene-Eocene aged units are unconformably overlain by the conglomerate-sandstone-mudstone-marl of a lower-middle Miocene lacustrine environment (Hançili Formation). The terrestrial conglomerate-sandstone alternation (Örencik Formation) is the youngest unit in the Cenozoic stratigraphy, and is assumed to be of Pliocene age based its stratigraphic position on older units. Field study shows existence of both folds and faults in the sedimentary cover. Stereographic projections of bedding measured in the field shows N25W/45NW and N60W/4SE-oriented fold axes in the Paleocene-Eocene age units. There are also N76W/12SE and N88E/8NE-oriented folds. The difference in fold-axis orientations suggests that some folds may have been rotated in blocks bound by faults during the post-Paleocene/Eocene period. Whereas, the lower-middle Miocene units manifest N88W/13SE-oriented fold axes. It is thus proposed that the observed difference in the azimuth of fold axes represent two different folding phases, one with NE-SW and the other with N

ACADEMICIAN N.A. LOGATCHEV AND HIS SCIENTIFIC SCHOOL: CONTRUBITION TO STUDIES OF THE CENOZOIC CONTINENTAL RIFTING

Directory of Open Access Journals (Sweden)

Sergey V. Rasskazov

2010-01-01

Full Text Available N.A. Florensov and N.A. Logatchev pioneered development of fundamental concepts of the structure and evolution of the Baikal system of rift basins. At the turn to the 21st century, in view of the wide availability of scientific research data on the Cenozoic continental rift zones located in Eurasia, Africa and North America, and taking into account the application of new research methods and options to process and analyze huge amounts of geological and geophysical data, a priority was comprehensive modeling of rifting from its origin to the current period of time. This scientific challenge was addressed by the research team under the leadership of N.A. Logachev.

Modes, tempo and spatial variability of Cenozoic cratonic denudation: morphoclimatic constraints from West Africa

Science.gov (United States)

Beauvais, Anicet; Chardon, Dominique

2010-05-01

After the onset of Gondwana break-up in the Early Mesozoic, the emerged part of the African plate underwent long Greenhouse effect climatic periods and epeirogeny. The last Greenhouse effect period in the Early Cenozoic and the alternation of wet and dry climatic periods since the Eocene enhanced episodes of rock chemical weathering and laterite production, forming bauxites and ferricretes, interrupted by drier periods of dominantly mechanical denudation, shaping glacis [1]. In Sub-Saharan West Africa, this evolution resulted in pulsate and essentially climatically-forced denudation that has shaped an ubiquitous sequence of five stepped lateritic paleosurfaces that synchronously developed over Cenozoic times. The modes, timing and spatial variability of continental denudation of the region are investigated by combining geomorphologic and geochronological data sets. The geomorphologic data set comprises the altitudinal distribution of the lateritic paleosurfaces relicts and their differential elevation from 42 locations in Sub-Saharan West Africa where the sequence (or part of it) has been documented. The geochronological data set consists in the age ranges of each paleosurface tackled by radiometric 39Ar-40Ar dating of the neoformed oxy-hydroxides (i.e., cryptomelane, K1-2Mn8O16, nH2O, [4]) carried by their laterites at the Tambao reference site, Burkina Faso [1, 3]. Five groups of 39Ar-40Ar ages, ~ 59 - 45 Ma, ~ 29 - 24 Ma, ~ 18 - 11.5 Ma, ~ 7.2 - 5.8 Ma, and ~ 3.4 - 2.9 Ma, characterize periods of chemical weathering whereas the time laps between these groups of ages correspond to episodes of mechanical denudation that reflect physical shaping of the paleosurfaces. For the last 45 Ma, the denudation rate estimates (3 to 8 m Ma-1) are comparable with those derived on shorter time scale (103 to 106 y.) in the same region by the cosmogenic radionuclide method [2]. Combined with the geomorphologic data set, these age ranges allow the visualization of the regional

Regionwide Geodynamic Analyses of the Cenozoic Carbonate Burial in Sri Lanka Related to Climate and Atmospheric CO2

Directory of Open Access Journals (Sweden)

Amila Sandaruwan Ratnayake

2016-12-01

Full Text Available Asian tectonism and exhumation are critical components to develop modern icehouse climate. In this study, stratigraphic sections of eight wells in the Mannar and Cauvery basins were considered. The author demonstrated that this local system records a wealth of information to understated regional and global paleoclimatic trends over the Cenozoic era. The lithostratigraphic framework has been generally characterized by deposition of carbonate-rich sediments since the Middle Cenozoic. Geological provenance of carbonate sediments had probably related to local sources from Sri Lankan and Indian land masses. The main controlling factor of carbonate burial is rather questionable. However, this carbonate burial has indicated the possible link to the Middle to Late Cenozoic global climatic transition. This major climatic shift was characterized by long-term reduction of atmospheric carbon dioxide concentration over the Cenozoic era. Consequently, this geological trend (carbonate burial has a straightforward teleconnection to the global cooling towards the glaciated earth followed by the development of polar ice sheets that persist today.

Equatorial heat accumulation as a long-term trigger of permanent Antarctic ice sheets during the Cenozoic.

Science.gov (United States)

Tremblin, Maxime; Hermoso, Michaël; Minoletti, Fabrice

2016-10-18

Growth of the first permanent Antarctic ice sheets at the Eocene-Oligocene Transition (EOT), ∼33.7 million years ago, indicates a major climate shift within long-term Cenozoic cooling. The driving mechanisms that set the stage for this glaciation event are not well constrained, however, owing to large uncertainties in temperature reconstructions during the Eocene, especially at lower latitudes. To address this deficiency, we used recent developments in coccolith biogeochemistry to reconstruct equatorial Atlantic sea surface temperature (SST) and atmospheric pCO 2 values from pelagic sequences preceding and spanning the EOT. We found significantly more variability in equatorial SSTs than previously reported, with pronounced cooling from the Early to Middle Eocene and subsequent warming during the Late Eocene. Thus, we show that the Antarctic glaciation at the Eocene-Oligocene boundary was preceded by a period of heat accumulation in the low latitudes, likely focused in a progressively contracting South Atlantic gyre, which contributed to cooling high-latitude austral regions. This prominent redistribution of heat corresponds to the emplacement of a strong meridional temperature gradient that typifies icehouse climate conditions. Our equatorial coccolith-derived geochemical record thus highlights an important period of global climatic and oceanic upheaval, which began 4 million years before the EOT and, superimposed on a long-term pCO 2 decline, drove the Earth system toward a glacial tipping point in the Cenozoic.

Cenozoic tectonic jumping and implications for hydrocarbon accumulation in basins in the East Asia Continental Margin

Science.gov (United States)

Suo, Yanhui; Li, Sanzhong; Yu, Shan; Somerville, Ian D.; Liu, Xin; Zhao, Shujuan; Dai, Liming

2014-07-01

Tectonic migration is a common geological process of basin formation and evolution. However, little is known about tectonic migration in the western Pacific margins. This paper focuses on the representative Cenozoic basins of East China and its surrounding seas in the western Pacific domain to discuss the phenomenon of tectonic jumping in Cenozoic basins, based on structural data from the Bohai Bay Basin, the South Yellow Sea Basin, the East China Sea Shelf Basin, and the South China Sea Continental Shelf Basin. The western Pacific active continental margin is the eastern margin of a global convergent system involving the Eurasian Plate, the Pacific Plate, and the Indian Plate. Under the combined effects of the India-Eurasia collision and retrogressive or roll-back subduction of the Pacific Plate, the western Pacific active continental margin had a wide basin-arc-trench system which migrated or ‘jumped’ eastward and further oceanward. This migration and jumping is characterized by progressive eastward younging of faulting, sedimentation, and subsidence within the basins. Owing to the tectonic migration, the geological conditions associated with hydrocarbon and gashydrate accumulation in the Cenozoic basins of East China and its adjacent seas also become progressively younger from west to east, showing eastward younging in the generation time of reservoirs, seals, traps, accumulations and preservation of hydrocarbon and gashydrate. Such a spatio-temporal distribution of Cenozoic hydrocarbon and gashydrate is significant for the oil, gas and gashydrate exploration in the East Asian Continental Margin. Finally, this study discusses the mechanism of Cenozoic intrabasinal and interbasinal tectonic migration in terms of interplate, intraplate and underplating processes. The migration or jumping regimes of three separate or interrelated events: (1) tectonism-magmatism, (2) basin formation, and (3) hydrocarbon-gashydrate accumulation are the combined effects of the

Mass Balance of Cenozoic Andes-Amazon Source to Sink System—Marañón Basin, Peru

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Gérôme Calvès

2018-05-01

Full Text Available We investigate the mass balance of the Cenozoic Andes-Amazon source to sink system using rock uplift proxies and solid sedimentation of the Marañón Basin in Peru. The evolution of sedimentation rates is calibrated with regional structural restored cross-section. The quantification of eroded sediments from reliefs to sedimentary basin is achieved with ×10 Myr resolution and compared to present day proxies from the HYBAM (HYdrologie et Biogéochimie du Bassin Amazonien Critical Zone Observatory. Erosion of the early Andean landforms started during the Upper Mesozoic period, but sediment rates significantly increase during the Neogene. This is in agreement with the calibrated increase of rock uplift in the Andean orogenic belt.

Review of cenozoic ooidal ironstones

Science.gov (United States)

van Houten, Franklyn B.

1992-06-01

Cenozoic (Tertiary) ooidal ironstones (COI) in 20 districts (39 deposits) developed between the equatorial zone and 60° N, except for one Eocene district in mid-southern latitude. Stratigraphic distribution. Paleocene OI occur in northern Pakistan, western Siberia, southern Germany, northwestern Venezuela, and northeastern Colombia: Eocene OI in western Siberia, southern Germany, northwestern Romania, central North Africa, central-west Saudi Arabia, southwestern Central Africa, northwestern Venezuela, northeastern Colombia, south-central USA, and northwestern Australia; Oligocene OI in northwest and west-central Kazakhstan, central Denmark, and north-central Iran?; Miocene OI in northwestern Venezuela, northeastern Colombia, and southeastern Malaysia; Pliocene OI in southeastern Ukraine. Geotectonic framework. Ten districts developed in an interior or fractured craton: five along the south-trending Uralian Seaway, and one along the east-trending Northern European Seaway, the south-trending Trans-Saharan Seaway, in or near an early Red Sea embayment, in southeastern Malaysia, and in northwestern Australia. Ten districts lay near a eratonic margin: one along divergent margin and nine along the broad east-trending Caribbean and Tethyan seaways. Almost all COI accumulated during the Paleogene relatively high stand of sea level, especially in Early and Middle Eocene time. As sea level fell gradually in Neogene time COI developed in only three marginal districts (including the giant Pliocene Kerch-Taman deposit in southeastern Ukraine). Sedimentary environment. Almost all of the COI developed in deltaic to shallow marine facies. These are commonly associated with shoaling-upward siliciclastic sequences; a few are in mixed siliciclastic-carbonate sequences. A few COI apparently occurred in fluvial and lacustrine facies; some of these may have been reworked from laterite or from marine ironstones. Sedimentary petrology. Many COI are less than a few tens of centimeters

Types of Cenozoic Mollusca from Java in the Martin Collection of Naturalis

NARCIS (Netherlands)

Leloux, J.; Wesselingh, F.P.

2009-01-01

An updated type catalogue of the Martin Collection (fossil Mollusca, predominantly from the Cenozoic of Java, Indonesia) is presented. Type specimen data, updated locality data, and illustrations are given.

Acute mesenteric ischemia of arterial origin: importance of early revascularization.

Science.gov (United States)

Plumereau, F; Mucci, S; Le Naoures, P; Finel, J B; Hamy, A

2015-02-01

The goal of our study was to show that survival was better when early revascularization was performed rather than gastrointestinal resection in the management of acute mesenteric ischemia of arterial origin. The reports of patients managed in our center between January 2005 and May 2012 for acute mesenteric ischemia of arterial origin were analyzed retrospectively. Data on clinical, laboratory and radiologic findings, the interval before treatment, the operative findings and the surgical procedures were collected. Follow-up information included the postoperative course, and mortality at 48 h, 30 days and 1 year, the latter being compared between patients undergoing revascularization versus gastrointestinal resection. Of 43 patients treated during this period, 20 had gastrointestinal lesions deemed to be beyond all therapeutic resources, 13 were treated with gastrointestinal resection without revascularization, while 10 underwent early revascularization. There were no statistically significant differences found in the extent of involvement between the two groups (P=0.22). Mortality at 48 h, 30 days and 1 year was 8% (n=1), 30% (n=4) and 68% (n=8) in patients who underwent enterectomy vs. 0% (n=0), 0% (n=0) and 10% (n=1) in patients who underwent revascularization procedures. The difference at 1 year was statistically significant (P=0.02). At 1 year, two patients in the revascularized group had a short bowel syndrome vs. one in the non-revascularized group. Acute mesenteric ischemia of arterial origin is associated with high morbidity and mortality. Optimal management should include early revascularization. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Cenozoic stratigraphy and structure of the Chesapeake Bay region

Science.gov (United States)

Powars, David S.; Edwards, Lucy E.; Kidwell, Susan M.; Schindler, J. Stephen

2015-01-01

The Salisbury embayment is a broad tectonic downwarp that is filled by generally seaward-thickening, wedge-shaped deposits of the central Atlantic Coastal Plain. Our two-day field trip will take us to the western side of this embayment from the Fall Zone in Washington, D.C., to some of the bluffs along Aquia Creek and the Potomac River in Virginia, and then to the Calvert Cliffs on the western shore of the Chesapeake Bay. We will see fluvial-deltaic Cretaceous deposits of the Potomac Formation. We will then focus on Cenozoic marine deposits. Transgressive and highstand deposits are stacked upon each other with unconformities separating them; rarely are regressive or lowstand deposits preserved. The Paleocene and Eocene shallow shelf deposits consist of glauconitic, silty sands that contain varying amounts of marine shells. The Miocene shallow shelf deposits consist of diatomaceous silts and silty and shelly sands. The lithology, thickness, dip, preservation, and distribution of the succession of coastal plain sediments that were deposited in our field-trip area are, to a great extent, structurally controlled. Surficial and subsurface mapping using numerous continuous cores, auger holes, water-well data, and seismic surveys has documented some folds and numerous high-angle reverse and normal faults that offset Cretaceous and Cenozoic deposits. Many of these structures are rooted in early Mesozoic and/or Paleozoic NE-trending regional tectonic fault systems that underlie the Atlantic Coastal Plain. On Day 1, we will focus on two fault systems (stops 1–2; Stafford fault system and the Skinkers Neck–Brandywine fault system and their constituent fault zones and faults). We will then see (stops 3–5) a few of the remaining exposures of largely unlithified marine Paleocene and Eocene strata along the Virginia side of the Potomac River including the Paleocene-Eocene Thermal Maximum boundary clay. These exposures are capped by fluvial-estuarine Pleistocene terrace

Cenozoic plant diversity of Yunnan: A review

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Yongjiang Huang

2016-12-01

Full Text Available Yunnan in southwestern China is renowned for its high plant diversity. To understand how this modern botanical richness formed, it is critical to investigate the past biodiversity throughout the geological time. In this review, we present a summary on plant diversity, floristics and climates in the Cenozoic of Yunnan and document their changes, by compiling published palaeobotanical sources. Our review demonstrates that thus far a total of 386 fossil species of ferns, gymnosperms and angiosperms belonging to 170 genera within 66 families have been reported from the Cenozoic, particularly the Neogene, of Yunnan. Angiosperms display the highest richness represented by 353 species grouped into 155 genera within 60 families, with Fagaceae, Fabaceae, Lauraceae and Juglandaceae being the most diversified. Most of the families and genera recorded as fossils still occur in Yunnan, but seven genera have disappeared, including Berryophyllum, Cedrelospermum, Cedrus, Palaeocarya, Podocarpium, Sequoia and Wataria. The regional extinction of these genera is commonly referred to an aridification of the dry season associated with Asian monsoon development. Floristic analyses indicate that in the late Miocene, Yunnan had three floristic regions: a northern subtropical floristic region in the northeast, a subtropical floristic region in the east, and a tropical floristic region in the southwest. In the late Pliocene, Yunnan saw two kinds of floristic regions: a subalpine floristic region in the northwest, and two subtropical floristic regions separately in the southwest and the eastern center. These floristic concepts are verified by results from our areal type analyses which suggest that in the Miocene southwestern Yunnan supported the most Pantropic elements, while in the Pliocene southwestern Yunnan had abundant Tropical Asia (Indo–Malaysia type and East Asia and North America disjunct type that were absent from northwestern Yunnan. From the late Miocene to

Sr-Nd isotope systematics of xenoliths in Cenozoic volcanic rocks from SW Japan

International Nuclear Information System (INIS)

Kagami, Hiroo; Iwata, Masatoshi; Iizumi, Shigeru; Nureki, Terukazu.

1993-01-01

Based on new and previously published Sr and Nd isotope data, we examined the petrogenetic relationship between deep crust- and upper mantle-derived xenoliths contained in Cenozoic volcanic rocks and Cretaceous-Paleogene granitoid rocks in SW Japan. The deep crust- and upper mantle-derived mafic to ultramafic xenoliths contained in Cenozoic volcanic rocks from SW Japan have comparable initial Sr and Nd isotope ratios to the Cretaceous-Paleogene granitoid rocks in their respective districts. This may suggest that these xenoliths were genetically related to the Cretaceous-Paleogene granitoid rocks in SW Japan, and that regional variations in Sr and Nd isotope ratios observed in the granitoid rocks are attributed to differences in the geochemistry of the magma sources. (author)

Tectono-sedimentary events and geodynamic evolution of the Mesozoic and Cenozoic basins of the Alpine Margin, Gulf of Tunis, north-eastern Tunisia offshore

Science.gov (United States)

Melki, Fetheddine; Zouaghi, Taher; Chelbi, Mohamed Ben; Bédir, Mourad; Zargouni, Fouad

2010-09-01

The structural pattern, tectono-sedimentary framework and geodynamic evolution for Mesozoic and Cenozoic deep structures of the Gulf of Tunis (north-eastern Tunisia) are proposed using petroleum well data and a 2-D seismic interpretation. The structural system of the study area is marked by two sets of faults that control the Mesozoic subsidence and inversions during the Paleogene and Neogene times: (i) a NE-SW striking set associated with folds and faults, which have a reverse component; and (ii) a NW-SE striking set active during the Tertiary extension episodes and delineating grabens and subsiding synclines. In order to better characterize the tectono-sedimentary evolution of the Gulf of Tunis structures, seismic data interpretations are compared to stratigraphic and structural data from wells and neighbouring outcrops. The Atlas and external Tell belonged to the southernmost Tethyan margin record a geodynamic evolution including: (i) rifting periods of subsidence and Tethyan oceanic accretions from Triassic until Early Cretaceous: we recognized high subsiding zones (Raja and Carthage domains), less subsiding zones (Gamart domain) and a completely emerged area (Raouad domain); (ii) compressive events during the Cenozoic with relaxation periods of the Oligocene-Aquitanian and Messinian-Early Pliocene. The NW-SE Late Eocene and Tortonian compressive events caused local inversions with sealed and eroded folded structures. During Middle to Late Miocene and Early Pliocene, we have identified depocentre structures corresponding to half-grabens and synclines in the Carthage and Karkouane domains. The north-south contractional events at the end of Early Pliocene and Late Pliocene periods are associated with significant inversion of subsidence and synsedimentary folded structures. Structuring and major tectonic events, recognized in the Gulf of Tunis, are linked to the common geodynamic evolution of the north African and western Mediterranean basins.

Climate vs. tectonic induced variations in Cenozoic sediment supply from western Scandinavia

DEFF Research Database (Denmark)

Gołędowski, Bartosz; Nielsen, S.B.; Clausen, O.R.

Eocene times tectonic activity related to the final stage of opening of the North Atlantic was apparently controlling the sediment input in the North Sea as sediment pulses correlate well with tectonic events. Although there is no signs of Cenozoic tectonic activity onshore Scandinavia (igneous bodies......, faulting), tectonic disturbance related to ocean opening could be responsible for deposition of thick Paleocene wedges along the western coast of Norway. During subsequent Cenozoic periods domal structures in the Norwegian shelf are a proof for mild and protracted compression. However, depositional...... patterns from offshore Scandinavia have been interpreted as a result of significant tectonic movements. In the absence of proofs for active tectonic agents we attempt to explain these sediment input variations as a result of climate fluctuations. The Eocene-Oligocene greenhouse-icehouse climate transition...

Relating Cenozoic North Sea sediments to topography in southern Norway:

DEFF Research Database (Denmark)

Anell, Ingrid Anna Margareta; Thybo, Hans; Stratford, Wanda Rose

2010-01-01

the Shetland platform continued throughout the Cenozoic while supply from southern Norway increased markedly around the Eocene–Oligocene, coeval with the greenhouse–icehouse transition. Mass balance calculations of sediment and eroded rock volumes suggest that while some topography along the western margin...... that Plio-Pleistocene erosion over-deepened a pre-existing topography....

Cenozoic basin thermal history reconstruction and petroleum systems in the eastern Colombian Andes

Science.gov (United States)

Parra, Mauricio; Mora, Andres; Ketcham, Richard A.; Stockli, Daniel F.; Almendral, Ariel

2017-04-01

Late Mesozoic-Cenozoic retro-arc foreland basins along the eastern margin of the Andes in South America host the world's best detrital record for the study of subduction orogenesis. There, the world's most prolific petroleum system occur in the northernmost of these foreland basin systems, in Ecuador, Colombia and Venezuela, yet over 90% of the discovered hydrocarbons there occur in one single province in norteastern Venezuela. A successful industry-academy collaboration applied a multidisciplinary approach to the study of the north Andes with the aim of investigating both, the driving mechanisms of orogenesis, and its impact on hydrocarbon accumulation in eastern Colombia. The Eastern Cordillera is an inversion orogen located at the leading edge of the northern Andes. Syn-rift subsidence favored the accumulation of km-thick organic matter rich shales in a back-arc basin in the early Cretaceous. Subsequent late Cretaceous thermal subsidence prompted the accumulation of shallow marine sandstones and shales, the latter including the Turonian-Cenomanian main hydrocarbon source-rock. Early Andean uplift since the Paleocene led to development of a flexural basin, filled with mainly non-marine strata. We have studied the Meso-Cenozoic thermal evolution of these basins through modeling of a large thermochronometric database including hundreds of apatite and zircon fission-track and (U-Th)/He data, as well as paleothermometric information based on vitrinite reflectance and present-day temperatures measured in boreholes. The detrital record of Andean construction was also investigated through detrital zircon U-Pb geochronometry in outcrop and borehole samples. A comprehensive burial/exhumation history has been accomplished through three main modeling strategies. First, one-dimensional subsidence was used to invert the pre-extensional lithospheric thicknesses, the magnitude of stretching, and the resulting heat flow associated to extension. The amount of eroded section and

Cenozoic Deformation of the Tarim Basin (Xinjiang, China): a Record of the Deformation Propagation through the Asian Orogenic System

Science.gov (United States)

Laborde, A.; Barrier, L.; Simoes, M.; Li, H.

2016-12-01

During the Cenozoic, the ongoing India-Eurasia collision resulted in the formation of the Himalayan-Tibetan plateau and reactivated the Tian Shan and Altai ranges located thousands of kilometers further north. Despite numerous studies carried out on the geology and tectonics of this large convergent orogenic system, several mechanisms remain controversial such as the stress propagation through the Asia Continent or the strain partitioning between crustal thickening and lateral extruding of its lithosphere. Located between the Tibetan Plateau and the Tian Shan Range, the Tarim Basin and its several kilometres thick Cenozoic sediments derived from the surrounding mountain belts are key recorders to reconstruct the evolution of the latters. Moreover, this basin is often considered as a relatively rigid block, which behaved as a secondary ``indenter'' transmitting collisional stresses to the Tian Shan. However, due to the size of the Tarim and its thick Cenozoic sedimentary series hiding most of its structures, the constraints on the spatial distribution and timing of the its Cenozoic deformation remain fragmentary. Therefore, the main objective of our study was to produce a synthetic view of this deformation at the scale of the whole basin. Based on numerous surface and subsurface data (satellite images, field surveys, seismic profiles, and well data), we established a tectonic map of the Cenozoic structures in the region and built balanced geological cross-sections across the basin. Our surface and subsurface observations confirm that, contrary to what had been proposed, the Tarim block has also undergone a major deformation during the Cenozoic. The quantification and history of this deformation provide useful insights into the modalities of the crustal shortening in the area and the problems of stress propagation and strain partitioning following the Indo-Asian collision.

Mid Cenozoic freshwater wetlands of the Sunda region

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Robert J. Morley

2013-08-01

Full Text Available The Sunda region was the scene of widespread rifting during the mid-Cenozoic, resulting in the development of numerous large lake-filled rifts, analogous in scale to the rift valley system of East Africa. The Tonle Sap in Cambodia forms the closest modern analogue for these lakes in the Southeast Asian region. Many of the palaeolakes were long lived, continuing uninterrupted as open lakes for several millions of years during the Oligocene. Smaller rift systems infilled with fluvial sediments, but the larger ones remained as lakes, and with Late Oligocene subsidence, were transformed by brackish, and in the earliest Miocene, by marine incursion, into large inland seas. These seas reached their greatest extent at the time of the mid Miocene thermal maximum. This paper describes the development and eventual demise of these lakes following marine transgression, and, based on their rich content of pollen and spores, illustrates the variety of fresh and brackish water swamp communities which developed around their margins. The marginal swamps can be divided into: i seasonally inundated swamps, mainly during the Oligocene, characterised by Barringtonia, Lagerstroemia and grasses/sedges; ii fern swamps and iii from the Late Oligocene onward alluvial swamps, often characterised by Pandanus; and iv peat swamps. The latter can be differentiated into kerapah peat swamps, first occurring during the Oligocene, and basinal peat swamps, becoming widespread from the Early Miocene onward.

Geometry and evolution of low-angle normal faults (LANF) within a Cenozoic high-angle rift system, Thailand: Implications for sedimentology and the mechanisms of LANF development

Science.gov (United States)

Morley, Chris K.

2009-10-01

At least eight examples of large (5-35 km heave), low-angle normal faults (LANFs, 20°-30° dip) occur in the Cenozoic rift basins of Thailand and laterally pass into high-angle extensional fault systems. Three large-displacement LANFs are found in late Oligocene-Miocene onshore rift basins (Suphan Buri, Phitsanulok, and Chiang Mai basins), they have (1) developed contemporaneous with, or after the onset of, high-angle extension, (2) acted as paths for magma and associated fluids, and (3) impacted sedimentation patterns. Displacement on low-angle faults appears to be episodic, marked by onset of lacustrine conditions followed by axial progradation of deltaic systems that infilled the lakes during periods of low or no displacement. The Chiang Mai LANF is a low-angle (15°-25°), high-displacement (15-35 km heave), ESE dipping LANF immediately east of the late early Miocene Doi Inthanon and Doi Suthep metamorphic core complexes. Early Cenozoic transpressional crustal thickening followed by the northward motion of India coupled with Burma relative to east Burma and Thailand (˜40-30 Ma) caused migmatization and gneiss dome uplift in the late Oligocene of the core complex region, followed by LANF activity. LANF displacement lasted 4-6 Ma during the early Miocene and possibly transported a late Oligocene-early Miocene high-angle rift system 35 km east. Other LANFs in Thailand have lower displacements and no associated metamorphic core complexes. The three LANFs were initiated as low-angle faults, not by isostatic rotation of high-angle faults. The low-angle dips appear to follow preexisting low-angle fabrics (thrusts, shear zones, and other low-angle ductile foliations) predominantly developed during Late Paleozoic and early Paleogene episodes of thrusting and folding.

Biogeography of speciation in Cenozoic marine ostracoda: the role of climatic change

Energy Technology Data Exchange (ETDEWEB)

Cronin, T.M.

1985-01-01

Evolutionary theory holds that geographic isolation of populations with its resultant reproductive isolation is an important factor in the origin of new species. Climatic change alters species' biogeography by creating and eliminating barriers that affect gene flow between populations. For benthic organisms such as shallow marine ostracodes, thermal gradients at biogeographic province boundaries and the area of continental shelf are factors affected by climatic and associated sea level changes. Studies of Cenozoic marine ostracodes show that allopatric speciation does not account for paleobiogeographic patterns of species subjected to climatic change. Studies of 127 endemic species from middle latitudes of the western Atlantic show that most speciation events in temperature and subtropical taxa are, in the zoogeographic sense, sympatric or parapatric-clinal and are induced by oceanographic changes related to climatic events rather than geographic isolation of populations. Most ostracode species in middle latitudes are adapted to frequent, cyclical climatic changes typical of these regions and originated during rare periods of major climatic transition. High-latitude arctic-subarctic genera such as Finmarchinella have circumpolar distributions. A parapatric-clinal model accounts for speciation patterns observed in some high-latitude and tropical taxa. However the dynamic nature of thermal gradients and species' biogeography during climatic change renders questionable the controversial distinction between parapatric and allopatric-peripatric speciation models.

From mantle roots to surface eruptions: Cenozoic and Mesozoic continental basaltic magmatism

Czech Academy of Sciences Publication Activity Database

Kämpf, H.; Németh, K.; Puziewicz, J.; Mrlina, Jan; Geissler, W.H.

2015-01-01

Roč. 104, č. 8 (2015), s. 1909-1912 ISSN 1437-3254 Institutional support: RVO:67985530 Keywords : continental basaltic volcanism * BASALT 2013 conference * Cenozoic * Mesozoic Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.133, year: 2015

The Cenozoic geological evolution of the Central and Northern North Sea based on seismic sequence stratigraphy

Energy Technology Data Exchange (ETDEWEB)

Jordt, Henrik

1996-03-01

This thesis represents scientific results from seismic sequence stratigraphic investigations. These investigations and results are integrated into an ongoing mineralogical study of the Cenozoic deposits. the main results from this mineralogical study are presented and discussed. The seismic investigations have provided boundary conditions for a forward modelling study of the Cenozoic depositional history. Results from the forward modelling are presented as they emphasise the influence of tectonics on sequence development. The tectonic motions described were important for the formation of the large oil and gas fields in the North Sea.

Analysing the Cenozoic depositional record

DEFF Research Database (Denmark)

Goledowski, Bartosz; Clausen, O.R.; Nielsen, S.B.

2008-01-01

It is well known that sediment deposition in the North Sea and on the Norwegian Shelf varied significantly during the Cenozoic as a consequence of varying erosion rate mainly in Western Scandinavia, in Scotland and in the Alps. Recent results have demonstrated that a causal relationship exists...... of variations in erosion rates. Here we present the rationale behind the project, the data available and some preliminary results. The dense seismic and well coverage in the area makes it possible to estimate the rate of deposition of matrix mass. Assuming that sediment storage is not important, this provides...... models. The matrix mass deposition history will be compared with the paleoclimate record (e.g. oxygen isotope curves) to see if the previously observed correlation in the eastern North Sea can be extended to other ages and locations.  ...

Cenozoic North American Drainage Basin Evolution, Sediment Yield, and Accumulation in the Gulf of Mexico Basin

Science.gov (United States)

Galloway, W.; Ganey-Curry, P. E.

2010-12-01

The Cenozoic fill of the Gulf of Mexico basin contains a continuous record of sediment supply from the North American continental interior for the past 65 million years. Regional mapping of unit thickness and paleogeography for 18 depositional episodes defines patterns of shifting entry points of continental fluvial systems and quantifies the total volume of sediment supplied during each episode. Eight fluvio-deltaic depocenters, named for geographic similarities to entry points and drainage basins of modern rivers, are present. From southwest to northeast, they are the Rio Bravo, Rio Grande, Guadalupe, Colorado, Houston-Brazos, Red, Mississippi, and Tennessee axes. Sediment volume was calculated from hand-contoured unit thickness maps compiled from basin-wide well and seismic control. Using a GIS algorithm to sum volumes within polygons bounding interpreted North American river contribution, the total extant volume was then calculated. General compaction factors were used to convert modern volume to quantitative approximations of total grain volume. Grain volume rate of supply for each depositional episode was then calculated. Values vary by more than an order of magnitude. Supply rate has commonly varied by two-fold or more between successive depositional episodes. Sediment supply is a significant, independent variable in development of stratigraphic sequences within the Gulf basin. Paleogeographic maps of the continental interior for eleven Cenozoic time intervals display the evolving and complex interplay of intracontinental tectonism, climate change, and drainage basin evolution. Five tectono-climatic eras are differentiated: Paleocene late Laramide era; early to middle Eocene terminal Laramide era; middle Cenozoic (Late Eocene—Early Miocene) dry, volcanogenic era; middle Neogene (Middle—Late Miocene) arid, extensional era; and late Neogene (Plio—Pleistocene) monsoonal, epeirogenic uplift era. Sediment supply to the GOM reflects the interplay of (1

Meso-Cenozoic tectonic evolution of the SE Brazilian continental margin: Petrographic, kinematic and dynamic analysis of the onshore Araruama Lagoon Fault System

Science.gov (United States)

Souza, Pricilla Camões Martins de; Schmitt, Renata da Silva; Stanton, Natasha

2017-09-01

The Ararauama Lagoon Fault System composes one of the most prominent set of lineaments of the SE Brazilian continental margin. It is located onshore in a key tectonic domain, where the basement inheritance rule is not followed. This fault system is characterized by ENE-WSW silicified tectonic breccias and cataclasites showing evidences of recurrent tectonic reactivations. Based on field work, microtectonic, kinematic and dynamic analysis, we reconstructed the paleostresses in the region and propose a sequence of three brittle deformational phases accountable for these reactivations: 1) NE-SW dextral transcurrence; 2) NNW-SSE dextral oblique extension that evolved to NNW-SSE "pure" extension; 3) ENE-WSW dextral oblique extension. These phases are reasonably correlated with the tectonic events responsible for the onset and evolution of the SE onshore rift basins, between the Neocretaceous and Holocene. However, based on petrographic studies and supported by regional geological correlations, we assume that the origin of this fault system is older, related to the Early Cretaceous South Atlantic rifting. This study provides significant information about one of the main structural trends of the SE Brazilian continental margin and the tectonic events that controlled its segmentation, since the Gondwana rifting, and compartmentalization of its onshore sedimentary deposits during the Cenozoic.

Late-Cenozoic relief evolution under evolving climate: A review

OpenAIRE

Champagnac Jean Daniel; Valla Pierre G.; Herman Frédéric

2014-01-01

The present review paper is an attempt to summarize quantitative evidence of Late Cenozoic changes in topographic relief. Different meanings of the word "relief" as it is commonly used and detail the metrics used to quantify it. We then specify methodological tools used to quantify relief change (primarily low temperature thermochronometry and terrestrial cosmogenic nuclides) and analyze published evidence for different regions.Our review first shows that relief changes and rates of changes a...

Cenozoic geology of the Yolomécatl-Tlaxiaco area, Northwestern Oaxaca, Southeastern Mexico: Stratigraphy, structure and regional significance

Science.gov (United States)

Ferrusquía-Villafranca, Ismael; Ruiz-González, José E.; Torres-Hernández, José Ramón; Anderson, Thomas H.; Urrutia-Fucugauchi, Jaime; Martínez-Hernández, Enrique; García-Villegas, Felipe

2016-12-01

The Yolomécatl-Tlaxiaco Area, lies in the rugged Sierra Madre del Sur (SMS) of northwestern Oaxaca (YOTLA), southeastern Mexico. Within the area Cenozoic units unconformably overlie metamorphic, clastic and carbonate rock units of Late Paleozoic to Cretaceous ages as well as the Mixteco/Oaxaca Terrane boundary. The Cenozoic sequence, emphasized herein, includes from botton to top: (1) basal, calcilithitic Early Tertiary Tamazulapam Conglomerate, (2) andesitic lava flows of Nduayaco "Group," (3-4) Epiclastic/pyroclastic strata composing Yolomécatl Formation (∼40.3 ± 1.0 Ma), and Tayata Pyroepiclastics (5) Early Oligocene (∼32.9 Ma), felsic, pyroclastic Nundichi "Group," (6) Late Oligocene (∼27.7 ± 0.7 Ma) andesitic lava flows of Nicananduta "Group" containing intercalations of unit (7) ?Chilapa Formation (largely lacustrine). Quaternary deposits unconformably overlie the sequence. The structural record includes NNW-SSE folds in the Mesozoic units, and one in Tayata Pyroepiclastics, as well as numerous fractures/faults of diverse types, whose pattern seems to roughly define four geographic/structural domains, NW, SW, S, and E. The Tertiary sequence records four magmatic and six deformational events: Pre-Late Eocene Extension accommodated by the Tamazulapam fault, along which magma of the Nduayaco "Group" moved upward. The next episode is the earliest Late Eocene extension recorded by the Yucuxaco-Santa Cruz Tayata fault was followed by accumulation of Yolomécatl Formation, Tayata Pyroepiclastics, and synsedimentary emplacement of tuff sheets at ∼40.3 ± 1.0 Ma. After this date, left lateral transpression emplaced a Teposcolula Limestone block over Nduayaco "Group" and ?Yolomécatl Formation, whereas the Tayata Pyroepiclastics was folded into an open anticline. Movement along the Yucuxaco-Santa Cruz Tayayata fault suite influenced accumulation of the Nundichi "Group" strata ca. ∼32.9 Ma. Subsequent ENE-WSW extension affected the Nundichi "Group," partly

Late Cenozoic Paleoceanography of the Central Arctic Ocean

International Nuclear Information System (INIS)

O'Regan, Matt

2011-01-01

The Arctic Ocean is the smallest and perhaps least accessible of the worlds oceans. It occupies only 26% of the global ocean area, and less than 10% of its volume. However, it exerts a disproportionately large influence on the global climate system through a complex set of positive and negative feedback mechanisms directly or indirectly related to terrestrial ice and snow cover and sea ice. Increasingly, the northern high latitude cryosphere is seen as an exceptionally fragile part of the global climate system, a fact exemplified by observed reductions in sea ice extent during the past decades [2]. The paleoceanographic evolution of the Arctic Ocean can provide important insights into the physical forcing mechanisms that affect the form, intensity and permanence of ice in the high Arctic, and its sensitivity to these mechanisms in vastly different climate states of the past. However, marine records capturing the late Cenozoic paleoceanography of the Arctic are limited - most notably because only a single deep borehole exists from the central parts of this Ocean. This paper reviews the principal late Cenozoic (Neogene/Quaternary) results from the Arctic Coring Expedition to the Lomonosov Ridge and in light of recent data and observations on modern sea ice, outlines emerging questions related to three main themes: 1) the establishment of the 'modern' Arctic Ocean and the opening of the Fram Strait 2) the inception of perennial sea ice 3) The Quaternary intensification of Northern Hemisphere glaciations.

Late Cenozoic History of the Genus Micromys (Mammalia, Rodentia) in Central Europe

Czech Academy of Sciences Publication Activity Database

Horáček, I.; Knitlová, M.; Wagner, Jan; Kordos, L.; Nadachowski, A.

2013-01-01

Roč. 8, č. 5 (2013), e62498 E-ISSN 1932-6203 R&D Projects: GA ČR GA205/09/0184 Institutional support: RVO:67985831 Keywords : Mammalia * Rodentia * Genus Micromys * Late Cenozoic Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.534, year: 2013

A Paleocene penguin from New Zealand substantiates multiple origins of gigantism in fossil Sphenisciformes

OpenAIRE

Mayr, Gerald; Scofield, R. Paul; De Pietri, Vanesa L.; Tennyson, Alan J. D.

2017-01-01

One of the notable features of penguin evolution is the occurrence of very large species in the early Cenozoic, whose body size greatly exceeded that of the largest extant penguins. Here we describe a new giant species from the late Paleocene of New Zealand that documents the very early evolution of large body size in penguins. Kumimanu biceae, n. gen. et sp. is larger than all other fossil penguins that have substantial skeletal portions preserved. Several plesiomorphic features place the ne...

Fires in the Cenozoic: a late flowering of flammable ecosystems

OpenAIRE

Bond, William J.

2015-01-01

Modern flammable ecosystems include tropical and subtropical savannas, steppe grasslands, boreal forests, and temperate sclerophyll shrublands. Despite the apparent fiery nature of much contemporary vegetation, terrestrial fossil evidence would suggest we live in a time of low fire activity relative to the deep past. The inertinite content of coal, fossil charcoal, is strikingly low from the Eocene to the Pleistocene and no charcoalified mesofossils have been reported for the Cenozoic. Marine...

The gap in the Arctic Cenozoic Record: Expect the Unexpected

Science.gov (United States)

Sangiorgi, F.; Brumsack, H.; Schouten, S.; Brinkhuis, H.; Kaminski, M. A.; Reichart, G.; Stickley, C. E.; Willard, D. A.; Sinninghe Damste', J. S.

2006-12-01

Integrated Ocean Drilling Program Expedition 302, a.k.a. the Arctic Coring Expedition (ACEX), drilled more than 400 meters below the seafloor at the central Lomonosov Ridge, ca 250 km from the modern North Pole in water depths of about 1300 m. The partially recovered sediments provide a unique record of the geological and paleoceanographical evolution of the Arctic Ocean during the Cenozoic. The record indicates a transition from a "greenhouse world", characterized by a relative shallow marine setting, with organic-rich sediment and frequent brackish or even fresh surface waters during the latest Palaeocene and the early Eocene, to an "icehouse world" of hemipelagic sedimentation affected by the occurrence of sea ice from the middle Miocene to present. Much to our surprise, these two states are separated by a major hiatus, not obvious from the seismic record and the lithology of the cores, spanning at least 25 Ma as derived from dinocyst and benthic foraminifer stratigraphies. These testify that deposits of probable late early Miocene age directly overlie early middle Eocene sediments. To unravel the nature of the hiatus, we performed a multiproxy micropaleontological and geochemical study on the surrounding record, i.e. lithological units 1/6, 1/5 and 1/4, where the sediment changes from homogeneous dark into a cm-scaled alternation ("zebra-like") black and grey bands to light grey, blue and reddish-brown. Paleoenvironmental reconstructions based on organic-walled dinoflagellate cysts, pollen and spores, benthic foraminifera, inorganic and organic geochemistry and siliceous remains reveal conspicuous changes, suggesting a transition from brackish-freshwater to shallow-lagoonal and to open marine environments. These environmental turnovers, coupled with the occurrence of such a large hiatus, cannot be due to climatic shifts alone, but suggest that major tectonic rearrangements likely changed the depositional setting. On-going organic geochemical analysis will be

The origins, early development and status of Bourdieu's concept of 'cultural capital'.

Science.gov (United States)

Robbins, Derek

2005-03-01

The paper examines the context of the first introduction of the concept of 'cultural capital' in the sociology of education analyses undertaken in the early 1960s and published by Bourdieu in collaboration with Jean-Claude Passeron in 'Les etudiants et leurs etudes' (1964a) and Les Heritiers (1964b). It first considers the cultural contexts within which Bourdieu's thinking about culture originated--both in relation to his social origins and in relation to his intellectual training. It then examines the extent to which Bourdieu's early anthropological research in Algeria was influenced by his knowledge of American acculturation theory. It concludes that Bourdieu sought to use acculturation theory in a distinctive way--one which he articulated more confidently as he explored the relationship between agency and structural explanation in the late 1960s and early 1970s. The specific educational researches which stimulated the articulation of the concept of 'linguistic' or 'cultural' capital belonged to the period in which Bourdieu was only just beginning to refine his post-structuralist philosophy of social scientific explanation. To use these concepts now involves deploying them reflexively in accordance with Bourdieu's later thinking rather than at face value as they were first developed during the period in which he and Passeron were 'apprentice' researchers.

Precise U-Pb dating of Cenozoic tropical reef carbonates: Linking the evolution of Cenozoic Caribbean reef carbonates to climatic and environmental changes.

Science.gov (United States)

Silva-Tamayo, J. C.; Ducea, M.; Cardona, A.; Montes, C.; Rincon, D.; Machado, A.; Flores, A.; Sial, A.; Pardo, A.; Niño, H.; Ramirez, V.; Jaramillo, C.; Zapata, P.; Barrios, L.; Rosero, S.; Bayona, G.; Zapata, V.

2012-04-01

Coral reefs are very diverse and productive ecosystems; and have long been the base of the economic activity of several countries along the tropics. Because coral reefs are very sensitive to environmental changes and their adaptation to changing stressing conditions is very slow, the combination of current rapid environmental changes and the additional stresses created by growing human populations (i.e. rapid anthropogenic CO2 additions to the atmosphere),plus the economic and coastal development may become a lethal synergy. The ongoing acidification of modern oceans is a major issue of concern because it may have serious consequences for the survival of shelly marine invertebrates as the 21st century progresses. Ocean Acidification (OA) is now being driven by rapid CO2 release to the atmosphere. Although evidences of the devastating effects of oceanic acidification in the marine biota are provided by the decreased rate of coral skeleton production and the reduced ability of algae and free-swimming zooplankton to maintain protective shells, among others, predicting the effects of oceanic acidification on the future oceans (2050-2100) has remained rather difficult because the atmospheric CO2 sequestration by the global oceans occurs in geologic time scales. Important changes in the atmospheric pCO2 and major climatic/environmental events seem to have controlled the evolution of the Cenozoic equatorial-tropical carbonates r1-10. Rapid additions of green house gases to the atmosphere occurred during the Paleocene-Eocene transition and would have promoted several other events of global warming until the early Oligocene (i.e. the Eocene thermal maximum). These periods of high greenhouse gases concentrations would have also resulted on OA, affecting the reef carbonate ecology and tropical carbonate budgets. Relating temporal variations in the Cenozoic reef carbonate structure, ecology and factory is vital to help understanding and predicting the future effects of the

The Amazonian Craton and its influence on past fluvial systems (Mesozoic-Cenozoic, Amazonia)

NARCIS (Netherlands)

Hoorn, C.; Roddaz, M.; Dino, R.; Soares, E.; Uba, C.; Ochoa-Lozano, D.; Mapes, R.; Hoorn, C.; Wesselingh, F.P.

2010-01-01

The Amazonian Craton is an old geological feature of Archaean/Proterozoic age that has determined the character of fluvial systems in Amazonia throughout most of its past. This situation radically changed during the Cenozoic, when uplift of the Andes reshaped the relief and drainage patterns of

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.

Age relationships and tectonic implications of late Cenozoic basaltic volcanism in Northland, New Zealand

Energy Technology Data Exchange (ETDEWEB)

Smith, I E.M. [Department of Geology, Auckland University, Auckland (New Zealand); Okada, T [Okayama University of Science, Hiruzen Research Institute, Okayama (Japan); Itaya, T [Okayama University of Science, Hiruzen Research Institute, Okayama (Japan); Black, P M [Department of Geology, Auckland University, Auckland (New Zealand)

1993-07-01

An episode of late Miocene-Recent essentially basaltic volcanism is the latest in a sequence of magmatic events recognised in the tectonically complex geological development of the Northland Peninsula. New K-Ar dates together with an extensive collection of new major and trace element chemical analyses prompt a reassessment of the significance of these late Cenozoic basalts. The main time/space groupings recognised are Tertiary volcanics in the Kaikohe-Bay of Islands, Puhipuhi, Ti Point, and Stony Batter areas and Quaternary basalts in the Kaikohe-Bay of Islands and Whangarei areas and at Tara. Basalts in the Kaikohe-Bay of Islands area are transitional to alkalic in character, while those in the south are transitional to tholeiitic, with the Ti Point and Stony Batter rocks being geochemically distinct. A consistent model for these observations is that the magmas originate from different levels of a layered mantle source in which the upper part carries a geochemical signature inherited from an earlier subduction event. (author). 27 refs., 7 figs., 1 tab.

Age relationships and tectonic implications of late Cenozoic basaltic volcanism in Northland, New Zealand

International Nuclear Information System (INIS)

Smith, I.E.M.; Okada, T.; Itaya, T.; Black, P.M.

1993-01-01

An episode of late Miocene-Recent essentially basaltic volcanism is the latest in a sequence of magmatic events recognised in the tectonically complex geological development of the Northland Peninsula. New K-Ar dates together with an extensive collection of new major and trace element chemical analyses prompt a reassessment of the significance of these late Cenozoic basalts. The main time/space groupings recognised are Tertiary volcanics in the Kaikohe-Bay of Islands, Puhipuhi, Ti Point, and Stony Batter areas and Quaternary basalts in the Kaikohe-Bay of Islands and Whangarei areas and at Tara. Basalts in the Kaikohe-Bay of Islands area are transitional to alkalic in character, while those in the south are transitional to tholeiitic, with the Ti Point and Stony Batter rocks being geochemically distinct. A consistent model for these observations is that the magmas originate from different levels of a layered mantle source in which the upper part carries a geochemical signature inherited from an earlier subduction event. (author). 27 refs., 7 figs., 1 tab

The Origin of the Soul from Antiquity to the early Modern Period

NARCIS (Netherlands)

Spruit, L.

2014-01-01

The origin of the soul became a systematic subject of speculation in Greek philosophy and medicine. In early Christian thought, three theories evolved: the soul was held to be either generated from the parents (traducianism) or it was believed to be formed by a special act of creation on God’s part

Footprints pull origin and diversification of dinosaur stem lineage deep into Early Triassic.

Science.gov (United States)

Brusatte, Stephen L; Niedźwiedzki, Grzegorz; Butler, Richard J

2011-04-07

The ascent of dinosaurs in the Triassic is an exemplary evolutionary radiation, but the earliest phase of dinosaur history remains poorly understood. Body fossils of close dinosaur relatives are rare, but indicate that the dinosaur stem lineage (Dinosauromorpha) originated by the latest Anisian (ca 242-244 Ma). Here, we report footprints from the Early-Middle Triassic of Poland, stratigraphically well constrained and identified using a conservative synapomorphy-based approach, which shifts the origin of the dinosaur stem lineage back to the Early Olenekian (ca 249-251 Ma), approximately 5-9 Myr earlier than indicated by body fossils, earlier than demonstrated by previous footprint records, and just a few million years after the Permian/Triassic mass extinction (252.3 Ma). Dinosauromorph tracks are rare in all Polish assemblages, suggesting that these animals were minor faunal components. The oldest tracks are quadrupedal, a morphology uncommon among the earliest dinosauromorph body fossils, but bipedality and moderately large body size had arisen by the Early Anisian (ca 246 Ma). Integrating trace fossils and body fossils demonstrates that the rise of dinosaurs was a drawn-out affair, perhaps initiated during recovery from the Permo-Triassic extinction.

Geochemistry and petrology of pyroxenite xenoliths from Cenozoic alkaline basalts, Bohemian Massif

Czech Academy of Sciences Publication Activity Database

Ackerman, Lukáš; Špaček, Petr; Medaris Jr., G.; Hegner, E.; Svojtka, Martin; Ulrych, Jaromír

2012-01-01

Roč. 57, č. 4 (2012), s. 199-219 ISSN 1802-6222 R&D Projects: GA ČR(CZ) GA205/09/1170 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z30120515 Institutional support: RVO:67985831 ; RVO:67985530 Keywords : pyroxenite * xenolith * Cenozoic * basalt * Sr-Nd isotopes * geothermobarometry Subject RIV: DD - Geochemistry Impact factor: 0.804, year: 2012

Biomarkers and their stable isotopes in Cenozoic sediments above the Chicxulub impact crater

Science.gov (United States)

Grice, K.; Schaefer, B.; Coolen, M.; Greenwood, P. F.; Scarlett, A. G.; Freeman, K.; Lyons, S. L.

2017-12-01

The most widely accepted hypothesis for the cause of the End-Cretaceous mass extinction (K/Pg event) 66 Ma ago is the impact of an extra-terrestrial body, which produced the 200 km wide Chicxulub impact structure. This event led to an extinction of 75% of all species on Earth. The massive extinction in the terrestrial realm is partly attributed to the intense heat pulse, the widespread wild fires caused by the impact and the ensuing darkness, as dust and sulfate aerosols blocked out the sun leading to photosynthesis shut off and productivity collapse in both the terrestrial and marine realms. The marine realm may additionally have experienced ocean acidification resulting in mass extinction of plankton (foraminifera and coccolithophorids) and marine reptiles. Samples from the Cenozoic marine sediments including the Paleocene-Eocene Thermal Maximum (PETM) have been extracted for hydrocarbons and analysed to investigate the molecular and isotopic organic record of biotic and environmental change after the K/Pg boundary event. Specific biomarker-precursor relationship has been established by the direct correlation of sedimentary biomarkers with the biochemicals (e.g. lipids) of extant biological systems. The structural characterisation of biomarkers as well as their stable isotopic compositions (C, H and N) are used to evaluate the source(s) of organic matter (OM) and to reconstruct paleoenvironmental depositional conditions. Throughout the Cenozoic sediments (including the PETM) the biomarker distribution suggests a variation in the source of organic matter from terrestrial to marine. Furthermore, the presence of sulfurised biomarkers indicates euxinic environmental conditions at the time of deposition. Biomarker distributions indicative of green sulfur bacteria reveal persistent photic zone euxinic conditions at several intervals in the Cenozoic. Further compound specific isotope analyses will provide insights into the long-term biogeochemical cycling of C, H and S

Late cenozoic magmatism in the South Patagonian batholith: SHRIMP U-Pb zircon age evidence

International Nuclear Information System (INIS)

Fanning, C.M; Herve, F; Pankhurst, R.J; Thomson, S; Faundez, V

2001-01-01

The North Patagonian Batholith (NPB) has a zonal age pattern which includes a well defined belt of Miocene and Mio-Pliocene plutons in its central portion (Pankhurst et al., 1999) which are spatially, and probably genetically related to the Liquine-Ofqui Fault Zone. Previous geochronological studies in the Southern Patagonian Batholith (SPB), as summarized by Bruce et al. (1991), have yielded 9 late Cenozoic K-Ar or Ar-Ar ages out of a total of 116 age determinations. None of these young ages correspond to U-Pb determinations on zircons, and some of the young ages correspond to satellite plutons east of the SPB proper, such as the Torres del Paine intrusion. In this paper we present the first late Cenozoic SHRIMP U-Pb zircon ages in the area of the SPB. The morphology of the analysed zircon crystals is described and leads to some inferences on the methodology and on the geological interpretation of the obtained ages (au)

Extensional vs contractional Cenozoic deformation in Ibiza (Balearic Promontory, Spain): Integration in the West Mediterranean back-arc setting

Science.gov (United States)

Etheve, Nathalie; Frizon de Lamotte, Dominique; Mohn, Geoffroy; Martos, Raquel; Roca, Eduard; Blanpied, Christian

2016-07-01

Based on field work and seismic reflection data, we investigate the Cenozoic tectono-sedimentary evolution offshore and onshore Ibiza allowing the proposal of a new tectonic agenda for the region and its integration in the geodynamic history of the West Mediterranean. The late Oligocene-early Miocene rifting event, which characterizes the Valencia Trough and the Algerian Basin, located north and south of the study area respectively, is also present in Ibiza and particularly well-expressed in the northern part of the island. Among these two rifted basins initiated in the frame of the European Cenozoic Rift System, the Valencia Trough failed rapidly while the Algerian Basin evolved after as a back-arc basin related to the subduction of the Alpine-Maghrebian Tethys. The subsequent middle Miocene compressional deformation was localized by the previous extensional faults, which were either inverted or passively translated depending on their initial orientation. Despite the lateral continuity between the External Betics and the Balearic Promontory, it appears from restored maps that this tectonic event cannot be directly related to the Betic orogen, but results from compressive stresses transmitted through the Algerian Basin. A still active back-arc asthenospheric rise likely explains the stiff behavior of this basin, which has remained poorly deformed up to recent time. During the late Miocene a new extensional episode reworked the southern part of the Balearic Promontory. It is suggested that this extensional deformation developed in a trans-tensional context related to the westward translation of the Alboran Domain and the coeval right-lateral strike-slip movement along the Emile Baudot Escarpment bounding the Algerian Basin to the north.

Glacial removal of late Cenozoic subglacially emplaced volcanic edifices by the West Antarctic ice sheet

Science.gov (United States)

Behrendt, John C.; Blankenship, D.D.; Damaske, D.; Cooper, A. K.

1995-01-01

Local maxima of the horizontal gradient of pseudogravity from closely spaced aeromagnetic surveys over the Ross Sea, northwestern Ross Ice Shelf, and the West Antarctic ice sheet, reveal a linear magnetic rift fabric and numerous subcircular, high-amplitude anomalies. Geophysical data indicate two or three youthful volcanic edifices at widely separated areas beneath the sea and ice cover in the West Antarctic rift system. In contrast, we suggest glacial removal of edifices of volcanic sources of many more anomalies. Magnetic models, controlled by marine seismic reflection and radar ice-sounding data, allow us to infer that glacial removal of the associated late Cenozoic volcanic edifices (probably debris, comprising pillow breccias, and hyaloclastites) has occurred essentially concomitantly with their subglacial eruption. "Removal' of unconsolidated volcanic debris erupted beneath the ice is probably a more appropriate term than "erosion', given its fragmented, ice-contact origin. The exposed volcanoes may have been protected from erosion by the surrounding ice sheet because of more competent rock or high elevation above the ice sheet. -from Authors

Origin of Bacteriochlorophyll a and the Early Diversification of Photosynthesis.

Directory of Open Access Journals (Sweden)

Tanai Cardona

Full Text Available Photosynthesis originated in the domain Bacteria billions of years ago; however, the identity of the last common ancestor to all phototrophic bacteria remains undetermined and speculative. Here I present the evolution of BchF or 3-vinyl-bacteriochlorophyll hydratase, an enzyme exclusively found in bacteria capable of synthetizing bacteriochlorophyll a. I show that BchF exists in two forms originating from an early divergence, one found in the phylum Chlorobi, including its paralogue BchV, and a second form that was ancestral to the enzyme found in the remaining anoxygenic phototrophic bacteria. The phylogeny of BchF is consistent with bacteriochlorophyll a evolving in an ancestral phototrophic bacterium that lived before the radiation event that gave rise to the phylum Chloroflexi, Chlorobi, Acidobacteria, Proteobacteria, and Gemmatimonadetes, but only after the divergence of Type I and Type II reaction centers. Consequently, it is suggested that the lack of phototrophy in many groups of extant bacteria is a derived trait.

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.

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

Fossil Cenozoic crassatelline bivalves from Peru: New species and generic insights

Directory of Open Access Journals (Sweden)

Thomas J. DeVries

2016-08-01

Full Text Available Discoveries of new fossil Cenozoic crassatellines in Peru provide a new phylogenetic perspective on “large” Neogene genera, in which four lineages are considered to have arisen independently from different Paleogene Crassatella ancestors. Latest Oligocene and early Miocene species of the new genus Tilicrassatella gen. nov.―T. ponderosa, T. torrens sp. nov., and T. sanmartini sp. nov. from the East Pisco Basin―probably evolved from the late Eocene species, Crassatella rafaeli sp. nov., which itself differed in significant respects from slightly older species of the East Pisco Basin, C. neorhynchus and C. pedroi sp. nov. The paciphilic genus, Hybolophus, is raised to full generic status. Added to its ranks are the East Pisco Miocene species H. maleficae sp. nov., H. terrestris sp. nov., and the oldest species of the genus, the late Eocene or Oligocene H. disenum sp. nov. from the Talara Basin of northern Peru. Kalolophus gen. nov., encompassing circum-Caribbean fossil species, the extant species, K. speciosus, and the trans-isthmus species, K. antillarum, appears to have evolved from the early Oligocene Floridian species, Crassatella portelli sp. nov. The genus Marvacrassatella is a western Atlantic Miocene lineage most likely descended from Kalolophus. The genus Eucrassatella is restricted to Australian and New Zealand taxa. The Eocene New Zealand species, Spissatella media, is transferred to Eucrassatella and deemed a candidate for the most recent common ancestor of younger Eucrassatella and all Spissatella species. In the southern Pacific Ocean, the circum-Caribbean region, and tropical western America, crassatelline lineages developed one or more of the following characters: large resilifers, smooth ventral margins, and an extended left anterior cardinal tooth. Some of these late Paleogene convergent character changes might have countered increased shear forces exerted on the crassatelline valves while burrowing into finer-grained and

Construction of the seawater 87Sr/86Sr curve for the Cenozoic and Cretaceous: supporting data

International Nuclear Information System (INIS)

Koepnick, R.B.; Burke, W.H.; Denison, R.E.; Hetherington, E.A.; Nelson, H.F.; Otto, J.B.; Waite, L.E.

1985-01-01

We present the data used to construct the Cenozoic and Cretaceous portion of the Phanerozoic curve of seawater 87 Sr/ 86 Sr that had been given in summary form by W.H. Burke and coworkers. All Cenozoic samples (128) and 22 Cretaceous samples are foram-nannofossil oozes and limestones from DSDP cores distributed among 13 sites in the Atlantic, Pacific and Indian Oceans, and the Caribbean Sea. Non-DSDP Cretaceous samples (126) include limestone, anhydrite and phosphate samples from North America, Europe and Asia. Determination of the 87 Sr/ 86 Sr value of seawater at particular times in the past is based on comparison of ratios derived from coeval marine samples from widely separated geographic areas. The general configuration of the Cenozoic and Cretaceous curve appears to be strongly influenced by the history of plate interactions and sea-floor spreading. Specific rises and falls in the 87 Sr/ 86 Sr of seawater, however, may be caused by a variety of factors such as variation in lithologic composition of the crust exposed to weathering, configuration and topographic relief of continents, volcanic activity, rate of sea-floor spreading, extent of continental inundation by epeiric seas, and variations in both climate and paleo-oceanographic conditions. Many or all of these factors are probably related to global tectonic processes, yet their combined effect on the temporal variation of seawater 87 Sr/ 86 Sr can complicate a direct plate-tectonic interpretation for portions of the seawater curve. (Auth.)

Late Cenozoic fluvial successions in northern and western India: an overview and synthesis

Science.gov (United States)

Sinha, R.; Kumar, R.; Sinha, S.; Tandon, S. K.; Gibling, M. R.

2007-11-01

Late Cenozoic fluvial successions are widespread in India. They include the deposits of the Siwalik basin which represent the accumulations of the ancient river systems of the Himalayan foreland basin. Palaeomagnetic studies reveal that fluvial architecture and styles of deposition were controlled by Himalayan tectonics as well as by major climatic fluctuations during the long (∼13 Ma) span of formation. The Indo-Gangetic plains form the world's most extensive Quaternary alluvial plains, and display spatially variable controls on sedimentation: Himalayan tectonics in the frontal parts, climate in the middle reaches, and eustasy in the lower reaches close to the Ganga-Brahmaputra delta. Climatic effects were mediated by strong fluctuations in the SW Indian Monsoon, and Himalayan rivers occupy deep valleys in the western Ganga plains where stream power is high, cut in part during early Holocene monsoon intensification; the broad interfluves record the simultaneous aggradation of plains-fed rivers since ∼100 ka. The eastward increase in precipitation across the Ganga Plains results in rivers with low stream power and a very high sediment flux, resulting in an aggradational mode and little incision. The river deposits of semi-arid to arid western India form important archives of Quaternary climate change through their intercalation with the eolian deposits of the Thar Desert. Although the synthesis documents strong variability-both spatial and temporal-in fluvial stratigraphy, climatic events such as the decline in precipitation during the Last Glacial Maximum and monsoon intensification in the early Holocene have influenced fluvial dynamics throughout the region.

Dual odontogenic origins develop at the early stage of rat maxillary incisor development.

Science.gov (United States)

Kriangkrai, Rungarun; Iseki, Sachiko; Eto, Kazuhiro; Chareonvit, Suconta

2006-03-01

Developmental process of rat maxillary incisor has been studied through histological analysis and investigation of tooth-related gene expression patterns at initial tooth development. The tooth-related genes studied here are fibroblast growth factor-8 (Fgf-8), pituitary homeobox gene-2 (Pitx-2), sonic hedgehog (Shh), muscle segment homeobox-1 (Msx-1), paired box-9 (Pax-9) and bone morphogenetic protein-4 (Bmp-4). The genes are expressed in oral epithelium and/or ectomesenchyme at the stage of epithelial thickening to the early bud stage of tooth development. Both the histological observation and tooth-related gene expression patterns during early stage of maxillary incisor development demonstrate that dual odontogenic origins aligned medio-laterally in the medial nasal process develop, subsequently only single functional maxillary incisor dental placode forms. The cascade of tooth-related gene expression patterns in rat maxillary incisor studied here is quite similar to those of the previous studies in mouse mandibular molar, even though the origins of oral epithelium and ectomesenchyme involved in development of maxillary incisor and mandibular molar are different. Thus, we conclude that maxillary incisor and mandibular molar share a similar signaling control of Fgf-8, Pitx-2, Shh, Msx-1, Pax-9 and Bmp-4 genes at the stage of oral epithelial thickening to the early bud stage of tooth development.

Origin of frontal lobe spikes in the early onset benign occipital lobe epilepsy (Panayiotopoulos syndrome).

Science.gov (United States)

Leal, Alberto J R; Ferreira, José C; Dias, Ana I; Calado, Eulália

2008-09-01

Early onset benign occipital lobe epilepsy (Panayiotopoulos syndrome [PS]) is a common and easily recognizable epilepsy. Interictal EEG spike activity is often multifocal but most frequently localized in the occipital lobes. The origin and clinical significance of the extra-occipital spikes remain poorly understood. Three patients with the PS and interictal EEG spikes with frontal lobe topography were studied using high-resolution EEG. Independent component analysis (ICA) was used to decompose the spikes in components with distinct temporal dynamics. The components were mapped in the scalp with a spline-laplacian algorithm. The change in scalp potential topography from spike onset to peak, suggests the contribution of several intracranial generators, with different kinetics of activation and significant overlap. ICA was able to separate the major contributors to frontal spikes and consistently revealed an early activating group of components over the occipital areas in all the patients. The local origin of these early potentials was established by the spline-laplacian montage. Frontal spikes in PS are consistently associated with early and unilateral occipital lobe activation, suggesting a postero-anterior spike propagation. Frontal spikes in the PS represent a secondary activation triggered by occipital interictal discharges and do not represent an independent focus.

Reviewing the current evidence supporting early B-cells as the cellular origin of Merkel cell carcinoma.

Science.gov (United States)

Sauer, C M; Haugg, A M; Chteinberg, E; Rennspiess, D; Winnepenninckx, V; Speel, E-J; Becker, J C; Kurz, A K; Zur Hausen, A

2017-08-01

Merkel cell carcinoma (MCC) is a highly malignant skin cancer characterized by early metastases and poor survival. Although MCC is a rare malignancy, its incidence is rapidly increasing in the U.S. and Europe. The discovery of the Merkel cell polyomavirus (MCPyV) has enormously impacted our understanding of its etiopathogenesis and biology. MCCs are characterized by trilinear differentiation, comprising the expression of neuroendocrine, epithelial and B-lymphoid lineage markers. To date, it is generally accepted that the initial assumption of MCC originating from Merkel cells (MCs) is unlikely. This is owed to their post-mitotic character, absence of MCPyV in MCs and discrepant protein expression pattern in comparison to MCC. Evidence from mouse models suggests that epidermal/dermal stem cells might be of cellular origin in MCC. The recently formulated hypothesis of MCC originating from early B-cells is based on morphology, the consistent expression of early B-cell lineage markers and the finding of clonal immunoglobulin chain rearrangement in MCC cells. In this review we elaborate on the cellular ancestry of MCC, the identification of which could pave the way for novel and more effective therapeutic regimens. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

New insights into the distribution and evolution of the Cenozoic Tan-Lu Fault Zone in the Liaohe sub-basin of the Bohai Bay Basin, eastern China

Science.gov (United States)

Huang, Lei; Liu, Chi-yang; Xu, Chang-gui; Wu, Kui; Wang, Guang-yuan; Jia, Nan

2018-01-01

As the largest strike-slip fault system in eastern China, the northeast-trending Tan-Lu Fault Zone (TLFZ) is a significant tectonic element contributing to the Mesozoic-Cenozoic regional geologic evolution of eastern Asia, as well as to the formation of ore deposits and oilfields. Because of the paucity of data, its distribution and evolutionary history in the offshore Liaohe sub-basin of the northern Bohai Bay Basin (BBB) are still poorly understood. Investigations of the strike-slip fault system in the western portion of the offshore Liaohe sub-basin via new seismic data provide us with new insights into the characteristics of the Cenozoic TLFZ. Results of this study show that Cenozoic dextral strike-slip faults occurred near the center of the Liaoxi graben in the offshore Liaohe sub-basin; these strike-slip faults connect with their counterparts to the north, the western part of the onshore Liaohe sub-basin, and have similar characteristics to those in other areas of the BBB in terms of kinematics, evolutionary history, and distribution; consequently, these faults are considered as the western branch of the TLFZ. All strike-slip faults within the Liaoxi graben merge at depth with a central subvertical basement fault induced by the reactivation of a pre-existing strike-slip basement fault, the pre-Cenozoic TLFZ. Data suggest that the TLFZ across the whole Liaohe sub-basin comprises two branches and that the Cenozoic distribution of this system was inherited from the pre-Cenozoic TLFZ. This characteristic distribution might be possessed by the whole TLFZ, thus the new understandings about the distribution and evolutionary model of the TLFZ in this study can be inferred in many research fields along the whole fault zone, such as regional geology, ore deposits, petroleum exploration and earthquake hazard.

Stratigraphy of the late Cenozoic sediments beneath the 216-A Crib Facilities

International Nuclear Information System (INIS)

Fecht, K.R.; Last, G.V.; Marratt, M.C.

1979-02-01

The stratigraphy of the late Cenozoic sediments beneath the 216-A Crib Facilities is presented as lithofacies cross sections and is based on textural variations of the sedimentary sequence lying above the basalt bedrock. The primary source of data in this study is geologic information obtained from well drilling operations and geophysical logging. Stratigraphic interpretations are based primarily on textural analysis and visual examination of sediment samples and supplemented by drillers logs and geophysical logs

Unusual ruby-sapphire transition in alluvial megacrysts, Cenozoic basaltic gem field, New England, New South Wales, Australia

Science.gov (United States)

Sutherland, Frederick L.; Graham, Ian T.; Harris, Stephen J.; Coldham, Terry; Powell, William; Belousova, Elena A.; Martin, Laure

2017-05-01

Rare ruby crystals appear among prevailing sapphire crystals mined from placers within basaltic areas in the New England gem-field, New South Wales, Australia. New England ruby (NER) has distinctive trace element features compared to those from ruby elsewhere in Australia and indeed most ruby from across the world. The NER suite includes ruby (up to 3370 ppm Cr), pink sapphire (up to 1520 ppm Cr), white sapphire (up to 910 ppm) and violet, mauve, purple, or bluish sapphire (up to 1410 ppm Cr). Some crystals show outward growth banding in this respective colour sequence. All four colour zones are notably high in Ga (up to 310 ppm) and Si (up to 1820 ppm). High Ga and Ga/Mg values are unusual in ruby and its trace element plots (laser ablation-inductively coupled plasma-mass spectrometry) and suggests that magmatic-metasomatic inputs were involved in the NER suite genesis. In situ oxygen isotope analyses (secondary ion mass spectrometry) across the NER suite colour range showed little variation (n = 22; δ18O = 4.4 ± 0.4, 2σ error), and are values typical for corundum associated with ultramafic/mafic rocks. The isolated NER xenocryst suite, corroded by basalt transport and with few internal inclusions, presents a challenge in deciphering its exact origin. Detailed consideration of its high Ga chemistry in relation to the known geology of the surrounding region was used to narrow down potential sources. These include Late Palaeozoic-Triassic fractionated I-type granitoid magmas or Mesozoic-Cenozoic felsic fractionates from basaltic magmas that interacted with early Palaeozoic Cr-bearing ophiolite bodies in the New England Orogen. Other potential sources may lie deeper within lower crust-mantle metamorphic assemblages, but need to match the anomalous high-Ga geochemistry of the New England ruby suite.

Seismic facies and stratigraphy of the Cenozoic succession in McMurdo Sound, Antarctica: Implications for tectonic, climatic and glacial history

Science.gov (United States)

Fielding, C.R.; Whittaker, J.; Henrys, S.A.; Wilson, T.J.; Nash, T.R.

2007-01-01

A new stratigraphic model is presented for the evolution of the Cenozoic Victoria Land Basin of the West Antarctic Rift, based on integration of seismic reflection and drilling data. The Early Rift phase (?latest Eocene to Early Oligocene) comprises wedges of strata confined by early extensional faults, and which contain seismic facies consistent with drainage via coarse-grained fans and deltas into discrete, actively subsiding grabens and half-grabens. The Main Rift phase (Early Oligocene to Early Miocene) comprises a lens of strata that thickens symmetrically from the basin margins into a central depocenter, and in which stratal events pass continuously over the top of the Early Rift extensional topography. Internal seismic facies and lithofacies indicate a more organized, cyclical shallow marine succession, influenced increasingly upward by cycles of glacial advance and retreat into the basin. The Passive Thermal Subsidence phase (Early Miocene to ?) comprises an evenly distributed sheet of strata that does not thicken appreciably into the depocentre, with more evidence for clinoform sets and large channels. These patterns are interpreted to record accumulation under similar environmental conditions but in a regime of slower subsidence. The Renewed Rifting phase (? to Recent, largely unsampled by coring thus far) has been further divided into 1, a lower interval, in which the section thickens passively towards a central depocentre, and 2. an upper interval, in which more dramatic thickening patterns are complicated by magmatic activity. The youngest part of the stratigraphy was accumulated under the influence of flexural loading imposed by the construction of large volcanic edifices, and involved minimal sediment supply from the western basin margin, suggesting a change in environmental (glacial) conditions at possibly c. 2 Ma.

Mesozoic and Cenozoic uplift and exhumation of the Bogda Mountain, NW China: Evidence from apatite fission track analysis

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Wenhao Tang

2015-07-01

Full Text Available Apatite fission track (AFT analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain, northwest China. AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths (11.0–13.2 μm mostly showing unimodal distribution are shorten, indicating significant track-annealing. Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassic–early Cretaceous and the Oligocene–Miocene. Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas. The fission-track ages of the southwest area are relatively older (>100 Ma, recording the earlier rapid uplift phase during the late Jurassic–Cretaceous, while the ages in the north piedmont of the Bogda Mountain (namely the northeast part are younger (<60 Ma, mainly reflecting the later rapid uplift phase in the Oligocene–Miocene. The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest. In the thrust fault-dominated northern limbs of the Bogda Mountain, AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones, showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic. The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic, respectively.

On the origin of Amazonian landscapes and biodiversity: a synthesis

NARCIS (Netherlands)

Wesselingh, F.P.; Hoorn, C.; Kroonenberg, S.B.; Antonelli, A.; Lundberg, J.G.; Vonhof, H.B.; Hooghiemstra, H.; Hoorn, M.; Wesselingh, F.P.

2010-01-01

In northern South America the Cenozoic was a period of intense tectonic and climatic interaction that resulted in a dynamic Amazonian landscape dominated by lowlands with local and shield-derived rivers. These drainage systems constantly changed shape and size. During the entire Cenozoic, the

An early and enduring advanced technology originating 71,000 years ago in South Africa.

Science.gov (United States)

Brown, Kyle S; Marean, Curtis W; Jacobs, Zenobia; Schoville, Benjamin J; Oestmo, Simen; Fisher, Erich C; Bernatchez, Jocelyn; Karkanas, Panagiotis; Matthews, Thalassa

2012-11-22

There is consensus that the modern human lineage appeared in Africa before 100,000 years ago. But there is debate as to when cultural and cognitive characteristics typical of modern humans first appeared, and the role that these had in the expansion of modern humans out of Africa. Scientists rely on symbolically specific proxies, such as artistic expression, to document the origins of complex cognition. Advanced technologies with elaborate chains of production are also proxies, as these often demand high-fidelity transmission and thus language. Some argue that advanced technologies in Africa appear and disappear and thus do not indicate complex cognition exclusive to early modern humans in Africa. The origins of composite tools and advanced projectile weapons figure prominently in modern human evolution research, and the latter have been argued to have been in the exclusive possession of modern humans. Here we describe a previously unrecognized advanced stone tool technology from Pinnacle Point Site 5-6 on the south coast of South Africa, originating approximately 71,000 years ago. This technology is dominated by the production of small bladelets (microliths) primarily from heat-treated stone. There is agreement that microlithic technology was used to create composite tool components as part of advanced projectile weapons. Microliths were common worldwide by the mid-Holocene epoch, but have a patchy pattern of first appearance that is rarely earlier than 40,000 years ago, and were thought to appear briefly between 65,000 and 60,000 years ago in South Africa and then disappear. Our research extends this record to ~71,000 years, shows that microlithic technology originated early in South Africa, evolved over a vast time span (~11,000 years), and was typically coupled to complex heat treatment that persisted for nearly 100,000 years. Advanced technologies in Africa were early and enduring; a small sample of excavated sites in Africa is the best explanation for any

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.

The original colours of fossil beetles.

Science.gov (United States)

McNamara, Maria E; Briggs, Derek E G; Orr, Patrick J; Noh, Heeso; Cao, Hui

2012-03-22

Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group.

Cenozoic alkaline volcanic rocks with carbonatite affinity in the Bohemian Massif: Their sources and magma generation

Czech Academy of Sciences Publication Activity Database

Ulrych, Jaromír; Štěpánková-Svobodová, Jana

2014-01-01

Roč. 46, 1/2 (2014), s. 45-58 ISSN 0369-2086 R&D Projects: GA AV ČR(CZ) IAA300130902 Institutional support: RVO:67985831 Keywords : alkaline volcanic rocks * melilitic rocks * carbonatites * magma generation * metasomatism * Cenozoic * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy

Origin and evolution of Sariñena Lake (central Ebro Basin): A piping-based model

Science.gov (United States)

Castañeda, Carmen; Javier Gracia, F.; Rodríguez-Ochoa, Rafael; Zarroca, Mario; Roqué, Carles; Linares, Rogelio; Desir, Gloria

2017-08-01

The origin and nature of the numerous lakes in the central Ebro Basin have been interpreted according to the prevailing arid or semiarid conditions, the easily-eroded materials and the solubility of the gypsum- and/or carbonate-rich Tertiary/Cenozoic substratum, involving important dissolution (karstic) and/or aeolian deflation. However, the origin of Sariñena Lake, the largest in the central Ebro Basin, remains unknown since the typical lake-generating processes in the region are not applicable. This work provides significant clues to the genesis and evolution of Sariñena Lake in a regional context. The combination of geomorphological mapping and high resolution LiDAR data together with sedimentological observations, the characterisation of soils and sediments around the lake, and the application of high-resolution geophysical techniques suggest that piping is the major genetic process driving the evolution of the Sariñena depression and lake. Field evidence demonstrates that piping is, at present, the most important erosive process in the region, generating significant collapse and surface lowering. Sariñena Lake is located within a deep endorheic depression excavated from Na-rich Tertiary materials. This work hypothesises that once an early, fluvially-originated palustrine area had developed, the progressive lowering of the regional water table linked to regional fluvial incision favoured the establishment of a hydrological gradient high enough to trigger piping processes within the claystones and siltstones underlying the original palustrine area. The Quaternary evolution of the Sariñena lacustrine basin was then controlled by successive water table fluctuations, linked to different phases of incision and alluvial deposition in the surrounding fluvial systems. All the evidence supporting a piping-related origin for this lake, together with examples of lakes generated by similar processes in different contexts, is used to propose a new genetic type of

Modern mammal origins: evolutionary grades in the Early Cretaceous of North America.

OpenAIRE

Jacobs, L L; Winkler, D A; Murry, P A

1989-01-01

Major groups of modern mammals have their origins in the Mesozoic Era, yet the mammalian fossil record is generally poor for that time interval. Fundamental morphological changes that led to modern mammals are often represented by small samples of isolated teeth. Fortunately, functional wear facets on teeth allow prediction of the morphology of occluding teeth that may be unrepresented by fossils. A major step in mammalian evolution occurred in the Early Cretaceous with the evolution of tribo...

The Biblicism of the Korean Protestant churches: Its origin and early development

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Jae-Buhm Hwang

2016-09-01

Full Text Available The purpose of this article is to clarify the origin and early stages of the Biblicism of the Korean Protestant churches in general, and of the Presbyterian Church of Korea (PCK in particular. The Biblicism is very important for Korean Protestant churches, because it is believed to be a main cause of their unusual growth on the one hand, and on the other hand, of their Fundamentalism and many schisms in the post-liberation era. The article, in the beginning part, investigates the four crucial elements of Korean Biblicism and then examines how the four elements worked together to form a resilient Biblicism whose two distinctive theological forms were practical on the one hand, and dogmatic (fundamentalist, on the other. Among the four basic Biblicist elements, the first was the firm Biblicist theology of the early North American missionaries in Korea who tried to follow and flower their original, puritanical and Old Princeton theology in Korea. The second was Korean Protestants’ original, Neo-Confucian biblicism, which facilitated them to readily accept the missionaries’ Biblicist teachings of the Bible. The third element was the so-called Nevius [Mission] Methods, which emphasised simplistic Biblicist Bible studies, and offered both opportunities of learning and ways to become meaningful leaders in their communities. The fourth and last element was the Biblicist creed of PCK, which became the fundamentalist weapon against its modernist or liberalist wing. To sum up, Korean Biblicism has been the result of those four Biblicist elements working together. The Korean Biblicism was developed into two more or less different positions; the one being practical, exemplified by Rev. Samuel A. Moffett; and the other, dogmatic and fundamentalist, represented by Rev. Dr W.D. Reynolds.

The Biblicism of the Korean Protestant churches: Its origin and early development

Directory of Open Access Journals (Sweden)

Jae-Buhm Hwang

2016-04-01

Full Text Available The purpose of this article is to clarify the origin and early stages of the Biblicism of the Korean Protestant churches in general, and of the Presbyterian Church of Korea (PCK in particular. The Biblicism is very important for Korean Protestant churches, because it is believed to be a main cause of their unusual growth on the one hand, and on the other hand, of their Fundamentalism and many schisms in the post-liberation era. The article, in the beginning part, investigates the four crucial elements of Korean Biblicism and then examines how the four elements worked together to form a resilient Biblicism whose two distinctive theological forms were practical on the one hand, and dogmatic (fundamentalist, on the other. Among the four basic Biblicist elements, the first was the firm Biblicist theology of the early North American missionaries in Korea who tried to follow and flower their original, puritanical and Old Princeton theology in Korea. The second was Korean Protestants’ original, Neo-Confucian biblicism, which facilitated them to readily accept the missionaries’ Biblicist teachings of the Bible. The third element was the so-called Nevius [Mission] Methods, which emphasised simplistic Biblicist Bible studies, and offered both opportunities of learning and ways to become meaningful leaders in their communities. The fourth and last element was the Biblicist creed of PCK, which became the fundamentalist weapon against its modernist or liberalist wing. To sum up, Korean Biblicism has been the result of those four Biblicist elements working together. The Korean Biblicism was developed into two more or less different positions; the one being practical, exemplified by Rev. Samuel A. Moffett; and the other, dogmatic and fundamentalist, represented by Rev. Dr W.D. Reynolds.

Early Origins of Child Obesity: Bridging Disciplines and Phases of Development - September 30–October 1, 2010

Science.gov (United States)

Christoffel, Katherine Kaufer; Wang, Xiaobin; Binns, Helen J.

2012-01-01

This report summarizes a conference: “Early Origins of Child Obesity: Bridging Disciplines and Phases of Development”, held in Chicago on September 30–October 1, 2010. The conference was funded in part by the National Institutes of Health and the Williams Heart Foundation, to achieve the conference objective: forging a next-step research agenda related to the early origins of childhood obesity. This research agenda was to include working with an array of factors (from genetic determinants to societal ones) along a continuum from prenatal life to age 7, with an emphasis on how the developing child deals with the challenges presented by his/her environment (prenatal, parental, nutritional, etc.). The conference offered a unique opportunity to facilitate communication and planning of future work among a variety of researchers whose work separately addresses different periods in early life. Over the span of two days, speakers addressed existing, critical research topics within each of the most-studied age ranges. On the final day, workshops fostered the discussion needed to identify the highest priority research topics related to linking varied early factor domains. These are presented for use in planning future research and research funding. PMID:23443002

Mexican-Origin Youth's Cultural Orientations and Adjustment: Changes from Early to Late Adolescence

Science.gov (United States)

Updegraff, Kimberly A.; Umaña-Taylor, Adriana J.; McHale, Susan M.; Wheeler, Lorey A.; Perez-Brena, Norma

2013-01-01

Drawing from developmental and cultural adaptation perspectives and using a longitudinal design, this study examined: (a) mean-level changes in Mexican-origin adolescents’ cultural orientations and adjustment from early to late adolescence; and (b) bidirectional associations between cultural orientations and adjustment using a cross-lag panel model. Participants included 246 Mexican-origin, predominantly immigrant families that participated in home interviews and a series of nightly phone calls when target adolescents were 12 years and 18 years of age. Girls exhibited more pronounced declines in traditional gender role attitudes than did boys, and all youth declined in familism values, time spent with family, and involvement in Mexican culture. Bidirectional relations between cultural orientations and adjustment emerged, and some associations were moderated by adolescent nativity and gender. PMID:22966929

Eocene and not Cretaceous origin of spider wasps: Fossil evidence from amber

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Juanita Rodriguez

2016-02-01

Full Text Available Spider wasps had long been proposed to originate in the mid-Cretaceous based on the Burmese amber fossil Bryopompilus interfector Engel and Grimaldi, 2006. We performed a morphological examination of this fossil and determined it does not belong to Pompilidae or any other described hymenopteran family. Instead, we place it in the new family Bryopompilidae. The oldest verifiable member of the Pompilidae is from Baltic amber, which suggests the family probably originated in the Eocene, not in the mid-Cretaceous as previously proposed. The origin of spider wasps appears to be correlated with an increase in spider familial diversity in the Cenozoic. We also we add two genera to the extinct pompilid fauna: Tainopompilus gen. nov., and Paleogenia gen. nov., and describe three new species of fossil spider wasps: Anoplius planeta sp. nov., from Dominican amber (Burdigalian to Langhian; Paleogenia wahisi sp. nov., from Baltic amber (Lutetian to Priabonian; and Tainopompilus argentum sp. nov, from Dominican amber (Chattian to Langhian.

Origin and early development of the chicken adenohypophysis.

Directory of Open Access Journals (Sweden)

Luisa eSanchez-Arrones

2015-02-01

Full Text Available The adenohypophysis (ADH is an important endocrine organ involved in the regulation of many physiological processes. The late morphogenesis of this organ at neural tube stages is well known: the epithelial ADH primordium is recognized as an invagination of the stomodeal roof (Rathke’s pouch, whose walls later thicken and differentiate as the primordium becomes pediculated, and then fully separated from the stomodeum. The primordium attaches to the pial surface of the basal hypothalamus, next to the neurohypophyseal field (NH; future posterior pituitary, from which it was previously separated by migrating prechordal plate cells. Once the NH evaginates, the ADH surrounds it and jointly forms with it the pituitary gland. In contrast, little is known about the precise origin of the ADH precursors at neural plate stages and how the primordium reaches the stomodeum. For that reason, we produced in the chicken a specific ADH fate map at early neural plate stages, which was amplified with gene markers. By means of experiments labelling the mapped presumptive ADH, we were able to follow the initial anlage into its transformation into Rathke’s pouch. The ADH origin was corroborated to be strictly extraneural, i.e., to lie at stage HH4/5 outside of the anterior neural plate within the pre-placodal field. The ADH primordium is fully segregated from the anterior neural border cells and the neighboring olfactory placodes both in terms of precursor cells and molecular profile from head fold stages onwards. The placode becomes visible as a molecularly characteristic ectodermal thickening from stage HH10 onwards. The onset of ADH genoarchitectonic regionalization into intermediate and anterior lobes occurs at closed neural tube stages.

Stratigraphic and structural relationships between Meso-Cenozoic Lagonegro basin and coeval carbonate platforms in southern Apennines, Italy

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Pescatore, Tullio; Renda, Pietro; Schiattarella, Marcello; Tramutoli, Mariano

1999-12-01

Lucanian segment — are shown by means of both regional and detailed geological cross-sections. The Lagonegro units constantly underlie the carbonate units originating from detachment and thrusting of the western platform and overlie the eastern (i.e. Apulian) platform. The Lagonegro units show a strong lateral variability of map-scale structures. Dome-and-basin folds are in fact largely observable in the Lucanian Apennine. Further, the belt is widely affected by Plio-Quaternary strike-slip and extensional faults. Yet, excluding the brittle deformation due to Quaternary faulting, the complexity of structural styles seems to result from the Neogene refolding of more ancient structures produced by Oligo-Miocene intraplate deformation. This hypothesis is supported by two independent lines of evidence: the first is the recognition of unconformities between the lower Miocene Numidian sandstone and the underlying Lagonegro successions, at least in the southwestern sectors; the second is that the internal (i.e. western) platform remains undeformed until the early Miocene. Both stratigraphic and structural data suggest an external position of the Meso-Cenozoic Lagonegro basin with regard to the coeval Apenninic platform.

Modern mammal origins: evolutionary grades in the Early Cretaceous of North America.

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Jacobs, L L; Winkler, D A; Murry, P A

1989-07-01

Major groups of modern mammals have their origins in the Mesozoic Era, yet the mammalian fossil record is generally poor for that time interval. Fundamental morphological changes that led to modern mammals are often represented by small samples of isolated teeth. Fortunately, functional wear facets on teeth allow prediction of the morphology of occluding teeth that may be unrepresented by fossils. A major step in mammalian evolution occurred in the Early Cretaceous with the evolution of tribosphenic molars, which characterize marsupials and placentals, the two most abundant and diverse extant groups of mammals. A tooth from the Early Cretaceous (110 million years before present) of Texas tests previous predictions (based on lower molars) of the morphology of upper molars in early tribosphenic dentitions. The lingual cusp (protocone) is primitively without shear facets, as expected, but the cheek side of the tooth is derived (advanced) in having distinctive cusps along the margin. The tooth, although distressingly inadequate to define many features of the organism, demonstrates unexpected morphological diversity at a strategic stage of mammalian evolution and falsifies previous claims of the earliest occurrence of true marsupials.

Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa.

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Toups, Melissa A; Kitchen, Andrew; Light, Jessica E; Reed, David L

2011-01-01

Clothing use is an important modern behavior that contributed to the successful expansion of humans into higher latitudes and cold climates. Previous research suggests that clothing use originated anywhere between 40,000 and 3 Ma, though there is little direct archaeological, fossil, or genetic evidence to support more specific estimates. Since clothing lice evolved from head louse ancestors once humans adopted clothing, dating the emergence of clothing lice may provide more specific estimates of the origin of clothing use. Here, we use a Bayesian coalescent modeling approach to estimate that clothing lice diverged from head louse ancestors at least by 83,000 and possibly as early as 170,000 years ago. Our analysis suggests that the use of clothing likely originated with anatomically modern humans in Africa and reinforces a broad trend of modern human developments in Africa during the Middle to Late Pleistocene.

Cenozoic deposits exposed along Rio de la Plata coast in the Canelones Department (Uruguay)

International Nuclear Information System (INIS)

Goso Aguilar, C.; Spoturno, J.

2004-01-01

This paper allows to know some sedimentological and stratigraphical features of the Cenozoic deposits exposed along Rio de la Plata coast in the Canelones department, Uruguay. The results, mainly collected from metric thickness of local stratigraphical sections and coastal outcrops of that region are presented. Both Tertiary and Quaternary sediments are present, however transitional Pleistocenic deposits of Chuy Formation and continental sediments of Libertad Formation are more dominant [es

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

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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.

Terrestrial origin of viviparity in mesozoic marine reptiles indicated by early triassic embryonic fossils.

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Motani, Ryosuke; Jiang, Da-yong; Tintori, Andrea; Rieppel, Olivier; Chen, Guan-bao

2014-01-01

Viviparity in Mesozoic marine reptiles has traditionally been considered an aquatic adaptation. We report a new fossil specimen that strongly contradicts this traditional interpretation. The new specimen contains the oldest fossil embryos of Mesozoic marine reptile that are about 10 million years older than previous such records. The fossil belongs to Chaohusaurus (Reptilia, Ichthyopterygia), which is the oldest of Mesozoic marine reptiles (ca. 248 million years ago, Early Triassic). This exceptional specimen captures an articulated embryo in birth position, with its skull just emerged from the maternal pelvis. Its headfirst birth posture, which is unlikely to be a breech condition, strongly indicates a terrestrial origin of viviparity, in contrast to the traditional view. The tail-first birth posture in derived ichthyopterygians, convergent with the conditions in whales and sea cows, therefore is a secondary feature. The unequivocally marine origin of viviparity is so far not known among amniotes, a subset of vertebrate animals comprising mammals and reptiles, including birds. Therefore, obligate marine amniotes appear to have evolved almost exclusively from viviparous land ancestors. Viviparous land reptiles most likely appeared much earlier than currently thought, at least as early as the recovery phase from the end-Permian mass extinction.

Brittle reactivation of mylonitic fabric and the origin of the Cenozoic Rio Santana Graben, southeastern Brazil

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Gontijo-Pascutti, Ambrosina; Bezerra, Francisco H. R.; Terra, Emanuele La; Almeida, Julio C. H.

2010-03-01

In the Ribeira belt, southeastern Brazil, the Precambrian mylonitic fabric mainly formed during the Brasiliano/Pan-African orogeny (640-480 Ma) and was reactivated as fault zones in the Cretaceous and Cenozoic. The reactivation process led to the development of the System of Continental Rifts of southeastern Brazil, from the Paleogene to the Quaternary. We investigated the brittle reactivation of a mylonitic zone, which is part of a major mylonitic belt, Arcádia-Areal. We used geological and geomorphological mapping, resistivity survey, controlled source audiomagnetotelluric survey, and luminescence dating. Our results indicate that this shear zone was reactivated and formed a 15 km long and 2 km wide sedimentary-filled trough, the Rio Santana Graben. It is located on the northwest border of a major structure, the Guanabara Graben, in the State of Rio de Janeiro. The Rio Santana Graben forms an almost entirely fault-bounded, NE-elongated depression that was accommodated entirely within the Arcádia-Areal shear zone. The graben consists of two main depocenters separated by a relay ramp. The graben formed by means of multistage activity of several faults during at least two main periods. The first period formed silicified fault breccia and occurred during alkaline magmatism in the Paleogene. The second formed fault breccia and gouge in shallow conditions and occurred at least until the Quaternary. The NE-trending and NW-dipping Precambrian fabric was reactivated as dip-slip and strike-slip faults. These faults triggered clastic-sediment deposition at least 300 m thick. The upper part of the graben consists of Quaternary alluvial and colluvial sediment fill, which yielded maximum luminescence deposition ages from 49 to 13 ka in the center of the trough. An organic layer at the top of the Quaternary alluvial deposits yielded 14C ages at ˜6000 years BP. The lower part of the graben may be composed of Paleogene to Neogene sedimentary deposits, which occur in other

Late Cenozoic continuous aridification in the western Qaidam Basin: evidence from sporopollen records

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Y. F. Miao

2013-08-01

Full Text Available Cenozoic climate changes in inner Asia provide a basis for understanding linkages between global cooling, the Tibetan Plateau uplift, and possibly the development of the East Asian monsoon. Based on a compilation of palynological results from the western Qaidam Basin, this study reconstructed a 15-million-year (Ma record of changing vegetation and paleoclimates spanning the middle Miocene to present (comprising two series: ~ 18–5 Ma and ~ 3.1–0 Ma, respectively. The thermophilic percentages were highest between 18 and 14 Ma, and decreased after 14 Ma, closely corresponding to the Middle Miocene Climatic Optimum (MMCO between 18 and 14 Ma and the following global climatic cooling between 14 and 5 Ma. At the same time, decreases in the xerophytic and coniferous taxa percentages, and the increasing logarithmic ratio of non-arboreal pollen to arboreal pollen (ln (NAP/AP, reveal the continuous aridification across both the basin and surrounding mountains. Between ~ 3.1 and 0 Ma, the percentages of the thermophilic, xerophytic and coniferous pollen as well as the ln (NAP/AP imply further cooling and drying in this region since 3.1 Ma. We argue that these vegetation and climate patterns during the late Cenozoic western Qaidam Basin are primarily a result of the global cooling, with the Tibetan Plateau uplift and East Asian summer monsoon having contributions of lesser importance.

Cenozoic extensional tectonics of the Western Anatolia Extended Terrane, Turkey

International Nuclear Information System (INIS)

Cemen, I; Catlos, E J; Gogus, O; Diniz, E; Hancer, M

2008-01-01

The Western Anatolia Extended Terrane in Turkey is located on the eastern side of the Aegean Extended Terrane and contains one of the largest metamorphic core complexes in the world, the Menderes massif. It has experienced a series of continental collisions from the Late Cretaceous to the Eocene during the formation of the Izmir-Ankara-Erzincan suture zone. Based our field work and monazite ages, we suggest that the north-directed postcollisional Cenozoic extension in the region is the product of three consecutive stages, triggered by three different mechanisms. The first stage was initiated about 30 Ma ago, in the Oligocene by the Orogenic Collapse the thermally weakened continental crust along the north-dipping Southwest Anatolian shear zone. The shear zone was formed as an extensional simple-shear zone with listric geometry at depth and exhibits predominantly normal-slip along its southwestern end. But, it becomes a high-angle oblique-slip shear zone along its northeastern termination. Evidence for the presence of the shear zone includes (1) the dominant top to the north-northeast shear sense indicators throughout the Menderes massif, such as stretching lineations trending N10E to N30E; and (2) a series of Oligocene extensional basins located adjacent to the shear zone that contain only carbonate and ophiolitic rock fragments, but no high grade metamorphic rock fragments. During this stage, erosion and extensional unroofing brought high-grade metamorphic rocks of the Central Menderes massif to the surface by the early Miocene. The second stage of the extension was triggered by subduction roll-back and associated back-arc extension in the early Miocene and produced the north-dipping Alasehir and the south-dipping Bueyuek Menderes detachments of the central Menderes massif and the north-dipping Simav detachment of the northern Menderes massif. The detachments control the Miocene sedimentation in the Alasehir, Bueyuek Menderes, and Simav grabens, containing high

Diets and environments of late Cenozoic mammals in the Qaidam Basin, Tibetan Plateau: Evidence from stable isotopes

Science.gov (United States)

Zhang, Chunfu; Wang, Yang; Li, Qiang; Wang, Xiaoming; Deng, Tao; Tseng, Zhijie J.; Takeuchi, Gary T.; Xie, Gangpu; Xu, Yingfeng

2012-06-01

The timing history and driving mechanisms of C4 expansion and Tibetan uplift are hotly debated issues. Paleoenvironmental evidence from within the Tibetan Plateau is essential to help resolve these issues. Here we report results of stable C and O isotope analyses of tooth enamel samples from a variety of late Cenozoic mammals, including deer, giraffe, horse, rhino, and elephant, from the Qaidam Basin in the northeastern Tibetan Plateau. The enamel-δ13C values are diets and only a few individuals (besides the exceptional rhino CD0722) may have consumed some C4 plants. Based on geological evidence, however, the Qaidam Basin was probably warmer and more humid during the late Miocene and early Pliocene than today. Thus, these δ13C values likely indicate that many individuals had significant dietary intakes of C4 plants, and the Qaidam Basin had more C4 plants in the late Miocene and early Pliocene than today. Moreover, the Qaidam Basin likely had much denser vegetation at those times in order to support such large mammals as rhinos and elephants. While the δ18O values did not increase monotonously with time, the range of variation seems to have increased considerably since the early Pliocene, indicating increased aridification in the basin. The mean δ18O values of large mammals and those reconstructed for local meteoric waters display a significant negative shift in the late Miocene, consistent with the marine δ18O record which shows a cooling trend in the same period. Taken together, the isotope data suggest a warmer, wetter, and perhaps lower Qaidam Basin during the late Miocene and early Pliocene. Increased aridification after the early Pliocene is likely due to a combined effect of regional tectonism, which resulted in a more effective barrier preventing moisture from the Indian Ocean or Bay of Bengal from reaching the basin, and global cooling.

The ATLAS3D project : X. On the origin of the molecular and ionized gas in early-type galaxies

NARCIS (Netherlands)

Davis, Timothy A.; Alatalo, Katherine; Sarzi, Marc; Bureau, Martin; Young, Lisa M.; Blitz, Leo; Serra, Paolo; Crocker, Alison F.; Krajnovic, Davor; McDermid, Richard M.; Bois, Maxime; Bournaud, Frederic; Cappellari, Michele; Davies, Roger L.; Duc, Pierre-Alain; de Zeeuw, P. Tim; Emsellem, Eric; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Weijmans, Anne-Marie

2011-01-01

We make use of interferometric CO and H i observations, and optical integral-field spectroscopy from the ATLAS3D survey, to probe the origin of the molecular and ionized interstellar medium (ISM) in local early-type galaxies. We find that 36 +/- 5 per cent of our sample of fast-rotating early-type

Unveiling the diversification dynamics of Australasian predaceous diving beetles in the Cenozoic.

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Toussaint, Emmanuel F A; Condamine, Fabien L; Hawlitschek, Oliver; Watts, Chris H; Porch, Nick; Hendrich, Lars; Balke, Michael

2015-01-01

During the Cenozoic, Australia experienced major climatic shifts that have had dramatic ecological consequences for the modern biota. Mesic tropical ecosystems were progressively restricted to the coasts and replaced by arid-adapted floral and faunal communities. Whilst the role of aridification has been investigated in a wide range of terrestrial lineages, the response of freshwater clades remains poorly investigated. To gain insights into the diversification processes underlying a freshwater radiation, we studied the evolutionary history of the Australasian predaceous diving beetles of the tribe Hydroporini (147 described species). We used an integrative approach including the latest methods in phylogenetics, divergence time estimation, ancestral character state reconstruction, and likelihood-based methods of diversification rate estimation. Phylogenies and dating analyses were reconstructed with molecular data from seven genes (mitochondrial and nuclear) for 117 species (plus 12 outgroups). Robust and well-resolved phylogenies indicate a late Oligocene origin of Australasian Hydroporini. Biogeographic analyses suggest an origin in the East Coast region of Australia, and a dynamic biogeographic scenario implying dispersal events. The group successfully colonized the tropical coastal regions carved by a rampant desertification, and also colonized groundwater ecosystems in Central Australia. Diversification rate analyses suggest that the ongoing aridification of Australia initiated in the Miocene contributed to a major wave of extinctions since the late Pliocene probably attributable to an increasing aridity, range contractions and seasonally disruptions resulting from Quaternary climatic changes. When comparing subterranean and epigean genera, our results show that contrasting mechanisms drove their diversification and therefore current diversity pattern. The Australasian Hydroporini radiation reflects a combination of processes that promoted both diversification

Interactions between magma and the lithospheric mantle during Cenozoic rifting in Central Europe

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Meyer, Romain; Elkins-Tanton, Linda T.

2010-05-01

During the Cenozoic, extensive intraplate volcanic activity occurred throughout Central Europe. Volcanic eruptions extend over France (the Massif Central), central Germany (Eifel, Vogelsberg, Rhön; Heldburg), the Czech Republic (the Eger graben) and SW Poland (Lower Silesia), a region ~1,200 km wide. The origin of this predominantly alkaline intraplate magmatism is often genetically linked to one or several mantle plumes, but there is no convincing evidence for this. We have measured Pb isotope ratios, together with major and trace elements, in a representative set of mafic to felsic igneous rocks from the intra-plate Cenozoic Rhön Mts. and the Heldburg dike swarm in order to gain insight into the melting source and petrogenetic history of these melts. Three different mafic rock types (tholeiitic basalt, alkali basalt, basanite) were distinguished based on petrography and geochemistry within the investigated areas. Except for the lherzolite-bearing phonolite from the Veste Heldburg all other evolved magmas are trachytes. REE geochemistry and calculated partial melting modeling experiments for the three mafic magma types point to different degrees of partial melting in a garnet-bearing mantle source. In addition a new version of the ternary Th-Hf-Ta diagram is presented in this study as a useful petrological tool. This diagram is not only able to define potentially involved melting source end-members (e.g. asthenosphere, sub-continental lithospheric mantle and continental crust) but also interactions between these members are illustrated. An advantage of this diagram compared to partial melting degree sensitive multi-element diagrams is that a ternary diagram is a closed system. An earlier version of this diagram has been recently used to establish the nature and extent of crust mantle melt interaction of volcanic rifted margins magmas (Meyer et al. 2009). The Th-Hf-Ta geochemistry of the investigated magmas is similar to spinel and garnet xenoliths from different

The ATLAS3D project - X. On the origin of the molecular and ionized gas in early-type galaxies

NARCIS (Netherlands)

Davis, Timothy A.; Alatalo, Katherine; Sarzi, Marc; Bureau, Martin; Young, Lisa M.; Blitz, Leo; Serra, Paolo; Crocker, Alison F.; Krajnović, Davor; McDermid, Richard M.; Bois, Maxime; Bournaud, Frédéric; Cappellari, Michele; Davies, Roger L.; Duc, Pierre-Alain; de Zeeuw, P. Tim; Emsellem, Eric; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Weijmans, Anne-Marie

2011-01-01

We make use of interferometric CO and H I observations, and optical integral-field spectroscopy from the ATLAS3D survey, to probe the origin of the molecular and ionized interstellar medium (ISM) in local early-type galaxies. We find that 36 ± 5 per cent of our sample of fast-rotating early-type

The impacts of Cenozoic climate and habitat changes on small mammal diversity of North America

Science.gov (United States)

Samuels, Joshua X.; Hopkins, Samantha S. B.

2017-02-01

Through the Cenozoic, paleoclimate records show general trends of global cooling and increased aridity, and environments in North America shifted from predominantly forests to more open habitats. Paleobotanical records indicate grasses were present on the continent in the Eocene; however, paleosol and phytolith studies indicate that open habitats did not arise until the late Eocene or even later in the Oligocene. Studies of large mammalian herbivores have documented changes in ecomorphology and community structure through time, revealing that shifts in mammalian morphology occurred millions of years after the environmental changes thought to have triggered them. Smaller mammals, like rodents and lagomorphs, should more closely track climate and habitat changes due to their shorter generation times and smaller ranges, but these animals have received much less study. To examine changes in smaller mammals through time, we have assembled and analyzed an ecomorphological database of all North American rodent and lagomorph species. Analyses of these data found that rodent and lagomorph community structure changed dramatically through the Cenozoic, and shifts in diversity and ecology correspond closely with the timing of habitat changes. Cenozoic rodent and lagomorph species diversity is strongly biased by sampling of localities, but sampling-corrected diversity reveals diversity dynamics that, after an initial density-dependent diversification in the Eocene, track habitat changes and the appearance of new ecological adaptations. As habitats became more open and arid through time, rodent and lagomorph crown heights increased while burrowing, jumping, and cursorial adaptations became more prevalent. Through time, open-habitat specialists were added during periods of diversification, while closed-habitat taxa were disproportionately lost in subsequent diversity declines. While shifts among rodents and lagomorphs parallel changes in ungulate communities, they started

Late Cenozoic Samtskhe-Javakheti Volcanic Highland, Georgia:The Result of Mantle Plumes Activity

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Okrostsvaridze, Avtandil

2017-04-01

Late Cenozoic Samtskhe-Javakheti continental volcanic highland (1500-2500 m a.s.l) is located in the SW part of the Lesser Caucasus. In Georgia the highland occupies more than 4500 km2, however its large part spreads towards the South over the territories of Turkey and Armenia. One can point out three stages of magmatic activity in this volcanic highland: 1. Early Pliocene activity (5.2-2.8 Ma; zircons U-Pb age) - when a large part of the highland was built up. It is formed from volcanic lava-breccias of andesite-dacitic composition, pyroclastic rocks and andesite-basalt lava flow. The evidences of this structure are: a large volume of volcanic material (>1500 km3); big thickness (700-1100 m in average), large-scale of lava flows (length 35 km, width 2.5-3.5 km, thickness 30-80 m), big thickness of volcanic ash horizons (300 cm at some places) and big size of volcanic breccias (diameter >1 m). Based on this data we assume that a source of this structure was a supervolcano (Okrostsvaridze et al., 2016); 2. Early Pleistocene activity (2.4 -1.6 Ma; zircons U-Pb age) - when continental flood basalts of 100-300 m thickness were formed. The flow is fully crystalline, coarse-grained, which mainly consist of olivine and basic labradorite. There 143Nd/144Nd parameter varies in the range of +0.41703 - +0.52304, and 87Sr/88Sr - from 0.7034 to 0.7039; 3. Late Pleistocene activity (0.35-0.021 Ma; zircons U-Pb age) - when intraplate Abul-Samsari linear volcanic ridge of andesite composition was formed stretching to the S-N direction for 40 km with the 8-12 km width and contains more than 20 volcanic edifices. To the South of the Abul-Samsari ridge the oldest (0.35-0.30 Ma; zircons U-Pb age) volcano Didi Abuli (3305 m a.s.l.) is located. To the North ages of volcano edifices gradually increase. Farther North the youngest volcano Tavkvetili (0.021-0. 030 Ma) is located (2583 m a.s.l.). One can see from this description that the Abul-Samsari ridge has all signs characterizing

Cool episodes in Early Tertiary Arctic climate: Evidence from Svalbard

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Spielhagen, R. F.; Tripati, A.

2009-04-01

The Arctic is a climatically sensitive and important region. However, very little is known about the climatic and oceanographic evolution of the area, particularly prior to the Neogene. Until recently, the Arctic was assumed to be characterized by relatively warm conditions during the early Cenozoic. The Early Tertiary sedimentary sequence on Svalbard contains several layers with coal seams and broad-leaved plants which were commonly accepted as indicators of a generally temperate-warm climate. Here we report on the intermittent occurrence of certain temperature indicators in the succession, which may represent the first northern high-latitude record of near-freezing temperatures for the early Cenozoic. Besides the findings of probably ice-rafted erratic clasts in the Paleocene and Eocene sandstones and shales, we note especially the occurrence of glendonites which are pseudomorphs of calcite after ikaite (calcium carbonate hexahydrate). We measured the chemical composition of Svalbard glendonites which is almost identical to that of similar pseudomorphs from the Lower Cretaceaous of Northern Canada. Mass spectrometric analyses of the glendonite calcite gave very low carbon isotope values. These values suggest a provenance of the calcium carbonate from marine organic carbon and connect our glendonites to the precursor mineral ikaite which has similar low values. Since a variety of studies has demonstrated that ikaite is stable only at temperatures close to freezing point, we have to infer low temperatures also for the deepositional environment of which the sediments were deposited that now hold glendonites. These results imply the occurrence of cooling phases episodically during the warm background climate of the Paleocene and Eocene, suggesting that temperature variability was much greater than previously recognized.

Ethnic Identity Trajectories among Mexican-Origin Girls during Early and Middle Adolescence: Predicting Future Psychosocial Adjustment

Science.gov (United States)

Gonzales-Backen, Melinda A.; Bámaca-Colbert, Mayra Y.; Allen, Kimberly

2016-01-01

We examined trajectories of ethnic identity exploration, resolution, and affirmation and their associations with depressive symptoms and self-esteem 3.5 years later among early and middle adolescent Mexican-origin girls (N = 338). Findings indicated that exploration, resolution, and affirmation increased over time for both cohorts. Among early…

Terrestrial origin of viviparity in mesozoic marine reptiles indicated by early triassic embryonic fossils.

Directory of Open Access Journals (Sweden)

Ryosuke Motani

Full Text Available Viviparity in Mesozoic marine reptiles has traditionally been considered an aquatic adaptation. We report a new fossil specimen that strongly contradicts this traditional interpretation. The new specimen contains the oldest fossil embryos of Mesozoic marine reptile that are about 10 million years older than previous such records. The fossil belongs to Chaohusaurus (Reptilia, Ichthyopterygia, which is the oldest of Mesozoic marine reptiles (ca. 248 million years ago, Early Triassic. This exceptional specimen captures an articulated embryo in birth position, with its skull just emerged from the maternal pelvis. Its headfirst birth posture, which is unlikely to be a breech condition, strongly indicates a terrestrial origin of viviparity, in contrast to the traditional view. The tail-first birth posture in derived ichthyopterygians, convergent with the conditions in whales and sea cows, therefore is a secondary feature. The unequivocally marine origin of viviparity is so far not known among amniotes, a subset of vertebrate animals comprising mammals and reptiles, including birds. Therefore, obligate marine amniotes appear to have evolved almost exclusively from viviparous land ancestors. Viviparous land reptiles most likely appeared much earlier than currently thought, at least as early as the recovery phase from the end-Permian mass extinction.

Stratigraphy of the late Cenozoic sediments beneath the 216-B and C crib facilities

International Nuclear Information System (INIS)

Fecht, K.R.; Last, G.V.; Marratt, M.C.

1979-02-01

The stratigraphy of the late Cenozoic sediments beneath the 216-B and C Crib Facilities is presented as lithofacies cross sections and is based on textural variations of the sedimentary sequence lying above the basalt bedrock. The primary source of data in this study is geologic information obtained from well drilling operations and geophysical logging. Stratigraphic interpretations are based primarily on textural analysis and visual examination of sediment samples and supplemented by drillers logs and geophysical logs

Geochemical prerequisites of petroleum-gas formation in the Mesozoic-Cenozoic sedimentary layer of the world's oceans

Energy Technology Data Exchange (ETDEWEB)

Trotsyuk, V Ya

1979-05-01

A summarization is given of the latest material on the geochemistry of trace organic matter of Mesozoic-Cenozoic deposits of the world's oceans, obtained as a result of deep-sea drilling. Trace organic matter was found to be present in the sedimentary layers of the ocean outskirts in amounts near that found in the continental stratosphere, but that content was five times less in the interior region of the oceans. The trace organic matter of deposits in the marginal region of the oceans was found to have a significant petroleum-gas matrix potential with respect to the level of content and composition characteristics. The distribution of organic carbon was found to be uneven in variously aged horizons of the Mesozoic-Cenozoic. The maximum content of organic carbon was noted in the Neogene-Quaternary and lower Cretaceous deposits. An elevated content of trace organic matter was found to be characteristic of the oceanic stratisphere in lithological mixed sediments: terrigenous-carbonate and terrigenous-silicons was 1.5 times greater than the trace organic matter in clays. Fundamental geochemical propagation laws were formulated, possibly for petroleum-gas-bearing sediment basins under the ocean bottom and beyond the shelf. 18 references, 3 figures.

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.

Mechanical origins of rightward torsion in early chick brain development

Science.gov (United States)

Chen, Zi; Guo, Qiaohang; Dai, Eric; Taber, Larry

2015-03-01

During early development, the neural tube of the chick embryo undergoes a combination of progressive ventral bending and rightward torsion. This torsional deformation is one of the major organ-level left-right asymmetry events in development. Previous studies suggested that bending is mainly due to differential growth, however, the mechanism for torsion remains poorly understood. Since the heart almost always loops rightwards that the brain twists, researchers have speculated that heart looping affects the direction of brain torsion. However, direct evidence is lacking, nor is the mechanical origin of such torsion understood. In our study, experimental perturbations show that the bending and torsional deformations in the brain are coupled and that the vitelline membrane applies an external load necessary for torsion to occur. Moreover, the asymmetry of the looping heart gives rise to the chirality of the twisted brain. A computational model and a 3D printed physical model are employed to help interpret these findings. Our work clarifies the mechanical origins of brain torsion and the associated left-right asymmetry, and further reveals that the asymmetric development in one organ can induce the asymmetry of another developing organ through mechanics, reminiscent of D'Arcy Thompson's view of biological form as ``diagram of forces''. Z.C. is supported by the Society in Science - Branco Weiss fellowship, administered by ETH Zurich. L.A.T acknowledges the support from NIH Grants R01 GM075200 and R01 NS070918.

The origin and early evolution of dinosaurs.

Science.gov (United States)

Langer, Max C; Ezcurra, Martin D; Bittencourt, Jonathas S; Novas, Fernando E

2010-02-01

The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis, and Panphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister-group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly monophyletic group composed of Mid-Late Triassic forms that may represent immediate sister taxa to dinosaurs. The first phylogenetic definition to fit the current understanding of Dinosauria as a node-based taxon solely composed of mutually exclusive Saurischia and Ornithischia was given as "all descendants of the most recent common ancestor of birds and Triceratops". Recent cladistic analyses of early dinosaurs agree that Pisanosaurus mertii is a basal ornithischian; that Herrerasaurus ischigualastensis and Staurikosaurus pricei belong in a monophyletic Herrerasauridae; that herrerasaurids, Eoraptor lunensis, and Guaibasaurus candelariensis are saurischians; that Saurischia includes two main groups, Sauropodomorpha and Theropoda; and that Saturnalia tupiniquim is a basal member of the sauropodomorph lineage. On the contrary, several aspects of basal dinosaur phylogeny remain controversial, including the position of herrerasaurids, E. lunensis, and G. candelariensis as basal theropods or basal saurischians, and the affinity and/or validity of more fragmentary taxa such as Agnosphitys cromhallensis, Alwalkeria maleriensis, Chindesaurus bryansmalli, Saltopus elginensis, and

Bayesian phylogenetic analysis of Semitic languages identifies an Early Bronze Age origin of Semitic in the Near East.

Science.gov (United States)

Kitchen, Andrew; Ehret, Christopher; Assefa, Shiferaw; Mulligan, Connie J

2009-08-07

The evolution of languages provides a unique opportunity to study human population history. The origin of Semitic and the nature of dispersals by Semitic-speaking populations are of great importance to our understanding of the ancient history of the Middle East and Horn of Africa. Semitic populations are associated with the oldest written languages and urban civilizations in the region, which gave rise to some of the world's first major religious and literary traditions. In this study, we employ Bayesian computational phylogenetic techniques recently developed in evolutionary biology to analyse Semitic lexical data by modelling language evolution and explicitly testing alternative hypotheses of Semitic history. We implement a relaxed linguistic clock to date language divergences and use epigraphic evidence for the sampling dates of extinct Semitic languages to calibrate the rate of language evolution. Our statistical tests of alternative Semitic histories support an initial divergence of Akkadian from ancestral Semitic over competing hypotheses (e.g. an African origin of Semitic). We estimate an Early Bronze Age origin for Semitic approximately 5750 years ago in the Levant, and further propose that contemporary Ethiosemitic languages of Africa reflect a single introduction of early Ethiosemitic from southern Arabia approximately 2800 years ago.

Meso-cenozoic extensional tectonics and uranium metallogenesis in southeast China

International Nuclear Information System (INIS)

Chen Yuehui; Chen Zuyi; Cai Yuqi; Fu Jin; Feng Quanhong; Shi Zuhai

1998-12-01

Through a systematic study on Meso-Cenozoic extensional tectonics in Southeast China, the authors point out that there are three major types of extensional tectonics such as taphrogenic thermo-upwelling, and gravitational extensional tectonics. The characteristics of structural forms, combination patterns, movement style and syn-tectonic magmatism of different extensional tectonics are studied. Then according to the known isotope age data of uranium mineralizations in the area, the relations between the process of extensional tectonics and regional uranium metallogenesis, as well as the corresponding relations in space and time between extensional tectonics and uranium deposits of different types are analyzed. In conclusion, the authors suggest that the uranium mineralizations of different types in Southeast China are characterized by an united ore-forming mechanism due to the apparent control of extensional tectonics to the regional uranium metallogenesis

Meso-Cenozoic tectonic evolution and uranium potential evaluations of basins in Beishan-Gansu corridor region

International Nuclear Information System (INIS)

Guo Qingyin; Chen Zuyi; Liu Hongxu; Yu Jinshui

2006-01-01

Beishan-Gansu Corridor region is located at the intersection of the plates of Tarim, North China, Kazakhstan, Siberia and Qaidam. During the Meso-Cenozoic, the region experienced movements of Indo-sinian, Yanshanian, Sichuanian, North China, Himalayan and Neotectonic, and over 20 medium-small size superimposed continental basins were formed. On the basis of analyzing the tectonic stress field, sediment-filling and structure-deformation; the general trending of tectonic evolution in the Meso-Cenozoic is summarized as three-time compressional uplifting and two-time extensional down-faulting. The different evolution of basins under the above mentioned setting can be divided into six stages according to characteristics of filled sediment. The sand bodies developed in down-faulted basins are favorable for uranium ore-formation as they are formed under humid paleoclimates, and rich in reducing matter. Therefore, the Lower-Middle Jurassic is selected as the main target horizon for sandstone-hosted uranium deposit, and the Lower Cretaceous as the minor one. Although the tectonic reactivation of the target horizon after its deposition was generally strong, the slopes formed in some basins could be favorable for the infiltration of uranium-and oxygen-bearing groundwater into sand bodies and form uranium deposits. According to the favorable sand bodies and tectonic reactivation, the northern parts of Chaoshui and Bayingobi basins are regarded as potential regions which are worthy of further exploration. (authors)

Annual review of earth and planetary sciences. Volume 8

International Nuclear Information System (INIS)

Donath, F.A.; Stehli, F.G.; Wetherill, G.W.

1980-01-01

Papers are presented on the geochemistry of evaporitic lacustrine deposits, the deformation of mantle rocks, the dynamics of sudden stratospheric warmings, the equatorial undercurrent, geomorphological processes on planetary surfaces, and rare earth elements in petrogenetic studies of igneous systems. Consideration is also given to evolutionary patterns in early Cenozoic animals, the origin and evolution of planetary atmospheres, the moons of Mars, and refractory inclusions in the Allende meteorite

Evolution of basin architecture in an incipient continental rift: the Cenozoic Most Basin, Eger Graben (Central Europe)

Czech Academy of Sciences Publication Activity Database

Rajchl, M.; Uličný, David; Grygar, R.; Mach, K.

2009-01-01

Roč. 21, č. 3 (2009), s. 269-294 ISSN 0950-091X R&D Projects: GA AV ČR IAA3012705; GA ČR GA205/01/0629; GA ČR(CZ) GA205/06/1823 Institutional research plan: CEZ:AV0Z30120515 Keywords : Cenozoic Most Basin * continental rift * Eger Graben Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.161, year: 2009

Evidence From Svalbard for Cool Episodes in Early Tertiary Arctic Climate

Science.gov (United States)

Spielhagen, R. F.; Tripati, A.; Mac Niocaill, C.

2008-12-01

The Arctic is a climatically sensitive and important region. However, very little is known about the climatic and oceanographic evolution of the area, particularly prior to the Neogene. Until recently, the Arctic was assumed to be characterized by relatively warm conditions during the early Cenozoic. The Early Tertiary sedimentary sequence on Svalbard contains several layers with coal seams and broad-leaved plants which were commonly accepted as indicators of a generally temperate-warm climate. Here we report on the intermittent occurrence of certain temperature indicators in the succession, which may represent the first northern high- latitude record of near-freezing temperatures for the early Cenozoic. Besides the findings of probably ice- rafted erratic clasts in the Paleocene and Eocene sandstones and shales, we note especially the occurrence of glendonites which are pseudomorphs of calcite after ikaite (calcium carbonate hexahydrate). Stratigraphic control for the most important glendonite layers was improved by paleomagnetic investigations on the host sediment. We measured the chemical composition of Svalbard glendonites which is almost identical to that of similar pseudomorphs from the Lower Cretaceaous of Northern Canada. Mass spectrometric analyses of the glendonite calcite gave very low carbon isotope values. These values suggest a provenance of the calcium carbonate from marine organic carbon and connect our glendonites to the precursor mineral ikaite which has similar low values. Since a variety of studies has demonstrated that ikaite is stable only at temperatures close to freezing point, we have to infer low temperatures also for the deepositional environment of which the sediments were deposited that now hold glendonites. These results imply the occurrence of cooling phases episodically during the warm background climate of the Paleocene and Eocene, suggesting that temperature variability was much greater than previously recognized.

Early diversification trend and Asian origin for extent bat lineages.

Science.gov (United States)

Yu, W; Wu, Y; Yang, G

2014-10-01

Bats are a unique mammalian group, which belong to one of the largest and most diverse mammalian radiations, but their early diversification is still poorly understood, and conflicting hypotheses have emerged regarding their biogeographic history. Understanding their diversification is crucial for untangling the enigmatic evolutionary history of bats. In this study, we elucidated the rate of diversification and the biogeographic history of extant bat lineages using genus-level chronograms. The results suggest that a rapid adaptive radiation persisted from the emergence of crown bats until the Early Eocene Climatic Optimum, whereas there was a major deceleration in diversification around 35-49 Ma. There was a positive association between changes in the palaeotemperature and the net diversification rate until 35 Ma, which suggests that the palaeotemperature may have played an important role in the regulation of ecological opportunities. By contrast, there were unexpectedly higher diversification rates around 25-35 Ma during a period characterized by intense and long-lasting global cooling, which implies that intrinsic innovations or adaptations may have released some lineages from the intense selective pressures associated with these severe conditions. Our reconstruction of the ancestral distribution suggests an Asian origin for bats, thereby indicating that the current panglobal but disjunct distribution pattern of extant bats may be related to events involving seriate cross-continental dispersal and local extinction, as well as the influence of geological events and the expansion and contraction of megathermal rainforests during the Tertiary. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Paleocene origin of the cockroach families Blaberidae and Corydiidae: Evidence from Amur River region of Russia.

Science.gov (United States)

Vršanský, Peter; Vidlička, L'Ubomír; Barna, Peter; Bugdaeva, Eugenia; Markevich, Valentina

2013-01-01

Morphna paleo sp. n., the earliest winged representative of any living cockroach genus and the earliest representative of the family Blaberidae, is described from the Danian Arkhara-Boguchan coal mine in the Amur River region (Russian Far East). The branched Sc and A suggest Ectobiidae (=Blattellidae) probably is not the ancestral family because Blaberidae were derived directly from the extinct family Mesoblattindae. The associated Danian locality Belaya Gora yielded Ergaula stonebut sp. n., the earliest record of the family Corydiidae. Both species belong to genera codominant in the Messel locality, thus validating their dominance in early Cenozoic assemblages.

CENOZOIC CONTINENTAL RIFTING SYMPOSIUM DEDICATED TO THE MEMORY OF ACADEMICIAN N.A. LOGATCHEV, IRKUTSK, RUSSIA, JUNE 7–11, 2010

Directory of Open Access Journals (Sweden)

Eugene V. Sklyarov

2010-01-01

Full Text Available The information on the «Cenozoic Continental Rifting» Symposium dedicated to the memory of Academician N.A. Logachev is presented. It was held on June 7–11, 2010 at the Institute of the Earth’s Crust, Irkutsk. The scope of conference is presented.

Continental deformation accommodated by non-rigid passive bookshelf faulting: An example from the Cenozoic tectonic development of northern Tibet

Science.gov (United States)

Zuza, Andrew V.; Yin, An

2016-05-01

Collision-induced continental deformation commonly involves complex interactions between strike-slip faulting and off-fault deformation, yet this relationship has rarely been quantified. In northern Tibet, Cenozoic deformation is expressed by the development of the > 1000-km-long east-striking left-slip Kunlun, Qinling, and Haiyuan faults. Each have a maximum slip in the central fault segment exceeding 10s to ~ 100 km but a much smaller slip magnitude (~bookshelf-fault model for the Cenozoic tectonic development of northern Tibet. Our model, quantitatively relating discrete left-slip faulting to distributed off-fault deformation during regional clockwise rotation, explains several puzzling features, including the: (1) clockwise rotation of east-striking left-slip faults against the northeast-striking left-slip Altyn Tagh fault along the northwestern margin of the Tibetan Plateau, (2) alternating fault-parallel extension and shortening in the off-fault regions, and (3) eastward-tapering map-view geometries of the Qimen Tagh, Qaidam, and Qilian Shan thrust belts that link with the three major left-slip faults in northern Tibet. We refer to this specific non-rigid bookshelf-fault system as a passive bookshelf-fault system because the rotating bookshelf panels are detached from the rigid bounding domains. As a consequence, the wallrock of the strike-slip faults deforms to accommodate both the clockwise rotation of the left-slip faults and off-fault strain that arises at the fault ends. An important implication of our model is that the style and magnitude of Cenozoic deformation in northern Tibet vary considerably in the east-west direction. Thus, any single north-south cross section and its kinematic reconstruction through the region do not properly quantify the complex deformational processes of plateau formation.

Date of shoot collection, genotype, and original shoot position affect early rooting of dormant hardwood cuttings of Populus

Science.gov (United States)

R. S., Jr. Zalesny; A.H. Wiese

2006-01-01

Identifying superior combinations among date of dormant- season shoot collection, genotype, and original shoot position can increase the rooting potential of Populus cuttings. Thus, the objectives of our study were to: 1) evaluate variation among clones in early rooting from hardwood cuttings processed every three weeks from shoots collected...

Gravity and magnetic survey of the Oaxaca city region: Cenozoic horst-and-graben structure superimposed on the Oaxaca-Juarez terrane boundary, southern Mexico

Science.gov (United States)

Campos-Enríquez, J. O.; Belmonte-Jiménez, S. I.; Keppie, J. D.; Ortega-Gutiérrez, F.; Arzate, J. A.; Martínez-Silva, J.; Martínez-Serrano, R. G.

2010-04-01

A geophysical survey of the Oaxaca Fault along the north-trending Etla and Zaachila valleys area, southern Mexico, shows a series of NNW-SSE Bouguer and magnetic anomalies with steeper gradients towards the east. The Oaxaca Fault represents Tertiary extensional reactivation of the Juarez shear zone that constitutes the boundary between the Oaxaca and Juárez terranes. Cooperative interpretation of six combined gravity and magnetic NE-SW profiles perpendicular to the valleys indicates the presence of a composite depression comprising three N-S sub-basins: the northern Etla and southern Zaachila sub-basins separated by the Atzompa sub-basin. The Etla sub-basin is bounded by the moderately E-dipping, Etla Fault and the more steeply W-dipping Oaxaca Fault, which together constitute a graben that continues southwards into the Atzompa graben. The deeper Zaachila sub-basin, south of Oaxaca city, is a wide V-shaped graben with a horst in the middle. The new geophysical data suggest that the Oaxaca-Juarez terrane boundary is displaced sinistrally ca. 20 km along the E-W Donají Fault, which defines the northern boundary of the Zaachila sub-basin. On the other hand, the Oaxaca Fault may either continue unbroken southwards along the western margin of the horst in the Zaachila sub-basin or be offset along with the terrane boundary. The sinistral movement may have taken place either during the Late Mesozoic-Early Cenozoic, Laramide Orogeny as a lateral ramp in the thrust plane or under Miocene-Pliocene, NE-SW extension. The former suggests that the Donají Fault is a transcurrent fault, whereas the latter implies that it is a transfer fault. The models imply that originally the suture was continuous south of the Donaji Fault and provide a constraint for the accretion of the Oaxaca and Juarez terranes.

Discussion on geological characteristics and types of uranium deposit of Mesozoic-cenozoic basin in Guangdong

International Nuclear Information System (INIS)

Wang Kesheng; Deng Shihua

1992-01-01

Systematic summary is briefly made of the distribution, classification, formation, regional geological setting, uranium deposit type, ore-controlling geological conditions of the Mesozoic-Cenozoic basin in Guangdong area, and on this basis it is proposed that there exist different ore-controlling conditions in different types of basin and different types of deposit can be formed in them, thus indicating the direction for exploration of the basin type uranium deposit from now on and expanding the prospect of ore-finding in the basins in Guangdong area

New Eocene damselflies and first Cenozoic damsel-dragonfly of the isophlebiopteran lineage (Insecta: Odonata).

Science.gov (United States)

Garrouste, Romain; Nel, André

2015-10-09

The study of a new specimen of Petrolestes hendersoni from the Eocene Green Formation allows a more precise description of the enigmatic damselfly and the diagnosis of the Petrolestini. Petrolestes messelensis sp. nov. is described from the Eocene Messel Formation in Germany, extending the distribution of the Petrolestini to the European Eocene. The new damsel-dragonfly family Pseudostenolestidae is described for the new genus and species Pseudostenolestes bechlyi, from the Eocene Messel Formation. It is the first Cenozoic representative of the Mesozoic clade Isophlebioptera.

Cenozoic mountain building on the northeastern Tibetan Plateau

Science.gov (United States)

Lease, Richard O.

2014-01-01

Northeastern Tibetan Plateau growth illuminates the kinematics, geodynamics, and climatic consequences of large-scale orogenesis, yet only recently have data become available to outline the spatiotemporal pattern and rates of this growth. I review the tectonic history of range growth across the plateau margin north of the Kunlun fault (35°–40°N) and east of the Qaidam basin (98°–107°E), synthesizing records from fault-bounded mountain ranges and adjacent sedimentary basins. Deformation began in Eocene time shortly after India-Asia collision, but the northeastern orogen boundary has largely remained stationary since this time. Widespread middle Miocene–Holocene range growth is portrayed by accelerated deformation, uplift, erosion, and deposition across northeastern Tibet. The extent of deformation, however, only expanded ~150 km outward to the north and east and ~150 km laterally to the west. A middle Miocene reorganization of deformation characterized by shortening at various orientations heralds the onset of the modern kinematic regime where shortening is coupled to strike slip. This regime is responsible for the majority of Cenozoic crustal shortening and thickening and the development of the northeastern Tibetan Plateau.

Mesozoic to Cenozoic magmatic history of the Pamir

Science.gov (United States)

Chapman, James B.; Scoggin, Shane H.; Kapp, Paul; Carrapa, Barbara; Ducea, Mihai N.; Worthington, James; Oimahmadov, Ilhomjon; Gadoev, Mustafo

2018-01-01

New geochronologic, geochemical, and isotopic data for Mesozoic to Cenozoic igneous rocks and detrital minerals from the Pamir Mountains help to distinguish major regional magmatic episodes and constrain the tectonic evolution of the Pamir orogenic system. After final accretion of the Central and South Pamir terranes during the Late Triassic to Early Jurassic, the Pamir was largely amagmatic until the emplacement of the intermediate (SiO2 > 60 wt.%), calc-alkaline, and isotopically evolved (-13 to -5 zircon εHf(t)) South Pamir batholith between 120-100 Ma, which is the most volumetrically significant magmatic complex in the Pamir and includes a high flux magmatic event at ∼105 Ma. The South Pamir batholith is interpreted as the northern (inboard) equivalent of the Cretaceous Karakoram batholith and the along-strike equivalent of an Early Cretaceous magmatic belt in the northern Lhasa terrane in Tibet. The northern Lhasa terrane is characterized by a similar high-flux event at ∼110 Ma. Migration of continental arc magmatism into the South Pamir terrane during the mid-Cretaceous is interpreted to reflect northward directed, low-angle to flat-slab subduction of the Neo-Tethyan oceanic lithosphere. Late Cretaceous magmatism (80-70 Ma) in the Pamir is scarce, but concentrated in the Central and northern South Pamir terranes where it is comparatively more mafic (SiO2 roll-back of the Neotethyan oceanic slab, which is consistent with similarly aged extension-related magmatism in the Karakoram terrane and Kohistan. There is an additional pulse of magmatism in the Pamir at 42-36 Ma that is geographically restricted (∼150 km diameter ellipsoidal area) and referred to as the Vanj magmatic complex. The Vanj complex comprises metaluminous, high-K calc-alkaline to shoshonitic monzonite, syenite, and granite that is adakitic (La/YbN = 13 to 57) with low Mg# (35-41). The Vanj complex displays a range of SiO2 (54-75 wt.%) and isotopic compositions (-7 to -3 εNd(i), 0.706 to

Mesozoic to Cenozoic tectonic transition process in Zhanhua Sag, Bohai Bay Basin, East China

Science.gov (United States)

Cheng, Yanjun; Wu, Zhiping; Lu, Shunan; Li, Xu; Lin, Chengyan; Huang, Zheng; Su, Wen; Jiang, Chao; Wang, Shouye

2018-04-01

The Zhanhua sag is part of the Bohai Bay intracontinental basin system that has developed since the Mesozoic in East China. The timing of this basin system coincides with the final assembly of East Asia and the development of Western Pacific-type plate margin. Here we use 3-D seismic and core log data to investigate the evolution of this basin and discuss its broad tectonic settings. Our new structural study of Zhanhua sag suggests that there are four major tectonic transitions occurred in the Bohai Bay Basin during Mesozoic and Cenozoic: (1) The first tectonic transition was from stable Craton to thrusting during the Triassic, mainly caused by the South China Block's subduction northward beneath the North China Block, which induced the formation of the NW-striking thrust faults. (2) The second tectonic transition was mainly characterized by a change from compression to extension, which can be further divided into two-stages. At the first stage, two episodes of NW-SE shortening occurred in East Asia during Early-Middle Jurassic and Late Jurassic-earliest Cretaceous, respectively. At the second stage, the extension and left-lateral shearing took place during Early Cretaceous while compression occurred during Late Cretaceous. The NW-striking thrust faults changed to normal faults and the NNE-striking left-lateral strike-slip faults started to influence the eastern part of the basin. (3) The third transition occurred when the NW-SE extension and NNE-striking right-lateral shearing started to form during Paleogene, and the peak deformation happen around 40 Ma due to the change of the subduction direction of Pacific Plate relative to Eurasia Plate. The NE-striking normal faults are the main structure, and the pre-existing NNE-striking strike-slip faults changed from left-lateral to right-lateral. (4) The fourth transition saw the regional subsidence during Neogene, which was probably caused by the India-Asia "Hard collision" between 25 and 20 Ma.

Late Cenozoic faulting and the stress state in the south-eastern segment of the Siberian platform

Directory of Open Access Journals (Sweden)

V. A. Sankov

2017-01-01

Full Text Available We have studied the structural geology and geomorphology of the fault zones in the junction area of the Angara-Lena uplift and the Predbaikalsky trough. We have analyzed faults and folds and reconstructed paleostresses for this junction area named the Irkutsk amphitheatre. Our study shows that syn-fold (Middle Paleozoic faults include thrusts, reverse faults and strike-slip faults with reverse components, that occurred due to compression from the neighbouring folded region. Recently, contrary to compression, faulting took place under the conditions of extension of the sedimentary cover: most of these recent faults have been classified as normal faults. In the Late Cenozoic, the platform cover was subjected to brittle and partly plicative deformation due to the NW–SE-trending extension that is most clearly observed in the adjacent Baikal rift. Thus, the divergent boundary between the Siberian block of the North Eurasian plate and the Transbaikalia block of the Amur plate is a zone of dynamic influence, which occupies the area considerably exceeding the mountainous region on the Siberian platform. Important factors of faulting are differentiated vertical movements of the blocks comprising the platform. Such vertical movements might have been related to displacements of brine volumes. In the Late Cenozoic basins, movements along separate faults took place in the Late Pleistocene – Holocene.

Paleomagnetic constraints on the Mesozoic-Cenozoic paleolatitudinal and rotational history of Indochina and South China : Review and updated kinematic reconstruction

NARCIS (Netherlands)

Li, Shihu; Advokaat, Eldert L.; van Hinsbergen, Douwe J.J.; Koymans, Mathijs; Deng, Chenglong; Zhu, Rixiang

Paleomagnetic data have long been used to hypothesize that the Cenozoic extrusion of the Indochina Block along the left-lateral Ailao Shan-Red River fault, as a result of the India-Asia collision, may have been associated with a major southward paleolatitude shift of as much as 10–15°, and a

Segmentation of the eastern North Greenland oblique-shear margin – regional plate tectonic implications

DEFF Research Database (Denmark)

Andreasen, Arne Døssing; Stemmerik, Lars; Dahl-Jensen, T.

2010-01-01

a highly complex, Paleozoic–early Cenozoic pre-opening setting. However, due to extreme ice conditions, very little is known about the offshore areas seawards of – and between – the peninsulas. Consequently, prevailing structural-tectonic models of the margin tend to be significantly oversimplified...... anticipated. In particular, we interpret strong margin segmentation along N/NE-striking fault structures. The structures are likely to have formed by Late Mesozoic–early Cenozoic strike-slip tectonics and have continued to be active during the late Cenozoic. A more than 8 km deep sedimentary basin...

Rates and style of Cenozoic deformation around the Gonghe Basin, northeastern Tibetan Plateau

Science.gov (United States)

Craddock, William H.; Kirby, Eric; Zhang, Huiping; Clark, Marin K.; Champagnac, Jean-Daniel; Yuan, Daoyang

2014-01-01

The northeastern Tibetan Plateau constitutes a transitional region between the low-relief physiographic plateau to the south and the high-relief ranges of the Qilian Shan to the north. Cenozoic deformation across this margin of the plateau is associated with localized growth of fault-cored mountain ranges and associated basins. Herein, we combine detailed structural analysis of the geometry of range-bounding faults and deformation of foreland basin strata with geomorphic and exhumational records of erosion in hanging-wall ranges in order to investigate the magnitude, timing, and style of deformation along the two primary fault systems, the Qinghai Nan Shan and the Gonghe Nan Shan. Structural mapping shows that both ranges have developed above imbricate fans of listric thrust faults, which sole into décollements in the middle crust. Restoration of shortening along balanced cross sections suggests a minimum of 0.8–2.2 km and 5.1–6.9 km of shortening, respectively. Growth strata in the associated foreland basin record the onset of deformation on the two fault systems at ca. 6–10 Ma and ca. 7–10 Ma, respectively, and thus our analysis suggests late Cenozoic shortening rates of 0.2 +0.2/–0.1 km/m.y. and 0.7 +0.3/–0.2 km/m.y. along the north and south sides of Gonghe Basin. Along the Qinghai Nan Shan, these rates are similar to late Pleistocene slip rates of ∼0.10 ± 0.04 mm/yr, derived from restoration and dating of a deformed alluvial-fan surface. Collectively, our results imply that deformation along both flanks of the doubly vergent Qilian Shan–Nan Shan initiated by ca. 10 Ma and that subsequent shortening has been relatively steady since that time.

Unravelling the depositional origins and diagenetic alteration of carbonate breccias

Science.gov (United States)

Madden, Robert H. C.; Wilson, Moyra E. J.; Mihaljević, Morana; Pandolfi, John M.; Welsh, Kevin

2017-07-01

Carbonate breccias dissociated from their platform top counterparts are little studied despite their potential to reveal the nature of past shallow-water carbonate systems and the sequential alteration of such systems. A petrographic and stable isotopic study allowed evaluation of the sedimentological and diagenetic variability of the Cenozoic Batu Gading Limestone breccia of Borneo. Sixteen lithofacies representing six facies groups have been identified mainly from the breccia clasts on the basis of shared textural and compositional features. Clasts of the breccia are representative of shallow carbonate platform top and associated flank to basinal deposits. Dominant inputs are from rocky (karstic) shorelines or localised seagrass environments, coral patch reef and larger foraminiferal-rich deposits. Early, pre-brecciation alteration (including micritisation, rare dissolution of bioclasts, minor syntaxial overgrowth cementation, pervasive neomorphism and calcitisation of bioclasts and matrix) was mainly associated with marine fluids in a near surface to shallow burial environment. The final stages of pre-brecciation diagenesis include mechanical compaction and cementation of open porosity in a shallow to moderate depth burial environment. Post-brecciation diagenesis took place at increasingly moderate to deep burial depths under the influence of dominantly marine burial fluids. Extensive compaction, circum-clast dissolution seams and stylolites have resulted in a tightly fitted breccia fabric, with some development of fractures and calcite cements. A degree of facies-specific controls are evident for the pre-brecciation diagenesis. Pervasive mineralogical stabilisation and cementation have, however, led to a broad similarity of diagenetic features in the breccia clasts thereby effectively preserving depositional features of near-original platform top and margin environments. There is little intra-clast alteration overprint associated with subsequent clast reworking

Cenozoic Uplift and Climate Change of the Northeast Tibetan Plateau: Evidence from Leaf Wax Stable Isotopic Records

Science.gov (United States)

Hou, M.; Zhuang, G.; Wu, M.

2017-12-01

Topics about the deformation history and uplift mechanism of Tibetan Plateau have been largely debated in the past few decades. Different geodynamic models present different predictions on the mountain building processes and hence the surface uplift history. For example, one tectonic model suggests a rapid uplift (>1.0 to 2.0 km) of the Tibetan Plateau in the period of ca. 10 to 8 Ma as result of isostatic rebound due to the removal of over-thickened mental lithosphere beneath. Whilst the stepwise uplift model infers that the high topography was growing progressively from south to north with the Northeast Tibetan Plateau being built in the Pliocene to present. In this case, the timing of Cenozoic uplift of Northeast Tibetan Plateau would provide information for distinguishing competing geodynamic processes. The stable isotope based paleoaltimetry holds the key to answering when the high topography was built. Additionally, the evolution of Cenozoic Asian climate was argued to be closely related to the high topography built up on the Tibetan Plateau since the India-Asian collision and/or impacted by the global change. To understand when the high topography was built and how the growth of Tibetan Plateau impacted the climate, we reconstructed the long-term histories of paleohydrology from hinterland and foreland basins in the Northeast Tibetan Plateau. We applied the compound-specific isotope hydrogen analysis to leaf wax n-alkanes (δ2Hn-alk) that are preserved in well-dated stratigraphic series (ca. 24 Ma to the present) in the Northeast Tibetan Plateau. The newly reconstructed δ2Hn-alk supports the inference of high topography on the Northeast Tibetan Plateau was built during the middle to late Miocene. Our inference is consistent with sedimentary and basement rock studies that show fundamental changes in facies and provenance and exhumation history. The new δ2Hn-alk record also reveals that the regional climate became drier since the middle Miocene following the

The SSC dipole: Its conceptual origin and early design history

International Nuclear Information System (INIS)

Dahl, P.F.

1992-05-01

The magnet system for the Superconducting Super Collider will likely remain the most ambitions-and challenging-application of superconducting technology for the foreseeable future. The centerpiece of the system is the behemoth collider dipole magnet. Its design, still evolving in its detailed features, dates from the mid-1980's when it emerged as the winter in an early technical showdown that occupied the fledgling SSC project. In the present report we chronicle the origins and chief milestones in the development of certain SSC dipole design concepts. Unfortunately, the chronicle must remain incomplete, with the design not yet frozen as we go to press and still subject to important modifications as the SSC Laboratory settles in near its future home in Ellis County, Texas, hard on the heels of a wide-ranging design review in the closing days of the SSC Central Design Group in (CDG) Berkeley. Be that as it may, in what follows we concentrate on the early years in an attempt to recapitulate the birth of the dipole, taking as our point of departure the SSC Reference Designs Study (RDS) of 1984. In Section 3 we touch on the background for the various RDS options, including ISABELLE/CBA and the Tevatron. In Section 4 the narrative focuses on the two final protagonists, a high-field cosine theta (cos θ) magnet and a low-field superferric magnet. Section 5 recounts the circumstances surrounding the selection of a particular magnet ''style'' for further development, and the ups and downs of the first model magnets. We conclude with a smattering of progress highlights in refining the design during the final push under the reign of the CDG. Beyond that, the ongoing chronicle must be left for others to amplify and complete

Petrology and geochemistry and K-Ar ages for Cenozoic tinguaites from the Ohře/Eger Rift (NW Bohemia)

Czech Academy of Sciences Publication Activity Database

Ulrych, Jaromír; Novák, Jiří Karel; Lang, Miloš; Balogh, K.; Hegner, E.; Řanda, Zdeněk

2006-01-01

Roč. 183, č. 1 (2006), s. 41-61 ISSN 0077-7757 R&D Projects: GA AV ČR IAA3048201 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z10480505 Keywords : České středohoří Mts. * Ohře/Eger Rift * Roztoky Intrusive Center * tinguaite dikes * Cenozoic volcanism Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.577, year: 2006

Review of the upper Cenozoic stratigraphy overlying the Columbia River Basalt Group in western Idaho

International Nuclear Information System (INIS)

Strowd, W.B.

1980-12-01

This report is a synthesis of information currently available on the rocks that stratigraphically overlie the Columbia River Basalt Group in Idaho. The primary objective is to furnish a brief but comprehensive review of the literature available on upper Cenozoic rocks in western Idaho and to discuss their general stratigraphic relationships. This study also reviews the derivation of the present stratigraphy and notes weaknesses in our present understanding of the geology and the stratigraphy. This report was prepared in support of a study to evaluate the feasibility of nuclear waste storage in the Columbia River Basalt Group of the Pasco Basin, Washington

Role of pre-existing structures in controlling the Cenozoic tectonic evolution of the eastern Tibetan plateau: New insights from analogue experiments

Science.gov (United States)

Sun, Ming; Yin, An; Yan, Danping; Ren, Hongyu; Mu, Hongxu; Zhu, Lutao; Qiu, Liang

2018-06-01

Pre-existing weakness due to repeated tectonic, metamorphic, and magmatic events is a fundamental feature of the continental lithosphere on Earth. Because of this, continental deformation results from a combined effect of boundary conditions imposed by plate tectonic processes and heterogeneous and anisotropic mechanical strength inherited from protracted continental evolution. In this study, we assess how this interaction may have controlled the Cenozoic evolution of the eastern Tibetan plateau during the India-Asia collision. Specifically, we use analogue models to evaluate how the pre-Cenozoic structures may have controlled the location, orientation, and kinematics of the northwest-striking Xianshuihe and northeast-striking Longmen Shan fault zones, the two most dominant Cenozoic structures in eastern Tibet. Our best model indicates that the correct location, trend, and kinematics of the two fault systems can only be generated and maintained if the following conditions are met: (1) the northern part of the Songpan-Ganzi terrane in eastern Tibet has a strong basement whereas its southern part has a weak basement, (2) the northern strong basement consists of two pieces bounded by a crustal-scale weak zone that is expressed by the Triassic development of a northwest-trending antiform exposing middle and lower crustal rocks, and (3) the region was under persistent northeast-southwest compression since ∼35 Ma. Our model makes correct prediction on the sequence of deformation in eastern Tibet; the Longmen Shan right-slip transpressional zone was initiated first as an instantaneous response to the northeast-southwest compression, which is followed by the formation of the Xianshuihe fault about a half way after the exertion of northeast-southwest shortening in the model. The success of our model highlights the importance of pre-existing weakness, a key factor that has been largely neglected in the current geodynamic models of continental deformation.

The origin of snakes: revealing the ecology, behavior, and evolutionary history of early snakes using genomics, phenomics, and the fossil record.

Science.gov (United States)

Hsiang, Allison Y; Field, Daniel J; Webster, Timothy H; Behlke, Adam D B; Davis, Matthew B; Racicot, Rachel A; Gauthier, Jacques A

2015-05-20

The highly derived morphology and astounding diversity of snakes has long inspired debate regarding the ecological and evolutionary origin of both the snake total-group (Pan-Serpentes) and crown snakes (Serpentes). Although speculation abounds on the ecology, behavior, and provenance of the earliest snakes, a rigorous, clade-wide analysis of snake origins has yet to be attempted, in part due to a dearth of adequate paleontological data on early stem snakes. Here, we present the first comprehensive analytical reconstruction of the ancestor of crown snakes and the ancestor of the snake total-group, as inferred using multiple methods of ancestral state reconstruction. We use a combined-data approach that includes new information from the fossil record on extinct crown snakes, new data on the anatomy of the stem snakes Najash rionegrina, Dinilysia patagonica, and Coniophis precedens, and a deeper understanding of the distribution of phenotypic apomorphies among the major clades of fossil and Recent snakes. Additionally, we infer time-calibrated phylogenies using both new 'tip-dating' and traditional node-based approaches, providing new insights on temporal patterns in the early evolutionary history of snakes. Comprehensive ancestral state reconstructions reveal that both the ancestor of crown snakes and the ancestor of total-group snakes were nocturnal, widely foraging, non-constricting stealth hunters. They likely consumed soft-bodied vertebrate and invertebrate prey that was subequal to head size, and occupied terrestrial settings in warm, well-watered, and well-vegetated environments. The snake total-group - approximated by the Coniophis node - is inferred to have originated on land during the middle Early Cretaceous (~128.5 Ma), with the crown-group following about 20 million years later, during the Albian stage. Our inferred divergence dates provide strong evidence for a major radiation of henophidian snake diversity in the wake of the Cretaceous-Paleogene (K

Late Jurassic – early Cretaceous inversion of rift structures, and linkage of petroleum system elements across post-rift unconformity, U.S. Chukchi Shelf, arctic Alaska

Science.gov (United States)

Houseknecht, David W.; Connors, Christopher D.

2015-01-01

Basin evolution of the U.S. Chukchi shelf involved multiple phases, including Late Devonian–Permian rifting, Permian–Early Jurassic sagging, Late Jurassic–Neocomian inversion, and Cretaceous–Cenozoic foreland-basin development. The focus of ongoing exploration is a petroleum system that includes sag-phase source rocks; inversion-phase reservoir rocks; structure spanning the rift, sag, and inversion phases; and hydrocarbon generation during the foreland-basin phase.

Detrital Zircon Provenance Record of Pre-Andean to Modern Tectonics in the Northern Andes: Examples from Peru, Ecuador, and Colombia

Science.gov (United States)

George, S. W. M.; Jackson, L. J.; Horton, B. K.

2015-12-01

Detrital zircon U-Pb age distributions from modern rivers and Mesozoic-Cenozoic basin fill in the northern Andes provide insights into pre-Andean, Andean, and active uplift and exhumation of distinctive sediment source regions. Diagnostic age signatures enable straightforward discrimination of competing sediment sources within the Andean magmatic arc (Western Cordillera-Central Cordillera), retroarc fold-thrust belt (Eastern Cordillera-Subandean Zone), and Amazonian craton (composed of several basement provinces). More complex, however, are the mid/late Cenozoic provenance records generated by recycling of basin fill originally deposited during early/mid Mesozoic extension, late Mesozoic thermal subsidence, and early Cenozoic shortening. Although subject to time-transgressive trends, regionally significant provenance patterns in Peru, Ecuador, and Colombia reveal: (1) Triassic-Jurassic growth of extensional subbasins fed by local block uplifts (with commonly unimodal 300­-150 Ma age peaks); (2) Cretaceous deposition in an extensive postrift setting fed by principally cratonic sources (with common 1800-900 Ma ages); and (3) Cenozoic growth of a broad flexural basin fed initially fed by magmatic-arc rocks (100-0 Ma), then later dominance by thrust-belt sedimentary rocks with progressively greater degrees of basin recycling (yielding diverse and variable age populations from the aforementioned source regions). U-Pb results from modern rivers and smaller subbasins prove useful in evaluating source-to-sink relationships, downstream mixing relationships, hinterland-foreland basin connectivity, paleodrainage integration, and tectonic/paleotopographic reconstructions. Most but not all of the elevated intermontane basins in the modern hinterland of the northern Andes contain provenance records consistent with genesis in a broader foreland basin developed at low elevation. Downstream variations within modern axial rivers and Cenozoic axial basins inform predictive models of

East African Cenozoic vegetation history.

Science.gov (United States)

Linder, Hans Peter

2017-11-01

The modern vegetation of East Africa is a complex mosaic of rainforest patches; small islands of tropic-alpine vegetation; extensive savannas, ranging from almost pure grassland to wooded savannas; thickets; and montane grassland and forest. Here I trace the evolution of these vegetation types through the Cenozoic. Paleogene East Africa was most likely geomorphologically subdued and, as the few Eocene fossil sites suggest, a woodland in a seasonal climate. Woodland rather than rainforest may well have been the regional vegetation. Mountain building started with the Oligocene trap lava flows in Ethiopia, on which rainforest developed, with little evidence of grass and none of montane forests. The uplift of the East African Plateau took place during the middle Miocene. Fossil sites indicate the presence of rainforest, montane forest and thicket, and wooded grassland, often in close juxtaposition, from 17 to 10 Ma. By 10 Ma, marine deposits indicate extensive grassland in the region and isotope analysis indicates that this was a C 3 grassland. In the later Miocene rifting, first of the western Albertine Rift and then of the eastern Gregory Rift, added to the complexity of the environment. The building of the high strato-volcanos during the later Mio-Pliocene added environments suitable for tropic-alpine vegetation. During this time, the C 3 grassland was replaced by C 4 savannas, although overall the extent of grassland was reduced from the mid-Miocene high to the current low level. Lake-level fluctuations during the Quaternary indicate substantial variation in rainfall, presumably as a result of movements in the intertropical convergence zone and the Congo air boundary, but the impact of these fluctuations on the vegetation is still speculative. I argue that, overall, there was an increase in the complexity of East African vegetation complexity during the Neogene, largely as a result of orogeny. The impact of Quaternary climatic fluctuation is still poorly understood

Cenozoic intra-plate magmatism in the Darfur volcanic province: mantle source, phonolite-trachyte genesis and relation to other volcanic provinces in NE Africa

Science.gov (United States)

Lucassen, Friedrich; Pudlo, Dieter; Franz, Gerhard; Romer, Rolf L.; Dulski, Peter

2013-01-01

Chemical and Sr, Nd and Pb isotopic compositions of Late Cenozoic to Quaternary small-volume phonolite, trachyte and related mafic rocks from the Darfur volcanic province/NW-Sudan have been investigated. Isotope signatures indicate variable but minor crustal contributions. Some phonolitic and trachytic rocks show the same isotopic composition as their primitive mantle-derived parents, and no crustal contributions are visible in the trace element patterns of these samples. The magmatic evolution of the evolved rocks is dominated by crystal fractionation. The Si-undersaturated strongly alkaline phonolite and the Si-saturated mildly alkaline trachyte can be modelled by fractionation of basanite and basalt, respectively. The suite of basanite-basalt-phonolite-trachyte with characteristic isotope signatures from the Darfur volcanic province fits the compositional features of other Cenozoic intra-plate magmatism scattered in North and Central Africa (e.g., Tibesti, Maghreb, Cameroon line), which evolved on a lithosphere that was reworked or formed during the Neoproterozoic.

GIS database and discussion for the distribution, composition, and age of Cenozoic volcanic rocks of the Pacific Northwest Volcanic Aquifer System study area

Science.gov (United States)

Sherrod, David R.; Keith, Mackenzie K.

2018-03-30

A substantial part of the U.S. Pacific Northwest is underlain by Cenozoic volcanic and continental sedimentary rocks and, where widespread, these strata form important aquifers. The legacy geologic mapping presented with this report contains new thematic categorization added to state digital compilations published by the U.S. Geological Survey for Oregon, California, Idaho, Nevada, Utah, and Washington (Ludington and others, 2005). Our additional coding is designed to allow rapid characterization, mainly for hydrogeologic purposes, of similar rocks and deposits within a boundary expanded slightly beyond that of the Pacific Northwest Volcanic Aquifer System study area. To be useful for hydrogeologic analysis and to be more statistically manageable, statewide compilations from Ludington and others (2005) were mosaicked into a regional map and then reinterpreted into four main categories on the basis of (1) age, (2) composition, (3) hydrogeologic grouping, and (4) lithologic pattern. The coding scheme emphasizes Cenozoic volcanic or volcanic-related rocks and deposits, and of primary interest are the codings for composition and age.

Discovery of Miocene adakitic dacite from the Eastern Pontides Belt (NE Turkey) and a revised geodynamic model for the late Cenozoic evolution of the Eastern Mediterranean region

Science.gov (United States)

Eyuboglu, Yener; Santosh, M.; Yi, Keewook; Bektaş, Osman; Kwon, Sanghoon

2012-08-01

The Cenozoic magmatic record within the ca. 500 km long eastern Pontides orogen, located within the Alpine metallogenic belt, is critical to evaluate the tectonic history and geodynamic evolution of the eastern Mediterranean region. In this paper we report for the first time late Miocene adakitic rocks from the southeastern part of the eastern Pontides belt and present results from geochemical and Sr-Nd isotopic studies as well as zircon U-Pb geochronology. The Tavdagi dacite that we investigate in this study is exposed as round or ellipsoidal shaped bodies, sills, and dikes in the southeastern part of the belt. Zircons in the dacite show euhedral crystal morphology with oscillatory zoning and high Th/U values (up to 1.69) typical of magmatic origin. Zircon LA-ICPMS analysis yielded a weighted mean 206Pb/238U age of 7.86 ± 0.15 Ma. SHRIMP analyses of zircons with typical magmatic zoning from another sample yielded a weighted mean 206Pb/238U age of 8.79 ± 0.19 Ma. Both ages are identical and constrain the timing of dacitic magmatism as late Miocene. The Miocene Tavdagi dacite shows adakitic affinity with high SiO2 (68.95-71.41 wt.%), Al2O3 (14.88-16.02 wt.%), Na2O (3.27-4.12 wt.%), Sr (331.4-462.1 ppm), Sr/Y (85-103.7), LaN/YbN (34.3-50.9) and low Y (3.2-5 ppm) values. Their initial 143Nd/144Nd (0.512723-0.512736) and 87Sr/86Sr (0.70484-0.70494) ratios are, respectively, lower and higher than those of normal oceanic crust. The geological, geochemical and isotopic data suggest that the adakitic magmatism was generated by partial melting of the mafic lower crust in the southeastern part of the eastern Pontide belt during the late Miocene. Based on the results presented in this study and a synthesis of the geological and tectonic information on the region, we propose that the entire northern edge of the eastern Pontides-Lesser Caucasus-Elbruz magmatic arc was an active continental margin during the Cenozoic. We identify a migration of the Cenozoic magmatism towards

A roller-like bird (Coracii) from the Early Eocene of Denmark.

Science.gov (United States)

Bourdon, Estelle; Kristoffersen, Anette V; Bonde, Niels

2016-09-27

The fossil record of crown group birds (Neornithes) prior to the Cretaceous-Paleogene boundary is scarce and fragmentary. Early Cenozoic bird fossils are more abundant, but are typically disarticulated and/or flattened. Here we report the oldest roller (Coracii), Septencoracias morsensis gen. et sp. nov. (Primobucconidae), based on a new specimen from the Early Eocene (about 54 million years ago) Fur Formation of Denmark. The new fossil is a nearly complete, three-dimensionally preserved and articulated skeleton. It lies at the lower end of the size range for extant rollers. Salient diagnostic features of Septencoracias relative to other Coracii include the proportionally larger skull and the small, ovoid and dorsally positioned narial openings. Our discovery adds to the evidence that the Coracii had a widespread northern hemisphere distribution in the Eocene. Septencoracias is the oldest substantial record of the Picocoraciae and provides a reliable calibration point for molecular phylogenetic studies.

Evidence for Cenozoic extensional basin development and tectonic inversion south of the flat-slab segment, southern Central Andes, Chile (33° 36°S.L.)

Science.gov (United States)

Charrier, R.; Baeza, O.; Elgueta, S.; Flynn, J. J.; Gans, P.; Kay, S. M.; Muñoz, N.; Wyss, A. R.; Zurita, E.

2002-04-01

The mainly volcanic Cenozoic deposits that make up much of the western part of the Principal Cordillera in Central Chile are generally subdivided into two major units: an older Abanico or Coya-Machalí Formation and a younger Farellones Formation. Difficulty in differentiating these units has led to considerable debate. On the basis of the wide distribution, great thickness, and presence of sedimentary intercalations, it has been postulated that these arc volcanics were deposited in an intermontane basin; more recently, it has been proposed that this basin developed under extensional conditions and underwent subsequent tectonic inversion. We present field, geochronologic, geochemical, and thermal maturity data that support the latter interpretation. Collectively, this new information clarifies the stratigraphic, tectonic, and paleogeographic evolution of these deposits. The vast geographic extent of the Abanico Formation and lateral equivalents, which reach from at least 32°30' to 44°S along the Principal Cordillera, its great thickness, and the presence of repeated thick fluvial and lacustrine intercalations all indicate deposition in a large, strongly subsident, and probably north-south oriented basin, developed between middle to late Eocene and Oligocene. The unconformable contact with underlying Mesozoic units observed at several localities indicates that deposition followed a substantial erosional episode during late Cretaceous and/or early Cenozoic time. Basal deposits of the Abanico Formation near Termas del Flaco increase rapidly in thickness to the west. Still further to the west, a thick Abanico section contains, in its upper part, mammal fossils older than those found in the basal deposits near Termas. This evidence indicates a major space of deposition west of this locality, which had been filled before deposition took place at Termas. The east-vergent, high-angle El Fierro thrust fault on the east side of the westward-growing deposits is interpreted

Early Planetary Environments and the Origin of

Indian Academy of Sciences (India)

Archaean-Hadean oceans releasing Hz- The solar flux in the. Hadean and ... universe. However, Rikken and Raupach (2000) have demonstrated that static magnetic field can bias .... origin of life is ho~ did such an interdependent system of.

The precise temporal calibration of dinosaur origins.

Science.gov (United States)

Marsicano, Claudia A; Irmis, Randall B; Mancuso, Adriana C; Mundil, Roland; Chemale, Farid

2016-01-19

Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U-Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic-Jurassic boundary.

Historical biogeography of the Fanniidae (Insecta, Diptera: A commentary on the age of the family Biogeografia histórica de Fanniidae (Insecta, Diptera: Un comentario sobre la edad de la familia

Directory of Open Access Journals (Sweden)

PETER LOWENBERG-NETO

2012-09-01

Full Text Available In a study on Fanniidae biogeography, Dominguez & Roig-Juñent (2011 argued that the family had a Pangeic origin, Late Jurassic/early Cretaceous (~146 Ma. However, recent literature on Diptera supports that Schizophora radiation occurred during Cenozoic. Fanniidae is a widespread taxon and it was interpreted under the maximum vicariance paradigm; the consequence was an analysis with no alternative hypothesis, but Pangeic origin. We verified that Fanniidae historical narrative was incongruent with the Gondwana sequential break-up. A second analysis, assuming the Fanniidae origin during early Paleocene (65 Ma, showed congruence with recent geological events and with the Muscidae diversification, a closely related Muscoidea family. Our hypothesis suggests that the Fanniidae originated in Paleogene and they were affected by few events of vicariance and several expansions during Cenozoic.En un estudio sobre biogeografía de Fanniidae, Domínguez & Roig-Juñent (2011 argumentaron que la familia era de origen Pangeico, Jurásico superior/Cretáceo inferior (~146 Ma. Sin embargo, literatura reciente sobre Diptera, confirma que la radiación de Schizophora ocurrió durante el Cenozoico. Fanniidae es un taxón ampliamente distribuido y fue interpretado bajo el paradigma de máxima vicarianza; la consecuencia, fue un análisis sin hipótesis alternativas, pero de origen pangeico. Nosotros verificamos que la narrativa histórica de Fanniidae es incongruente con la quiebra secuencial de Gondwana. Un segundo análisis, asumiendo el origen de Fanniidae durante el Paleoceno inferior (65 Ma, mostró congruencia con eventos geológicos recientes y con la diversificación de Muscidae, una familia de Muscoidea próximamente relacionada. Nuestra hipótesis sugiere que Fanniidae se originó en el Paleógeno y fueron afectados por pocos eventos de vicarianza y muchas expansiones durante el Cenozoico.

Preliminary Depositional and Provenance Records of Mesozoic Basin Evolution and Cenozoic Shortening in the High Andes, La Ramada Fold-Thrust Belt, Southern-Central Andes (32-33°S)

Science.gov (United States)

Mackaman-Lofland, C.; Horton, B. K.; Fuentes, F.; Constenius, K. N.; McKenzie, R.; Alvarado, P. M.

2015-12-01

The Argentinian Andes define key examples of retroarc shortening and basin evolution above a zone of active subduction. The La Ramada fold-thrust belt (RFTB) in the High Andes provides insights into the relative influence and temporal records of diverse convergent margin processes (e.g. flat-slab subduction, convergent wedge dynamics, structural inversion). The RFTB contains Mesozoic extensional basin strata deformed by later Andean shortening. New detrital zircon U-Pb analyses of Mesozoic rift sediments reveal: (1) a dominant Permo-Triassic age signature (220-280 Ma) associated with proximal sources of effective basement (Choiyoi Group) during Triassic synrift deposition; (2) upsection younging of maximum depositional ages from Late Triassic through Early Cretaceous (230 to 100 Ma) with the increasing influence of western Andean arc sources; and (3) a significant Late Cretaceous influx of Paleozoic (~350-550 Ma) and Proterozoic (~650-1300 Ma) populations during the earliest shift from back-arc post-extensional subsidence to upper-plate shortening. The Cenozoic detrital record of the Manantiales foreland basin (between the Frontal Cordillera and Precordillera) records RFTB deformation prior to flat-slab subduction. A Permo-Triassic Choiyoi age signature dominates the Miocene succession, consistent with sources in the proximal Espinacito range. Subordinate Mesozoic (~80-250 Ma) to Proterozoic (~850-1800 Ma) U-Pb populations record exhumation of the Andean magmatic arc and recycling of different structural levels in the RFTB during thrusting/inversion of Mesozoic rift basin strata and subjacent Paleozoic units. Whereas maximum depositional ages of sampled Manantiales units cluster at 18-20 Ma, the Estancia Uspallata basin (~50 km to the south) shows consistent upsection younging of Cenozoic populations attributed to proximal volcanic centers. Ongoing work will apply low-temperature thermochronology to pinpoint basin accumulation histories and thrust timing.

Early UV emission from disc-originated matter (DOM) in Type Ia supernovae in the double-degenerate scenario

Science.gov (United States)

Levanon, Naveh; Soker, Noam

2017-09-01

We show that the blue and UV excess emission in the first few days of some Type Ia supernovae (SNe Ia) can be accounted in the double-degenerate (DD) scenario by the collision of the SN ejecta with circumstellar matter that was blown by the accretion disc formed during the merger process of the two white dwarfs (WDs). We assume that in cases of excess early light, the disc blows the circumstellar matter, that we term disc-originated matter (DOM), hours to days before explosion. To perform our analysis, we first provide a model-based definition for early excess light, replacing the definition of excess light relative to a power-law fit to the rising luminosity. We then examine the light curves of the SNe Ia iPTF14atg and SN 2012cg, and find that the collision of the ejecta with a DOM in the frame of the DD scenario can account for their early excess emission. Thus, early excess light does not necessarily imply the presence of a stellar companion in the frame of the single-degenerate scenario. Our findings further increase the variety of phenomena that the DD scenario can account for, and emphasize the need to consider all different SN Ia scenarios when interpreting observations.

The SSC dipole: Its conceptual origin and early design history

International Nuclear Information System (INIS)

Dahl, P.F.

1990-06-01

The magnet system for the Superconducting Super Collider will likely remain the most ambitious -- and challenging -- application of superconducting technology for the foreseeable future. The centerpiece of the system is the behemoth collider dipole magnet. Its design, still evolving in its detailed features, dates from the mid-1980's when it emerged as the winner in an early technical showdown that occupied the fledgling SSC project. However, some of its gross features can be traced back to three path-breaking superconducting accelerator initiatives under way a decade earlier -- on the East Coast, on the West Coast, and in the Midwest. Other features have a still earlier legacy. In the present report we chronicle the origins and chief milestones in the development of certain SSC dipole design concepts. Unfortunately, the chronicle must remain incomplete, with the design not yet frozen as we go to press and still subject to important modifications as the SSC Laboratory settles in near its future home in Ellis County, Texas, hard on the heels of a wide-ranging design review in the closing days of the SSC Central Design Group in (CDG) Berkeley. Be that as it may, in what follows we concentrate on the early years in an attempt to recapitulate the birth of the dipole, taking as our point of departure the SSC Reference Designs Study (RDS) of 1984. In Section 3 we touch on the background for the various RDS options, including ISABELLE/CBA and the Tevatron. In Section 4 the narrative focuses on the two final protagonists, a high-field cosine theta (cos θ) magnet and a low-field superferric magnet. Section 5 recounts the circumstances surrounding the selection of a particular magnet ''style'' for further development, and the ups and downs of the first model magnets. We conclude with a smattering of progress highlights in refining the design during the final push under the reign of the CDG

Late Cretaceous and Cenozoic exhumation history of the Malay Peninsula

Science.gov (United States)

François, Thomas; Daanen, Twan; Matenco, Liviu; Willingshofer, Ernst; van der Wal, Jorien

2015-04-01

The evolution of Peninsular Malaysia up to the collisional period in the Triassic is well described but the evolution since the collision between Indochina and the Sukhothai Arc in Triassic times is less well described in the literature. The processes affecting Peninsular Malaysia during the Jurassic up to current day times have to explain the emplacement multiple intrusions (the Stong Complex, and the Kemahang granite), the Jurassic/Cretaceous onland basins, the Cenozoic offshore basins, and the asymmetric extension, which caused the exhumation of Taku Schists dome. The orogenic period in Permo-Triassic times, which also formed the Bentong-Raub suture zone, resulted in thickening of the continental crust of current day Peninsular Malaysia due to the collision of the Indochina continental block and the Sukhothai Arc, and is related to the subduction of oceanic crust once present between these continental blocks. The Jurassic/Cretaceous is a period of extension, resulting in the onland Jurassic/Cretaceous basins, synchronous melting of the crust, resulting in the emplacement Stong Complex and the Kemahang granite and thinning of the continental crust on the scale of the Peninsular, followed by uplift of the Peninsular. Different models can explain these observations: continental root removal, oceanic slab detachment, or slab delamination. These models all describe the melting of the lower crust due to asthenospheric upwelling, resulting in uplift and subsequent extension either due to mantle convective movements or gravitational instabilities related to uplift. The Cenozoic period is dominated by extension and rapid exhumation in the area as documented by low temperature thermocrological ages The extension in this period is most likely related to the subduction, which resumed at 45 Ma, of the Australian plate beneath the Eurasian plate after it terminated in Cretaceous times due to the collision of an Australian microcontinental fragment with the Sunda margin in the

Radioactive occurrence in sediments of Cenozoic age near Bandha village, Jaisalmer district, Rajasthan

International Nuclear Information System (INIS)

Gupta, Sumangal; Barik, Maninee P.; Ariketi, Ravinder; Jain, D.; Biswal, Samir

2017-01-01

The radioactivity is dependent on the isotope and their concentration in the mineral such as potassium (K), uranium (U) and thorium (Th). In this paper the presence of a 3 to 5 m thick uranium and thorium bearing sediment of Cenozoic age is reported above Goru Formation of Jaisalmer basin. Gamma ray log response of Well-1 which falls under the study area has marked with very high GR (gamma ray) readings ranging from 350-1488 API coupled with high uranium and thorium content from spectral gamma ray log ranging from 92-178 ppm and 60-80 ppm respectively at the depth of 50 m from ground surface (-110m above MSL). Further studies are required to delineate the lateral thickness variation for mining purpose which may be a radioactive source. (author)

Active faults paragenesis and the state of crustal stresses in the Late Cenozoic in Central Mongolia

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V. A. Sankov

2015-01-01

Full Text Available Active faults of the Hangay-Hentiy tectonic saddle region in Central Mongolia are studied by space images interpretation, relief analysis, structural methods and tectonic stress reconstruction. The study results show that faults activation during the Late Cenozoic stage was selective, and a cluster pattern of active faults is typical for the study region. Morphological and genetic types and the kinematics of faults in the Hangay-Hentiy saddle region are related the direction of the ancient inherited structural heterogeneities. Latitudinal and WNW trending faults are left lateral strike-slips with reverse or thrust component (Dzhargalantgol and North Burd faults. NW trending faults are reverse faults or thrusts with left lateral horizontal component. NNW trending faults have right lateral horizontal component. The horizontal component of the displacements, as a rule, exceeds the vertical one. Brittle deformations in fault zones do not conform with the Pliocene and, for the most part, Pleistocene topography. With some caution it may be concluded that the last phase of revitalization of strike slip and reverse movements along the faults commenced in the Late Pleistocene. NE trending disjunctives are normal faults distributed mainly within the Hangay uplift. Their features are more early activation within the Late Cenozoic and the lack of relation to large linear structures of the previous tectonic stages. According to the stress tensor reconstructions of the last phase of deformation in zones of active faults of the Hangay-Hentiy saddle using data on tectonic fractures and fault displacements, it is revealed that conditions of compression and strike-slip with NNE direction of the axis of maximum compression were dominant. Stress tensors of extensional type with NNW direction of minimum compression are reconstructed for the Orkhon graben. It is concluded that the activation of faults in Central Mongolia in the Pleistocene-Holocene, as well as

Re-evaluation of the age of the Brandon Lignite (Vermont, USA) based on plant megafossils. [USA - Vermont

Energy Technology Data Exchange (ETDEWEB)

Tiffney, B.H. (University of California at Santa Barbara, Santa Barbara, CA (United States). Dept. of Geological Sciences)

1994-07-01

The Brandon Lignite of west-central Vermont contains the northernmost megafossil flora of Cenozoic angiosperms, and one of the most diverse Cenozoic pollen floras in northeastern North America. While the floristic composition clearly indicates deposition of the Brandon sediments in the warmer parts of the Cenozoic, previous attempts at a more precise stratigraphic placement have been inconclusive, ranging from Cretaceous to Miocene. Re-evaluation of existing and new fruit, seed and wood data from the Brandon flora in the context of other floras in the Northern Hemisphere leads to the conservative conclusion that the deposit could range from earliest Oligocene to Early Miocene. Several lines of potentially weak evidence favor an Early Miocene age, in agreement with recent biostratigraphic data from the associated pollen flora. It is concluded that the Brandon Lignite is Early Miocene.

The origin and early evolution of metatherian mammals: the Cretaceous record

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Thomas E. Williamson

2014-12-01

Full Text Available Metatherians, which comprise marsupials and their closest fossil relatives, were one of the most dominant clades of mammals during the Cretaceous and are the most diverse clade of living mammals after Placentalia. Our understanding of this group has increased greatly over the past 20 years, with the discovery of new specimens and the application of new analytical tools. Here we provide a review of the phylogenetic relationships of metatherians with respect to other mammals, discuss the taxonomic definition and diagnosis of Metatheria, outline the Cretaceous history of major metatherian clades, describe the paleobiology, biogeography, and macroevolution of Cretaceous metatherians, and provide a physical and climatic background of Cretaceous metatherian faunas. Metatherians are a clade of boreosphendian mammals that must have originated by the Late Jurassic, but the first unequivocal metatherian fossil is from the Early Cretaceous of Asia. Metatherians have the distinctive tightly interlocking occlusal molar pattern of tribosphenic mammals, but differ from Eutheria in their dental formula and tooth replacement pattern, which may be related to the metatherian reproductive process which includes an extended period of lactation followed by birth of extremely altricial young. Metatherians were widespread over Laurasia during the Cretaceous, with members present in Asia, Europe, and North America by the early Late Cretaceous. In particular, they were taxonomically and morphologically diverse and relatively abundant in the Late Cretaceous of western North America, where they have been used to examine patterns of biogeography, macroevolution, diversification, and extinction through the Late Cretaceous and across the Cretaceous-Paleogene (K-Pg boundary. Metatherian diversification patterns suggest that they were not strongly affected by a Cretaceous Terrestrial Revolution, but they clearly underwent a severe extinction across the K-Pg boundary.

Cenozoic tectonic and climatic events in southern Iberian Peninsula: Implications for the evolutionary history of freshwater fish of the genus Squalius (Actinopterygii, Cyprinidae).

Science.gov (United States)

Perea, Silvia; Cobo-Simon, Marta; Doadrio, Ignacio

2016-04-01

Southern Iberian freshwater ecosystems located at the border between the European and African plates represent a tectonically complex region spanning several geological ages, from the uplifting of the Betic Mountains in the Serravalian-Tortonian periods to the present. This area has also been subjected to the influence of changing climate conditions since the Middle-Upper Pliocene when seasonal weather patterns were established. Consequently, the ichthyofauna of southern Iberia is an interesting model system for analyzing the influence of Cenozoic tectonic and climatic events on its evolutionary history. The cyprinids Squalius malacitanus and Squalius pyrenaicus are allopatrically distributed in southern Iberia and their evolutionary history may have been defined by Cenozoic tectonic and climatic events. We analyzed MT-CYB (510 specimens) and RAG1 (140 specimens) genes of both species to reconstruct phylogenetic relationships and to estimate divergence times and ancestral distribution ranges of the species and their populations. We also assessed their levels of genetic structure and diversity as well as the amount of gene flow between populations. To investigate recent paleogeographical and climatic factors in southern Iberia, we modeled changes-through-time in sea level from the LGM to the present. Phylogenetic, geographic and population structure analyses revealed two well-supported species (S. malacitanus and S. pyrenaicus) in southern Iberia and two subclades (Atlantic and Mediterranean) within S. malacitanus. The origin of S. malacitanus and the separation of its Atlantic and Mediterranean populations occurred during the Serravalian-Tortonian and Miocene-Pliocene periods, respectively. These divergence events occurred in the Middle Pliocene and Pleistocene in S. pyrenaicus. In both species, Atlantic basins possessed populations with higher genetic diversity than Mediterranean, which may be explained by the Janda Lagoon. The isolation of S. malacitanus was

Cdc7 is required throughout the yeast S phase to activate replication origins.

Science.gov (United States)

Donaldson, A D; Fangman, W L; Brewer, B J

1998-02-15

The long-standing conclusion that the Cdc7 kinase of Saccharomyces cerevisiae is required only to trigger S phase has been challenged by recent data that suggests it acts directly on individual replication origins. We tested the possibility that early- and late-activated origins have different requirements for Cdc7 activity. Cells carrying a cdc7(ts) allele were first arrested in G1 at the cdc7 block by incubation at 37 degrees C, and then were allowed to enter S phase by brief incubation at 23 degrees C. During the S phase, after return to 37 degrees C, early-firing replication origins were activated, but late origins failed to fire. Similarly, a plasmid with a late-activated origin was defective in replication. As a consequence of the origin activation defect, duplication of chromosomal sequences that are normally replicated from late origins was greatly delayed. Early-replicating regions of the genome duplicated at approximately their normal time. The requirements of early and late origins for Cdc7 appear to be temporally rather than quantitatively different, as reducing overall levels of Cdc7 by growth at semi-permissive temperature reduced activation at early and late origins approximately equally. Our results show that Cdc7 activates early and late origins separately, with late origins requiring the activity later in S phase to permit replication initiation.

Geodynamic controls on the contamination of Cenozoic arc magmas in the southern Central Andes: Insights from the O and Hf isotopic composition of zircon

Science.gov (United States)

Jones, Rosemary E.; Kirstein, Linda A.; Kasemann, Simone A.; Dhuime, Bruno; Elliott, Tim; Litvak, Vanesa D.; Alonso, Ricardo; Hinton, Richard

2015-09-01

Subduction zones, such as the Andean convergent margin of South America, are sites of active continental growth and crustal recycling. The composition of arc magmas, and therefore new continental crust, reflects variable contributions from mantle, crustal and subducted reservoirs. Temporal (Ma) and spatial (km) variations in these contributions to southern Central Andean arc magmas are investigated in relation to the changing plate geometry and geodynamic setting of the southern Central Andes (28-32° S) during the Cenozoic. The in-situ analysis of O and Hf isotopes in zircon, from both intrusive (granitoids) and extrusive (basaltic andesites to rhyolites) Late Cretaceous - Late Miocene arc magmatic rocks, combined with high resolution U-Pb dating, demonstrates distinct across-arc variations. Mantle-like δ18O(zircon) values (+5.4‰ to +5.7‰ (±0.4 (2σ))) and juvenile initial εHf(zircon) values (+8.3 (±0.8 (2σ)) to +10.0 (±0.9 (2σ))), combined with a lack of zircon inheritance suggests that the Late Cretaceous (∼73 Ma) to Eocene (∼39 Ma) granitoids emplaced in the Principal Cordillera of Chile formed from mantle-derived melts with very limited interaction with continental crustal material, therefore representing a sustained period of upper crustal growth. Late Eocene (∼36 Ma) to Early Miocene (∼17 Ma) volcanic arc rocks present in the Frontal Cordillera have 'mantle-like' δ18O(zircon) values (+4.8‰ (±0.2 (2σ) to +5.8‰ (±0.5 (2σ))), but less radiogenic initial εHf(zircon) values (+1.0 (±1.1 (2σ)) to +4.0 (±0.6 (2σ))) providing evidence for mixing of mantle-derived melts with the Late Paleozoic - Early Mesozoic basement (up to ∼20%). The assimilation of both Late Paleozoic - Early Mesozoic Andean crust and a Grenville-aged basement is required to produce the higher than 'mantle-like' δ18O(zircon) values (+5.5‰ (±0.6 (2σ) to +7.2‰ (±0.4 (2σ))) and unradiogenic, initial εHf(zircon) values (-3.9 (±1.0 (2σ)) to +1.6 (±4.4 (2�

Medicated early weaning to obtain pigs free from pathogens endemic in the herd of origin.

Science.gov (United States)

Alexander, T J; Thornton, K; Boon, G; Lysons, R J; Gush, A F

1980-02-09

A field trial was conducted to assess the value of medicated early weaning for obtaining pigs free from some of the pathogens endemic in their herd of origin. The trial comprised 51 sows from a closed herd, which were farrowed in an isolated farrowing house in seven separate groups. The sows in each group were bred at the same time and induced to farrow on the same day. Their thriftiest piglets were weaned at five days of age and moved to an isolated early-weaning unit. At about six weeks of age they were moved to one of three isolated grow-out units where they were held to slaughter weight. Sows in five of the groups were dosed with high levels of tiamulin and trimethoprim-sulphonamide preparations from their entry into the farrowing house until their biggest piglets were weaned. Their piglets were dosed with similar drugs from birth until 10 days of age. The first and seventh groups of sows and their litters were not medicated. Tests were carried out on pigs aged five to 11 weeks, on slaughter pigs, and on pigs which died or were killed at different ages, for Mycoplasma hyopneumoniae, Bordetella bronchiseptica and colonic treponemes, which were readily detectable in the herd of origin. No evidence could be found of mycoplasma or bordetella. Colonic treponemes were recovered from some of the pigs at slaughter, but not from younger pigs. Thirty-seven boars and gilts from the medicated groups were introduced into 11 herds thought to be free of enzootic pneumonia and 13 were introduced into three herds which had enzootic pneumonia. No subsequent signs of enzootic pneumonia were noted in 10 of the enzootic pneumonia-free herds.

Changing provenance of late Cenozoic sediments in the Jianghan Basin

Directory of Open Access Journals (Sweden)

Lei Shao

2015-07-01

Full Text Available The Yangtze River is one of the most important components of the East Asia river system. In this study, sediments in the Jianghan Basin, middle Yangtze River, were selected for trace element and rare earth element (REE measurements, in order to decipher information on the change of sediment provenance and evolution of the Yangtze River. According to the elemental variations, the late Cenozoic sediments of the Jianghan Basin could be divided into four parts. During 2.68–2.28 Ma and 1.25–0 Ma, provenance of the sediments was consistent, whereas sediments were derived from variable sources during 2.28–1.25 Ma. Comparison of the elemental compositions between the Pliocene and Quaternary sediments revealed a change in sediment source from a more felsic source area to a more basic source area around the Pliocene–Quaternary boundary. Input from the Emeishan LIP should account for this provenance change. Based on the provenance analysis of sediments in the Jianghan Basin, we infer that the Yangtze River developed into a large river with its drainage basin extended to the Emeishan LIP no later than the Pliocene–Quaternary boundary.

Literary Origins of the Term "School Psychologist" Revisited

Science.gov (United States)

Fagan, Thomas K.

2005-01-01

Previous research on the literary origins of the term "school psychologist" is revisited, and conclusions are revised in light of new evidence. It appears that the origin of the term in the American literature occurred as early as 1898 in an article by Hugo Munsterberg, predating the usage by Wilhelm Stern in 1911. The early references to the…

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

Determination of Cenozoic sedimentary structures using integrated geophysical surveys: A case study in the Barkol Basin, Xinjiang, China

Science.gov (United States)

Sun, Kai; Chen, Chao; Du, Jinsong; Wang, Limin; Lei, Binhua

2018-01-01

Thickness estimation of sedimentary basin is a complex geological problem, especially in an orogenic environment. Intense and multiple tectonic movements and climate changes result in inhomogeneity of sedimentary layers and basement configurations, which making sedimentary structure modelling difficult. In this study, integrated geophysical methods, including gravity, magnetotelluric (MT) sounding and electrical resistivity tomography (ERT), were used to estimate basement relief to understand the geological structure and evolution of the eastern Barkol Basin in China. This basin formed with the uplift of the eastern Tianshan during the Cenozoic. Gravity anomaly map revealed the framework of the entire area, and ERT as well as MT sections reflected the geoelectric features of the Cenozoic two-layer distribution. Therefore, gravity data, constrained by MT, ERT and boreholes, were utilized to estimate the spatial distribution of the Quaternary layer. The gravity effect of the Quaternary layer related to the Tertiary layer was later subtracted to obtain the residual anomaly for inversion. For the Tertiary layer, the study area was divided into several parts because of lateral difference of density contrasts. Gravity data were interpreted to determine the density contrast constrained by the MT results. The basement relief can be verified by geological investigation, including the uplift process and regional tectonic setting. The agreement between geophysical survey and prior information from geology emphasizes the importance of integrated geophysical survey as a complementary means of geological studies in this region.

Colorado Late Cenozoic Fault and Fold Database and Internet Map Server: User-friendly technology for complex information

Science.gov (United States)

Morgan, K.S.; Pattyn, G.J.; Morgan, M.L.

2005-01-01

Internet mapping applications for geologic data allow simultaneous data delivery and collection, enabling quick data modification while efficiently supplying the end user with information. Utilizing Web-based technologies, the Colorado Geological Survey's Colorado Late Cenozoic Fault and Fold Database was transformed from a monothematic, nonspatial Microsoft Access database into a complex information set incorporating multiple data sources. The resulting user-friendly format supports easy analysis and browsing. The core of the application is the Microsoft Access database, which contains information compiled from available literature about faults and folds that are known or suspected to have moved during the late Cenozoic. The database contains nonspatial fields such as structure type, age, and rate of movement. Geographic locations of the fault and fold traces were compiled from previous studies at 1:250,000 scale to form a spatial database containing information such as length and strike. Integration of the two databases allowed both spatial and nonspatial information to be presented on the Internet as a single dataset (http://geosurvey.state.co.us/pubs/ceno/). The user-friendly interface enables users to view and query the data in an integrated manner, thus providing multiple ways to locate desired information. Retaining the digital data format also allows continuous data updating and quick delivery of newly acquired information. This dataset is a valuable resource to anyone interested in earthquake hazards and the activity of faults and folds in Colorado. Additional geologic hazard layers and imagery may aid in decision support and hazard evaluation. The up-to-date and customizable maps are invaluable tools for researchers or the public.

The Origins of Soviet Sociolinguistics.

Science.gov (United States)

Brandist, Craig

2003-01-01

Discusses the origins of Soviet sociolinguistics and suggests that the historical significance of the reception and reinterpretation of these ideas is considerable, leading to a reconsideration of the origins of sociolinguistics and the relationship between Marxism and the language sciences in the early years of the Soviet Union. (Author/VWL)

Pre-Cenozoic basement rocks of the Proto-Philippine Sea Plate: Constraints for the birthplace of the Izu-Bonin-Mariana Arc

Science.gov (United States)

Tani, K.; Ishizuka, O.; Horie, K.; Barth, A. P.; Harigane, Y.; Ueda, H.

2016-12-01

The Izu-Bonin-Mariana Arc is widely regarded to be a typical intra-oceanic arc, with the oceanic Pacific Plate subducting beneath the Philippine Sea Plate, an evolving complex of active and inactive arcs and back-arc basins. However, little is known about the origin of the proto-Philippine Sea Plate, which existed along with the Pacific Plate at the time of subduction initiation in the Eocene. To investigate the crustal structures of the proto-Philippine Sea Plate, we conducted manned-submersible and dredge surveys in the Daito Ridges and the Kyushu-Palau Ridge. The Daito Ridges comprise the northwestern Philippine Sea Plate along with what are regarded as remnants of the proto-Philippine Sea Plate. Submersible observations and rock sampling revealed that the Daito Ridges expose deep crustal sections of gabbroic, granitic, metamorphic, and ultra-mafic rocks, along with volcanic rocks ranging from basalt to andesite. Mesozoic magmatic zircon U-Pb ages have been obtained from the plutonic rocks, and whole-rock geochemistry of the igneous rocks indicates arc origins. Furthermore, mafic schist collected from the Daito Ridge has experienced amphibolite facies metamorphism, with phase assemblages suggesting that the crust was thicker than 20 km at the time. Similar amphibolite-facies metamorphic rocks with Proterozoic zircons have been recovered in the southern Kyushu-Palau Ridge, indicating that such distinctively older basement rocks exist as isolated tectonic blocks within the present Philippine Sea Plate. These finds show that the parts of the Daito Ridges and Kyushu-Palau Ridge represent developed crustal sections of the Pre-Cenozoic arc that comprises part of the proto-Philippine Sea Plate, and, together with the tectonic reconstruction of the proto-Philippine Sea Plate (Deschamps and Lallemand 2002, JGR), they suggest that subduction of the Izu-Bonin-Mariana Arc initiated at the continental margin of the Southeast Asia.

The Mesozoic-Cenozoic igneous intrusions and related sediment-dominated hydrothermal activities in the South Yellow Sea Basin, the Western Pacific continental margin

Science.gov (United States)

Yumao, Pang; Xunhua, Zhang; Guolin, Xiao; Luning, Shang; Xingwei, Guo; Zhenhe, Wen

2018-04-01

Various igneous complexes were identified in multi-channel seismic reflection profiles from the South Yellow Sea Basin. It is not rare that magmatic intrusions in sedimentary basins cause strong thermal perturbations and hydrothermal activities. Some intrusion-related hydrothermal vent complexes have been identified and they are considered to originate from the deep sedimentary contact aureole around igneous intrusions and terminate in upper vents structures, and are linked by a vertical conduit system. The upper vent complexes are usually eye-shaped, dome-shaped, fault-related, crater-shaped or pock-shaped in seismic profiles. A schematic model was proposed to illustrate the structures of different types of hydrothermal vent complexes. A conceptual conduit model composed of an upper pipe-like part and a lower branching part was also derived. Hydrothermal vent complexes mainly developed during the Middle-Late Cretaceous, which is coeval with, or shortly after the intrusion. The back-arc basin evolution of the area which is related to the subduction of the Paleo-Pacific plate during the Mesozoic-Cenozoic may be the principal factor for voluminous igneous complexes and vent complexes in this area. It is significant to study the characteristics of igneous complexes and related hydrothermal vent complexes, which will have implications for the future study of this area.

Original Article

African Journals Online (AJOL)

Pezhman Kharazm

treatment in 32 patients who were admitted in Shohada-E-Tajrish hospital with final diagnosis of AMI from March 1996 to March 2002. ... of the patient and diagnostic studies and early surgical or non surgical intervention is the most ... operative diagnosis of etiology was based on presence of pulse at the origin of mesenteric.

Two fossil species of Metrosideros (Myrtaceae) from the Oligo-Miocene Golden Fleece locality in Tasmania, Australia.

Science.gov (United States)

Tarran, Myall; Wilson, Peter G; Macphail, Michael K; Jordan, Greg J; Hill, Robert S

2017-06-01

The capsular-fruited genus Metrosideros (Myrtaceae) is one of the most widely distributed flowering plant genera in the Pacific but is extinct in Australia today. The center of geographic origin for the genus and the reason for and timing of its extinction in Australia remain uncertain. We identify fossil Metrosideros fruits from the newly discovered Golden Fleece fossil flora in the Oligo-Miocene of Tasmania, Australia, shedding further light on these problems. Standard paleopalynological techniques were used to date the fossil-bearing sediments. Scanning electron microscopy and an auto-montage camera system were used to take high-resolution images of fossil and extant fruits taken from herbarium specimens. Fossils are identified using a nearest-living-relative approach. The fossil-bearing sediments are palynostratigraphically dated as being Proteacidites tuberculatus Zone Equivalent (ca. 33-16 Ma) in age and provide a confident Oligo-Miocene age for the macrofossils. Two new fossil species of Metrosideros are described and are here named Metrosideros dawsonii sp. nov. and Metrosideros wrightii sp. nov. These newly described fossil species of Metrosideros provide a second record of the genus in the Cenozoic of Australia, placing them in the late Early Oligocene to late Early Miocene. It is now apparent not only that Metrosideros was present in Australia, where the genus is now extinct, but that at least several Metrosideros species were present during the Cenozoic. These fossils further strengthen the case for an Australian origin of the genus. © 2017 Botanical Society of America.

Cenozoic pulsed compression of Da'an-Dedu Fault Zone in Songliao Basin (NE China) and its implications for earthquake potential: Evidence from seismic data

Science.gov (United States)

Yu, Zhongyuan; Zhang, Peizhen; Min, Wei; Wei, Qinghai; Zhao, Bin

2018-01-01

The Da'an-Dedu Fault Zone (DDFZ) is a major tectonic feature cutting through the Songliao Basin from south to north in NE China. Pulsed compression deformation of DDFZ during the Cenozoic implies a complex geodynamic process, and the latest stage of which occurred in the Quaternary directly influences the present seismicity of the interior basin. Although most of the evidence for Quaternary deformation about the Songliao Basin in the past decades was concentrated in marginal faults, all five earthquake swarms with magnitudes over 5.0 along the buried DDFZ with no surface expression during the past 30 years suggest it is a main seismogenic structure with seismic potential, which should deserve more attention of geologists. However, limited by the coverage of the Quaternary sedimentary and absence of strong historic and instrumental earthquakes records (M > 7), the geometric pattern, Quaternary activity and seismic potential of the DDFZ remain poorly understood. Thus, unlike previous geophysical studies focused on crust/mantle velocity structure across the fault and the aim of exploring possible mineral resources in the basin, in this study we have integrated a variety of the latest seismic data and drilling holes from petroleum explorations and shallow-depth seismic reflection profiles, to recognize the Cenozoic pulsed compression deformation of the DDFZ, and to discuss its implication for earthquake potential. The results show that at least four stages of compression deformation have occurred along the DDFZ in the Cenozoic: 65 Ma, 23 Ma, 5.3 Ma, and 1.8 Ma, respectively, although the geodynamic process behind which still in dispute. The results also imply that the tectonic style of the DDFZ fits well with the occurrence of modern seismic swarms. Moderate earthquake potential (M ≤ 7.0) is suggested along the DDFZ.

Geologic framework of the Alaska Peninsula, southwest Alaska, and the Alaska Peninsula terrane

Science.gov (United States)

Wilson, Frederic H.; Detterman, Robert L.; DuBois, Gregory D.

2015-01-01

The Alaska Peninsula is composed of the late Paleozoic to Quaternary sedimentary, igneous, and minor metamorphic rocks that record the history of a number of magmatic arcs. These magmatic arcs include an unnamed Late Triassic(?) and Early Jurassic island arc, the early Cenozoic Meshik arc, and the late Cenozoic Aleutian arc. Also found on the Alaska Peninsula is one of the most complete nonmetamorphosed, fossiliferous, marine Jurassic sedimentary sections known. As much as 8,500 m of section of Mesozoic sedimentary rocks record the growth and erosion of the Early Jurassic island arc.

Geochemical insights into the lithology of mantle sources for Cenozoic alkali basalts in West Qinling, China

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Dai, Li-Qun; Zheng, Fei; Zhao, Zi-Fu; Zheng, Yong-Fei

2018-03-01

Although alkali basalts are common in oceanic islands and continental rifts, the lithology of their mantle sources is still controversial. While the peridotite is usually viewed as a common source lithology, there are increasing studies suggesting significant contributions from ultramafic metasomatites such as carbonated peridotite, pyroxenite and hornblendite to the origin of alkali basalts. The present study indicates that carbonated peridotite plus hornblendite would have served as the mantle sources of Cenozoic alkali basalts from the West Qinling orogen in China. The target basalts show low SiO2 contents of 36.9 to 40.8 wt% and highly variable Na2O + K2O contents from 0.86 to 4.77 wt%, but high CaO contents of 12.5 to 16.3 wt% and CaO/Al2O3 ratios of 1.42 to 2.19. They are highly enriched in the majority of incompatible trace elements, but depleted in Rb, K, Pb, Zr, Hf, and Ti. Furthermore, they exhibit high (La/Yb)N, Zr/Hf, Ce/Pb and Nb/Ta ratios, but low Ti/Eu and Hf/Sm ratios. Generally, with increasing (La/Yb)N and CaO/Al2O3 ratios, their Ti/Eu and Hf/Sm ratios decrease whereas their Zr/Hf, Ce/Pb and Nb/Ta ratios increase. These major and trace element features are similar to those of carbonatites and hornblendite-derived melts to some extent, but significantly different from those of mid-ocean ridge basalts (MORB). This suggests that the alkali basalts would be originated from metasomatic mantle sources. A comparison of the major-trace elements in the alkali basalts with those of some representative mantle-derived melts indicates that the source lithology of alkali basalts is a kind of ultramafic metasomatites that are composed of carbonated peridotite and hornblendite. Such metasomatites would be generated by reaction of the depleted MORB mantle peridotite with hydrous, carbonate-bearing felsic melts derived from partial melting of the subducted Paleotethyan oceanic crust. Therefore, the melt-peridotite reaction at the slab-mantle interface in the

Comparative genomics of neuroglobin reveals its early origins.

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Jasmin Dröge

Full Text Available Neuroglobin (Ngb is a hexacoordinated globin expressed mainly in the central and peripheral nervous system of vertebrates. Although several hypotheses have been put forward regarding the role of neuroglobin, its definite function remains uncertain. Ngb appears to have a neuro-protective role enhancing cell viability under hypoxia and other types of oxidative stress. Ngb is phylogenetically ancient and has a substitution rate nearly four times lower than that of other vertebrate globins, e.g. hemoglobin. Despite its high sequence conservation among vertebrates Ngb seems to be elusive in invertebrates.We determined candidate orthologs in invertebrates and identified a globin of the placozoan Trichoplax adhaerens that is most likely orthologous to vertebrate Ngb and confirmed the orthologous relationship of the polymeric globin of the sea urchin Strongylocentrotus purpuratus to Ngb. The putative orthologous globin genes are located next to genes orthologous to vertebrate POMT2 similarly to localization of vertebrate Ngb. The shared syntenic position of the globins from Trichoplax, the sea urchin and of vertebrate Ngb strongly suggests that they are orthologous. A search for conserved transcription factor binding sites (TFBSs in the promoter regions of the Ngb genes of different vertebrates via phylogenetic footprinting revealed several TFBSs, which may contribute to the specific expression of Ngb, whereas a comparative analysis with myoglobin revealed several common TFBSs, suggestive of regulatory mechanisms common to globin genes.Identification of the placozoan and echinoderm genes orthologous to vertebrate neuroglobin strongly supports the hypothesis of the early evolutionary origin of this globin, as it shows that neuroglobin was already present in the placozoan-bilaterian last common ancestor. Computational determination of the transcription factor binding sites repertoire provides on the one hand a set of transcriptional factors that are

Cenozoic structural evolution of the southwestern Bükk Mts. and the southern part of the Darnó Deformation Belt (NE Hungary

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Petrik Attila

2016-02-01

Full Text Available Extensive structural field observations and seismic interpretation allowed us to delineate 7 deformation phases in the study area for the Cenozoic period. Phase D1 indicates NW–SE compression and perpendicular extension in the Late Oligocene–early Eggenburgian and it was responsible for the development of a wedge-shaped Paleogene sequence in front of north-westward propagating blind reverse faults. D2 is represented by E–W compression and perpendicular extension in the middle Eggenburgian–early Ottnangian. The D1 and D2 phases resulted in the erosion of Paleogene suites on elevated highs. Phase D2 was followed by a counterclockwise rotation, described in earlier publications. When considering the age of sediments deformed by the syn-sedimentary D3 deformation and preliminary geochronological ages of deformed volcanites the time of the first CCW rotation can be shifted slightly younger (~17–16.5 Ma than previously thought (18.5–17.5 Ma. Another consequence of our new timing is that the extrusional tectonics of the ALCAPA unit, the D2 local phase, could also terminate somewhat later by 1 Myr. D4 shows NE–SW extension in the late Karpatian–Early Badenian creating NW–SE trending normal faults which connected the major NNE–SSW trending sinistral faults. The D5 and D6 phases are late syn-rift deformations indicating E–W extension and NW–SE extension, respectively. D5 indicates syn-sedimentary deformation in the Middle Badenian–early Sarmatian and caused the synsedimentary thickening of mid-Miocene suites along NNE–SSW trending transtensional faults. D5 postdates the second CCW rotation which can be bracketed between ~16–15 Ma. This timing is somewhat older than previously considered and is based on new geochronological dates of pyroclastite rocks which were not deformed by this phase. D6 was responsible for further deepening of half-grabens during the Sarmatian. D7 is post-tilt NNW–SSE extension and induced the

Eocene volcanism and the origin of horizon A

Science.gov (United States)

Gibson, T.G.; Towe, K.M.

1971-01-01

A series of closely time-equivalent deposits that correlate with seismic reflector horizon A exists along the coast of eastern North America. These sediments of Late-Early to Early-Middle Eocene age contain an authigenic mineral suite indicative of the alteration of volcanic glass. A volcanic origin for these siliceous deposits onshore is consistent with a volcanic origin for the cherts of horizon A offshore.

The ICE hypothesis stands: How the dogma of late Cenozoic tectonic uplift can no longer be sustained in the light of data and physical laws

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Nielsen, S. B.; Clausen, O. R.; Jacobsen, B. H.; Thomsen, E.; Huuse, M.; Gallagher, K.; Balling, N.; Egholm, D.

2010-08-01

In this reply, we address the issues raised by the comment of Chalmers et al. (2010) regarding our ICE hypothesis for the evolution of western Scandinavia. We reject their conjectures as based, uncritically and without consideration of physical mechanisms, on the long-standing dogma of late Cenozoic tectonic uplift. Our hypothesis, in contrast, honours well-documented physical laws and the present wealth of actual data constraints (as opposed to dogma-biased inferences). After careful consideration of the points raised by Chalmers et al. (2010) we maintain our simple explanation for the evolution of Scandinavian topography, as it honours well-documented actual data constraints, such as crustal structure (including its spatio-temporal variability), thermal history in the eastern North Sea, global and regional climatic change (including eustacy) and sedimentation in the adjacent basins. The inevitable conclusion is that, although more data constraints are desirable, the current best fit hypothesis, is that the Scandinavian topography is of Caledonide origin, and has been shaped by fluvial and glacial buzzsaw and periglacial processes, and most recently (last few Myr) been re-invigorated by extensive glacial erosion in the fjords and on the shelf.

Trace-element and Sr-Nd isotopic evidence for the origin of the Sardinian fluorite mineralization (Italy)

International Nuclear Information System (INIS)

Castorina, F.; Masi, U.; Padalino, G.; Palomba, M.

2008-01-01

The fluorite-bearing hydrothermal mineralization in Sardinia mainly occurs within Paleozoic volcanic and metasedimentary rocks. Only 3 occurrences are located in volcanic and siliciclastic Cenozoic rocks. Most Sardinian fluorites exhibit relatively high rare earth and Y (REY) contents, strong positive Y anomalies, slightly negative Ce and generally positive Eu anomalies. These features indicate that the REY were mobilized mainly from non-carbonate rocks. Neither Sr nor Nd isotopes can be used to date radiometrically the Sardinian fluorites. However, the measured Sr-isotope ratios of the fluorites hosted by Paleozoic rocks fit mixing lines in the 1000/Sr versus 87 Sr/ 86 Sr plot once recalculated at 280 Ma, suggesting that the age inferred for the correction probably represents that of the formation of the fluorite mineralization. Mixing likely occurred between diluted surficial waters and brines circulating mainly through the Lower Paleozoic metasedimentary basement. The Cenozoic fluorites exhibit chemical and isotopic features similar to those of the Paleozoic fluorites, except the Nuraghe Onigu fluorite displaying a possible contribution of Sr from Cenozoic magmatic rocks. The initial ε Nd values of the Paleozoic fluorites fit the age proposed for the formation of the deposits. Moreover, the values suggest that radiogenic Nd was provided to the fluids from the Ordovician siliciclastic basement, except for 3 deposits where the potential source rocks of Nd were mainly Ordovician acidic magmatic rocks. The initial ε Nd values of the Cenozoic fluorites suggest a provenance of Nd essentially from the leaching of Variscan granitoids

Cenozoic intraplate tectonics in Central Patagonia: Record of main Andean phases in a weak upper plate

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Gianni, G. M.; Echaurren, A.; Folguera, A.; Likerman, J.; Encinas, A.; García, H. P. A.; Dal Molin, C.; Valencia, V. A.

2017-11-01

Contraction in intraplate areas is still poorly understood relative to similar deformation at plate margins. In order to contribute to its comprehension, we study the Patagonian broken foreland (PBF) in South America whose evolution remains controversial. Time constraints of tectonic events and structural characterization of this belt are limited. Also, major causes of strain location in this orogen far from the plate margin are enigmatic. To unravel tectonic events, we studied the Cenozoic sedimentary record of the central sector of the Patagonian broken foreland (San Bernardo fold and thrust belt, 44°30‧S-46°S) and the Andes (Meseta de Chalia, 46°S) following an approach involving growth-strata detection, U-Pb geochronology and structural modeling. Additionally, we elaborate a high resolution analysis of the effective elastic thickness (Te) to examine the relation between intraplate contraction location and variations in lithospheric strength. The occurrence of Eocene growth-strata ( 44-40 Ma) suggests that contraction in the Andes and the Patagonian broken foreland was linked to the Incaic phase. Detection of synextensional deposits suggests that the broken foreland collapsed partially during Oligocene to early Miocene. During middle Miocene times, the Quechua contractional phase produced folding of Neogene volcanic rocks and olistostrome deposition at 17 Ma. Finally, the presented Te map shows that intraplate contraction related to Andean phases localized preferentially along weak lithospheric zones (Te < 15 km). Hence, the observed strain distribution in the PBF appears to be controlled by lateral variations in the lithospheric strength. Variations in this parameter could be related to thermo-mechanical weakening produced by intraplate rifting in Paleozoic-Mesozoic times.

A major reorganization of Asian climate by the early Miocene

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Z. T. Guo

2008-08-01

Full Text Available The global climate system experienced a series of drastic changes during the Cenozoic. In Asia, these include the climate transformation from a zonal pattern to a monsoon-dominated pattern, the disappearance of typical subtropical aridity, and the onset of inland deserts. Despite major advances in the last two decades in characterizing and understanding these climate phenomena, disagreements persist relative to the timing, behaviors and underlying causes.

This paper addresses these issues mainly based on two lines of evidence. First, we compiled newly collected data from geological indicators of the Cenozoic environment in China as paleoenvironmental maps of ten intervals. In confirming the earlier observation that a zonal climate pattern was transformed into a monsoonal one, the maps within the Miocene indicate that this change was achieved by the early Miocene, roughly consistent with the onset of loess deposition in China. Although a monsoon-like regime would have existed in the Eocene, it was restricted to tropical-subtropical regions. The latitudinal oscillations of the climate zones during the Paleogene are likely attributable to the imbalance in evolution of polar ice-sheets between the two hemispheres.

Secondly, we examine the relevant depositional and soil forming processes of the Miocene loess-soil sequences to determine the circulation characteristics with emphasis on the early Miocene. Continuous eolian deposition in the middle reaches of the Yellow River since the early Miocene firmly indicates the formation of inland deserts, which have been constantly maintained during the past 22 Ma. Grain-size gradients between loess sections indicate northerly dust-carrying winds from northern sources, a clear indication of an Asian winter monsoon system. Meanwhile, well-developed Luvisols show evidence that moisture from the oceans reached northern China. This evidence shows the coexistence of two kinds of

Mean annual precipitation explains spatiotemporal patterns of Cenozoic mammal beta diversity and latitudinal diversity gradients in North America.

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Danielle Fraser

Full Text Available Spatial diversity patterns are thought to be driven by climate-mediated processes. However, temporal patterns of community composition remain poorly studied. We provide two complementary analyses of North American mammal diversity, using (i a paleontological dataset (2077 localities with 2493 taxon occurrences spanning 21 discrete subdivisions of the Cenozoic based on North American Land Mammal Ages (36 Ma--present, and (ii climate space model predictions for 744 extant mammals under eight scenarios of future climate change. Spatial variation in fossil mammal community structure (β diversity is highest at intermediate values of continental mean annual precipitation (MAP estimated from paleosols (∼ 450 mm/year and declines under both wetter and drier conditions, reflecting diversity patterns of modern mammals. Latitudinal gradients in community change (latitudinal turnover gradients, aka LTGs increase in strength through the Cenozoic, but also show a cyclical pattern that is significantly explained by MAP. In general, LTGs are weakest when continental MAP is highest, similar to modern tropical ecosystems in which latitudinal diversity gradients are weak or undetectable. Projections under modeled climate change show no substantial change in β diversity or LTG strength for North American mammals. Our results suggest that similar climate-mediated mechanisms might drive spatial and temporal patterns of community composition in both fossil and extant mammals. We also provide empirical evidence that the ecological processes on which climate space models are based are insufficient for accurately forecasting long-term mammalian response to anthropogenic climate change and inclusion of historical parameters may be essential.

The early life origin theory in the development of cardiovascular disease and type 2 diabetes.

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Lindblom, Runa; Ververis, Katherine; Tortorella, Stephanie M; Karagiannis, Tom C

2015-04-01

Life expectancy has been examined from a variety of perspectives in recent history. Epidemiology is one perspective which examines causes of morbidity and mortality at the population level. Over the past few 100 years there have been dramatic shifts in the major causes of death and expected life length. This change has suffered from inconsistency across time and space with vast inequalities observed between population groups. In current focus is the challenge of rising non-communicable diseases (NCD), such as cardiovascular disease and type 2 diabetes mellitus. In the search to discover methods to combat the rising incidence of these diseases, a number of new theories on the development of morbidity have arisen. A pertinent example is the hypothesis published by David Barker in 1995 which postulates the prenatal and early developmental origin of adult onset disease, and highlights the importance of the maternal environment. This theory has been subject to criticism however it has gradually gained acceptance. In addition, the relatively new field of epigenetics is contributing evidence in support of the theory. This review aims to explore the implication and limitations of the developmental origin hypothesis, via an historical perspective, in order to enhance understanding of the increasing incidence of NCDs, and facilitate an improvement in planning public health policy.

The early Eocene birds of the Messel fossil site: a 48 million-year-old bird community adds a temporal perspective to the evolution of tropical avifaunas.

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Mayr, Gerald

2017-05-01

Birds play an important role in studies addressing the diversity and species richness of tropical ecosystems, but because of the poor avian fossil record in all extant tropical regions, a temporal perspective is mainly provided by divergence dates derived from calibrated molecular analyses. Tropical ecosystems were, however, widespread in the Northern Hemisphere during the early Cenozoic, and the early Eocene German fossil site Messel in particular has yielded a rich avian fossil record. The Messel avifauna is characterized by a considerable number of flightless birds, as well as a high diversity of aerial insectivores and the absence of large arboreal birds. With about 70 currently known species in 42 named genus-level and at least 39 family-level taxa, it approaches extant tropical biotas in terms of species richness and taxonomic diversity. With regard to its taxonomic composition and presumed ecological characteristics, the Messel avifauna is more similar to the Neotropics, Madagascar, and New Guinea than to tropical forests in continental Africa and Asia. Because the former regions were geographically isolated during most of the Cenozoic, their characteristics may be due to the absence of biotic factors, especially those related to the diversification of placental mammals, which impacted tropical avifaunas in Africa and Asia. The crown groups of most avian taxa that already existed in early Eocene forests are species-poor. This does not support the hypothesis that the antiquity of tropical ecosystems is key to the diversity of tropical avifaunas, and suggests that high diversification rates may be of greater significance. © 2016 Cambridge Philosophical Society.

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

The Gestural Theory of Language Origins

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Armstrong, David F.

2008-01-01

The idea that iconic visible gesture had something to do with the origin of language, particularly speech, is a frequent element in speculation about this phenomenon and appears early in its history. Socrates hypothesizes about the origins of Greek words in Plato's satirical dialogue, "Cratylus", and his speculation includes a possible…

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada

Science.gov (United States)

du Bray, Edward A.; John, David A.; Box, Stephen E.; Vikre, Peter G.; Fleck, Robert J.; Cousens, Brian L.

2013-04-23

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada // // This report presents petrographic and geochemical data for samples collected during investigations of Tertiary volcanism in the Bodie Hills of California and Nevada. Igneous rocks in the area are principally 15–6 Ma subduction-related volcanic rocks of the Bodie Hills volcanic field but also include 3.9–0.1 Ma rocks of the bimodal, post-subduction Aurora volcanic field. Limited petrographic results for local basement rocks, including Mesozoic granitoid rocks and their metamorphic host rocks, are also included in the compilation. The petrographic data include visual estimates of phenocryst abundances as well as other diagnostic petrographic criteria. The geochemical data include whole-rock major oxide and trace element data, as well as limited whole-rock isotopic data.

Geochemistry of cenozoic basaltic rocks from Shandong province and its implication for mantle process in North China

International Nuclear Information System (INIS)

Lee Yungtan; Chen Juchin; Huang Shaowei; Shih Jyhyi; Lin Menglung; Juang Wenshing; Yang Huaijen

2006-01-01

Cenozoic (Miocene to Pleistocene) basaltic rocks found in Shandong province of northern China include tholeiite, olivine tholeiite and alkali basalt. We present major, trace and rare earth elements data of these basalts and together with Sr-Nd isotopic data in the literatures to discuss the petrogenesis of these basalts. The basalts from Penglai area have higher K, Na and P and incompatible elements, but lower Ca, Mg and compatible elements contents than those from Changle area of Shandong province. Spidergrams indicate that Cenozoic basalts from Shandong province have geochemical characteristics similar to those of ocean island basalts (OIB) with slight positive Nb anomaly. The negative Ba, Rb and K anomalies found in the alkali basalts suggest the presence of residual phlogopite in the mantle source, indicating a metasomatic event occurred before the partial melting. The 143 Nd/ 144 Nd vs. 87 Sr/ 86 Sr plot suggested that basalts from Shandong province can be produced by MORB and EM-I components mixing. We propose that the EM-I type lithospheric mantle may have been produced by the recent H 2 O-CO 2 -fluids metasomatism and the fluids may be derived from dehydration of the subducted slab. Based on Shaw's equation, the basalts from eastern and central Shandong province have undergone different degrees of particle melting from the mantle source. Degrees of partial melting and chemical composition of basalts from Shandong province suggest that the lithosphere has thickened progressively since the Miocene. On the basis of Ar-Ar ages of this study and the fractional crystallization model proposed by Brooks and Nielsen (1982), we suggest that basalts from Changle and Penglai areas belong to different magmatic systems which have undergone fractional crystallization and evolved progressively to produce other types of basalts. (author)

Study on Sr-Nd isotopes of mesozoic-cenozoic granites in Qinghai-Tibetan plateau

International Nuclear Information System (INIS)

Qiu Ruizhao; Deng Jinfu; Zhou Su; Xiao Qinghui; Cai Zhiyong

2003-01-01

Mesozoic-Cenozoic magmatic activities were intensive in Qinghai-Tibetan plateau. Nd-Sr isotopic compositions of representative granitic plutons in western Qinghai-Tibetan plateau are reported in this paper. Combining with past isotopic data, which has reported in eastern Qinghai-Tibetan plateau, Sr-Nd isotopic compositions and material source and genesis of Mesozoic and Cenozoic granites in Qinghai-Tibetan plateau have been studied. The research result indicates there are three types of granite existing in Qinghai-Tibetan plateau, the granites of Late stage of Yanshan Period which distributing on north and south boundary of Gandes block (namely in north and south granitic belts of Dangdes) and cause of oceanic crust subduction, have ( 87 Sr/ 86 Sr)i of 0.7041-0.7064, ε (Nd) t of +2.5 - +5.7 and TDM age of 312-562 Ma, positive ε Nd, low ( 87 Sr/ 86 Sr)i ratio and young Nd model ages suggest relatively high contents of mantle-derived components in their sources, and this type granite might melt from subduction oceanic crust. The granites occurred intra-Gangdes block which were caused by collision of continent and post-collision, have ( 87 Sr/ 86 Sr)i of 0.706-0.719, ε (Nd) t of -5.3 - -8.3 and TDM age of 1323-1496 Ma, negative ε Nd, relative high ( 87 Sr/ 86 Sr)i ratio with an mid-Proterozoic Nd model ages, suggest granite has the mixing genesis of mantle-derived components and old crustal components in their sources. With relatively small variation range in ε (Nd) t and TDM age, it might imply granitic isotopic source in Gandes block to keep relative homogenization in long period. The granites in Himalayan block which there is not oceanic material to join in melting and to cause of intra-continental subduction, has most ( 87 Sr/ 86 Sr)i ratio more than 0.720, ε (Nd) t of -10.3 - -16.3 and TDM age of 1792-2206 Ma, high ( 87 Sr/ 86 Sr)i ratio, low negative ε (Nd)t with old Nd isotopic model ages and consistent with the Sr, Nd isotopic compositions of basement

Review of and contribution to the Stratigraphy of the Cenozoic Igneous Rocks in the Republic of Yemen

International Nuclear Information System (INIS)

El-Nakhal, H.A.

2002-01-01

In Yemen the Cenozoic igneous rocks consists of intrusive and extrusive rocks with interlayered sediments, all of which are included within the Manakha Group (latest Cretaceous-Holocene). This group is subdivided into the Haraz Formation which includes the latest Cretaceous-Tertiary volcanics and the interlayered sediments, the Aden Formation which includes the Late Tertiary-Holocene volcanics, and the Bura Formations are introduced here as new units. The Haraz Formation replaces the informal names: Trap Series, Yemen Volcanics and Aden Trap Series, Yemen Volcanics and Adan Trap Series.The Adan Formation are a readaptation of the term Aden Vocanic Series. A startotype for the Aden Formation is designated in the Shuqra-Ahwar area. (author)

Sr isotope evidence for a lacustrine origin for the upper Miocene to Pliocene Bouse Formation, lower Colorado River trough, and implications for timing of Colorado Plateau uplift

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Spencer, J.E.; Patchett, P.J.

1997-01-01

The upper Miocene to Pliocene Bouse Formation in the lower Colorado River trough, which consists largely of siltstone with basal tufa and marl, has been interpreted as estuarine on the basis of paleontology. This interpretation requires abrupt marine inundation that has been linked to early rifting in the Gulf of California and Salton trough. New strontium isotope measurements reported here from carbonates and invertebrate shells in the Bouse Formation reveal no evidence of marine water, but are consistent with deposition in a lake or chain of lakes fed by the Colorado River. Furthermore, the absence of a southward decrease in 87Sr/86Sr within the Bouse Formation does not support the estuarine model in which low 87Sr/86Sr marine Sr would have dominated the mouth of the hypothetical Bouse estuary. Elevation of originally marine 87Sr/86Sr in the Bouse Formation to its present level, due to postdepositional interaction with ground water, is unlikely because Sr from secondary calcite above, below, and within the Bouse Formation is consistently less radiogenic, not more, than Bouse marl and shells. In contrast to Bouse Sr, strontium from mollusks in tidal-flat and delta-front paleoenvironments in the contemporaneous Imperial Formation in the Salton trough and from the subsurface south of Yuma was derived from sea water and confirms the dominance of marine strontium near or at the mouth of the late Miocene to early Pliocene Colorado River. Inferred post-early Pliocene uplift of the Bouse Formation from below sea level to modern elevations of up to 550 m has been used to support a late Cenozoic uplift age for the nearby Colorado Plateau. This constraint on uplift timing is eliminated if the Bouse Formation is lacustrine.

Stratigraphy and Mesozoic–Cenozoic tectonic history of northern Sierra Los Ajos and adjacent areas, Sonora, Mexico

Science.gov (United States)

Page, William R.; Gray, Floyd; Iriondo, Alexander; Miggins, Daniel P.; Blodgett, Robert B.; Maldonado, Florian; Miller, Robert J.

2010-01-01

Geologic mapping in the northern Sierra Los Ajos reveals new stratigraphic and structural data relevant to deciphering the Mesozoic–Cenozoic tectonic evolution of the range. The northern Sierra Los Ajos is cored by Proterozoic, Cambrian, Devonian, Mississippian, and Pennsylvanian strata, equivalent respectively to the Pinal Schist, Bolsa Quartzite and Abrigo Limestone, Martin Formation, Escabrosa Limestone, and Horquilla Limestone. The Proterozoic–Paleozoic sequence is mantled by Upper Cretaceous rocks partly equivalent to the Fort Crittenden and Salero Formations in Arizona, and the Cabullona Group in Sonora, Mexico.Absence of the Upper Jurassic–Lower Cretaceous Bisbee Group below the Upper Cretaceous rocks and above the Proterozoic–Paleozoic rocks indicates that the Sierra Los Ajos was part of the Cananea high, a topographic highland during the Late Jurassic and Early Cretaceous. Deposition of Upper Cretaceous rocks directly on Paleozoic and Proterozoic rocks indicates that the Sierra Los Ajos area had subsided as part of the Laramide Cabullona basin during Late Cretaceous time. Basal beds of the Upper Cretaceous sequence are clast-supported conglomerate composed locally of basement (Paleozoic) clasts. The conglomerate represents erosion of Paleozoic basement in the Sierra Los Ajos area coincident with development of the Cabullona basin.The present-day Sierra Los Ajos reaches elevations of greater than 2600 m, and was uplifted during Tertiary basin-and-range extension. Upper Cretaceous rocks are exposed at higher elevations in the northern Sierra Los Ajos and represent an uplifted part of the inverted Cabullona basin. Tertiary uplift of the Sierra Los Ajos was largely accommodated by vertical movement along the north-to-northwest-striking Sierra Los Ajos fault zone flanking the west side of the range. This fault zone structurally controls the configuration of the headwaters of the San Pedro River basin, an important bi-national water resource in the US

A new sauropodomorph dinosaur from the Early Jurassic of Patagonia and the origin and evolution of the sauropod-type sacrum.

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Diego Pol

2011-01-01

Full Text Available The origin of sauropod dinosaurs is one of the major landmarks of dinosaur evolution but is still poorly understood. This drastic transformation involved major skeletal modifications, including a shift from the small and gracile condition of primitive sauropodomorphs to the gigantic and quadrupedal condition of sauropods. Recent findings in the Late Triassic-Early Jurassic of Gondwana provide critical evidence to understand the origin and early evolution of sauropods.A new sauropodomorph dinosaur, Leonerasaurus taquetrensis gen. et sp. nov., is described from the Las Leoneras Formation of Central Patagonia (Argentina. The new taxon is diagnosed by the presence of anterior unserrated teeth with a low spoon-shaped crown, amphicoelous and acamerate vertebral centra, four sacral vertebrae, and humeral deltopectoral crest low and medially deflected along its distal half. The phylogenetic analysis depicts Leonerasaurus as one of the closest outgroups of Sauropoda, being the sister taxon of a clade of large bodied taxa composed of Melanorosaurus and Sauropoda.The dental and postcranial anatomy of Leonerasaurus supports its close affinities with basal sauropods. Despite the small size and plesiomorphic skeletal anatomy of Leonerasaurus, the four vertebrae that compose its sacrum resemble that of the large-bodied primitive sauropods. This shows that the appearance of the sauropod-type of sacrum predated the marked increase in body size that characterizes the origins of sauropods, rejecting a causal explanation and evolutionary linkage between this sacral configuration and body size. Alternative phylogenetic placements of Leonerasaurus as a basal anchisaurian imply a convergent acquisition of the sauropod-type sacrum in the new small-bodied taxon, also rejecting an evolutionary dependence of sacral configuration and body size in sauropodomorphs. This and other recent discoveries are showing that the characteristic sauropod body plan evolved gradually

Late Cenozoic basin evolution and fold-thrust deformation in the southern Central Andes: Initial constraints from synorogenic deposits of the Precordillera, Argentina

Science.gov (United States)

Levina, M.; Horton, B. K.; Fuentes, F.; Stockli, D. F.

2012-12-01

In the Precordillera region of the Argentine Andes, Cenozoic shortening associated with flattening of the Pampean segment of the subducting Nazca plate has resulted in a series of thin skinned fold-thrust systems that partitioned and uplifted Cenozoic foreland basin deposits. The kinematic and temporal evolution of the Andean Precordillera can be approached through detailed analyses of the sedimentary fill now preserved in intermontane regions and the bedrock low-temperature thermochronology of the fold-thrust belt. In this project, we focus on Neogene foreland basin fill exposed in the central and eastern Precordillera along the San Juan River (Quebrada Albarracín and Pachaco regions), on the western flank of the Sierra Talacasto, and in the Loma de las Tapias area near the Ullum dam. The sedimentary successions exposed in these regions record the hinterland development of the Frontal Cordillera (detrital zircon provenance and composition of sandstone and conglomeratic units), regional volcanism (pyroclastic flows and tuffaceous sandstone units), and initial construction of the Precordillera (fault cutoff relationships, growth strata, and paleocurrent changes). We investigate the development and subsequent partitioning and deformation of these synorogenic sections using sediment provenance (detrital zircon U-Pb geochronology, conglomerate clast counts, sandstone petrography, and paleocurrent measurements), facies analysis of measured stratigraphic successions, and initial apatite (U-Th)/He cooling histories to constrain the age of uplift-induced exhumation of successive thrust sheets in the Andean Precordillera.

THE ORIGIN OF DUST IN EARLY-TYPE GALAXIES AND IMPLICATIONS FOR ACCRETION ONTO SUPERMASSIVE BLACK HOLES

Energy Technology Data Exchange (ETDEWEB)

Martini, Paul [Department of Astronomy and Center for Cosmology and Astroparticle Physics, The Ohio State University, Columbus, OH 43210 (United States); Dicken, Daniel [Institut de Astrophysique Spatiale, Paris (France); Storchi-Bergmann, Thaisa [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Caixa Postal 15051, 91501-970 Porto Alegre, RS (Brazil)

2013-04-01

We have conducted an archival Spitzer study of 38 early-type galaxies in order to determine the origin of the dust in approximately half of this population. Our sample galaxies generally have good wavelength coverage from 3.6 {mu}m to 160 {mu}m, as well as visible-wavelength Hubble Space Telescope (HST) images. We use the Spitzer data to estimate dust masses, or establish upper limits, and find that all of the early-type galaxies with dust lanes in the HST data are detected in all of the Spitzer bands and have dust masses of {approx}10{sup 5}-10{sup 6.5} M{sub Sun }, while galaxies without dust lanes are not detected at 70 {mu}m and 160 {mu}m and typically have <10{sup 5} M{sub Sun} of dust. The apparently dust-free galaxies do have 24 {mu}m emission that scales with the shorter-wavelength flux, yet substantially exceeds the expectations of photospheric emission by approximately a factor of three. We conclude this emission is dominated by hot, circumstellar dust around evolved stars that does not survive to form a substantial interstellar component. The order-of-magnitude variations in dust masses between galaxies with similar stellar populations rule out a substantial contribution from continual, internal production in spite of the clear evidence for circumstellar dust. We demonstrate that the interstellar dust is not due to purely external accretion, unless the product of the merger rate of dusty satellites and the dust lifetime is at least an order of magnitude higher than expected. We propose that dust in early-type galaxies is seeded by external accretion, yet the accreted dust is maintained by continued growth in externally accreted cold gas beyond the nominal lifetime of individual grains. The several Gyr depletion time of the cold gas is long enough to reconcile the fraction of dusty early-type galaxies with the merger rate of gas-rich satellites. As the majority of dusty early-type galaxies are also low-luminosity active galactic nuclei and likely fueled

Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe

Energy Technology Data Exchange (ETDEWEB)

Mayer, Lucio; /Zurich, ETH /Zurich U.; Kazantzidis, Stelios; /KIPAC, Menlo Park /KICP, Chicago; Mastropietro, Chiara; /Munich U. Observ.; Wadsley, James; /McMaster U.

2007-02-28

The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid of gas, known as dwarf spheroidals, and have by far the highest ratio of dark to luminous matter. None of the models proposed to unravel their origin can simultaneously explain their exceptional dark matter content and their proximity to a much larger galaxy. Here we report simulations showing that the progenitors of these galaxies were probably gas-dominated dwarf galaxies that became satellites of a larger galaxy earlier than the other dwarf spheroidals. We find that a combination of tidal shocks and ram pressure swept away the entire gas content of such progenitors about ten billion years ago because heating by the cosmic ultraviolet background kept the gas loosely bound: a tiny stellar component embedded in a relatively massive dark halo survived until today. All luminous galaxies should be surrounded by a few extremely dark-matter-dominated dwarf spheroidal satellites, and these should have the shortest orbital periods among dwarf spheroidals because they were accreted early.

Contextualising primate origins--an ecomorphological framework.

Science.gov (United States)

Soligo, Christophe; Smaers, Jeroen B

2016-04-01

Ecomorphology - the characterisation of the adaptive relationship between an organism's morphology and its ecological role - has long been central to theories of the origin and early evolution of the primate order. This is exemplified by two of the most influential theories of primate origins: Matt Cartmill's Visual Predation Hypothesis, and Bob Sussman's Angiosperm Co-Evolution Hypothesis. However, the study of primate origins is constrained by the absence of data directly documenting the events under investigation, and has to rely instead on a fragmentary fossil record and the methodological assumptions inherent in phylogenetic comparative analyses of extant species. These constraints introduce particular challenges for inferring the ecomorphology of primate origins, as morphology and environmental context must first be inferred before the relationship between the two can be considered. Fossils can be integrated in comparative analyses and observations of extant model species and laboratory experiments of form-function relationships are critical for the functional interpretation of the morphology of extinct species. Recent developments have led to important advancements, including phylogenetic comparative methods based on more realistic models of evolution, and improved methods for the inference of clade divergence times, as well as an improved fossil record. This contribution will review current perspectives on the origin and early evolution of primates, paying particular attention to their phylogenetic (including cladistic relationships and character evolution) and environmental (including chronology, geography, and physical environments) contextualisation, before attempting an up-to-date ecomorphological synthesis of primate origins. © 2016 Anatomical Society.

Cenozoic aridization in Central Eurasia shaped diversification of toad-headed agamas (Phrynocephalus; Agamidae, Reptilia).

Science.gov (United States)

Solovyeva, Evgeniya N; Lebedev, Vladimir S; Dunayev, Evgeniy A; Nazarov, Roman A; Bannikova, Anna A; Che, Jing; Murphy, Robert W; Poyarkov, Nikolay A

2018-01-01

We hypothesize the phylogenetic relationships of the agamid genus Phrynocephalus to assess how past environmental changes shaped the evolutionary and biogeographic history of these lizards and especially the impact of paleogeography and climatic factors. Phrynocephalus is one of the most diverse and taxonomically confusing lizard genera. As a key element of Palearctic deserts, it serves as a promising model for studies of historical biogeography and formation of arid habitats in Eurasia. We used 51 samples representing 33 of 40 recognized species of Phrynocephalus covering all major areas of the genus. Molecular data included four mtDNA ( COI , ND2 , ND4 , Cytb ; 2,703 bp) and four nuDNA protein-coding genes ( RAG1 , BDNF , AKAP9 , NKTR ; 4,188 bp). AU-tests were implemented to test for significant differences between mtDNA- and nuDNA-based topologies. A time-calibrated phylogeny was estimated using a Bayesian relaxed molecular clock with nine fossil calibrations. We reconstructed the ancestral area of origin, biogeographic scenarios, body size, and the evolution of habitat preference. Phylogenetic analyses of nuDNA genes recovered a well-resolved and supported topology. Analyses detected significant discordance with the less-supported mtDNA genealogy. The position of Phrynocephalus mystaceus conflicted greatly between the two datasets. MtDNA introgression due to ancient hybridization best explained this result. Monophyletic Phrynocephalus contained three main clades: (I) oviparous species from south-western and Middle Asia; (II) viviparous species of Qinghai-Tibetan Plateau (QTP); and (III) oviparous species of the Caspian Basin, Middle and Central Asia. Phrynocephalus originated in late Oligocene (26.9 Ma) and modern species diversified during the middle Miocene (14.8-13.5 Ma). The reconstruction of ancestral areas indicated that Phrynocephalus originated in Middle East-southern Middle Asia. Body size miniaturization likely occurred early in the history of

Origin of sulphur compounds and application of isotope geothermometry in selected geothermal systems of China

International Nuclear Information System (INIS)

Pang Zhonghe

2005-01-01

Geothermal and groundwater samples from East of Heber (EH) Province in the North China Basin and South of Fujian (SF) Province in Southeast of China were studied using sulphur and water isotopes. EH is located in a Mesozoic-Cenozoic sedimentary basin while SF is composed of small fault-block basins formed in Quaternary period. These systems belong to non-volcanic geothermal environments. Samples were collected from exploratory and production geothermal wells: 11 wells in EH and 17 wells in SF. The samples were analyzed for oxygen-18 (δ 18 O) and deuterium (δ 2 H) in water, sulfur-34 (δ 34 S) and oxygen-18 ((δ 18 O) in aqueous sulphate (SO 4 ). Chemical composition of the water samples was also determined. Results show that aqueous sulphate in the saline thermal waters of SF is of marine origin. The aqueous sulphate in EH waters is of non-marine origin. Reservoir temperature estimated using the oxygen isotope geothermometer is not compatible to those by chemical geothermometers or by down-hole measurements in the sedimentary environment for EH, different from that for the SF samples where aqueous sulphate seems to have reached equilibrium with thermal waters in the main up-flow zone. (author)

Evolutionary patterns in the sequence and structure of transfer RNA: early origins of archaea and viruses.

Directory of Open Access Journals (Sweden)

Feng-Jie Sun

2008-03-01

Full Text Available Transfer RNAs (tRNAs are ancient molecules that are central to translation. Since they probably carry evolutionary signatures that were left behind when the living world diversified, we reconstructed phylogenies directly from the sequence and structure of tRNA using well-established phylogenetic methods. The trees placed tRNAs with long variable arms charging Sec, Tyr, Ser, and Leu consistently at the base of the rooted phylogenies, but failed to reveal groupings that would indicate clear evolutionary links to organismal origin or molecular functions. In order to uncover evolutionary patterns in the trees, we forced tRNAs into monophyletic groups using constraint analyses to generate timelines of organismal diversification and test competing evolutionary hypotheses. Remarkably, organismal timelines showed Archaea was the most ancestral superkingdom, followed by viruses, then superkingdoms Eukarya and Bacteria, in that order, supporting conclusions from recent phylogenomic studies of protein architecture. Strikingly, constraint analyses showed that the origin of viruses was not only ancient, but was linked to Archaea. Our findings have important implications. They support the notion that the archaeal lineage was very ancient, resulted in the first organismal divide, and predated diversification of tRNA function and specificity. Results are also consistent with the concept that viruses contributed to the development of the DNA replication machinery during the early diversification of the living world.

Recycling of Amazonian detrital zircons in the Mixteco terrane, southern Mexico: Paleogeographic implications during Jurassic-Early Cretaceous and Paleogene times

Science.gov (United States)

Silva-Romo, Gilberto; Mendoza-Rosales, Claudia Cristina; Campos-Madrigal, Emiliano; Morales-Yáñez, Axél; de la Torre-González, Alam Israel; Nápoles-Valenzuela, Juan Ivan

2018-04-01

In the northeastern Mixteco terrane of southern Mexico, in the Ixcaquixtla-Atzumba region, the recycling of Amazonian detrital zircons records the paleogeography during the Mesozoic period in the context of the breakup of Pangea, a phenomenon that disarticulated the Sanozama-La Mora paleo-river. The clastic units of southern Mexico in the Ayuquila, Otlaltepec and Zapotitlán Mesozoic basins, as well as in the Atzumba Cenozoic basin, are characterized by detrital zircon contents with ages specific to the Amazonian craton, ranging between 3040 and 1278 Ma. The presence of zircons of Amazonian affinity suggests a provenance by recycling from carrier units such as the La Mora Formation or the Ayú Complex. In the area, the Ayú and Acatlán complexes form the Cosoltepec block, a paleogeographic element that during Early Cretaceous time acted as the divide between the slopes of the paleo-Gulf of Mexico and the paleo-Pacific Ocean. The sedimentological characteristics of the Jurassic-Cenozoic clastic successions in the Ixcaquixtla-Atzumba region denote relatively short transport in braided fluvial systems and alluvial fans. In this way, several basins are recognized around the Cosoltepec block. At the southeastern edge of the Cosoltepec block, the Ayuquila and Tecomazúchil formations accumulated in the Ayuquila continental basin on the paleo-Pacific Ocean slope. On the other hand, within the paleo-Gulf of Mexico slope, in the Otlaltepec continental basin, the Piedra Hueca and the Otlaltepec formations accumulated. The upper member of the Santa Lucía Formation accumulated in a transitional environment on the southwestern shoulder of the Zapotitlán basin, as well as on the paleo-Gulf of Mexico slope. In the Ayuquila basin, a marine transgression is recognized that advanced from south to north during the Late Jurassic. At the northeastern edge of the Cosoltepec block, we propose that the Santa Lucía formation attests to a transgression from the paleo-Gulf of Mexico

Origin of secretin receptor precedes the advent of tetrapoda: evidence on the separated origins of secretin and orexin.

Directory of Open Access Journals (Sweden)

Janice K V Tam

Full Text Available At present, secretin and its receptor have only been identified in mammals, and the origin of this ligand-receptor pair in early vertebrates is unclear. In addition, the elusive similarities of secretin and orexin in terms of both structures and functions suggest a common ancestral origin early in the vertebrate lineage. In this article, with the cloning and functional characterization of secretin receptors from lungfish and X. laevis as well as frog (X. laevis and Rana rugulosa secretins, we provide evidence that the secretin ligand-receptor pair has already diverged and become highly specific by the emergence of tetrapods. The secretin receptor-like sequence cloned from lungfish indicates that the secretin receptor was descended from a VPAC-like receptor prior the advent of sarcopterygians. To clarify the controversial relationship of secretin and orexin, orexin type-2 receptor was cloned from X. laevis. We demonstrated that, in frog, secretin and orexin could activate their mutual receptors, indicating their coordinated complementary role in mediating physiological processes in non-mammalian vertebrates. However, among the peptides in the secretin/glucagon superfamily, secretin was found to be the only peptide that could activate the orexin receptor. We therefore hypothesize that secretin and orexin are of different ancestral origins early in the vertebrate lineage.

An early Oligocene fossil demonstrates treeshrews are slowly evolving "living fossils".

Science.gov (United States)

Li, Qiang; Ni, Xijun

2016-01-14

Treeshrews are widely considered a "living model" of an ancestral primate, and have long been called "living fossils". Actual fossils of treeshrews, however, are extremely rare. We report a new fossil species of Ptilocercus treeshrew recovered from the early Oligocene (~34 Ma) of China that represents the oldest definitive fossil record of the crown group of treeshrews and nearly doubles the temporal length of their fossil record. The fossil species is strikingly similar to the living Ptilocercus lowii, a species generally recognized as the most plesiomorphic extant treeshrew. It demonstrates that Ptilocercus treeshrews have undergone little evolutionary change in their morphology since the early Oligocene. Morphological comparisons and phylogenetic analysis support the long-standing idea that Ptilocercus treeshrews are morphologically conservative and have probably retained many characters present in the common stock that gave rise to archontans, which include primates, flying lemurs, plesiadapiforms and treeshrews. This discovery provides an exceptional example of slow morphological evolution in a mammalian group over a period of 34 million years. The persistent and stable tropical environment in Southeast Asia through the Cenozoic likely played a critical role in the survival of such a morphologically conservative lineage.

The initiation and tectonic regimes of the Cenozoic extension in the Bohai Bay Basin, North China revealed by numerical modelling

Science.gov (United States)

Li, Lu; Qiu, Nansheng

2017-06-01

In this study the dynamic aspects of the Cenozoic extension in the Bohai Bay Basin are considered in the context of initial thickness of the crust and lithosphere, tectonic force, strain rate and thermal rheology, which are directly or indirectly estimated from a pure shear extensional model. It is accordingly reasonable to expect that, in the Bohai Bay Basin, the thickness variation could be present prior to the initiation of extension. The extensional deformation is localized by a thickness variation of the crust and lithosphere and the heterogeneity of the initial thickness plays an important role in rifting dynamics. The onset of rifting requires a critical tectonic force (initial tectonic force) to be applied, which then immediately begins to decay gradually. Rifting will only occur when the total effective buoyancy force of the subducting slab reaches a critical level, after a certain amount of subduction taking place. The magnitude of the tectonic force decreases with time in the early phase of rifting, which indicates the weakening due to the increase in geothermal gradient. In order to deform the continental lithosphere within the currently accepted maximum magnitude of the force derived from subducted slab roll-back, the following conditions should be satisfied: (1) the thickness of the continental lithosphere is significantly thin and less than 125 km and (2) the lithosphere has a wet and hot rheology, which provides implications for rheological layering in continental lithosphere. Our results are strongly supported by the ;crème brûlée; model, in which the lower crust and mantle are relatively ductile.

Early stages of formation and dispersal of the temperate flora in the Boreal region

International Nuclear Information System (INIS)

Budantsev, L.Y.

1992-01-01

The thesis of this review is that the composition of a flora can be understood only as a process, or separate stage, in the context of migration in time and space of various floristic assemblages and their isolation, as induced by transformation of continental and ocean shapes, changes in climate, and the environment as a whole. Thus the formation of geofloras of the past was influenced by gradually changing environments that determined the spread, patterning, and spatial differentiation of floras and their evolution. Parallel to the more commonly-seen names of eras-Paleozoic, Mesozoic, and Cenozoic-we can speak of the Paleophytic, Mesophytic, and Cenophytic eras. Eras defined in these two ways (by faunistic or by floristic criteria) do not completely coincide. Generally, changes in the flora have, necessarily, preceded changes in the fauna. It is the Cenophytic with which this review is mostly concerned, the era of Angiosperm dominance. The movement of early subtropical and warm temperate floras in the Early Cenophytic, followed by temperate or even boreal floras, as the climate changes, is traced in detail

Origin of marginal basins of the NW Pacific and their plate tectonic reconstructions

Science.gov (United States)

Xu, Junyuan; Ben-Avraham, Zvi; Kelty, Tom; Yu, Ho-Shing

2014-03-01

Geometry of basins can indicate their tectonic origin whether they are small or large. The basins of Bohai Gulf, South China Sea, East China Sea, Japan Sea, Andaman Sea, Okhotsk Sea and Bering Sea have typical geometry of dextral pull-apart. The Java, Makassar, Celebes and Sulu Seas basins together with grabens in Borneo also comprise a local dextral, transform-margin type basin system similar to the central and southern parts of the Shanxi Basin in geometry. The overall configuration of the Philippine Sea resembles a typical sinistral transpressional "pop-up" structure. These marginal basins except the Philippine Sea basin generally have similar (or compatible) rift history in the Cenozoic, but there do be some differences in the rifting history between major basins or their sub-basins due to local differences in tectonic settings. Rifting kinematics of each of these marginal basins can be explained by dextral pull-apart or transtension. These marginal basins except the Philippine Sea basin constitute a gigantic linked, dextral pull-apart basin system.

Late Cenozoic thrusting of major faults along the central segment of Longmen Shan, eastern Tibet: Evidence from low-temperature thermochronology

Science.gov (United States)

Tan, Xi-Bin; Xu, Xi-Wei; Lee, Yuan-Hsi; Lu, Ren-Qi; Liu, Yiduo; Xu, Chong; Li, Kang; Yu, Gui-Hua; Kang, Wen-Jun

2017-08-01

The Cenozoic orogenic process of the Longmen Shan (LMS) and the kinematics of major faults along the LMS are crucial for understanding the growth history and mechanism of the eastern Tibetan Plateau. Three major faults, from west to east, are present in the central segment of the LMS: the Wenchuan-Maoxian Fault (WMF), the Beichuan-Yingxiu Fault (BYF), and the Jiangyou-Guanxian Fault (JGF). Previous researchers have placed great impetus on the Pengguan Massif, between the WMF and BYF. However, limited low-temperature thermochronology data coverage in other areas prevents us from fully delineating the tectonic history of the LMS. In this study, we collect 22 samples from vertical profiles in the Xuelongbao Massif and the range frontal area located at the hanging walls of the WMF and JGF respectively, and conduct apatite and zircon fission track analyses. New fission track data reveal that the Xuelongbao Massif has been undergoing rapid exhumation with an average rate of 0.7-0.9 mm/yr since 11 Ma, and the range frontal area began rapid exhumation at 7.5 Ma with total exhumation of 2.5-4.5 km. The exhumation histories indicate that the three major faults (WMF, BYF and JGF) in the central LMS are all reverse faults, and show a basinward in-sequence propagation from middle Miocene to present-day. Such a pattern further implies that upper crustal shortening is the primary driver for the LMS' uplift during the Late Cenozoic. Nevertheless, middle-lower crustal deformation is difficult to be constrained by the exhumation histories, and its contribution to LMS' uplift cannot be ruled out.

Cenozoic aridization in Central Eurasia shaped diversification of toad-headed agamas (Phrynocephalus; Agamidae, Reptilia

Directory of Open Access Journals (Sweden)

Evgeniya N. Solovyeva

2018-03-01

Full Text Available We hypothesize the phylogenetic relationships of the agamid genus Phrynocephalus to assess how past environmental changes shaped the evolutionary and biogeographic history of these lizards and especially the impact of paleogeography and climatic factors. Phrynocephalus is one of the most diverse and taxonomically confusing lizard genera. As a key element of Palearctic deserts, it serves as a promising model for studies of historical biogeography and formation of arid habitats in Eurasia. We used 51 samples representing 33 of 40 recognized species of Phrynocephalus covering all major areas of the genus. Molecular data included four mtDNA (COI, ND2, ND4, Cytb; 2,703 bp and four nuDNA protein-coding genes (RAG1, BDNF, AKAP9, NKTR; 4,188 bp. AU-tests were implemented to test for significant differences between mtDNA- and nuDNA-based topologies. A time-calibrated phylogeny was estimated using a Bayesian relaxed molecular clock with nine fossil calibrations. We reconstructed the ancestral area of origin, biogeographic scenarios, body size, and the evolution of habitat preference. Phylogenetic analyses of nuDNA genes recovered a well-resolved and supported topology. Analyses detected significant discordance with the less-supported mtDNA genealogy. The position of Phrynocephalus mystaceus conflicted greatly between the two datasets. MtDNA introgression due to ancient hybridization best explained this result. Monophyletic Phrynocephalus contained three main clades: (I oviparous species from south-western and Middle Asia; (II viviparous species of Qinghai–Tibetan Plateau (QTP; and (III oviparous species of the Caspian Basin, Middle and Central Asia. Phrynocephalus originated in late Oligocene (26.9 Ma and modern species diversified during the middle Miocene (14.8–13.5 Ma. The reconstruction of ancestral areas indicated that Phrynocephalus originated in Middle East–southern Middle Asia. Body size miniaturization likely occurred early in the history

Did the Bering Sea Form as a Cenozoic Backarc Basin?

Science.gov (United States)

Stern, R. J.; Barth, G. A.; Scheirer, D. S.; Scholl, D. W.

2012-12-01

Understanding the origins of Bering Sea marginal basins (Aleutian, Bowers, and Komandorsky basins; AB, BB, KB) is key for reconstructing N. Pacific tectonic and magmatic evolution. New acquisitions and recompilations of MCS, OBS, and potential field data (Barth et al. poster. this session) for USGS Extended Continental Shelf project and selection of Aleutians as GeoPrisms Subduction Cycles and Deformation focus site stimulate reconsideration of BB, KB, and especially AB origins. AB has long been regarded as N. Pacific crust trapped when the Aleutian subduction began ~45-50 Ma. BB and KB probably formed together as Miocene backarc basins. Presence of Oligo-Miocene arc volcanics on Bowers and Shirshov ridges suggests that these are remnant arcs, orphaned by AB and KB opening. Seven lines of evidence suggest that AB formed as a Paleogene backarc basin: 1) AB heatflow suggests an age of about 44 Ma (Langseth et al 1980 JGR). 2) Formation of NNW-trending rift basins on Bering shelf (Navarin, Pribilof, and St. George basins) in Paleogene time indicate extension at this time. 3) The early Paleogene "red unconformity" of the Beringian margin could indicate uplift, erosion, and subsidence associated with AB opening. 4) ~N-S magnetic anomalies in AB contrasts with E-W Kula anomalies on N. Pacific, indicating that the two tracts of oceanic crust formed at different spreading ridges. 5) Thicker sediment in AB (2-4 km) vs. BB and KB (oceanic crust.ectonic scenario for formation of Aleutian Arc and Bering Sea basins. Green = present land; yellow = shelf; AB = Aleutian Basin; KB = Komandorsky Basin; BB = Bowers Basin; SR = Shirshov Ridge, BR = Bowers Ridge; Red = active volcanism and spreading ; Blue = extinct volcanism and spreading

Geobiological constraints on Earth system sensitivity to CO₂ during the Cretaceous and Cenozoic.

Science.gov (United States)

Royer, D L; Pagani, M; Beerling, D J

2012-07-01

Earth system climate sensitivity (ESS) is the long-term (>10³ year) response of global surface temperature to doubled CO₂ that integrates fast and slow climate feedbacks. ESS has energy policy implications because global temperatures are not expected to decline appreciably for at least 10³ year, even if anthropogenic greenhouse gas emissions drop to zero. We report provisional ESS estimates of 3 °C or higher for some of the Cretaceous and Cenozoic based on paleo-reconstructions of CO₂ and temperature. These estimates are generally higher than climate sensitivities simulated from global climate models for the same ancient periods (approximately 3 °C). Climate models probably do not capture the full suite of positive climate feedbacks that amplify global temperatures during some globally warm periods, as well as other characteristic features of warm climates such as low meridional temperature gradients. These absent feedbacks may be related to clouds, trace greenhouse gases (GHGs), seasonal snow cover, and/or vegetation, especially in polar regions. Better characterization and quantification of these feedbacks is a priority given the current accumulation of atmospheric GHGs. © 2012 Blackwell Publishing Ltd.

The origins of medical physics.

Science.gov (United States)

Duck, Francis A

2014-06-01

The historical origins of medical physics are traced from the first use of weighing as a means of monitoring health by Sanctorius in the early seventeenth century to the emergence of radiology, phototherapy and electrotherapy at the end of the nineteenth century. The origins of biomechanics, due to Borelli, and of medical electricity following Musschenbroek's report of the Leyden Jar, are included. Medical physics emerged as a separate academic discipline in France at the time of the Revolution, with Jean Hallé as its first professor. Physiological physics flowered in Germany during the mid-nineteenth century, led by the work of Adolf Fick. The introduction of the term medical physics into English by Neil Arnott failed to accelerate its acceptance in Britain or the USA. Contributions from Newton, Euler, Bernoulli, Nollet, Matteucci, Pelletan, Gavarret, d'Arsonval, Finsen, Röntgen and others are noted. There are many origins of medical physics, stemming from the many intersections between physics and medicine. Overall, the early nineteenth-century definition of medical physics still holds today: 'Physics applied to the knowledge of the human body, to its preservation and to the cure of its illnesses'. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Aerial gamma ray and magnetic survey: Mississippi and Florida airborne survey, Jackson quadrangle of Mississippi and Louisiana. Final report

International Nuclear Information System (INIS)

1980-07-01

The Jackson quadrangle covers a region largely within the Mississippi River flood plain. In the extreme northern Gulf Coastal Physiographic Province. Underlying Mesozoic and Cenozoic sediments of the Mississippi Embayment are relatively thick. Exposed sediments are largely Quaternary in age, though older Cenozoic material of both marine and nonmarine origin are exposed in areas adjacent to the flood plain in the east. A search of the available literature revealed no known uranium deposits. Seventy-three uranium anomalies were detected and are discussed briefly. None were considered significant, and most appeared to be of cultural origin. Magnetic data appears to be in agreement with existing structural interpretations of the region

Origin of marine planktonic cyanobacteria.

Science.gov (United States)

Sánchez-Baracaldo, Patricia

2015-12-01

Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600-2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500-542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600-1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000-542 Mya).

Origin and earliest state of the earth's hydrosphere

International Nuclear Information System (INIS)

Cogley, J.G.; Henderson-Sellers, A.

1984-01-01

The origin and earliest history of the earth's hydrosphere, the inventory of excess volatiles defined by Rubey in 1951, can be constrained within wide but useful limits by a consideration of empirical and theoretical evidence from astrophysics and geology. Models for the evolution of the solar system from the protoplanetary nebula and for the growth of the earth to its present dimensions suggest quite strongly that the hydrosphere came into being during accretion. Its format, with H 2 O mostly in the oceans, CO 2 mostly in sediments, and a residual atmosphere dominated by N 2 , CO 2 , and H 2 O was established at a very early data and has persisted without large, destabilizing climatic excursions until the present day. Alternative accounts of early history, in which the earth either loses a massive primordial atmosphere or acquires its secondary atmosphere by gradual degassing, seem improbable on the basis of a series of circumstantial but cumulatively persuasive arguments. The difficulty of dissipating a massive atmosphere of solar composition in reasonable times, the likelihood that accretion was a highly energetic process and that it triggered early segregation of the core, and the tendency of the planet to accumulate volatiles preferentially in the later stages of accretion are examples of arguments favoring an early origin for the hydrosphere. Several geological isotope systems which can be sampled today require early separation of the atmosphere and probably the hydrosphere ass a whole; these systems recorrd radiogenic enrichment patterns in the noble gases and stable isotope fractionations which suggest an early origin of the biosphere. Certain geological indicators of atmsopheric composition. and the broadly equable character of the rock record, are also consistent with a hydrosphere established in the earliest stages of history and having an initial neutral or weakly reduced composition

Preliminary geologic map of the Turayf Quadrangle, sheet 31C, and part of the An Nabk quadrangle, sheet 31B, Kingdom of Saudi Arabia

Science.gov (United States)

Meissner, C.R.; Riddler, G.P.; Van Eck, Marcel; Aspinall, N.C.; Farasani, A.M.; Dini, S.M.

1989-01-01

The An Nabk and Turayf quadrangles lie at the northern border of the Kingdom of Saudi Arabia. Middle and upper Cenozoic sedimentary and volcanic rocks form the surface of the quadrangles, and sedimentary rocks of the Paleozoic, Mesozoic, and lower Cenozoic are found in the subsurface. The Paleozoic and Mesozoic rocks, described from drill hole records, include the Tabuk, Upper Sudair, Lower Jilh and Aruma formations which are mostly of marine origin.

Late Cenozoic structure and stratigraphy of south-central Washington

International Nuclear Information System (INIS)

Reidel, S.P.; Fecht, K.R.; Lindsey, K.A.

1993-01-01

The structural framework of the Columbia Basin began developing before Columbia River Basalt Group (CRBG) volcanism. Prior to 17.5 Ma, the eastern part of the basin was a relatively stable area, with a basement of Paleozoic and older crystalline rock. The western part was an area of subsidence in which large volumes of sediment and volcanic rocks accumulated. Concurrent with eruption of the CRBG, anticlinal ridges of the Yakima Fold Belt (YFB) were growing under north-south compression. Topographic expression of these features was later masked by the large volume of CRBG basalt flowing west from fissures in the eastern Columbia Basin. The folds continued to develop after cessation of volcanism, leading to as much as 1,000 m of structural relief in the past 10 million years. Post-CRBG evolution of the Columbia Basin is recorded principally in folding and faulting in the YFB and sediments deposited in the basins. The accompanying tectonism resulted in lateral migration of major depositional systems into subsiding structural lows. Although known late Cenozoic faults are on anticlinal ridges, earthquake focal mechanisms and contemporary strain measurements indicate most stress release is occurring in the synclinal areas under north-south compression. There is no obvious correlation between focal mechanisms for earthquakes whose foci are in the CRBG and the location of known faults. High in situ stress values help to explain the occurrence of microseismicity in the Columbia Basin but not the pattern. Microseismicity appears to occur in unaltered fresh basalt. Faulted basalt associated with the YFB is highly brecciated and commonly altered to clay. The high stress, abundance of ground water in confined aquifers of the CRBG, and altered basalt in fault zones suggest that the frontal faults on the anticlinal ridges probably have some aseismic deformation. 85 refs

Estimates of late Cenozoic climate change relevant to Earth surface processes in tectonically active orogens

Science.gov (United States)

Mutz, Sebastian G.; Ehlers, Todd A.; Werner, Martin; Lohmann, Gerrit; Stepanek, Christian; Li, Jingmin

2018-04-01

The denudation history of active orogens is often interpreted in the context of modern climate gradients. Here we address the validity of this approach and ask what are the spatial and temporal variations in palaeoclimate for a latitudinally diverse range of active orogens? We do this using high-resolution (T159, ca. 80 × 80 km at the Equator) palaeoclimate simulations from the ECHAM5 global atmospheric general circulation model and a statistical cluster analysis of climate over different orogens (Andes, Himalayas, SE Alaska, Pacific NW USA). Time periods and boundary conditions considered include the Pliocene (PLIO, ˜ 3 Ma), the Last Glacial Maximum (LGM, ˜ 21 ka), mid-Holocene (MH, ˜ 6 ka), and pre-industrial (PI, reference year 1850). The regional simulated climates of each orogen are described by means of cluster analyses based on the variability in precipitation, 2 m air temperature, the intra-annual amplitude of these values, and monsoonal wind speeds where appropriate. Results indicate the largest differences in the PI climate existed for the LGM and PLIO climates in the form of widespread cooling and reduced precipitation in the LGM and warming and enhanced precipitation during the PLIO. The LGM climate shows the largest deviation in annual precipitation from the PI climate and shows enhanced precipitation in the temperate Andes and coastal regions for both SE Alaska and the US Pacific Northwest. Furthermore, LGM precipitation is reduced in the western Himalayas and enhanced in the eastern Himalayas, resulting in a shift of the wettest regional climates eastward along the orogen. The cluster-analysis results also suggest more climatic variability across latitudes east of the Andes in the PLIO climate than in other time slice experiments conducted here. Taken together, these results highlight significant changes in late Cenozoic regional climatology over the last ˜ 3 Myr. Comparison of simulated climate with proxy-based reconstructions for the MH and

Tectonic/climatic control on sediment provenance in the Cape Roberts Project core record (southern Victoria Land, Antarctica): A pulsing late Oligocene/early Miocene signal from south revealed by detrital thermochronology

Science.gov (United States)

Olivetti, V.; Balestrieri, M. L.; Rossetti, F.; Talarico, F. M.

2012-04-01

The Mesozoic-Cenozoic West Antarctic Rift System (WARS) is one of the largest intracontinental rift on Earth. The Transantarctic Mountains (TAM) form its western shoulder, marking the boundary between the East and West Antarctica. The rifting evolution is commonly considered polyphase and involves an Early Cretaceous phase linked to the Gondwana break-up followed by a major Cenozoic one, starting at c. 50-40 Ma. This Cenozoic episode corresponds to the major uplift/denudation phase of the TAM, which occurred concurrently with transition from orthogonal to oblique rifting. The Cenozoic rift reorganization occurred concurrently with a major change in the global climate system and a global reorganization of plate motions. This area thus provide an outstanding natural laboratory for studying a range of geological problems that involve feedback relationships between tectonics and climate. A key to address the tectonic/climate feedback relations is to look on apparent synchronicity in erosion signal between different segments, and to compare these with well-dated regional and global climatic events. However, due to the paucity of Cenozoic rock sequences exposed along the TAM front, a few information is available about the neotectonics of the rift and rift-flank uplift system. The direct physical record of the tectonic/climate history of the WARS recovered by core drillings along the western margin of the Ross sea (DSDP, CIROS, Cape Roberts and ANDRILL projects) provides an invaluable tool to address this issue. Twenty-three samples distributed throughout the entire composite drill-cored stratigraphic succession of Cape Roberts were analyzed. Age probability plots of eighteen detrital samples with depositional ages between 34 Ma and the Pliocene were decomposed into statistically significant age populations or peaks using binomial peak-fitting. Moreover, three granitic pebbles, one dolerite clast and one sample of Beacon sandstones have been dated. From detrital samples

Heterogeneous Cenozoic cooling of central Britain: insights into the complex evolution of the North Atlantic passive margin

Science.gov (United States)

Łuszczak, Katarzyna; Persano, Cristina; Stuart, Finlay

2015-04-01

The western flank of the North Atlantic passive margin has experienced multiple episodes of rock uplift and denudation during the Cenozoic that have been locally variable in scale. Two regional scale exhumation events have been identified: early Palaeogene and Neogene [see 1 for review]. The former has been identified both onshore and offshore and it appears to be temporally coincident with basaltic magmatism related to the arrival of the proto-Iceland mantle plume beneath thinned continental lithosphere, which may have cause long wavelength, low amplitude dynamic uplift. Quantifying the amount of early Palaeogene exhumation using mineral thermochronometers may be complicated by elevated heat flow. The magnitude and timing of exhumation during the Neogene is even less clear, as is the driving mechanism. Quantifying the amount of early Palaeogene exhumation, determining the precise timing as well as the amount of uplift and erosion in the Neogene, require detailed application of low temperature thermochronometers. Here we present the first multiple low temperature thermochronometer study from S Scotland, N England and N Wales. New apatite fission track (AFT) data are integrated with apatite and zircon (U-Th-Sm)/He (AHe and ZHe, respectively) ages to establish regional rock cooling history from 200°C to 30°C. To precisely constrain the early Palaeogene cooling history, and to better define the possible Neogene cooling event, >20 single grain AHe ages have been produced on key samples and modelled using the newly codified HelFrag technique. The new AFT and AHe ages confirm earlier studies that show the Lake District and North Pennines experienced rapid cooling from >120°C in the Palaeogene. The amount of cooling/exhumation gradually decreases northwards into S Scotland and southwards in N Wales; there is no evidence for the rapid Palaeogene event in areas ~70 km from the Lake District centre. Inverse modelling of the AHe and AFT data suggest that the rapid cooling

Understanding the uplift pattern in Mesozoic and Cenozoic,, eastern Dabie area, China using fission track dating of apatite

International Nuclear Information System (INIS)

Wu Qianhong; Liu Shunsheng

2002-01-01

By using the fission track dating technique, a preliminary study was carried out on the fission track ages (FTA) of apatite, their distribution patterns and hints over the tectonics activities during Mesozoic and Cenozoic in the east Dabie area. Attempts were also made to improve the conventional statistical method for the tracks. Ranging from 59.4 +- 3.4 Ma to 105.6 +- 9.8 Ma, the FTA results of apatite spread in the wide range and increased rapidly from the east to the west area. Sine 95 Ma, the uplift rate has been quite slow and asymmetry. The FTA value in the middle area of Xiaotian-Mozitan Fault may imply its uplift in Cretaceous. The faulting should be the main control factor for the uplift of this area

Cenozoic exhumation and tectonic evolution of the Qimen Tagh Range, northern Tibetan Plateau: Insights from the heavy mineral compositions, detrital zircon U-Pb ages and seismic interpretations

Science.gov (United States)

Zhu, W.; Wu, C.; Wang, J.; Zhou, T.; Zhang, C.; Li, J.

2017-12-01

The Qaidam Basin is the largest intermountain basin within the Tibetan Plateau. The Cenozoic sedimentary flling characteristics of the basin was significantly influenced by the surrounding tectonic belt, such as the Altyn Tagh Range to the north-west and Qimen Tagh Range to the south. The tectonic evolution of the Qimen Tagh Range and the structural relationship between the Qaidam Basin and Qimen Tagh Range remain controversial. To address these issues, we analyzed thousands of heavy mineral data, 720 detrital zircon ages and seismic data of the Qaidam Basin. Based on the regional geological framework and our kinematic analyses, the Cenozoic tectonic evolution of the Qimen Tagh Range can be divided into two stages. From the Early Eocene to the Middle Miocene, the Devonian (400-360 Ma) and Permian to Triassic (300-200 Ma) zircons which were sourced from the Qimen Tagh Range and the heavy mineral assemblage of zircon-leucoxene-garnet-sphene on the north flank of the Qimen Tagh Range indicated that the Qimen Tagh Range has been exhumed before the Eocene and acted as the primary provenance of the Qaidam Basin. The Kunbei fault system (i.e. the Kunbei, Arlar and Hongliuquan faults) in the southwest of the Qaidam Basin, which can be seen as a natural study window of the Qimen Tagh Range, was characterized by left-lateral strike-slip faults and weak south-dipping thrust faults based on the seismic sections. This strike-slip motion was generated by the uplift of the Tibetan Plateau caused by the onset of the Indian-Eurasian collision. Since the Middle Miocene, the primary mineral assemblages along the northern flank of the Qimen Tagh Range changed from the zircon-leucoxene-garnet-sphene assemblage to the epidote-hornblende-garnet-leucoxene assemblage. Simultaneously, the Kunbei fault system underwent intense south-dipping thrusting, and a nearly 2.2-km uplift can be observed in the hanging wall of the Arlar fault. We attributed these variations to the rapid uplift event of

Exhumation history of the western Kyrgyz Tien Shan: Implications for intramontane basin formation

Science.gov (United States)

Bande, Alejandro; Sobel, Edward R.; Mikolaichuk, Alexander; Schmidt, Alexander; Stockli, Daniel F.

2017-01-01

The dextral Talas-Fergana Fault separates the western from the central Tien Shan. Recent work has shed light on the Cenozoic evolution of the eastern and central Tien Shan; much less attention has been paid to the western Tien Shan. In this contribution we present new thermochronological ages for the Fergana and Alai ranges that, combined with the available data set, constrain the Cenozoic exhumation history of the western Tien Shan. Following a tectonically quiet early Cenozoic period, we suggest an onset of exhumation at 25 Ma. This early onset was followed by a period of slower exhumation and in some areas minor reheating. A final, strong late Miocene rapid cooling event is well represented in the western Tien Shan as in other sectors of the range. The early onset of uplift of the western Tien Shan dissected the previously continuous westernmost Parathethyan Sea, progressively isolating basins (e.g., Fergana, Tarim, and Alai basins) in the central Asian hinterland. Moreover, the coeval timing of late Miocene uplift along the length of entire Tien Shan implies that neither the Pamir nor Tarim can be the sole driver for exhumation of the entire range.

The origin of the universe. Chapter 1

International Nuclear Information System (INIS)

Sciama, D.W.

1980-01-01

The observational and theoretical evidence in favour of the Big Bang origin, and the question whether an actually singular origin of the universe can be avoided, are discussed. Sections are headed: the world of galaxies (main facts about galaxies); the recession of the galaxies (red-shift, Hubble's law); the cosmic black body background (behaviour of the Universe in its hot early epochs, nuclear reactions, abundance of hydrogen, helium and deuterium). (U.K.)

Early vertebrate origin and diversification of small transmembrane regulators of cellular ion transport.

Science.gov (United States)

Pirkmajer, Sergej; Kirchner, Henriette; Lundell, Leonidas S; Zelenin, Pavel V; Zierath, Juleen R; Makarova, Kira S; Wolf, Yuri I; Chibalin, Alexander V

2017-07-15

Small transmembrane proteins such as FXYDs, which interact with Na + ,K + -ATPase, and the micropeptides that interact with sarco/endoplasmic reticulum Ca 2+ -ATPase play fundamental roles in regulation of ion transport in vertebrates. Uncertain evolutionary origins and phylogenetic relationships among these regulators of ion transport have led to inconsistencies in their classification across vertebrate species, thus hampering comparative studies of their functions. We discovered the first FXYD homologue in sea lamprey, a basal jawless vertebrate, which suggests small transmembrane regulators of ion transport emerged early in the vertebrate lineage. We also identified 13 gene subfamilies of FXYDs and propose a revised, phylogeny-based FXYD classification that is consistent across vertebrate species. These findings provide an improved framework for investigating physiological and pathophysiological functions of small transmembrane regulators of ion transport. Small transmembrane proteins are important for regulation of cellular ion transport. The most prominent among these are members of the FXYD family (FXYD1-12), which regulate Na + ,K + -ATPase, and phospholamban, sarcolipin, myoregulin and DWORF, which regulate the sarco/endoplasmic reticulum Ca 2+ -ATPase (SERCA). FXYDs and regulators of SERCA are present in fishes, as well as terrestrial vertebrates; however, their evolutionary origins and phylogenetic relationships are obscure, thus hampering comparative physiological studies. Here we discovered that sea lamprey (Petromyzon marinus), a representative of extant jawless vertebrates (Cyclostomata), expresses an FXYD homologue, which strongly suggests that FXYDs predate the emergence of fishes and other jawed vertebrates (Gnathostomata). Using a combination of sequence-based phylogenetic analysis and conservation of local chromosome context, we determined that FXYDs markedly diversified in the lineages leading to cartilaginous fishes (Chondrichthyes) and bony

The origins of scientific cinematography and early medical applications.

Science.gov (United States)

Barboi, Alexandru C; Goetz, Christopher G; Musetoiu, Radu

2004-06-08

To examine the neurologic cinematographic contributions of Gheorghe Marinescu. Near the end of the 19th century, cinematography developed and was immediately recognized as a new technique applicable to medical documentation. After studying with several prominent European neurologists and deeply influenced by Jean-Martin Charcot, Marinescu returned to Bucharest in 1897 and applied moving picture techniques to the study of neurologic patients. The Romanian State Archives were researched for original Marinescu films, and related publications were translated from Romanian and French. Between 1899 and 1902, Marinescu perfected the use of cinematography as a research method in neurosciences and published five articles based on cinematographic documents. He focused his studies particularly on organic gait disorders, locomotor ataxia, and hysteria. He adapted Charcot's method of lining up several patients with the same disorder and showing them together to permit appreciation of archetypes and formes frustes. He decomposed the moving pictures into sequential tracings for publication. He documented treatment results with cases filmed before and after therapy. Processed and digitized excerpts of these films accompany this manuscript. Marinescu's cinematographic studies led to several original contributions in clinical neurology. Remaining film archives include examples of many neurologic diseases, his examination techniques, and the working medical environment of the young founder of the Romanian school of neurology.

Active Galactic Nuclei Feedback and the Origin and Fate of the Hot Gas in Early-type Galaxies

Science.gov (United States)

Pellegrini, Silvia; Ciotti, Luca; Negri, Andrea; Ostriker, Jeremiah P.

2018-04-01

A recent determination of the relationships between the X-ray luminosity of the ISM (L X) and the stellar and total mass for a sample of nearby early-type galaxies (ETGs) is used to investigate the origin of the hot gas, via a comparison with the results of hydrodynamical simulations of the ISM evolution for a large set of isolated ETGs. After the epoch of major galaxy formation (after z ≃ 2), the ISM is replenished by stellar mass losses and SN ejecta, at the rate predicted by stellar evolution, and is depleted by star formation; it is heated by the thermalization of stellar motions, SNe explosions, and the mechanical (from winds) and radiative AGN feedback. The models agree well with the observed relations, even for the largely different L X values at the same mass, thanks to the sensitivity of the gas flow to many galaxy properties; this holds for models including AGN feedback, and those without. Therefore, the mass input from the stellar population is able to account for a major part of the observed L X; and AGN feedback, while very important to maintain massive ETGs in a time-averaged quasi-steady state, keeping low star formation and the black hole mass, does not dramatically alter the gas content originating in stellar recycled material. These conclusions are based on theoretical predictions for the stellar population contributions in mass and energy, and on a self-consistent modeling of AGN feedback.

Fetal and infant origins of asthma

NARCIS (Netherlands)

L. Duijts (Liesbeth)

2012-01-01

textabstractPrevious studies have suggested that asthma, like other common diseases, has at least part of its origin early in life. Low birth weight has been shown to be associated with increased risks of asthma, chronic obstructive airway disease, and impaired lung function in adults, and increased

Mesozoic lithofacies palaeogeography and petroleum prospectivity in North Carnarvon Basin, Australia

Directory of Open Access Journals (Sweden)

Tao Chongzhi

2013-01-01

Full Text Available The North Carnarvon Basin, which lies in the North West Shelf of Australia, is highly rich in gas resources. As a typical passive marginal basin, it experienced the pre-rifting, early rifting, main rifting, late rifting, post-rifting sagging and passive margin stages. The basin was mainly filled with thick Mesozoic-Cenozoic sediments, of which the Mesozoic hosts the principal source, reservoir and seal intervals. Mesozoic palaeogeography has an important control on the oil and gas distribution. Triassic gas-prone source rocks of deltaic origin determine the high endowment of natural gases in the North Carnarvon Basin. The more restricted distribution of oil accumulations is controlled by oil source rocks in the Upper Jurassic Dingo Claystone. The Muderong Shale deposited in the Early Cretaceous marine transgression provides the effective regional seal for the underlying oil and gas reservoirs.

A new yeti crab phylogeny: Vent origins with indications of regional extinction in the East Pacific.

Science.gov (United States)

Roterman, Christopher Nicolai; Lee, Won-Kyung; Liu, Xinming; Lin, Rongcheng; Li, Xinzheng; Won, Yong-Jin

2018-01-01

The recent discovery of two new species of kiwaid squat lobsters on hydrothermal vents in the Pacific Ocean and in the Pacific sector of the Southern Ocean has prompted a re-analysis of Kiwaid biogeographical history. Using a larger alignment with more fossil calibrated nodes than previously, we consider the precise relationship between Kiwaidae, Chirostylidae and Eumunididae within Chirostyloidea (Decapoda: Anomura) to be still unresolved at present. Additionally, the placement of both new species within a new "Bristly" clade along with the seep-associated Kiwa puravida is most parsimoniously interpreted as supporting a vent origin for the family, rather than a seep-to-vent progression. Fossil-calibrated divergence analysis indicates an origin for the clade around the Eocene-Oligocene boundary in the eastern Pacific ~33-38 Ma, coincident with a lowering of bottom temperatures and increased ventilation in the Pacific deep sea. Likewise, the mid-Miocene (~10-16 Ma) rapid radiation of the new Bristly clade also coincides with a similar cooling event in the tropical East Pacific. The distribution, diversity, tree topology and divergence timing of Kiwaidae in the East Pacific is most consistent with a pattern of extinctions, recolonisations and radiations along fast-spreading ridges in this region and may have been punctuated by large-scale fluctuations in deep-water ventilation and temperature during the Cenozoic; further affecting the viability of Kiwaidae populations along portions of mid-ocean ridge.

Cenozoic extinction and recolonization in the New Zealand flora: the case of the fleshy-fruited epacrids (Styphelieae, Styphelioideae, Ericaceae).

Science.gov (United States)

Puente-Lelièvre, Caroline; Harrington, Mark G; Brown, Elizabeth A; Kuzmina, Maria; Crayn, Darren M

2013-01-01

The origins and evolutionary history of the New Zealand flora has been the subject of much debate. The recent description of Cyathodophyllum novaezelandieae from early Miocene sediments in New Zealand provides possible evidence for the antiquity of the fleshy fruited epacrids (tribe Styphelieae, Ericaceae) in New Zealand. Yet the extant species in this tribe are thought to be very closely related to or conspecific with Australian taxa, suggesting recent trans-Tasman origins. In order to investigate the origins and evolution of the extant New Zealand Styphelieae we produced molecular phylogenetic trees based on sequences of three plastid regions that include representatives of all the genera of the tribe and eight of the ten New Zealand species. We estimated the range of minimum ages of the New Zealand lineages with Bayesian relaxed-clock analyses using different calibration methods and relative dating. We found strong support for each of the eight extant species of New Zealand Styphelieae being a distinct lineage that is nested within an Australian clade. In all except one case the sister is from Tasmania and/or the east coast of mainland Australia; for Acrothamnus colensoi the sister is in New Guinea. Estimated dates indicate that all of the New Zealand lineages diverged from their non-New Zealand sisters within the last 7 Ma. Time discontinuity between the fossil C.novae-zelandiae (20-23 Ma) and the origins of the extant New Zealand lineages (none older than 5 Ma) indicates that the fossil and extant Styphelieae in New Zealand are not related. The relative dating analysis showed that to accept this relationship, it would be necessary to accept that the Styphelieae arose in the early-mid Mesozoic (210-120 Ma), which is starkly at odds with multiple lines of evidence on the age of Ericales and indeed the angiosperms. Therefore, our results do not support the hypothesis that Styphelieae have been continuously present in New Zealand since the early Miocene. Instead

Early anti-correlated BOLD signal changes of physiologic origin.

Science.gov (United States)

Bright, Molly G; Bianciardi, Marta; de Zwart, Jacco A; Murphy, Kevin; Duyn, Jeff H

2014-02-15

Negative BOLD signals that are synchronous with resting state fluctuations have been observed in large vessels in the cortical sulci and surrounding the ventricles. In this study, we investigated the origin of these negative BOLD signals by applying a Cued Deep Breathing (CDB) task to create transient hypocapnia and a resultant global fMRI signal decrease. We hypothesized that a global stimulus would amplify the effect in large vessels and that using a global negative (vasoconstrictive) stimulus would test whether these voxels exhibit either inherently negative or simply anti-correlated BOLD responses. Significantly anti-correlated, but positive, BOLD signal changes during respiratory challenges were identified in voxels primarily located near edges of brain spaces containing CSF. These positive BOLD responses occurred earlier than the negative CDB response across most of gray matter voxels. These findings confirm earlier suggestions that in some brain regions, local, fractional changes in CSF volume may overwhelm BOLD-related signal changes, leading to signal anti-correlation. We show that regions with CDB anti-correlated signals coincide with most, but not all, of the regions with negative BOLD signal changes observed during a visual and motor stimulus task. Thus, the addition of a physiological challenge to fMRI experiments can help identify which negative BOLD signals are passive physiological anti-correlations and which may have a putative neuronal origin. Published by Elsevier Inc.

On the origin and evolution of Antarctic Peracarida (Crustacea, Malacostraca

Directory of Open Access Journals (Sweden)

Angelika Brandt

1999-12-01

Full Text Available The early separation of Gondwana and the subsequent isolation of Antarctica caused a long evolutionary history of its fauna. Both, long environmental stability over millions of years and habitat heterogeneity, due to an abundance of sessile suspension feeders on the continental shelf, favoured evolutionary processes of preadapted taxa, like for example the Peracarida. This taxon performs brood protection and this might be one of the most important reasons why it is very successful (i.e. abundant and diverse in most terrestrial and aquatic environments, with some species even occupying deserts. The extinction of many decapod crustaceans in the Cenozoic might have allowed the Peracarida to find and use free ecological niches. Therefore the palaeogeographic, palaeoclimatologic, and palaeo-hydrographic changes since the Palaeocene (at least since about 60 Ma ago and the evolutionary success of some peracarid taxa (e.g. Amphipoda, Isopoda led to the evolution of many endemic species in the Antarctic. Based on a phylogenetic analysis of the Antarctic Tanaidacea, Sieg (1988 demonstrated that the tanaid fauna of the Antarctic is mainly represented by phylogenetically younger taxa, and data from other crustacean taxa led Sieg (1988 to conclude that the recent Antarctic crustacean fauna must be comparatively young. His arguments are scrutinized on the basis of more recent data on the phylogeny and biodiversity of crustacean taxa, namely the Ostracoda, Decapoda, Mysidacea, Cumacea, Amphipoda, and Isopoda. This analysis demonstrates that the origin of the Antarctic fauna probably has different roots: an adaptive radiation of descendants from old Gondwanian ancestors was hypothesized for the isopod families Serolidae and Arcturidae, an evolution and radiation of phylogenetically old taxa in Antarctica could also be shown for the Ostracoda and the amphipod family Iphimediidae. A recolonization via the Scotia Arc appears possible for some species, though it is

The origins of cognitive vulnerability in early childhood: mechanisms linking early attachment to later depression.

Science.gov (United States)

Morley, Tara E; Moran, Greg

2011-11-01

This paper examines the theory and research linking attachment relationships to cognitive vulnerability to depression and assesses evidence that early attachment experiences contribute to the development of these cognitive processes. Most research in this area has involved adult participants using self-report measures of both attachment and depressive vulnerabilities and thus cannot convincingly speak to the existence of such a developmental pathway. Several studies, however, have followed individuals from infancy and examined the emergence of self-esteem and responses to failure throughout childhood and adolescence. These studies suggest that early experiences in non-secure attachment relationships place an individual at-risk for developing a cognitive framework that increases their vulnerability to depression following stressful life events. The paper concludes with a discussion of how future research might best explore specific mechanisms through which distinct attachment relationships may lead to divergent developmental pathways sharing the common outcome of cognitive processes that place individuals at risk for depression. Copyright © 2011 Elsevier Ltd. All rights reserved.

The origin of Scythian caldrons in the context of the late Bronze − Early Iron Age of Eurasia

Directory of Open Access Journals (Sweden)

Romashko, O. V.

2017-09-01

Full Text Available A detailed analysis of the historiography of the issue is presented, which takes into account works devoted to the antiquities of the early Iron Age. The authors come to the conclusion about the local production of Scythian metal boilers, seeing in this a very high level of development of metalworking of Scythian masters. With regard to the issue associated with the origin of the tradition of manufacturing these products, then in the historiography there were two theories: the Asian (L. N. Chlenova, S. V. Demidenko, V. S. Bochkarev, etc. and native (O. A. Krivtsova-Grakova and others. In our opinion, the question of the origin of boilers should be considered taking into account the specific features of their morphology. Thus, open-shell boilers that dominate the archaic times (VII−VI centuries BC are made taking into account the clearly formulated traditions and requirements for products of this category brought from the East to the Northern Black Sea Coast. Regarding the boilers with closed housing, which begin to appear in the VI century BC, we can say the following. Their production originates in the local traditions of the production of boilers, which were formed back in Cimmerian times (riveted boilers. But these traditions do not receive a direct line of development in Scythian time. We see rather complicated processes of formation of the Scythian center for the production of archaic cast caldrons in the Kuban region, where this tradition spreads throughout the Northern Black Sea Coast. In the course of this complex and multifaceted process, new syncretic traditions of the production of boilers are formed, combining the innovative method of production (casting and the local traditions of perception of the shape of the caldron.

Cenozoic climate change shaped the evolutionary ecophysiology of the Cupressaceae conifers.

Science.gov (United States)

Pittermann, Jarmila; Stuart, Stephanie A; Dawson, Todd E; Moreau, Astrid

2012-06-12

The Cupressaceae clade has the broadest diversity in habitat and morphology of any conifer family. This clade is characterized by highly divergent physiological strategies, with deciduous swamp-adapted genera-like Taxodium at one extreme, and evergreen desert genera-like Cupressus at the other. The size disparity within the Cupressaceae is equally impressive, with members ranging from 5-m-tall juniper shrubs to 100-m-tall redwood trees. Phylogenetic studies demonstrate that despite this variation, these taxa all share a single common ancestor; by extension, they also share a common ancestral habitat. Here, we use a common-garden approach to compare xylem and leaf-level physiology in this family. We then apply comparative phylogenetic methods to infer how Cenozoic climatic change shaped the morphological and physiological differences between modern-day members of the Cupressaceae. Our data show that drought-resistant crown clades (the Cupressoid and Callitroid clades) most likely evolved from drought-intolerant Mesozoic ancestors, and that this pattern is consistent with proposed shifts in post-Eocene paleoclimates. We also provide evidence that within the Cupressaceae, the evolution of drought-resistant xylem is coupled to increased carbon investment in xylem tissue, reduced xylem transport efficiency, and at the leaf level, reduced photosynthetic capacity. Phylogenetically based analyses suggest that the ancestors of the Cupressaceae were dependent upon moist habitats, and that drought-resistant physiology developed along with increasing habitat aridity from the Oligocene onward. We conclude that the modern biogeography of the Cupressaceae conifers was shaped in large part by their capacity to adapt to drought.

Pre-Gondwanan-breakup origin of Beauprea (Proteaceae) explains its historical presence in New Caledonia and New Zealand.

Science.gov (United States)

He, Tianhua; Lamont, Byron B; Fogliani, Bruno

2016-04-01

New Caledonia and New Zealand belong to the now largely submerged continent Zealandia. Their high levels of endemism and species richness are usually considered the result of transoceanic dispersal events followed by diversification after they re-emerged from the Pacific Ocean in the mid-Cenozoic. We explore the origin and evolutionary history of Beauprea (Proteaceae), which is now endemic to New Caledonia but was once spread throughout eastern Gondwana, including New Zealand. We review the extensive Beauprea-type pollen data in the fossil records and analyze the relationship of these fossil taxa to extant genera within Proteaceae. We further reconstruct the phylogenetic relations among nine extant species of Beauprea and estimate the age of the Beauprea clade. By incorporating extinct taxa into the Beauprea phylogenetic tree, we reconstruct the ancient distribution of this genus. Our analysis shows that Beauprea originated c. 88 Ma (million years ago) in Antarctica-Southeastern Australia and spread throughout Gondwana before its complete breakup. We propose that Beauprea, already existing as two lineages, was carried with Zealandia when it separated from the rest of Gondwana c. 82 Ma, thus supporting an autochthonous origin for Beauprea species now in New Caledonia and historically in New Zealand up to 1 Ma. We show that the presence of Beauprea through transoceanic dispersal is implausible. This means that neither New Caledonia nor New Zealand has been entirely submerged since the Upper Cretaceous; thus, possible vicariance and allopatry must be taken into account when considering the high levels of endemism and species richness of these island groups.

How Vulnerable is Perennial Sea Ice? Insights from Earth's Late Cenozoic Natural Experiments (Invited)

Science.gov (United States)

Brigham-Grette, J.; Polyak, L. V.; Caissie, B.; Sharko, C. J.; Petsch, S.

2010-12-01

Sea ice is an important component of the climate system. Yet, reconstructions of Arctic sea ice conditions reflecting glacial and interglacial change over the past 3 million years are almost nonexistent. Our work to evaluate the sea ice and sea surface temperature record of the Bering Strait region builds on a review of the sea ice history of the pan-Arctic. The best estimates of sea ice make use of indirect proxies based on reconstructions of treeline, sea surface temperatures, depositional systems, and the ecological preferences of extant marine microfossil species. The development of new proxies of past sea ice extent including microfossil assemblages (diatoms, ostracodes) and biomarker proxies (IP25) show promise for quantifying seasonal concentrations of sea ice cover on centennial to millennial timescales. Using both marine and terrestrial information, periods of restricted sea ice and ice-free Arctic conditions can be inferred for parts of the late Cenozoic. The Arctic Ocean borderlands contain clear stratigraphic evidence for forested conditions at intervals over the past 50 million years, recording the migration of treeline from High Arctic coastal locations within the Canadian Archipelago. Metasequoia forests of the peak Eocene gave way to a variety of biomass-rich circumarctic redwood forests by 46 Ma. Between 23 and 16 Ma, cool-temperate metasequoia forests dominated NE Alaska and the Yukon while mixed conifer-hardwood forests (similar to those of modern southern maritime Canada and New England) dominated the central Canadian Archipelago. By 16 Ma, these forests gave way to larch and spruce. From 5 to 3 Ma the braid plains of the Beaufort Fm were dominated by over 100 vascular plants including pine and birch, while other locations remained dominated by spruce and larch. Boreal conditions across northern Greenland and arctic Alaska are consistent with the presence of bivalve Arctica islandica in marine sediments capping the Beaufort Formation on Meighen

Evaluating the Link between Self-Esteem and Temperament in Mexican Origin Early Adolescents

OpenAIRE

Robins, Richard W.; Donnellan, M. Brent; Widaman, Keith F.; Conger, Rand D.

2009-01-01

The present study examined the relation between self-esteem and temperament in a sample of 646 Mexican-American early adolescents (mean age=10.4). Self-esteem was assessed using child reports on the Self-Description Questionnaire II—Short (SDQII-S; Marsh et al., 2005) and temperament was assessed using child and mother reports on the revised Early Adolescent Temperament Questionnaire (Ellis & Rothbart, 2001). Findings show that: (a) early adolescents with high self-esteem show higher levels o...

The Parchment of the "Torre Turpiana ": the original document and its early interpreters

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van Koningsveld, P. S.

2003-12-01

Full Text Available The present contribution deals with the famous parchment found in 1588 in the old minaret of the former Friday Mosque of Granada, with texts in Arabic, Spanish, and Latin. Together with the Lead Books, discovered in various caves in the outskirts of Granada in the years 1595-1600, the parchment stood at the beginning of an important national cult. After being transferred to the Vatican at the beginning of the seventeenth century and following their anathematization in 1682 the parchment and the Lead Books were kept in Rome until the year 2000 when they were returned to the Archbishopry of Granada. The article presents an analysis of the layout and script of the parchment (2 followed by a survey of translations and transcripts by early (Christian and Muslim eyewitnesses (3.1. The data of these early eyewitnesses are critically compared with the main elements of the parchment (3.2 Then follows a discussion of the palaeographic comments made by a few (Christian and Muslim eyewitnesses (4. In the final conclusions, the authors argue that the document under discussion is indeed the original parchment as found in 1588 notwithstanding the incomprehensibility of its Arabic texts and the many inconsistencies and corruptions of its Spanish and Latin texts (5.1. According to the authors, there is no evidence for the interpretation of the parchment as a pro to-Islamic document, as we are dealing here with a Roman Catholic message heralding the destruction of Islam. At the same time, however, the document also contained a symbolic message, viz. in stipulating that the first-century Granadan Christians, including the well-known figure of Cecilius, wrote Arabic and Spanish, just as many Moriscos did. In other words: even though Islam had to be extirpated, Arabic as a language could harmoniously accompany a genuine Christian life.

Este artículo está dedicado al famoso pergamino encontrado en 1588 en el antiguo minarete de la que había sido mezquita

The application of apatite fission track analysis to hydrocarbon exploration of Yanqi basin

International Nuclear Information System (INIS)

Wu Fuqiang; Liu Jiaduo; He Mingxi; Chen Gang

2000-01-01

The author introduces the method and principle of AFTA, i.e. annealing characteristics. Through analysing the AFT data of the six Jurassic samples from the Well Bonan-1 and the Well Yancan-1 in the Yanqi Basin, the authors conclude that in the north sag, the thickness of Cenozoic group was generally more than 2000 meters, the north sag was situated in Cenozoic compensation geothermal district, and the maximum palaeo-temperature of the middle-lower Jurassic was about 70-110 degree C in late Cenozoic; while in the south sag, the thickness of Cenozoic group was generally less than 1500 meters, the south sag was situated in Cenozoic deficient geothermal district, and the maximum palaeo-temperature of the lower middle lower Jurassic was about 80-110 degree C in latest Jurassic. The AFT ages show that in the north sag, the uplift event took place in late Cretaceous, while in the south sag, the uplift event took place in early Cretaceous. Therefore the main uplift event of the Yanqi Basin took place in Cretaceous period, and the uplift of the south was earlier than that of the north

Cenozoic sedimentation and exhumation of the foreland basin system preserved in the Precordillera thrust belt (31-32°S), southern central Andes, Argentina

Science.gov (United States)

Levina, Mariya; Horton, Brian K.; Fuentes, Facundo; Stockli, Daniel F.

2014-09-01

Andean retroarc compression associated with subduction and shallowing of the oceanic Nazca plate resulted in thin-skinned thrusting that partitioned and uplifted Cenozoic foreland basin fill in the Precordillera of west-central Argentina. Evolution of the central segment of the Precordillera fold-thrust belt is informed by new analyses of clastic nonmarine deposits now preserved in three intermontane regions between major east directed thrust faults. We focus on uppermost Oligocene-Miocene basin fill in the axial to frontal Precordillera at 31-32°S along the Río San Juan (Albarracín and Pachaco sections) and the flank of one of the leading thrust structures (Talacasto section). The three successions record hinterland construction of the Frontal Cordillera, regional arc volcanism, and initial exhumation of Precordillera thrust sheets. Provenance changes recorded by detrital zircon U-Pb age populations suggest that initial shortening in the Frontal Cordillera coincided with an early Miocene shift from eolian to fluvial accumulation in the adjacent foreland basin. Upward coarsening of fluvial deposits and increased proportions of Paleozoic clasts reflect cratonward (eastward) advance of deformation into the Precordillera and resultant structural fragmentation of the foreland basin into isolated intermontane segments. Apatite (U-Th)/He thermochronometry of basin fill constrains to 12-9 Ma the most probable age of uplift-induced exhumation and cooling of Precordillera thrust sheets. This apparent pulse of exhumation is evident in each succession, suggestive of rapid, large-scale exhumation by synchronous thrusting above a single décollement linking major structures of the Precordillera.

Structure of an inverted basin from subsurface and field data: the Late Jurassic-Early Cretaceous Maestrat Basin (Iberian Chain)

Energy Technology Data Exchange (ETDEWEB)

Nebot, M.; Guimera, J.

2016-07-01

The Maestrat Basin experienced two main rifting events: Late Permian-Late Triassic and Late Jurassic-Early Cretaceous, and was inverted during the Cenozoic Alpine orogeny. During the inversion, an E-W-trending, N-verging fold-and-thrust belt developed along its northern margin, detached in the Triassic evaporites, while southwards it also involved the Variscan basement. A structural study of the transition between these two areas is presented, using 2D seismic profiles, exploration wells and field data, to characterize its evolution during the Mesozoic extension and the Cenozoic contraction. The S-dipping Maestrat basement thrust traverses the Maestrat Basin from E to W; it is the result of the Cenozoic inversion of the lower segment–within the acoustic basement–of the Mesozoic extensional fault system that generated the Salzedella sub-basin. The syn-rift Lower Cretaceous rocks filling the Salzedella sub-basin thicken progressively northwards, from 350m to 1100m. During the inversion, a wide uplifted area –40km wide in the N-S direction– developed in the hanging wall of the Maestrat basement thrust. This uplifted area is limited to the North by the E-W-trending Calders monocline, whose limb is about 13km wide in its central part, dips about 5ºN, and generates a vertical tectonic step of 800-1200m. We interpreted the Calders monocline as a fault-bend fold; therefore, a flat-ramp-flat geometry is assumed in depth for the Maestrat basement thrust. The northern synformal hinge of the Calders monocline coincides with the transition from thick-skinned to thin-skinned areas. The vast uplifted area and the low-dip of the monocline suggest a very low-dip for the basement ramp, rooted in the upper crust. The Calders monocline narrows and disappears laterally, in coincidence with the outcrop of the Maestrat basement thrust. The evaporitic Middle Muschelkalk detachment conditioned the structural style. Salt structures are also related to it; they developed during the

Symbiotic Origin of Aging.

Science.gov (United States)

Greenberg, Edward F; Vatolin, Sergei

2018-06-01

Normally aging cells are characterized by an unbalanced mitochondrial dynamic skewed toward punctate mitochondria. Genetic and pharmacological manipulation of mitochondrial fission/fusion cycles can contribute to both accelerated and decelerated cellular or organismal aging. In this work, we connect these experimental data with the symbiotic theory of mitochondrial origin to generate new insight into the evolutionary origin of aging. Mitochondria originated from autotrophic α-proteobacteria during an ancient endosymbiotic event early in eukaryote evolution. To expand beyond individual host cells, dividing α-proteobacteria initiated host cell lysis; apoptosis is a product of this original symbiont cell lytic exit program. Over the course of evolution, the host eukaryotic cell attenuated the harmful effect of symbiotic proto-mitochondria, and modern mitochondria are now functionally interdependent with eukaryotic cells; they retain their own circular genomes and independent replication timing. In nondividing differentiated or multipotent eukaryotic cells, intracellular mitochondria undergo repeated fission/fusion cycles, favoring fission as organisms age. The discordance between cellular quiescence and mitochondrial proliferation generates intracellular stress, eventually leading to a gradual decline in host cell performance and age-related pathology. Hence, aging evolved from a conflict between maintenance of a quiescent, nonproliferative state and the evolutionarily conserved propagation program driving the life cycle of former symbiotic organisms: mitochondria.

Aerial gamma ray and magnetic survey: Mississippi and Florida airborne survey, Natchez quadrangle of, of Mississippi and Louisiana. Final report

International Nuclear Information System (INIS)

1980-07-01

The Natchez quadrangle covers a region within and adjacent to the Mississippi River flood plain in the northern Gulf Coastal Physiographic Province. The underlying Mesozoic and Cenozoic sediments of the Mississippi Embayment are extremely thick and contain many piercement structures. Exposed sediments consist largely of recent alluvium in the flood plain area, and Cenozoic sediments of marine and nonmarine origin in adjacent areas. A search of available literature revealed no known uranium deposits in the area. Eighty-three uranium anomalies were found, using the selection criteria set forth in Appendix A, and are discussed briefly. None were considered significant, and most appeared to be of cultural origin. Magnetic data suggests extremely deep sources, and some possible structural complexity in the source area

Early life nutritional programming of health and disease in The Gambia

OpenAIRE

Moore, S. E.

2015-01-01

Exposures during the early life (periconceptional, prenatal and early postnatal) period are increasingly recognized as playing an important role in the aetiology of chronic non-communicable diseases (NCD), including coronary heart disease, stroke, hypertension, Type 2 diabetes and osteoporosis. The ?Developmental Origins of Health and Disease? (DOHaD) hypothesis states that these disorders originate through unbalanced nutrition early in life and risk is highest when there is a ?mismatch? betw...

Early-life stress origins of gastrointestinal disease: animal models, intestinal pathophysiology, and translational implications

Science.gov (United States)

Pohl, Calvin S.; Medland, Julia E.

2015-01-01

Early-life stress and adversity are major risk factors in the onset and severity of gastrointestinal (GI) disease in humans later in life. The mechanisms by which early-life stress leads to increased GI disease susceptibility in adult life remain poorly understood. Animal models of early-life stress have provided a foundation from which to gain a more fundamental understanding of this important GI disease paradigm. This review focuses on animal models of early-life stress-induced GI disease, with a specific emphasis on translational aspects of each model to specific human GI disease states. Early postnatal development of major GI systems and the consequences of stress on their development are discussed in detail. Relevant translational differences between species and models are highlighted. PMID:26451004

An earlier origin for the Acheulian.

Science.gov (United States)

Lepre, Christopher J; Roche, Hélène; Kent, Dennis V; Harmand, Sonia; Quinn, Rhonda L; Brugal, Jean-Philippe; Texier, Pierre-Jean; Lenoble, Arnaud; Feibel, Craig S

2011-08-31

The Acheulian is one of the first defined prehistoric techno-complexes and is characterized by shaped bifacial stone tools. It probably originated in Africa, spreading to Europe and Asia perhaps as early as ∼1 million years (Myr) ago. The origin of the Acheulian is thought to have closely coincided with major changes in human brain evolution, allowing for further technological developments. Nonetheless, the emergence of the Acheulian remains unclear because well-dated sites older than 1.4 Myr ago are scarce. Here we report on the lithic assemblage and geological context for the Kokiselei 4 archaeological site from the Nachukui formation (West Turkana, Kenya) that bears characteristic early Acheulian tools and pushes the first appearance datum for this stone-age technology back to 1.76 Myr ago. Moreover, co-occurrence of Oldowan and Acheulian artefacts at the Kokiselei site complex indicates that the two technologies are not mutually exclusive time-successive components of an evolving cultural lineage, and suggests that the Acheulian was either imported from another location yet to be identified or originated from Oldowan hominins at this vicinity. In either case, the Acheulian did not accompany the first human dispersal from Africa despite being available at the time. This may indicate that multiple groups of hominins distinguished by separate stone-tool-making behaviours and dispersal strategies coexisted in Africa at 1.76 Myr ago.

Recovering the geographic origin of early modern humans by realistic and spatially explicit simulations

OpenAIRE

Ray, Nicolas; Currat, Mathias; Berthier, Pierre; Excoffier, Laurent

2005-01-01

Most genetic and archeological evidence argue in favor of a recent and unique origin of modern humans in sub-Saharan Africa, but no attempt has ever been made at quantifying the likelihood of this model, relative to alternative hypotheses of human evolution. In this paper, we investigate the possibility of using multilocus genetic data to correctly infer the geographic origin of humans, and to distinguish between a unique origin (UO) and a multiregional evolution (ME) model. We introduce here...

Preliminary geologic map of the late Cenozoic sediments of the western half of the Pasco Basin

International Nuclear Information System (INIS)

Lillie, J.T.; Tallman, A.M.; Caggiano, J.A.

1978-09-01

The U.S. Department of Energy, through the Basalt Waste Isolation Program within the Rockwell Hanford Operations, is investigating the feasibility of terminal storage of radioactive waste in deep caverns constructed in Columbia River Basalt. This report represents a portion of the geological work conducted during fiscal year 1978 to assess the geological conditions in the Pasco Basin. The surficial geology of the western half of the Pasco Basin was studied and mapped in a reconnaissance fashion at a scale of 1:62,500. The map was produced through a compilation of existing geologic mapping publications and additional field data collected during the spring of 1978. The map was produced primarily to: (1) complement other mapping work currently being conducted in the Pasco Basin and in the region by Rockwell Hanford Operations and its subcontractors; and, (2) to provide a framework for more detailed late Cenozoic studies within the Pasco Basin. A description of procedures used to produce the surficial geologic map and geologic map units is summarized in this report

WHERE DO THE ALPS' FOOTHILLS END? THE DEPTHS OF THE PRE-CENOZOIC BASEMENT IN THE FOREGROUND OF VAS-HEGY– ALPOKALJA, WESTERN HUNGARY

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SZÉKELY BALÁZS

2013-11-01

Full Text Available In the past three decades numerous researches have been published containing maps describing basement morphology. The first basement interpretations were based on the correlation of borehole data, then in the ’80s further seismic surveys offered the possibility to refine the outcomes. We collected and compared these data – by following a geoinformatical approach - and integrated them during the preparation stage of the measurement obtained in the 2012 field trip of Eötvös Loránd University, Department of Geophysics and Space Science. By summing up all the data we are able to create a more accurate Pre-Cenozioc basemap of the studied area. The map covers approx. 300 km2 area in the west of Hungary, between the national border and Szombathely, in the eastern foreground of Vas-hegy. We compared five basemaps (KILENYI & RUMPLER 1984, FLÜGEL 1988, KILÉNYI & ŠEFARA 1989, DANK & FÜLÖP 1990, HASS et al. 2010, two magnetic (HOFFER 1960, FANCSIK et al. 2006, a Bouguer-anomaly map (FANCSIK et al. 2005 and torsion balance anomaly map (VAJK 1938. Apparently, by this comparison we can see that the depth of Pre-Cenozoic basement is interpreted in different ways in each article. In contradictory and information deficient areas an attempt was made to produce supplement data with seismic and magnetic measurements. Eventually, a refined Pre-Cenozoic basemap of the area has been created with the help of our complementing measurements, the old maps and more than twenty boreholes reaching basement. Our results revealed an eastern foothill buried under the surface, although the saddle morphology is unlikely. The model contains a basement with fairly steady slope based on industrial sesmic surveys, our results doubt its hole-like feature.

Early-life stress origins of gastrointestinal disease: animal models, intestinal pathophysiology, and translational implications.

Science.gov (United States)

Pohl, Calvin S; Medland, Julia E; Moeser, Adam J

2015-12-15

Early-life stress and adversity are major risk factors in the onset and severity of gastrointestinal (GI) disease in humans later in life. The mechanisms by which early-life stress leads to increased GI disease susceptibility in adult life remain poorly understood. Animal models of early-life stress have provided a foundation from which to gain a more fundamental understanding of this important GI disease paradigm. This review focuses on animal models of early-life stress-induced GI disease, with a specific emphasis on translational aspects of each model to specific human GI disease states. Early postnatal development of major GI systems and the consequences of stress on their development are discussed in detail. Relevant translational differences between species and models are highlighted. Copyright © 2015 the American Physiological Society.

The role of population origin and microenvironment in seedling emergence and early survival in Mediterranean maritime pine (Pinus pinaster Aiton.

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Natalia Vizcaíno-Palomar

Full Text Available Understanding tree recruitment is needed to forecast future forest distribution. Many studies have reported the relevant ecological factors that affect recruitment success in trees, but the potential for genetic-based differences in recruitment has often been neglected. In this study, we established a semi-natural reciprocal sowing experiment to test for local adaptation and microenvironment effects (evaluated here by canopy cover in the emergence and early survival of maritime pine (Pinus pinaster Aiton, an emblematic Mediterranean forest tree. A novel application of molecular markers was also developed to test for family selection and, thus, for potential genetic change over generations. Overall, we did not find evidence to support local adaptation at the recruitment stage in our semi-natural experiment. Moreover, only weak family selection (if any was found, suggesting that in stressful environments with low survival, stochastic processes and among-year climate variability may drive recruitment. Nevertheless, our study revealed that, at early stages of recruitment, microenvironments may favor the population with the best adapted life strategy, irrespectively of its (local or non-local origin. We also found that emergence time is a key factor for seedling survival in stressful Mediterranean environments. Our study highlights the complexity of the factors influencing the early stages of establishment of maritime pine and provides insights into possible management actions aimed at environmental change impact mitigation. In particular, we found that the high stochasticity of the recruitment process in stressful environments and the differences in population-specific adaptive strategies may difficult assisted migration schemes.

The role of population origin and microenvironment in seedling emergence and early survival in Mediterranean maritime pine (Pinus pinaster Aiton).

Science.gov (United States)

Vizcaíno-Palomar, Natalia; Revuelta-Eugercios, Bárbara; Zavala, Miguel A; Alía, Ricardo; González-Martínez, Santiago C

2014-01-01

Understanding tree recruitment is needed to forecast future forest distribution. Many studies have reported the relevant ecological factors that affect recruitment success in trees, but the potential for genetic-based differences in recruitment has often been neglected. In this study, we established a semi-natural reciprocal sowing experiment to test for local adaptation and microenvironment effects (evaluated here by canopy cover) in the emergence and early survival of maritime pine (Pinus pinaster Aiton), an emblematic Mediterranean forest tree. A novel application of molecular markers was also developed to test for family selection and, thus, for potential genetic change over generations. Overall, we did not find evidence to support local adaptation at the recruitment stage in our semi-natural experiment. Moreover, only weak family selection (if any) was found, suggesting that in stressful environments with low survival, stochastic processes and among-year climate variability may drive recruitment. Nevertheless, our study revealed that, at early stages of recruitment, microenvironments may favor the population with the best adapted life strategy, irrespectively of its (local or non-local) origin. We also found that emergence time is a key factor for seedling survival in stressful Mediterranean environments. Our study highlights the complexity of the factors influencing the early stages of establishment of maritime pine and provides insights into possible management actions aimed at environmental change impact mitigation. In particular, we found that the high stochasticity of the recruitment process in stressful environments and the differences in population-specific adaptive strategies may difficult assisted migration schemes.

Origins Of Magnetospheric Physics An Expanded Edition

CERN Document Server

Van Allen, James A

2004-01-01

Early in 1958, instruments on the space satellites Explorer I and Explorer III revealed the presence of radiation belts, enormous populations of energetic particles trapped in the magnetic field of the earth. Originally published in 1983 but long out of print until now, Origins of Magnetospheric Physics tells the story of this dramatic and hugely transformative period in scientific and Cold War history. Writing in an accessible style and drawing on personal journals, correspondence, published papers, and the recollections of colleagues, James Van Allen documents a trail-blazing era in space hi

Origins and early development of human body knowledge.

Science.gov (United States)

Slaughter, Virginia; Heron, Michelle

2004-01-01

As a knowable object, the human body is highly complex. Evidence from several converging lines of research, including psychological studies, neuroimaging and clinical neuropsychology, indicates that human body knowledge is widely distributed in the adult brain, and is instantiated in at least three partially independent levels of representation. Sensorimotor body knowledge is responsible for on-line control and movement of one's own body and may also contribute to the perception of others' moving bodies; visuo-spatial body knowledge specifies detailed structural descriptions of the spatial attributes of the human body; and lexical-semantic body knowledge contains language-based knowledge about the human body. In the first chapter of this Monograph, we outline the evidence for these three hypothesized levels of human body knowledge, then review relevant literature on infants' and young children's human body knowledge in terms of the three-level framework. In Chapters II and III, we report two complimentary series of studies that specifically investigate the emergence of visuo-spatial body knowledge in infancy. Our technique is to compare infants'responses to typical and scrambled human bodies, in order to evaluate when and how infants acquire knowledge about the canonical spatial layout of the human body. Data from a series of visual habituation studies indicate that infants first discriminate scrambled from typical human body picture sat 15 to 18 months of age. Data from object examination studies similarly indicate that infants are sensitive to violations of three-dimensional human body stimuli starting at 15-18 months of age. The overall pattern of data supports several conclusions about the early development of human body knowledge: (a) detailed visuo-spatial knowledge about the human body is first evident in the second year of life, (b) visuo-spatial knowledge of human faces and human bodies are at least partially independent in infancy and (c) infants' initial

ORIGIN AND HISTORY OF PROGRAM BUDGETING.

Science.gov (United States)

NOVICK, DAVID

THE ORIGIN AND HISTORICAL DEVELOPMENT OF PROGRAM BUDGETING, WHICH IS CURRENTLY APPLIED TO ALL THE EXECUTIVE OFFICES AND AGENCIES OF THE UNITED STATES GOVERNMENT, IS TRACED. IT WAS RECOGNIZED AND APPLIED AS EARLY AS 1924 BY INDUSTRY, UTILIZED AS PART OF THE WARTIME CONTROL SYSTEM IN 1942, AND IS USED TODAY BY THE DEPARTMENT OF DEFENSE. THIS IS A…

Chemodynamical deuterium fractionation in the early solar nebula: The origin of water on earth and in asteroids and comets

Energy Technology Data Exchange (ETDEWEB)

Albertsson, T.; Semenov, D.; Henning, Th., E-mail: albertsson@mpia.de [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)

2014-03-20

Formation and evolution of water in the solar system and the origin of water on Earth constitute one of the most interesting questions in astronomy. The prevailing hypothesis for the origin of water on Earth is by delivery through water-rich small solar system bodies. In this paper, the isotopic and chemical evolution of water during the early history of the solar nebula, before the onset of planetesimal formation, is studied. A gas-grain chemical model that includes multiply deuterated species and nuclear spin-states is combined with a steady-state solar nebula model. To calculate initial abundances, we simulated 1 Myr of evolution of a cold and dark TMC-1-like prestellar core. Two time-dependent chemical models of the solar nebula are calculated over 1 Myr: (1) a laminar model and (2) a model with two-dimensional (2D) turbulent mixing. We find that the radial outward increase of the H{sub 2}O D/H ratio is shallower in the chemodynamical nebular model than in the laminar model. This is related to more efficient defractionation of HDO via rapid gas-phase processes because the 2D mixing model allows the water ice to be transported either inward and thermally evaporated or upward and photodesorbed. The laminar model shows the Earth water D/H ratio at r ≲ 2.5 AU, whereas for the 2D chemodynamical model this zone is larger, r ≲ 9 AU. Similarly, the water D/H ratios representative of the Oort-family comets, ∼2.5-10 × 10{sup –4}, are achieved within ∼2-6 AU and ∼2-20 AU in the laminar and the 2D model, respectively. We find that with regards to the water isotopic composition and the origin of the comets, the mixing model seems to be favored over the laminar model.

Chemodynamical deuterium fractionation in the early solar nebula: The origin of water on earth and in asteroids and comets

International Nuclear Information System (INIS)

Albertsson, T.; Semenov, D.; Henning, Th.

2014-01-01

Formation and evolution of water in the solar system and the origin of water on Earth constitute one of the most interesting questions in astronomy. The prevailing hypothesis for the origin of water on Earth is by delivery through water-rich small solar system bodies. In this paper, the isotopic and chemical evolution of water during the early history of the solar nebula, before the onset of planetesimal formation, is studied. A gas-grain chemical model that includes multiply deuterated species and nuclear spin-states is combined with a steady-state solar nebula model. To calculate initial abundances, we simulated 1 Myr of evolution of a cold and dark TMC-1-like prestellar core. Two time-dependent chemical models of the solar nebula are calculated over 1 Myr: (1) a laminar model and (2) a model with two-dimensional (2D) turbulent mixing. We find that the radial outward increase of the H 2 O D/H ratio is shallower in the chemodynamical nebular model than in the laminar model. This is related to more efficient defractionation of HDO via rapid gas-phase processes because the 2D mixing model allows the water ice to be transported either inward and thermally evaporated or upward and photodesorbed. The laminar model shows the Earth water D/H ratio at r ≲ 2.5 AU, whereas for the 2D chemodynamical model this zone is larger, r ≲ 9 AU. Similarly, the water D/H ratios representative of the Oort-family comets, ∼2.5-10 × 10 –4 , are achieved within ∼2-6 AU and ∼2-20 AU in the laminar and the 2D model, respectively. We find that with regards to the water isotopic composition and the origin of the comets, the mixing model seems to be favored over the laminar model.

A new sphenodontian (Lepidosauria: Rhynchocephalia) from the Late Triassic of Argentina and the early origin of the herbivore opisthodontians

Science.gov (United States)

Martínez, Ricardo N.; Apaldetti, Cecilia; Colombi, Carina E.; Praderio, Angel; Fernandez, Eliana; Malnis, Paula Santi; Correa, Gustavo A.; Abelin, Diego; Alcober, Oscar

2013-01-01

Sphenodontians were a successful group of rhynchocephalian reptiles that dominated the fossil record of Lepidosauria during the Triassic and Jurassic. Although evidence of extinction is seen at the end of the Laurasian Early Cretaceous, they appeared to remain numerically abundant in South America until the end of the period. Most of the known Late Cretaceous record in South America is composed of opisthodontians, the herbivorous branch of Sphenodontia, whose oldest members were until recently reported to be from the Kimmeridgian–Tithonian (Late Jurassic). Here, we report a new sphenodontian, Sphenotitan leyesi gen. et sp. nov., collected from the Upper Triassic Quebrada del Barro Formation of northwestern Argentina. Phylogenetic analysis identifies Sphenotitan as a basal member of Opisthodontia, extending the known record of opisthodontians and the origin of herbivory in this group by 50 Myr. PMID:24132307

Kinematics and 40Ar/ 39Ar geochronology of the Gaoligong and Chongshan shear systems, western Yunnan, China: Implications for early Oligocene tectonic extrusion of SE Asia

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Wang, Yuejun; Fan, Weiming; Zhang, Yanhua; Peng, Touping; Chen, Xinyue; Xu, Yigang

2006-06-01

The Gaoligong and Chongshan shear systems (GLSS and CSSS) in western Yunnan, China, have similar tectonic significance to the Ailaoshan-Red River shear system (ASRRSS) during the Cenozoic tectonic development of the southeastern Tibetan syntaxis. To better understand their kinematics and the Cenozoic tectonic evolution of SE Asia, this paper presents new kinematic and 40Ar/ 39Ar geochronological data for these shear systems. All the structural and microstructural evidence indicate that the GLSS is a dextral strike-slip shear system while the CSSS is a sinistral strike-slip shear system, and both were developed under amphibolite- to greenschist-grade conditions. The 40Ar/ 39Ar dating of synkinematic minerals revealed that the strike-slip shearing on the GLSS and CSSS at least began at ˜ 32 Ma, possibly coeval with the onset of other major shear systems in SE Asia. The late-stage shearing on the GLSS and CSSS is dated at ˜ 27-29 Ma by the biotite 40Ar/ 39Ar ages, consistent with that of the Wang Chao shear zone (WCSZ), but ˜ 10 Ma earlier than that of the ASRRSS. The dextral Gaoligong shear zone within the GLSS may have separated the India plate from the Indochina Block during early Oligocene. Combined with other data in western Yunnan, we propose that the Baoshan/Southern Indochina Block escaped faster southeastward along the CSSS to the east and the GLSS to the west than the Northern Indochina Block along the ASRRSS, accompanying with the obliquely northward motion of the India plate during early Oligocene (28-36 Ma). During 28-17 Ma, the Northern Indochina Block was rotationally extruded along the ASRRSS relative to the South China Block as a result of continuously impinging of the India plate.

Mesozoic-Cenozoic evolution of the Zoige depression in the Songpan-Ganzi flysch basin, eastern Tibetan Plateau: Constraints from detrital zircon U-Pb ages and fission-track ages of the Triassic sedimentary sequence

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Tang, Yan; Zhang, Yunpeng; Tong, Lili

2018-01-01

The Zoige depression is an important depocenter within the northeast Songpan-Ganzi flysch basin, which is bounded by the South China, North China and Qiangtang Blocks and forms the northeastern margin of the Tibetan Plateau. This paper discusses the sediment provenance and Mesozoic-Cenozoic evolution of the Zoige depression in the Songpan-Ganzi flysch basin, eastern Tibetan Plateau, using the detrital zircon U-Pb ages and apatite fission-track data from the Middle to Late Triassic sedimentary rocks in the area. The U-Pb ages of the Middle to Late Triassic zircons range from 260-280 Ma, 429-480 Ma, 792-974 Ma and 1800-2500 Ma and represent distinct source region. Our new results demonstrate that the detritus deposited during the Middle Triassic (Ladinian, T2zg) primarily originated from the Eastern Kunlun and North Qinling Orogens, with lesser contributions from the North China Block. By the Late Triassic (early Carnian, T3z), the materials at the southern margin of the North China Block were generally transported westward to the basin along a river network that flowed through the Qinling region between the North China and South China Blocks: this interpretation is supported by the predominance of the bimodal distribution of 1.8 Ga and 2.5 Ga age peaks and a lack of significant Neoproterozoic zircon. Since the Late Triassic (middle Carnian, T3zh), considerable changes have occurred in the source terranes, such as the cessation of the Eastern Kunlun Orogen and North China Block sources and the rise of the northwestern margin of the Yangtze Block and South Qinling Orogen. These drastic changes are compatible with a model of a sustained westward collision between the South China and North China Blocks during the late Triassic and the clockwise rotation of the South China Block progressively closed the basin. Subsequently, orogeny-associated folds have formed in the basin since the Late Triassic (late Carnian), and the study area was generally subjected to uplifting and

Factors controlling late Cenozoic continental margin growth from the Ebro Delta to the western Mediterranean deep sea

Science.gov (United States)

Nelson, C.H.; Maldonado, A.

1990-01-01

The Ebro continental margin sedimentation system originated with a Messinian fluvial system. This system eroded both a major subaerial canyon cutting the margin southeastward from the present Ebro Delta and an axial valley that drained northeastward down Valencia Trough. Post-Messinian submergence of this topography and the Pliocene regime of high sea levels resulted in a marine hemipelagic drape over the margin. Late Pliocene to Pleistocene glacial climatic cycles, drainagebasin deforestation, and sea-level lowstands combined to increase sediment supply, cause the margin to prograde, and create a regime of lowstand sediment-gravity flows in the deeper margin. The depositional patterns of regressive, transgressive and highstand sea-level regimes suggest that location of the sediment source near the present Ebro Delta throughout the late Cenozoic, southward current advection of sediment, and greater subsidence in the southern margin combined to cause generally asymmetric progradation of the margin to the southeast. Thicker, less stable deposits filling the Messinian subaerial canyon underwent multiple retrograde failures, eroded wide gullied canyons and formed unchanneled base-of-slope sediment aprons in the central margin area; other margin areas to the north and south developed a series of channel-levee complexes. On the basin floor, the formation of Valencia Valley over the Messinian subaerial valley and earlier faults led to draining of about 20% of the Ebro Pleistocene sediment from channel-levee complexes through the valley to prograde Valencia Fan as much as 500 km northeast of the margin. Thus, the Ebro margin has two growth directions, mainly southeastward during higher sea levels, and eastward to northeastward during lower sea levels. The northeastward draining of turbidity currents has produced unusually thin and widely dispersed turbidite systems compared to those on ponded basin floors. During the past few centuries, man's impact has exceeded natural

Mexican-origin Early Adolescents’ Ethnic Socialization, Ethnic Identity, and Psychosocial Functioning

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Umaña-Taylor, Adriana J.; O’Donnell, Megan; Knight, George P.; Roosa, Mark W.; Berkel, Cady; Nair, Rajni

2013-01-01

The current study examined how parental ethnic socialization informed adolescents’ ethnic identity development and, in turn, youths’ psychosocial functioning (i.e., mental health, social competence, academic efficacy, externalizing behaviors) among 749 Mexican-origin families. In addition, school ethnic composition was examined as a moderator of these associations. Findings indicated that mothers’ and fathers’ ethnic socialization were significant longitudinal predictors of adolescents’ ethnic identity, although fathers’ ethnic socialization interacted significantly with youths’ school ethnic composition in 5th grade to influence ethnic identity in 7th grade. Furthermore, adolescents’ ethnic identity was significantly associated with increased academic self-efficacy and social competence, and decreased depressive symptoms and externalizing behaviors. Findings support theoretical predictions regarding the central role parents play in Mexican-origin adolescents’ normative developmental processes and adjustment and, importantly, underscore the need to consider variability that is introduced into these processes by features of the social context such as school ethnic composition. PMID:24465033

New Mesozoic and Cenozoic fossils from Ecuador: Invertebrates, vertebrates, plants, and microfossils

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Cadena, Edwin A.; Mejia-Molina, Alejandra; Brito, Carla M.; Peñafiel, Sofia; Sanmartin, Kleber J.; Sarmiento, Luis B.

2018-04-01

Ecuador is well known for its extensive extant biodiversity, however, its paleobiodiversity is still poorly explored. Here we report seven new Mesozoic and Cenozoic fossil localities from the Pacific coast, inter-Andean depression and Napo basin of Ecuador, including vertebrates, invertebrates, plants, and microfossils. The first of these localities is called El Refugio, located near the small town of Chota, Imbabura Province, from where we report several morphotypes of fossil leaves and a mycetopodid freshwater mussel of the Upper Miocene Chota Formation. A second site is also located near the town of Chota, corresponding to potentially Pleistocene to Holocene lake deposits from which we report the occurrence of leaves and fossil diatoms. A third locality is at the Pacific coast of the country, near Rocafuerte, a town in Esmeraldas Province, from which we report a late Miocene palm leaf. We also report the first partially articulated skull with teeth from a Miocene scombridid (Mackerels) fish from El Cruce locality, and completely preserved seeds from La Pila locality, both sites from Manabí Province. Two late Cretaceous fossil sites from the Napo Province, one near Puerto Napo showing a good record of fossil shrimps and a second near the town of Loreto shows the occurrence of granular amber and small gymnosperms seeds and cuticles. All these new sites and fossils show the high potential of the sedimentary sequences and basins of Ecuador for paleontological studies and for a better understanding of the fossil record of the country and northern South America.

Modern turtle origins: the oldest known cryptodire.

Science.gov (United States)

Gaffney, E S; Hutchison, J H; Jenkins, F A; Meeker, L J

1987-07-17

The discovery of a turtle in the Early Jurassic(185 million years before present) Kayenta Formation of northeastern Arizona provides significant evidence about the origin of modern turtles. This new taxon possesses many of the primitive features expected in the hypothetical common ancestor of pleurodires and cryptodires, the two groups of modern turtles. It is identified as the oldest known cryptodire because of the presence of a distinctive cryptodiran jaw mechanism consisting of a trochlea over the otic chamber that redirects the line of action of the adductor muscle. Aquatic habits appear to have developed very early in turtle evolution. Kayentachelys extends the known record of cryptodires back at least 45 million years and documents a very early stage in the evolution of modern turtles.

Origins of narcissism in children.

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Brummelman, Eddie; Thomaes, Sander; Nelemans, Stefanie A; Orobio de Castro, Bram; Overbeek, Geertjan; Bushman, Brad J

2015-03-24

Narcissism levels have been increasing among Western youth, and contribute to societal problems such as aggression and violence. The origins of narcissism, however, are not well understood. Here, we report, to our knowledge, the first prospective longitudinal evidence on the origins of narcissism in children. We compared two perspectives: social learning theory (positing that narcissism is cultivated by parental overvaluation) and psychoanalytic theory (positing that narcissism is cultivated by lack of parental warmth). We timed the study in late childhood (ages 7-12), when individual differences in narcissism first emerge. In four 6-mo waves, 565 children and their parents reported child narcissism, child self-esteem, parental overvaluation, and parental warmth. Four-wave cross-lagged panel models were conducted. Results support social learning theory and contradict psychoanalytic theory: Narcissism was predicted by parental overvaluation, not by lack of parental warmth. Thus, children seem to acquire narcissism, in part, by internalizing parents' inflated views of them (e.g., "I am superior to others" and "I am entitled to privileges"). Attesting to the specificity of this finding, self-esteem was predicted by parental warmth, not by parental overvaluation. These findings uncover early socialization experiences that cultivate narcissism, and may inform interventions to curtail narcissistic development at an early age.

Evaluating the Link between Self-Esteem and Temperament in Mexican Origin Early Adolescents

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Robins, Richard W.; Donnellan, M. Brent; Widaman, Keith F.; Conger, Rand D.

2010-01-01

The present study examined the relation between self-esteem and temperament in a sample of 646 Mexican-American early adolescents (mean age = 10.4). Findings show that (a) early adolescents with high self-esteem exhibit higher levels of Effortful Control but, contrary to findings in adult samples, do not differ from low self-esteem adolescents in…

Late cenozoic tectonic and geomorphic evolution of the Patagonian Andes between 42oS and 52oS, southern Chile assessed using fission-track thermochronology

International Nuclear Information System (INIS)

Thomson, S.N; Herve, F; Stockhert, B.; Brix, M.R.; Adriasola, A

2001-01-01

Fission-track (FT) analysis has been applied in the Patagonian Andes of southern Chile to assess the late Cenozoic geomorphic and tectonic response of the overriding plate to subduction of the Chile rise active oceanic spreading centre (Thomson et al., 2001). The timing and nature of tectonic uplift and denudation along the southern parts of the major transpression intra-arc Liquine-Ofqui fault (LOF) system have also been investigated (Thomson, 2001, submitted). Results from 130 FT ages (72 zircon and 58 apatite ages) and 39 apatite track length measurements reveal initiation of rapid cooling and denudation at ca. 30 Ma at the western margin of southern continental South America. This was followed by a ca. 200km eastward migration of the locus of maximum denudation to the position of the present day topographic divide between ca. 30 Ma and ca. 12 to 10 Ma. East of the Andean divide less than 3 km of denudation has occurred since the Late Cretaceous. Enhanced denudation is interpreted to be the result of increased tectonic uplift driven by a large increase in convergence rates at ca. 28 to 26 Ma that triggered orographically enhanced precipitation on the west-side of the Patagonian Andes allowing increased erosion by fluvial incision and mass transport processes. The eastward migration of the locus of maximum denudation can be related to either coeval eastward migration of the retro-arc deformation front, the effects of subduction erosion in the overriding plate at the Peru-Chile trench or shallowing of the angle of subduction. Away from the influence of the LOF the process of spreading centre subduction and collision itself coincides with an overall slow-down in denudation rates in the overriding plate most likely caused by a major reduction in the main tectonic force driving tectonic uplift in the upper plate to subduction. In contrast to the Andes south of ca. 46 o S, increased cooling and denudation related to transpression induced rock uplift and erosion along

The origins of the universe for dummies

CERN Document Server

Pincock, Stephen

2007-01-01

Do you want to learn about the physical origin of the Universe, but don't have the rest of eternity to read up on it? Do you want to know what scientists know about where you and your planet came from, but without the science blinding you? 'Course you do - and who better than For Dummies to tackle the biggest, strangest and most wonderful question there is! The Origins of the Universe For Dummies covers: Early ideas about our universeModern cosmologyBig Bang theoryDark matter and gravityGalaxies and solar systemsLife on earthFi

Mesozoic-Cenozoic tectonic evolution and its relation to sandstone-type uranium mineralization in northern Tarim area--Evidence from apatite fission track

International Nuclear Information System (INIS)

Liu Hongxu; Dong Wenming; Liu Zhangyue; Chen Xiaolin

2009-01-01

The apatite fission track dating and inversion result of geological thermal history of four rock specimens from Sawafuqi area and Talike area in northern Tarim Basin show that two areas uplifted at different ages. The apatite fission track ages of Sawafuqi range from 3.5 to 3.9 Ma, while the ages of Talike range from 53 to 59 Ma. The thermal history recorded by rock samples reveals that there are at least three prominent cooling phases since Late Cretaceous epoch. Detailed study was made on the division of uplifting stages during Mesozoic and Cenozoic tectonic evolution with the existing data in northern Tarim area. And new ideas on tectonic evolution and sandstone-type uranium mineralization have been put forward by combining with the sandstone-type uranium mineralization ages in this area.(authors)

The evolution of a Late Cretaceous-Cenozoic intraplate basin (Duaringa Basin), eastern Australia: evidence for the negative inversion of a pre-existing fold-thrust belt

Science.gov (United States)

Babaahmadi, Abbas; Sliwa, Renate; Esterle, Joan; Rosenbaum, Gideon

2017-12-01

The Duaringa Basin in eastern Australia is a Late Cretaceous?-early Cenozoic sedimentary basin that developed simultaneously with the opening of the Tasman and Coral Seas. The basin occurs on the top of an earlier (Permian-Triassic) fold-thrust belt, but the negative inversion of this fold-thrust belt, and its contribution to the development of the Duaringa Basin, are not well understood. Here, we present geophysical datasets, including recently surveyed 2D seismic reflection lines, aeromagnetic and Bouguer gravity data. These data provide new insights into the structural style in the Duaringa Basin, showing that the NNW-striking, NE-dipping, deep-seated Duaringa Fault is the main boundary fault that controlled sedimentation in the Duaringa Basin. The major activity of the Duaringa Fault is observed in the southern part of the basin, where it has undergone the highest amount of displacement, resulting in the deepest and oldest depocentre. The results reveal that the Duaringa Basin developed in response to the partial negative inversion of the pre-existing Permian-Triassic fold-thrust belt, which has similar orientation to the extensional faults. The Duaringa Fault is the negative inverted part of a single Triassic thrust, known as the Banana Thrust. Furthermore, small syn-depositional normal faults at the base of the basin likely developed due to the reactivation of pre-existing foliations, accommodation faults, and joints associated with Permian-Triassic folds. In contrast to equivalent offshore basins, the Duaringa Basin lacks a complex structural style and thick syn-rift sediments, possibly because of the weakening of extensional stresses away from the developing Tasman Sea.

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

Distributional patterns and possible origin of leafhoppers (Homoptera, Cicadellidae

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Mervin W. Nielson

2000-03-01

Full Text Available The zoogeographical distribution of 42 cicadellid subfamilies and their assigned tribes and genera is compiled with distributional maps and proposed dispersal pathways of genera that are shared interzoogeographically. Possible origin of the subfamilies and tribes is proposed in an ancestral context from which the more modern extant groups evolved whereas origin of genera is in a more modern context. Notwithstanding their complex biogeography, the distributional data of the higher groups indicate that all of the cosmopolitan and near cosmopolitan subfamilies arose during early Cretaceous or possibly the late Jurassic period (140-116 m.y.a. when continental drift was in its early stages. Nearly all of the New World and some Old World subfamilies are considered of more recent origin (late Cretaceous-Tertiary. Ninety percent of the known genera (2,126 are endemic to their respective zoogeographical region and subregion, thus indicating relatively high host specificity and low rate of dispersal. The majority (76% of known extant genera are pantropical in origin, suggesting early or possible Gondwanaland origin of their ancestors. Dispersal pathways of genera shared by more than one zoogeographical region were generally south to north (Neotropical/Nearctic, Oriental/Palaearctic or west to east (Palaearctic/Nearctic, Oriental/Australian, from regions of high diversity to regions of low diversity and from warmer climates to cooler climates. The most diverse and richest leafhopper fauna are present in the Neotropical and Ethiopian regions although taxal affinities between them are poorest. The most depauperate fauna are in the Nearctic region and in Australia, reflecting the impact of isolating and ecological factors on distribution and radiation. Ecological barriers were more evident between the Ethiopian and Oriental fauna than between any other zoogeographical combination. Taxal affinities appeared to be correlated with close continental proximities

A genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of land

Science.gov (United States)

Battistuzzi, Fabia U.; Feijao, Andreia; Hedges, S. Blair

2004-01-01

BACKGROUND: The timescale of prokaryote evolution has been difficult to reconstruct because of a limited fossil record and complexities associated with molecular clocks and deep divergences. However, the relatively large number of genome sequences currently available has provided a better opportunity to control for potential biases such as horizontal gene transfer and rate differences among lineages. We assembled a data set of sequences from 32 proteins (approximately 7600 amino acids) common to 72 species and estimated phylogenetic relationships and divergence times with a local clock method. RESULTS: Our phylogenetic results support most of the currently recognized higher-level groupings of prokaryotes. Of particular interest is a well-supported group of three major lineages of eubacteria (Actinobacteria, Deinococcus, and Cyanobacteria) that we call Terrabacteria and associate with an early colonization of land. Divergence time estimates for the major groups of eubacteria are between 2.5-3.2 billion years ago (Ga) while those for archaebacteria are mostly between 3.1-4.1 Ga. The time estimates suggest a Hadean origin of life (prior to 4.1 Ga), an early origin of methanogenesis (3.8-4.1 Ga), an origin of anaerobic methanotrophy after 3.1 Ga, an origin of phototrophy prior to 3.2 Ga, an early colonization of land 2.8-3.1 Ga, and an origin of aerobic methanotrophy 2.5-2.8 Ga. CONCLUSIONS: Our early time estimates for methanogenesis support the consideration of methane, in addition to carbon dioxide, as a greenhouse gas responsible for the early warming of the Earths' surface. Our divergence times for the origin of anaerobic methanotrophy are compatible with highly depleted carbon isotopic values found in rocks dated 2.8-2.6 Ga. An early origin of phototrophy is consistent with the earliest bacterial mats and structures identified as stromatolites, but a 2.6 Ga origin of cyanobacteria suggests that those Archean structures, if biologically produced, were made by

A genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of land

Directory of Open Access Journals (Sweden)

Hedges S Blair

2004-11-01

Full Text Available Abstract Background The timescale of prokaryote evolution has been difficult to reconstruct because of a limited fossil record and complexities associated with molecular clocks and deep divergences. However, the relatively large number of genome sequences currently available has provided a better opportunity to control for potential biases such as horizontal gene transfer and rate differences among lineages. We assembled a data set of sequences from 32 proteins (~7600 amino acids common to 72 species and estimated phylogenetic relationships and divergence times with a local clock method. Results Our phylogenetic results support most of the currently recognized higher-level groupings of prokaryotes. Of particular interest is a well-supported group of three major lineages of eubacteria (Actinobacteria, Deinococcus, and Cyanobacteria that we call Terrabacteria and associate with an early colonization of land. Divergence time estimates for the major groups of eubacteria are between 2.5–3.2 billion years ago (Ga while those for archaebacteria are mostly between 3.1–4.1 Ga. The time estimates suggest a Hadean origin of life (prior to 4.1 Ga, an early origin of methanogenesis (3.8–4.1 Ga, an origin of anaerobic methanotrophy after 3.1 Ga, an origin of phototrophy prior to 3.2 Ga, an early colonization of land 2.8–3.1 Ga, and an origin of aerobic methanotrophy 2.5–2.8 Ga. Conclusions Our early time estimates for methanogenesis support the consideration of methane, in addition to carbon dioxide, as a greenhouse gas responsible for the early warming of the Earths' surface. Our divergence times for the origin of anaerobic methanotrophy are compatible with highly depleted carbon isotopic values found in rocks dated 2.8–2.6 Ga. An early origin of phototrophy is consistent with the earliest bacterial mats and structures identified as stromatolites, but a 2.6 Ga origin of cyanobacteria suggests that those Archean structures, if biologically

Evidence for ephemeral middle Eocene to early Oligocene Greenland glacial ice and pan-Arctic sea ice.

Science.gov (United States)

Tripati, Aradhna; Darby, Dennis

2018-03-12

Earth's modern climate is defined by the presence of ice at both poles, but that ice is now disappearing. Therefore understanding the origin and causes of polar ice stability is more critical than ever. Here we provide novel geochemical data that constrain past dynamics of glacial ice on Greenland and Arctic sea ice. Based on accurate source determinations of individual ice-rafted Fe-oxide grains, we find evidence for episodic glaciation of distinct source regions on Greenland as far-ranging as ~68°N and ~80°N synchronous with ice-rafting from circum-Arctic sources, beginning in the middle Eocene. Glacial intervals broadly coincide with reduced CO 2 , with a potential threshold for glacial ice stability near ~500 p.p.m.v. The middle Eocene represents the Cenozoic onset of a dynamic cryosphere, with ice in both hemispheres during transient glacials and substantial regional climate heterogeneity. A more stable cryosphere developed at the Eocene-Oligocene transition, and is now threatened by anthropogenic emissions.

U-Pb ages of detrital zircon from Cenozoic sediments in the southwestern Tarim Basin, NW China: Implications for Eocene-Pliocene source-to-sink relations and new insights into Cretaceous-Paleogene magmatic sources

Science.gov (United States)

Yang, Wei; Fu, Ling; Wu, Chaodong; Song, Yan; Jiang, Zhenxue; Luo, Qun; Zhang, Ziya; Zhang, Chen; Zhu, Bei

2018-05-01

A detailed investigation of potential provenance is still lacking in the southwestern Tarim Basin, which restricts our complete understanding of Cenozoic source-to-sink relations between the basin interior and the Pamir salient - western Kunlun Mountain Range. Debate also exists concerning the potential sources of the Paleogene and Cretaceous igneous detritus present in the Cenozoic sedimentary sequences. Here, we present U-Pb (LA-ICP-MS) ages of detrital zircons from the continuous Eocene-Pliocene sediment series in the well-exposed Aertashi section to investigate changes in sediment provenance through time. The U-Pb detrital zircon ages range widely from 45 to 3204 Ma and can be divided into seven main groups: 45-65 Ma (sub-peak at 49 Ma), 67-103 Ma (sub-peak at 95 Ma), 196-251 Ma (sub-peak at 208 Ma), 252-416 Ma (sub-peak at 296 Ma), 417-540 Ma (sub-peak at 446 Ma), 550-1429 Ma (sub-peaks at 614 Ma, 828 Ma and 942 Ma) and 1345-3204 Ma (sub-peaks at 1773 Ma and 2480 Ma). These zircons were mainly derived from the western Kunlun Mountain Range and northern Pamir salient to the west and south. The evolution of the provenance and source-to-sink relationship patterns in the southwestern Tarim Basin can be divided into three stages: (1) The Middle Eocene to Lower Oligocene sediments display a wide variety of detrital zircon ages, suggesting that the source area was extensive. (2) A major change in provenance occurred during the Late Oligocene to Early Miocene and was characterized by an abrupt increase in the proportion of Triassic and Lower Paleozoic igneous components, implying a significant adjustment in topography induced by the initial uplift and exhumation of the western Kunlun Mountain Range and northern Pamir salient. (3) In the Late Miocene, the source-to-sink system transformed again, and contributions of Triassic to Lower Paleozoic material weakened substantially due to the sufficient indentation of the Pamir salient. Our integrated analyses of zircon

Three-dimensional geologic mapping of the Cenozoic basin fill, Amargosa Desert basin, Nevada and California

Science.gov (United States)

Taylor, Emily M.; Sweetkind, Donald S.

2014-01-01

Understanding the subsurface geologic framework of the Cenozoic basin fill that underlies the Amargosa Desert in southern Nevada and southeastern California has been improved by using borehole data to construct three-dimensional lithologic and interpreted facies models. Lithologic data from 210 boreholes from a 20-kilometer (km) by 90-km area were reduced to a limited suite of descriptors based on geologic knowledge of the basin and distributed in three-dimensional space using interpolation methods. The resulting lithologic model of the Amargosa Desert basin portrays a complex system of interfingered coarse- to fine-grained alluvium, playa and palustrine deposits, eolian sands, and interbedded volcanic units. Lithologic units could not be represented in the model as a stacked stratigraphic sequence due to the complex interfingering of lithologic units and the absence of available time-stratigraphic markers. Instead, lithologic units were grouped into interpreted genetic classes, such as playa or alluvial fan, to create a three-dimensional model of the interpreted facies data. Three-dimensional facies models computed from these data portray the alluvial infilling of a tectonically formed basin with intermittent internal drainage and localized regional groundwater discharge. The lithologic and interpreted facies models compare favorably to resistivity, aeromagnetic, and geologic map data, lending confidence to the interpretation.

Diversification rates indicate an early role of adaptive radiations at the origin of modern echinoid fauna.

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Simon Boivin

Full Text Available Evolutionary radiations are fascinating phenomena corresponding to a dramatic diversification of taxa and a burst of cladogenesis over short periods of time. Most evolutionary radiations have long been regarded as adaptive but this has seldom been demonstrated with large-scale comparative datasets including fossil data. Originating in the Early Jurassic, irregular echinoids are emblematic of the spectacular diversification of mobile marine faunas during the Mesozoic Marine Revolution. They diversified as they colonized various habitats, and now constitute the main component of echinoid fauna in modern seas. The evolutionary radiation of irregular echinoids has long been considered as adaptive but this hypothesis has never been tested. In the present work we analyze the evolution of echinoid species richness and morphological disparity over 37 million years based on an extensive fossil dataset. Our results demonstrate that morphological and functional diversifications in certain clades of irregular echinoids were exceptionally high compared to other clades and that they were associated with the evolution of new modes of life and so can be defined as adaptive radiations. The role played by ecological opportunities in the diversification of these clades was critical, with the evolution of the infaunal mode of life promoting the adaptive radiation of irregular echinoids.

Chemostratigraphy of Late Cretaceous deltaic and marine sedimentary rocks from high northern palaeolatitudes in the Nuussuaq Basin, West Greenland

DEFF Research Database (Denmark)

Lenniger, Marc; Pedersen, Gunver Krarup; Bjerrum, Christian J.

The Nuussuaq Basin in the Baffin Bay area in West Greenland formed as a result of the opening of the Labrador Sea in Late Mesozoic to Early Cenozoic times. The first rifting and the development of the Nuussuaq Basin took place during the Early Cretaceous and was followed by a second rifting phase...

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

The origin of the eukaryotic cell

Science.gov (United States)

Hartman, H.

1984-01-01

The endosymbiotic hypothesis for the origin of the eukaryotic cell has been applied to the origin of the mitochondria and chloroplasts. However as has been pointed out by Mereschowsky in 1905, it should also be applied to the nucleus as well. If the nucleus, mitochondria and chloroplasts are endosymbionts, then it is likely that the organism that did the engulfing was not a DNA-based organism. In fact, it is useful to postulate that this organism was a primitive RNA-based organism. This hypothesis would explain the preponderance of RNA viruses found in eukaryotic cells. The centriole and basal body do not have a double membrane or DNA. Like all MTOCs (microtubule organising centres), they have a structural or morphic RNA implicated in their formation. This would argue for their origin in the early RNA-based organism rather than in an endosymbiotic event involving bacteria. Finally, the eukaryotic cell uses RNA in ways quite unlike bacteria, thus pointing to a greater emphasis of RNA in both control and structure in the cell. The origin of the eukaryotic cell may tell us why it rather than its prokaryotic relative evolved into the metazoans who are reading this paper.

Tracking the multi-stage exhumation history of the western Chinese Tianshan by Apatite Fission Track (AFT) dating - Implications for the preservation of epithermal deposits in ancient orogenic belt

Science.gov (United States)

Wang, Yannan; Cai, Keda

2017-04-01

The western Chinese Tianshan, located in the southern domain of the Central Asian Orogenic Belt (CAOB), was originally constructed by multiple accretion-collision processes in the Paleozoic, and was superimposed by complex intracontinental tectonic evolution in the Mesozoic-Cenozoic. Understanding the timing and mechanism of the latter geological processes is critical to unravel the preservation conditions of the epithermal deposits in the western Chinese Tianshan. This work presents new apatite fission track (AFT) data for three mountain ranges of the western Chinese Tianshan to track their exhumation history. Our AFT data gave a wide range of ages from 76.8 ± 5.5 Ma to 182.3 ± 9.9 Ma, and the mean confined fission track lengths are between 9.8 ± 0.5 μm and 12.3 ± 0.2 μm. The new data, in combination with the thermal history modeling，enable us to attribute the exhumation history to three primary stages, including Early Permian (300-280 Ma), Late Triassic-Early Cretaceous (230-130 Ma), and Late Oligocene-Early Miocene (30-20 Ma). The first stage may be caused by the terrane accretion-collision in the late Paleozoic. The second stage was likely related to the closure of the Mongol-Okhotsk Ocean during the Mesozoic. The last one is regarded as the result of the collision between the Indian Plate and the Eurasia Plate in the Cenozoic. The extraordinary exhumation processes of these three major mountain ranges might have been responsible for sediment supply to the corresponding intra-mountain basins in the western Chinese Tianshan, and the particularly mountain-basin coupling evolution is ascribed to an essential condition for the preservation of epithermal deposits in ancient orogenic belt.

Galaxy clustering and small-scale CBR anisotropy constraints on galaxy origin scenarios

International Nuclear Information System (INIS)

Lucchin, F.

1986-01-01

The problem of the origin of cosmic structures (galaxies, galaxy clusters,......) represents the crossroads of the modern cosmology: it is correlated both with the theoretical model of the very early universe and with most of the present observational data. In this context, galaxy origin scenarios are reviewed. The cosmological relevance of the observed clustering properties of the universe is outlined. The observational constraints, due to small-scale cosmic background radiation (CBR) anisotropies, on galaxy origin scenarios are discussed. (author)

Social grooming network in captive chimpanzees: does the wild or captive origin of group members affect sociality?

Science.gov (United States)

Levé, Marine; Sueur, Cédric; Petit, Odile; Matsuzawa, Tetsuro; Hirata, Satoshi

2016-01-01

Many chimpanzees throughout the world are housed in captivity, and there is an increasing effort to recreate social groups by mixing individuals with captive origins with those with wild origins. Captive origins may entail restricted rearing conditions during early infant life, including, for example, no maternal rearing and a limited social life. Early rearing conditions have been linked with differences in tool-use behavior between captive- and wild-born chimpanzees. If physical cognition can be impaired by non-natural rearing, what might be the consequences for social capacities? This study describes the results of network analysis based on grooming interactions in chimpanzees with wild and captive origins living in the Kumamoto Sanctuary in Kumamoto, Japan. Grooming is a complex social activity occupying up to 25% of chimpanzees' waking hours and plays a role in the emergence and maintenance of social relationships. We assessed whether the social centralities and roles of chimpanzees might be affected by their origin (captive vs wild). We found that captive- and wild-origin chimpanzees did not differ in their grooming behavior, but that theoretical removal of individuals from the network had differing impacts depending on the origin of the individual. Contrary to findings that non-natural early rearing has long-term effects on physical cognition, living in social groups seems to compensate for the negative effects of non-natural early rearing. Social network analysis (SNA) and, in particular, theoretical removal analysis, were able to highlight differences between individuals that would have been impossible to show using classical methods. The social environment of captive animals is important to their well-being, and we are only beginning to understand how SNA might help to enhance animal welfare.

The Origin of Basalt and Cause of Melting Beneath East Antarctica as Revealed by the Southernmost Volcanoes on Earth

Science.gov (United States)

Reindel, J. L.; Panter, K. S.; Smellie, J. L.; McIntosh, W. C.

2017-12-01

Mt. Early and Sheridan Bluff are two basaltic monogenetic volcanoes located at 87° South latitude at the head of the Scott Glacier. These Early Miocene volcanoes lie 800 km from any other volcano and 200 km inland from the shoulder of the West Antarctic Rift System (WARS), which is the foci of most Cenozoic alkaline volcanism in Antarctica. Preliminary 40Ar/39Ar dates suggest that Mt. Early is older than previously determined and closer in age to Sheridan Bluff ( 19 Ma). Petrography, mineral chemistry and whole rock major and trace element concentrations are used to characterize the basalts and to determine whether they are genetically related to mafic volcanism in the WARS. The basalts are porphyritic with phenocrysts of olivine (Fo 58-84%), plagioclase (An 48-67%) ± clinopyroxene (Wo 43-48%). Whole rock MgO range from 10 to 4 wt.% and have restricted SiO2 (48 to 50 wt.%) contents. The basalts vary from alkaline (up to 6 wt.% Ne-normative) to subalkaline (up to 6 wt.% Hy-normative). The alkaline basalts that occur at both Mt. Early and Sheridan Bluff are more strongly enriched in incompatible elements (La 33-49 ppm, Ba 270-484 ppm, Sr 712-1009 ppm), have LaN/YbN ratios >10 and show prominent Pb negative anomalies with only slight K negative anomalies on primitive mantle normalized, multi-element diagrams. Subalkaline basalts (only at Sheridan Bluff) have lower concentrations of incompatible elements (La 14-16 ppm, Ba 110-144 ppm, and Sr 358-380 ppm), LaN/YbN ratios base of the East Antarctic craton and its replacement by warmer asthenosphere has been proposed for this region based on geophysical evidence (Heeszel et al., 2016). The volcanism may constrain the timing of this event. Heeszel et al. (2016) JGR, 121, 1758-1775.

The origin of life and its methodological challenge.

Science.gov (United States)

Wächtershäuser, G

1997-08-21

The problem of the origin of life is discussed from a methodological point of view as an encounter between the teleological thinking of the historian and the mechanistic thinking of the chemist; and as the Kantian task of replacing teleology by mechanism. It is shown how the Popperian situational logic of historic understanding and the Popperian principle of explanatory power of scientific theories, when jointly applied to biochemistry, lead to a methodology of biochemical retrodiction, whereby common precursor functions are constructed for disparate successor functions. This methodology is exemplified by central tenets of the theory of the chemo-autotrophic origin of life: the proposal of a surface metabolism with a two-dimensional order; the basic polarity of life with negatively charged constituents on positively charged mineral surfaces; the surface-metabolic origin of phosphorylated sugar metabolism and nucleic acids; the origin of membrane lipids and of chemi-osmosis on pyrite surfaces; and the principles of the origin of the genetic machinery. The theory presents the early evolution of life as a process that begins with chemical necessity and winds up in genetic chance.

School Readiness of Children from Immigrant Families: Contributions of Region of Origin, Home, and Childcare

Science.gov (United States)

Koury, Amanda S.; Votruba-Drzal, Elizabeth

2014-01-01

Children from immigrant families make up a growing proportion of young children in the United States. This study highlights the heterogeneity in early academic skills related to parental region of origin. It also considers the contributions of early home and nonparental care settings to the diversity in early academic performance. Using nationally…

Cenozoic sedimentation in the Mumbai Offshore Basin: Implications for tectonic evolution of the western continental margin of India

Science.gov (United States)

Nair, Nisha; Pandey, Dhananjai K.

2018-02-01

Interpretation of multichannel seismic reflection data along the Mumbai Offshore Basin (MOB) revealed the tectonic processes that led to the development of sedimentary basins during Cenozoic evolution. Structural interpretation along three selected MCS profiles from MOB revealed seven major sedimentary sequences (∼3.0 s TWT, thick) and the associated complex fault patterns. These stratigraphic sequences are interpreted to host detritus of syn- to post rift events during rift-drift process. The acoustic basement appeared to be faulted with interspaced intrusive bodies. The sections also depicted the presence of slumping of sediments, subsidence, marginal basins, rollover anticlines, mud diapirs etc accompanied by normal to thrust faults related to recent tectonics. Presence of upthrusts in the slope region marks the locations of local compression during collision. Forward gravity modeling constrained with results from seismic and drill results, revealed that the crustal structure beneath the MOB has undergone an extensional type tectonics intruded with intrusive bodies. Results from the seismo-gravity modeling in association with litholog data from drilled wells from the western continental margin of India (WCMI) are presented here.

The ``Problem of the quaternary'' and the taxonomic rank of the late cenozoic in the international stratigraphic scale

Science.gov (United States)

Zubakov, V. A.

2011-02-01

An international scientific conflict has arisen around the International Stratigraphic Scale, the main document that regulates the rules of reading of geological records and, hence, concerns all Earth sciences. The matter of debate is the geological time scale of 2004, developed by the International Commission on Stratigraphy, where the Quaternary system was abandoned. This ICS decision triggered a protest among Quaternary geologists, members of INQUA, and became the subject of much controversy. This article provides a comprehensive analysis of the Quaternary problem and proposes a reasonable scientific solution that may be appropriate for both parties. The subject of Late Cenozoic geology is discussed: glaciations, human evolution, and recent deposits. In contrast to Charles Lyell's definition of the Plio-Pleistocene according to the percentage of modern mollusk species, it is defined here as a blanket formation, which is correlative to the topography and consists of mapped stratogens hosting fossils of modern biogeocenoses. Features of the description of the Plio-Pleistocene in terms of gravitational orbital tuning are considered. Four paleogeographic phases of modern environment evolution are recognized and ranked as stages: (1) The Messinian evolutionary explosion involved the appearance of many biogeocenoses and the bipedal walking of our extinct ancestors armed with sticks. It was a consequence of the Early Greenland (7.6 Ma BP) and Patagonian (6.7 Ma BP) hyperglaciations. (2) The Zanclean age is marked by climatic and hydrological but not evolutionary boundaries. (3) The appearance of the Villafranchian animal assemblage and Australopithecus, who used stones as weapon: 4.0-3.6 Ma BP. Orogeny and isolation of the Arctic Ocean changed the global climate dramatically. (4) The sexual revolution became the third evolutionary jump: the appearance of the first woman, "Eve", and the genus Homo with her: 1.9 Ma BP. According to the current view, the Plio

ORIGIN: Metal Creation and Evolution from the Cosmic Dawn

DEFF Research Database (Denmark)

Herder, J. W. den; Piro, L.; Ohashi, T.

2011-01-01

, and beyond. The mission will answer questions such as: When were the first metals created? How does the cosmic metal content evolve? Where do most of the metals reside in the Universe? What is the role of metals in structure formation and evolution? To reach out to the early Universe ORIGIN will use Gamma......ORIGIN is a proposal for the M3 mission call of ESA aimed at the study of metal creation from the epoch of cosmic dawn. Using high-spectral resolution in the soft X-ray band, ORIGIN will be able to identify the physical conditions of all abundant elements between C and Ni to red-shifts of z=10...

Origin of the p-process radionuclides 92Nb and 146Sm in the early solar system and inferences on the birth of the Sun.

Science.gov (United States)

Lugaro, Maria; Pignatari, Marco; Ott, Ulrich; Zuber, Kai; Travaglio, Claudia; Gyürky, György; Fülöp, Zsolt

2016-01-26

The abundances of (92)Nb and (146)Sm in the early solar system are determined from meteoritic analysis, and their stellar production is attributed to the p process. We investigate if their origin from thermonuclear supernovae deriving from the explosion of white dwarfs with mass above the Chandrasekhar limit is in agreement with the abundance of (53)Mn, another radionuclide present in the early solar system and produced in the same events. A consistent solution for (92)Nb and (53)Mn cannot be found within the current uncertainties and requires the (92)Nb/(92)Mo ratio in the early solar system to be at least 50% lower than the current nominal value, which is outside its present error bars. A different solution is to invoke another production site for (92)Nb, which we find in the α-rich freezeout during core-collapse supernovae from massive stars. Whichever scenario we consider, we find that a relatively long time interval of at least ∼ 10 My must have elapsed from when the star-forming region where the Sun was born was isolated from the interstellar medium and the birth of the Sun. This is in agreement with results obtained from radionuclides heavier than iron produced by neutron captures and lends further support to the idea that the Sun was born in a massive star-forming region together with many thousands of stellar siblings.

What can we infer about the origin of sex in early eukaryotes?

NARCIS (Netherlands)

Speijer, Dave

2016-01-01

Current analysis shows that the last eukaryotic common ancestor (LECA) was capable of full meiotic sex. The original eukaryotic life cycle can probably be described as clonal, interrupted by episodic sex triggered by external or internal stressors. The cycle could have started in a highly flexible

Young Sun, Early Earth and the Origins of Life Lessons for Astrobiology

CERN Document Server

Gargaud, Muriel; López-García, Purificación; Montmerle, Thierry; Pascal, Robert

2012-01-01

- How did the Sun come into existence? - How was the Earth formed? - How long has Earth been the way it is now, with its combination of oceans and continents? - How do you define “life”? - How did the first life forms emerge? - What conditions made it possible for living things to evolve? All these questions are answered in this colourful textbook addressing undergraduate students in "Origins of Life" courses and the scientifically interested public. The authors take the reader on an amazing voyage through time, beginning five thousand million years ago in a cloud of interstellar dust and ending five hundred million years ago, when the living world that we see today was finally formed. A chapter on exoplanets provides an overview of the search for planets outside the solar system, especially for habitable ones. The appendix closes the book with a glossary, a bibliography of further readings and a summary of the Origins of the Earth and life in fourteen boxes.

Magnetic Fields in the Early Universe

CERN Document Server

Grasso, D; Grasso, D

2001-01-01

This review concerns the origin and the possible effects of magnetic fields in the early Universe. We start by providing to the reader with a short overview of the current state of art of observations of cosmic magnetic fields. We then illustrate the arguments in favour of a primordial origin of magnetic fields in the galaxies and in the clusters of galaxies. We argue that the most promising way to test this hypothesis is to look for possible imprints of magnetic fields on the temperature and polarization anisotropies of the cosmic microwave background radiation (CMBR). With this purpose in mind, we provide a review of the most relevant effects of magnetic fields on the CMBR. A long chapter of this review is dedicated to particle physics inspired models which predict the generation of magnetic fields during the early Universe evolution. Although it is still unclear if any of these models can really explain the origin of galactic and intergalactic magnetic fields, we show that interesting effects may arise any...

Origin and Development of El Bajío Basin in the Central Sector of Trans-Mexican Volcanic Belt

Science.gov (United States)

Botero, P. A.; Alaniz Álvarez, S. A.; Nieto Samaniego, Á. F.; Lopez-Martinez, M.; Levresse, G.; Xu, S.; Ortega Obregón, C.

2015-12-01

Volcanism of the Trans-Mexican Volcanic Belt has been placed on pre-existing tectonic basins; one of them is El Bajío Basin. We present the origin and evolution of this basin through the study of its deformation events occurring mainly on the El Bajío fault, at the boundary between the Trans-Mexican Volcanic Belt and the Mesa Central. Detailed stratigraphy, and structural analysis suggest 4 deformation events in the northwest of the Sierra de Guanajuato. The first event (D1) with E-W shortening is characterized by the development of axial plane foliation (S1) with N-S direction, this event occurred between the Tithonian and Aptian age. In the second event (D2), occurred between the Albian and the early Eocene, foliations NW-SE (S2) were generated with a NE-SW shortening trend dated between the Albian and early Eocene, this deformation is related to the Laramide Orogeny. The Granito Comanja was emplaced during the third event (D3) and generated foliation (S3) in sediments of the complejo vulcanosedimentario Sierra de Guanajuato that circumscribes the Granito Comanja in response to its intrusion. After its emplacement, NW-SE normal faults were generated along the S-SE contact of the Granito Comanja, at that time El Bajío fault began. The fourth event (D4) has three phases that affected the sedimentary and volcanic Cenozoic rocks. D4F1 is marked by continental conglomerates deposition with variable thickness along of the main trace of the El Bajío fault. D4F2 affected the Oligocene volcanic rocks showing an important fault activity at that time, as evidenced the tilting above 45o in the Oligocene rocks, temporarily coincides with the triaxial extension to the Mesa Central. The direction of elongation of D4F3 is ESE-WNW, El Bajío fault had little movement. Since the Miocene the deformation was concentrated along the southern central sector of the Trans-mexican Volcanic Belt and there were few deformation in the Mesa central. During the three phases of deformation

Could the early environment of Mars have supported the development of life?

Science.gov (United States)

Mckay, Christopher P.; Stoker, Carol R.

1990-01-01

The environment of Mars and its correlation to the origin of life on earth are examined. Evidence of liquid water and nitrogen on early Mars is discussed. The similarities between the early Mars and early earth environments are described.

A glimpse into the early origins of medieval anatomy through the oldest conserved human dissection (Western Europe, 13(th) c. A.D.).

Science.gov (United States)

Charlier, Philippe; Huynh-Charlier, Isabelle; Poupon, Joël; Lancelot, Eloïse; Campos, Paula F; Favier, Dominique; Jeannel, Gaël-François; Bonati, Maurizio Rippa; de la Grandmaison, Geoffroy Lorin; Hervé, Christian

2014-05-12

Medieval autopsy practice is very poorly known in Western Europe, due to a lack of both descriptive medico-surgical texts and conserved dissected human remains. This period is currently considered the dark ages according to a common belief of systematic opposition of Christian religious authorities to the opening of human cadavers. The identification in a private collection of an autopsied human individual dated from the 13(th) century A.D. is an opportunity for better knowledge of such practice in this chrono-cultural context, i.e. the early origins of occidental dissections. A complete forensic anthropological procedure was carried out, completed by radiological and elemental analyses. The complete procedure of this body opening and internal organs exploration is explained, and compared with historical data about forensic and anatomical autopsies from this period. During the analysis, a red substance filling all arterial cavities, made of mercury sulfide (cinnabar) mixed with vegetal oil (oleic and palmitic acids) was identified; it was presumably used to highlight vascularization by coloring in red such vessels, and help in the preservation of the body. Of particular interest for the description of early medical and anatomical knowledge, this "human preparation" is the oldest known yet, and is particularly important for the fields of history of medicine, surgery and anatomical practice.

Origins of Early Adolescents' Hope: Personality, Parental Attachment, and Stressful Life Events

Science.gov (United States)

Otis, Kristin L.; Huebner, E. Scott; Hills, Kimberly J.

2016-01-01

Psychology has recently increased attention to identifying psychological qualities in individuals that indicate positive mental health, such as hope. In an effort to understand further the origins of hope, we examined the relations among parental attachment, stressful life events, personality variables, and hope in a sample of 647 middle school…

Shallow gas in Cenozoic sediments of the Southern North Sea

Science.gov (United States)

Trampe, Anna F.; Lutz, Rüdiger; Franke, Dieter; Thöle, Hauke; Arfai, Jashar

2013-04-01

Shallow petroleum systems in the southern North Sea are known for several decades but they were not actively explored for a long time. In recent years these unconventional shallow petroleum systems are studied in greater detail and one shallow gas field (A-12) is in production in the Netherlands. Additionally, oil was encountered in Miocene sandstones in the southern Danish North Sea (Lille John well) just north of the Danish-German border. Seismic amplitude anomalies are an indication for hydrocarbons in sediments. Therefore we have mapped the occurrence of seismic amplitude anomalies in the German North Sea based on more than 25.000 km of 2D seismic data and around 4.000 km2 of 3D seismic data. Amplitude anomalies are ubiquitous phenomena in the study area. These anomalies are not only caused by hydrocarbons but also by changing lithologies e.g. peat or fluid migration. Therefore several classes of seismic anomalies, e.g. bright spots, chimneys, blanking areas and velocity pull-down were mapped. Examples for these classes were studied with AVO (amplitude variation with offset) analyses to verify the existence or non-existence of gas in the sediments. Shallow gas can be produced and transported through the dense pipeline grid of the southern and central North Sea or it could be burned offshore close to wind parks in small power plants and the electric energy then transported through the existing power connections of the wind parks. Thus enabling a continuous energy supply during calm wind periods. This study is carried out within the framework of the project "Geoscientific Potential of the German North Sea (GPDN)" in which the Cenozoic sedimentary system was mapped in great detail. A detailed model of delta evolution (Baltic river system) was developed which serves as a structural framework. The studied interval is time equivalent to the Utsira formation which is used offshore Norway for sequestration of CO2. These different possibilities of using or exploiting

Factors determining early internationalization of entrepreneurial SMEs: Theoretical approach

Directory of Open Access Journals (Sweden)

Agne Matiusinaite

2015-12-01

Full Text Available Purpose – This study extends the scientific discussion of early internationalization of SMEs. The main purpose of this paper – to develop a theoretical framework to investigate factors determining early internationalization of international new ventures. Design/methodology/approach – The conceptual framework is built on the analysis and synthesis of scientific literature. Findings – This paper presents different factors, which determine early internationalization of international new ventures. These factors are divided to entrepreneurial, organizational and contextual factors. We argue that early internationalization of international new ventures is defined by entrepreneurial characteristics and previous experience of the entrepreneur, opportunities recognition and exploitation, risk tolerance, specific of the organization, involvement into networks and contextual factors. Study proved that only interaction between factors and categories has an effect for business development and successful implementation of early internationalization. Research limitations/implications – The research was conducted on the theoretical basis of scientific literature. The future studies could include a practical confirmation or denial of such allocation of factors. Originality/value – The originality of this study lies in the finding that factor itself has limited effect to early internationalization. Only the interoperability of categories and factors gives a positive impact on early internationalization of entrepreneurial SMEs.

New evidence on the origin of non-spinose pitted-cancellate species of the early Danian planktonic foraminifera

Science.gov (United States)

Arenillas, Ignacio; Arz, Jose Antonio

2013-06-01

Intermediate forms identified in some of the most continuous lower Danian sections allow a better understanding of the origin and evolution of pitted (Globanomalina) and cancellate (Praemurica) planktonic foraminifera. Both Globanomalina and Praemurica are part of a major Paleocene lineage, namely the "non-spinose lineage", which started to diverge in the early Danian. Transitional specimens strongly suggest the evolution from Parvularugoglobigerina to Globanomalina, and then to Praemurica. These evolutionary turnovers were quite rapid (probably lasting less than 10 kyr), and seem to have begun in the time equivalent of the lower part of the E. simplicissima Subzone, namely the middle part of the standard Zone Pa. The initial evolutionary trends within this non-spinose lineage were the increase of test size and lip thickness, and the evolution from tiny pore-murals to large pore-pits, and from smooth to pitted and finally cancellate walls. Biostratigraphic data suggest that evolution of the wall texture preceded the morphological evolution within each genus. The oldest species of both Globanomalina and Praemurica, namely G. archeocompressa and Pr. taurica, initially retained the external morphology of the ancestral Parvularugoglobigerina eugubina. Since their divergence, Globanomalina and Praemurica followed a separate evolutionary path, evolving into morphologically different species.

Agricultural origins on the Anatolian plateau

OpenAIRE

Baird, D.; Fairbairn, A.; Jenkins, Emma L.; Martin, L.; Middleton, C.; Pearson, J.; Asouti, E.; Edwards, Y.; Kabukcu, C.; Mustafaoğlu, G.; Russell, N.; Bar-Yosef, O.; Jacobsen, G.; Wu, X.

2018-01-01

This paper explores explanations for, and consequences of, the early appearance of food production outside the Fertile Crescent of Southwest Asia, where it had originated in the 10th/9th millennium cal BC. We present evidence that cultivation appeared in Central Anatolia through adoption by indigenous foragers in the mid 9th millennium cal BC, but also demonstrate that uptake was not uniform, and that some communities chose to actively disregard cultivation. Adoption of cultivation seems to h...

A fossil unicorn crestfish (Teleostei, Lampridiformes, Lophotidae) from the Eocene of Iran.

Science.gov (United States)

Davesne, Donald

2017-01-01

Lophotidae, or crestfishes, is a family of rare deep-sea teleosts characterised by an enlarged horn-like crest on the forehead. They are poorly represented in the fossil record, by only three described taxa. One specimen attributed to Lophotidae has been described from the pelagic fauna of the middle-late Eocene Zagros Basin, Iran. Originally considered as a specimen of the fossil lophotid † Protolophotus , it is proposed hereby as a new genus and species † Babelichthys olneyi , gen. et sp. nov., differs from the other fossil lophotids by its relatively long and strongly projecting crest, suggesting a close relationship with the modern unicorn crestfish, Eumecichthys . This new taxon increases the diversity of the deep-sea teleost fauna to which it belongs, improving our understanding of the taxonomic composition of the early Cenozoic mesopelagic ecosystems.

Polyphased Inversions of an Intracontinental Rift: Case Study of the Marrakech High Atlas, Morocco

Science.gov (United States)

Leprêtre, R.; Missenard, Y.; Barbarand, J.; Gautheron, C.; Jouvie, I.; Saddiqi, O.

2018-03-01

The High and Middle Atlas intraplate belts in Morocco correspond to Mesozoic rifted basins inverted during the Cenozoic during Africa/Eurasia convergence. The Marrakech High Atlas lies at a key location between Atlantic and Tethyan influences during the Mesozoic rifting phase but represents today high reliefs. Age and style of deformation and the mechanisms underlying the Cenozoic inversion are nevertheless still debated. To solve this issue, we produced new low-temperature thermochronology data (fission track and [U-Th]/He on apatite). Two cross sections were investigated in the western and eastern Marrakech High Atlas. Results of inverse modeling allow recognizing five cooling events attributed to erosion since Early Jurassic. Apart from a first erosional event from Middle/Late Jurassic to Early Cretaceous, four stages can be related to the convergence processes between Africa and Europe since the Late Cretaceous. Our data and thermal modeling results suggest that the inversion processes are guided at first order by the fault network inherited from the rifting episodes. The sedimentary cover and the Neogene lithospheric thinning produced a significant thermal weakening that facilitated the inversion of this ancient rift. Our data show that the Marrakech High Atlas has been behaving as a giant pop-up since the beginning of Cenozoic inversion stages.

Coevolution between human's anticancer activities and functional foods from crop origin center in the world.

Science.gov (United States)

Zeng, Ya-Wen; Du, Juan; Pu, Xiao-Ying; Yang, Jia-Zhen; Yang, Tao; Yang, Shu-Ming; Yang, Xiao-Meng

2015-01-01

Cancer is the leading cause of death around the world. Anticancer activities from many functional food sources have been reported in years, but correlation between cancer prevalence and types of food with anticancer activities from crop origin center in the world as well as food source with human migration are unclear. Hunger from food shortage is the cause of early human evolution from Africa to Asia and later into Eurasia. The richest functional foods are found in crop origin centers, housing about 70% in the world populations. Crop origin centers have lower cancer incidence and mortality in the world, especially Central Asia, Middle East, Southwest China, India and Ethiopia. Asia and Africa with the richest anticancer crops is not only the most important evolution base of humans and origin center of anticancer functional crop, but also is the lowest mortality and incidence of cancers in the world. Cancer prevention of early human migrations was associated with functional foods from crop origin centers, especially Asia with four centers and one subcenter of crop origin, accounting for 58% of the world population. These results reveal that coevolution between human's anticancer activities associated with functional foods for crop origin centers, especially in Asia and Africa.

Infection of goose with genotype VIId Newcastle disease virus of goose origin elicits strong immune responses at early stage

Directory of Open Access Journals (Sweden)

Qianqian Xu

2016-10-01

Full Text Available Newcastle disease (ND, caused by virulent strains of Newcastle disease virus (NDV, is a highly contagious disease of birds that is responsible for heavy economic losses for the poultry industry worldwide. However, little is known about host-virus interactions in waterfowl, goose. In this study, we aim to characterize the host immune response in goose, based on the previous reports on the host response to NDV in chickens. Here, we evaluated viral replication and mRNA expression of 27 immune-related genes in 10 tissues of geese challenged with a genotype VIId NDV strain of goose origin (go/CH/LHLJ/1/06. The virus showed early replication, especially in digestive and immune tissues. The expression profiles showed up-regulation of Toll-like receptor (TLR1–3, 5, 7 and 15, avian β-defensin (AvBD 5–7, 10, 12 and 16, cytokines interleukin (IL-8, IL-18, IL-1β and interferon-γ, inducible NO synthase (iNOS, and MHC class I in some tissues of geese in response to NDV. In contrast, NDV infection suppressed expression of AvBD1 in cecal tonsil of geese. Moreover, we observed a highly positive correlation between viral replication and host mRNA expressions of TLR1-5 and 7, AvBD4-6, 10 and 12, all the cytokines measured, MHC class I, FAS ligand, and iNOS, mainly at 72 h post-infection. Taken together, these results demonstrated that NDV infection induces strong innate immune responses and intense inflammatory responses at early stage in goose which may associate with the viral pathogenesis.

The Centennial of Counselor Education: Origin and Early Development of a Discipline

Science.gov (United States)

Savickas, Mark L.

2011-01-01

July 7, 2011, marks the centennial of counselor education as a formal discipline. In recognition of its 100th birthday, the author of this article describes the origins of the discipline, beginning with its prehistory in the work of Frank Parsons to establish the practice of vocational guidance, describing the 1st course in counselor education at…

The genetic origins of the Andaman Islanders

DEFF Research Database (Denmark)

Endicott, Phillip; Gilbert, M Thomas P; Stringer, Chris

2002-01-01

Mitochondrial sequences were retrieved from museum specimens of the enigmatic Andaman Islanders to analyze their evolutionary history. D-loop and protein-coding data reveal that phenotypic similarities with African pygmoid groups are convergent. Genetic and epigenetic data are interpreted as favo...... of humans through Asia. The results demonstrate that Victorian anthropological collections can be used to study extinct, or seriously admixed populations, to provide new data about early human origins....

Death Valley turtlebacks: Mesozoic contractional structures overprinted by Cenozoic extension and metamorphism beneath syn-extensional plutons

Science.gov (United States)

Pavlis, T. L.; Miller, M.; Serpa, L.

2008-07-01

The term turtleback was first coined to describe the curvilinear fault surfaces that produced a distinctive geomorphic form in the Black Mountains east of Death Valley, and although it was decades before their full significance was appreciated, they remain one of the most distinctive features of the extensional structure of the Death Valley region. Historically the interpretation of the features has varied markedly, and misconceptions about their character continue to abound, including descriptions in popular field guides for the area. It the 1990's, however, the full history of the systems began to be apparent from several key data: 1) the dating of the plutonic assemblage associated with the turtlebacks demonstrated that late Miocene, syn-extensional plutonism was fundamental to their formation; 2) the plutonic assemblage forms an intrusive sheet structurally above the turtlebacks, indicating a tie between much of the high grade metamorphism and Cenozoic plutonism; 3) a modern analog for the syn-extensional plutonism in the Black Mountains was recognized beneath Death Valley with the imaging of a mid-crustal magma body; 4) the Neogene structural history was worked out in the turtlebacks showing that folding of early-formed shear zones formed the turtleback anticlinoria but overprinting by brittle faults produced the final form as they cut obliquely across the older structure; and 5) the pre-extensional structural history was clarified, demonstrating that Mesozoic basement-involved thrust systems are present within the turtlebacks, but have been overprinted by the extensional system. An unresolved issue is the significance of Eocene U-Pb dates for pegmatites within the region, but presumably these relate somehow to the pre-extensional history. Miller and Pavlis (2005; E. Sci. Rev.) reviewed many features of the turtlebacks, and our working model for the region is that the turtlebacks originated as mid-crustal ductile-thrust systems within the Cordilleran fold

Death Valley turtlebacks: Mesozoic contractional structures overprinted by Cenozoic extension and metamorphism beneath syn-extensional plutons

Energy Technology Data Exchange (ETDEWEB)

Pavlis, T L; Serpa, L [Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 7996 (United States); Miller, M [Department of Geological Sciences, University of Oregon, Eugene, OR 97403 (United States)], E-mail: tlpavlis@utep.edu

2008-07-01

The term turtleback was first coined to describe the curvilinear fault surfaces that produced a distinctive geomorphic form in the Black Mountains east of Death Valley, and although it was decades before their full significance was appreciated, they remain one of the most distinctive features of the extensional structure of the Death Valley region. Historically the interpretation of the features has varied markedly, and misconceptions about their character continue to abound, including descriptions in popular field guides for the area. It the 1990's, however, the full history of the systems began to be apparent from several key data: 1) the dating of the plutonic assemblage associated with the turtlebacks demonstrated that late Miocene, syn-extensional plutonism was fundamental to their formation; 2) the plutonic assemblage forms an intrusive sheet structurally above the turtlebacks, indicating a tie between much of the high grade metamorphism and Cenozoic plutonism; 3) a modern analog for the syn-extensional plutonism in the Black Mountains was recognized beneath Death Valley with the imaging of a mid-crustal magma body; 4) the Neogene structural history was worked out in the turtlebacks showing that folding of early-formed shear zones formed the turtleback anticlinoria but overprinting by brittle faults produced the final form as they cut obliquely across the older structure; and 5) the pre-extensional structural history was clarified, demonstrating that Mesozoic basement-involved thrust systems are present within the turtlebacks, but have been overprinted by the extensional system. An unresolved issue is the significance of Eocene U-Pb dates for pegmatites within the region, but presumably these relate somehow to the pre-extensional history. Miller and Pavlis (2005; E. Sci. Rev.) reviewed many features of the turtlebacks, and our working model for the region is that the turtlebacks originated as mid-crustal ductile-thrust systems within the Cordilleran fold

Death Valley turtlebacks: Mesozoic contractional structures overprinted by Cenozoic extension and metamorphism beneath syn-extensional plutons

International Nuclear Information System (INIS)

Pavlis, T L; Serpa, L; Miller, M

2008-01-01

The term turtleback was first coined to describe the curvilinear fault surfaces that produced a distinctive geomorphic form in the Black Mountains east of Death Valley, and although it was decades before their full significance was appreciated, they remain one of the most distinctive features of the extensional structure of the Death Valley region. Historically the interpretation of the features has varied markedly, and misconceptions about their character continue to abound, including descriptions in popular field guides for the area. It the 1990's, however, the full history of the systems began to be apparent from several key data: 1) the dating of the plutonic assemblage associated with the turtlebacks demonstrated that late Miocene, syn-extensional plutonism was fundamental to their formation; 2) the plutonic assemblage forms an intrusive sheet structurally above the turtlebacks, indicating a tie between much of the high grade metamorphism and Cenozoic plutonism; 3) a modern analog for the syn-extensional plutonism in the Black Mountains was recognized beneath Death Valley with the imaging of a mid-crustal magma body; 4) the Neogene structural history was worked out in the turtlebacks showing that folding of early-formed shear zones formed the turtleback anticlinoria but overprinting by brittle faults produced the final form as they cut obliquely across the older structure; and 5) the pre-extensional structural history was clarified, demonstrating that Mesozoic basement-involved thrust systems are present within the turtlebacks, but have been overprinted by the extensional system. An unresolved issue is the significance of Eocene U-Pb dates for pegmatites within the region, but presumably these relate somehow to the pre-extensional history. Miller and Pavlis (2005; E. Sci. Rev.) reviewed many features of the turtlebacks, and our working model for the region is that the turtlebacks originated as mid-crustal ductile-thrust systems within the Cordilleran fold

How and why multiple MCMs are loaded at origins of DNA replication.

Science.gov (United States)

Das, Shankar P; Rhind, Nicholas

2016-07-01

Recent work suggests that DNA replication origins are regulated by the number of multiple mini-chromosome maintenance (MCM) complexes loaded. Origins are defined by the loading of MCM - the replicative helicase which initiates DNA replication and replication kinetics determined by origin's location and firing times. However, activation of MCM is heterogeneous; different origins firing at different times in different cells. Also, more MCMs are loaded in G1 than are used in S phase. These aspects of MCM biology are explained by the observation that multiple MCMs are loaded at origins. Having more MCMs at early origins makes them more likely to fire, effecting differences in origin efficiency that define replication timing. Nonetheless, multiple MCM loading raises new questions, such as how they are loaded, where these MCMs reside at origins, and how their presence affects replication timing. In this review, we address these questions and discuss future avenues of research. © 2016 WILEY Periodicals, Inc.

Checkpoint independence of most DNA replication origins in fission yeast.

Science.gov (United States)

Mickle, Katie L; Ramanathan, Sunita; Rosebrock, Adam; Oliva, Anna; Chaudari, Amna; Yompakdee, Chulee; Scott, Donna; Leatherwood, Janet; Huberman, Joel A

2007-12-19

In budding yeast, the replication checkpoint slows progress through S phase by inhibiting replication origin firing. In mammals, the replication checkpoint inhibits both origin firing and replication fork movement. To find out which strategy is employed in the fission yeast, Schizosaccharomyces pombe, we used microarrays to investigate the use of origins by wild-type and checkpoint-mutant strains in the presence of hydroxyurea (HU), which limits the pool of deoxyribonucleoside triphosphates (dNTPs) and activates the replication checkpoint. The checkpoint-mutant cells carried deletions either of rad3 (which encodes the fission yeast homologue of ATR) or cds1 (which encodes the fission yeast homologue of Chk2). Our microarray results proved to be largely consistent with those independently obtained and recently published by three other laboratories. However, we were able to reconcile differences between the previous studies regarding the extent to which fission yeast replication origins are affected by the replication checkpoint. We found (consistent with the three previous studies after appropriate interpretation) that, in surprising contrast to budding yeast, most fission yeast origins, including both early- and late-firing origins, are not significantly affected by checkpoint mutations during replication in the presence of HU. A few origins (approximately 3%) behaved like those in budding yeast: they replicated earlier in the checkpoint mutants than in wild type. These were located primarily in the heterochromatic subtelomeric regions of chromosomes 1 and 2. Indeed, the subtelomeric regions defined by the strongest checkpoint restraint correspond precisely to previously mapped subtelomeric heterochromatin. This observation implies that subtelomeric heterochromatin in fission yeast differs from heterochromatin at centromeres, in the mating type region, and in ribosomal DNA, since these regions replicated at least as efficiently in wild-type cells as in checkpoint

Checkpoint independence of most DNA replication origins in fission yeast

Science.gov (United States)

Mickle, Katie L; Ramanathan, Sunita; Rosebrock, Adam; Oliva, Anna; Chaudari, Amna; Yompakdee, Chulee; Scott, Donna; Leatherwood, Janet; Huberman, Joel A

2007-01-01

Background In budding yeast, the replication checkpoint slows progress through S phase by inhibiting replication origin firing. In mammals, the replication checkpoint inhibits both origin firing and replication fork movement. To find out which strategy is employed in the fission yeast, Schizosaccharomyces pombe, we used microarrays to investigate the use of origins by wild-type and checkpoint-mutant strains in the presence of hydroxyurea (HU), which limits the pool of deoxyribonucleoside triphosphates (dNTPs) and activates the replication checkpoint. The checkpoint-mutant cells carried deletions either of rad3 (which encodes the fission yeast homologue of ATR) or cds1 (which encodes the fission yeast homologue of Chk2). Results Our microarray results proved to be largely consistent with those independently obtained and recently published by three other laboratories. However, we were able to reconcile differences between the previous studies regarding the extent to which fission yeast replication origins are affected by the replication checkpoint. We found (consistent with the three previous studies after appropriate interpretation) that, in surprising contrast to budding yeast, most fission yeast origins, including both early- and late-firing origins, are not significantly affected by checkpoint mutations during replication in the presence of HU. A few origins (~3%) behaved like those in budding yeast: they replicated earlier in the checkpoint mutants than in wild type. These were located primarily in the heterochromatic subtelomeric regions of chromosomes 1 and 2. Indeed, the subtelomeric regions defined by the strongest checkpoint restraint correspond precisely to previously mapped subtelomeric heterochromatin. This observation implies that subtelomeric heterochromatin in fission yeast differs from heterochromatin at centromeres, in the mating type region, and in ribosomal DNA, since these regions replicated at least as efficiently in wild-type cells as in

Checkpoint independence of most DNA replication origins in fission yeast

Directory of Open Access Journals (Sweden)

Scott Donna

2007-12-01

Full Text Available Abstract Background In budding yeast, the replication checkpoint slows progress through S phase by inhibiting replication origin firing. In mammals, the replication checkpoint inhibits both origin firing and replication fork movement. To find out which strategy is employed in the fission yeast, Schizosaccharomyces pombe, we used microarrays to investigate the use of origins by wild-type and checkpoint-mutant strains in the presence of hydroxyurea (HU, which limits the pool of deoxyribonucleoside triphosphates (dNTPs and activates the replication checkpoint. The checkpoint-mutant cells carried deletions either of rad3 (which encodes the fission yeast homologue of ATR or cds1 (which encodes the fission yeast homologue of Chk2. Results Our microarray results proved to be largely consistent with those independently obtained and recently published by three other laboratories. However, we were able to reconcile differences between the previous studies regarding the extent to which fission yeast replication origins are affected by the replication checkpoint. We found (consistent with the three previous studies after appropriate interpretation that, in surprising contrast to budding yeast, most fission yeast origins, including both early- and late-firing origins, are not significantly affected by checkpoint mutations during replication in the presence of HU. A few origins (~3% behaved like those in budding yeast: they replicated earlier in the checkpoint mutants than in wild type. These were located primarily in the heterochromatic subtelomeric regions of chromosomes 1 and 2. Indeed, the subtelomeric regions defined by the strongest checkpoint restraint correspond precisely to previously mapped subtelomeric heterochromatin. This observation implies that subtelomeric heterochromatin in fission yeast differs from heterochromatin at centromeres, in the mating type region, and in ribosomal DNA, since these regions replicated at least as efficiently in wild

Tectonic regime and evolution of exogenous uranium ore formation in sedimentary rocks

International Nuclear Information System (INIS)

Danchev, V.I.; Shumlyanskij, V.A.; AN Ukrainskoj SSR, Kiev. Inst. Geokhimii i Fiziki Mineralov)

1981-01-01

Regularities of the formation and location of exogenous uranium deposits are studied depending on the tectonics regime. It is shown that the successive alternation of sedimentogenous deposits by diagenetic and, subsequently, catogene ones takes place from early Proterozoic to Cenozoic, i.e. exogenous ore formation in the history of the Earth proceeds from early to late stages of lithogenesis [ru

K-Ar ages of Early Miocene arc-type volcanoes in northern New Zealand

International Nuclear Information System (INIS)

Hayward, B.W.; Black, P.M.; Smith, I.E.M.; Ballance, P.F.; Itaya, T.; Doi, M.; Takagi, M.; Bergman, S.; Adams, C.J.; Herzer, R.H.; Robertson, D.J.

2001-01-01

Understanding the temporal and spatial development of the Early Miocene Northland Volcanic Arc is critical to interpreting the patterns of volcanic activity in northern New Zealand through the Late Cenozoic. The northwesterly trending arc is considered to have developed above a southwest-dipping subduction system. The distribution of its constituent eruptive centres is described in terms of an eastern belt that extends along the eastern side of Northland and a complementary broad western belt which includes subaerial and submarine volcanic edifices. Critical examination of all 216 K-Ar ages available, including 180 previously unpublished ages, and their assessment against tectonic, lithostratigraphic, seismic stratigraphic, and biostratigraphic constraints, leads us to deduce a detailed chronology of periods of activity for the various Early (and Middle) Miocene arc-type volcanic complexes and centres of northern New Zealand: Waipoua Shield Volcano Complex (19-18 Ma, Altonian); Kaipara Volcanic Complex (23-16 Ma, Waitakian-Altonian); Manukau Volcanic Complex (c. 23-15.5 Ma, Waitakian-Clifdenian); North Cape Volcanic Centre (23-18 Ma, Waitakian-Altonian); Whangaroa Volcanic Complex (22.5-17.5 Ma, Waitakian-Altonian); Taurikura Volcanic Complex (22-15.5 Ma, Otaian-Clifdenian); Parahaki Dacites (22.5-18 Ma, Waitakian-Altonian); Kuaotunu Volcanic Complex (18.5-11 Ma, Altonian-Waiauan). In general, volcanic activity does not show geographic migration with time, and the western (25-15.5 Ma) and eastern (23-11 Ma) belts appear to have developed concurrently. (author). 123 refs., 9 figs., 1 tab

Australian plate motion and topography linked to fossil New Guinea slab below Lake Eyre

NARCIS (Netherlands)

Schellart, W. P.; Spakman, W.

2015-01-01

Unravelling causes for absolute plate velocity change and continental dynamic topography change is challenging because of the interdependence of large-scale geodynamic driving processes. Here, we unravel a clear spatio-temporal relation between latest Cretaceous-Early Cenozoic subduction at the

An atmosphere-ocean GCM modelling study of the climate response to changing Arctic seaways in the early Cenozoic.

Science.gov (United States)

Roberts, C. D.; Legrande, A. N.; Tripati, A. K.

2008-12-01

The report of fossil Azolla (a freshwater aquatic fern) in sediments from the Lomonosov Ridge suggests low salinity conditions occurred in the Arctic Ocean in the early Eocene. Restricted passages between the Arctic Ocean and the surrounding oceans are hypothesized to have caused this Arctic freshening. We investigate this scenario using a water-isotope enabled atmosphere-ocean general circulation model with Eocene boundary conditions including 4xCO2, 7xCH4, altered bathymetry and topography, and an estimated distribution of Eocene vegetational types. In one experiment, oceanic exchange between the Arctic Ocean and other ocean basins was restricted to two shallow (~250 m) seaways, one in the North Atlantic, the Greenland-Norwegian seaway, and the second connecting the Arctic Ocean with the Tethys Ocean, the Turgai Straits. In the restricted configuration, the Greenland-Norwegian seaway was closed and exchange through the Turgai Straits was limited to a depth of ~60 m. The simulations suggest that the severe restriction of Arctic seaways in the early Eocene may have been sufficient to freshen Arctic Ocean surface waters, conducive to Azolla blooms. When exchange with the Arctic Ocean is limited, salinities in the upper several hundred meters of the water column decrease by ~10 psu. In some regions, surface salinity is within 2-3 psu of the reported maximum modern conditions tolerated by Azolla (~5 psu). In the restricted scenario, salt is stored preferentially in the North Atlantic and Tethys oceans, resulting in enhanced meridional overturning, increased poleward heat transport in the North Atlantic western boundary current, and warming of surface and intermediate waters in the North Atlantic by several degrees. Increased sensible and latent heat fluxes from the North Atlantic Ocean, combined with a reduction in cloud albedo, also lead to an increase in surface air temperature of over much of North America, Greenland and Eurasia. Our work is consistent with

Liver CT for vascular mapping during radioembolisation workup: comparison of an early and late arterial phase protocol

Energy Technology Data Exchange (ETDEWEB)

Hoven, Andor F. van den; Braat, Manon N.G.J.A.; Prince, Jip F.; Doormaal, Pieter J. van; Leeuwen, Maarten S. van; Lam, Marnix G.E.H.; Bosch, Maurice A.A.J. van den [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands)

2017-01-15

To compare right gastric (RGA) and segment 4 artery (A4) origin detection rates during radioembolisation workup between early and late arterial phase liver CT protocols. 100 consecutive patients who underwent liver CT between May 2012-January 2015 with early or late arterial phase protocol (n = 50 each, 10- vs. 20-s post-threshold delay) were included. RGA/A4 origin detection rates, assessed by two raters, and contrast-to-noise ratio (CNR) of the hepatic artery relative to the portal vein were compared between the protocols. The first-second rater scored the RGA origin as visible in 58-65 % (specific proportion of agreement 82 %, κ = 0.62); A4 origin in 96-89 % (94 %, κ = 0.54). Thirty-six percent of RGA origins not detectable by DSA were identified on CT. Origin detection rates were not significantly different for early/late arterial phases. Mean CNR was higher in the early arterial phase protocol (1.7 vs. 1.2, p < 0.001). A 10-s delay arterial phase CT protocol does not significantly improve detection of small intra- and extrahepatic branches. RGA origin detection requires further optimization, whereas A4/MHA origin detection is adequate, with good inter-rater reproducibility. CT remains important for preprocedural planning, because it may reveal arterial anatomy not discernible on DSA. (orig.)

Intra-Continental Deformation by Mid-Crustal Shearing and Doming in a Cenozoic Compressive Setting Along the Ailao Shan-Red River Shear Zone

Science.gov (United States)

Zhang, B.

2016-12-01

Large-scale lateral strike-slip shear zones have been a key point in the debate about the deformation mechanisms of Asia in response to the India-Asia collision. The exhumed gneiss has been attributed to lateral strike-slip shear zone. This hypothesis has been challenged by recent discoveries indicating that a contractional doming deformation prior to the initiation of lateral strike-slip shearing. The Cenozoic Xuelong Shan antiformal dome is located at the northern segment of the Ailao Shan-Red River shear zone. Subhorizontal foliation in the gneiss core are recognized, representing a broad top-to-NE shear initiated under amphibolite facies conditions and propagated into greenschist facies in the mantling schist and strike-slip shear zone. Quartz CPOs and opening angles of crossed girdle fabrics in quartz suggest that the deformation temperatures increased with increasing structural depth from 300-500 °C in the mantling schist to ≥650 °C in the gneissic core. This trend is mirrored by variations in the metamorphic grade of the syn-kinematic mineral assemblages and microstructures, which ranges from garnet + amphibole + biotite + sillimanite + rutite + feldspar in the core to garnet + staurolite + biotite + epidote + muscovite within the limb units. Five-stage deformation is identified: (1) a broad top-to-NE shear in the subhorizontal level (D1); (2) opposing reverse-sense shear along the two schist limbs of the dome during contraction-related doming (D2-D3); (3) sinistral strike-slip shearing within the eastern limb (D4); and (4) extensional deformation (D5). The antiformal dome formation had been roughly coeval with top-to-NE ductile shearing in the mid-crust at 32 Ma or earlier. The geometries of the antiformal dome in the Xuelong Shan dome are similar to those associated with the antiform in the Dai Nui Con Voi, Diancang Shan and Ailao Shan zones. It is likely that the complex massifs, which define a regional linear gneiss dome zone in Cenozoic intra

Environmental Adaptation from the Origin of Life to the Last Universal Common Ancestor

Science.gov (United States)

Cantine, Marjorie D.; Fournier, Gregory P.

2018-03-01

Extensive fundamental molecular and biological evolution took place between the prebiotic origins of life and the state of the Last Universal Common Ancestor (LUCA). Considering the evolutionary innovations between these two endpoints from the perspective of environmental adaptation, we explore the hypothesis that LUCA was temporally, spatially, and environmentally distinct from life's earliest origins in an RNA world. Using this lens, we interpret several molecular biological features as indicating an environmental transition between a cold, radiation-shielded origin of life and a mesophilic, surface-dwelling LUCA. Cellularity provides motility and permits Darwinian evolution by connecting genetic material and its products, and thus establishing heredity and lineage. Considering the importance of compartmentalization and motility, we propose that the early emergence of cellularity is required for environmental dispersal and diversification during these transitions. Early diversification and the emergence of ecology before LUCA could be an important pre-adaptation for life's persistence on a changing planet.

The origin of multicellularity in cyanobacteria

Science.gov (United States)

2011-01-01

Background Cyanobacteria are one of the oldest and morphologically most diverse prokaryotic phyla on our planet. The early development of an oxygen-containing atmosphere approximately 2.45 - 2.22 billion years ago is attributed to the photosynthetic activity of cyanobacteria. Furthermore, they are one of the few prokaryotic phyla where multicellularity has evolved. Understanding when and how multicellularity evolved in these ancient organisms would provide fundamental information on the early history of life and further our knowledge of complex life forms. Results We conducted and compared phylogenetic analyses of 16S rDNA sequences from a large sample of taxa representing the morphological and genetic diversity of cyanobacteria. We reconstructed ancestral character states on 10,000 phylogenetic trees. The results suggest that the majority of extant cyanobacteria descend from multicellular ancestors. Reversals to unicellularity occurred at least 5 times. Multicellularity was established again at least once within a single-celled clade. Comparison to the fossil record supports an early origin of multicellularity, possibly as early as the "Great Oxygenation Event" that occurred 2.45 - 2.22 billion years ago. Conclusions The results indicate that a multicellular morphotype evolved early in the cyanobacterial lineage and was regained at least once after a previous loss. Most of the morphological diversity exhibited in cyanobacteria today —including the majority of single-celled species— arose from ancient multicellular lineages. Multicellularity could have conferred a considerable advantage for exploring new niches and hence facilitated the diversification of new lineages. PMID:21320320

THE ORIGIN OF THE CONCEPT OF NEUROPATHIC PAIN IN EARLY MEDIEVAL PERSIA (9TH-12TH CENTURY CE).

Science.gov (United States)

Heydari, Mojtaba; Shams, Mesbah; Hashempur, Mohammad Hashem; Zargaran, Arman; Dalfardi, Behnam; Borhani-Haghighi, Afshin

2015-01-01

Neuropathic pain is supposed to be a post-renaissance described medical entity. Although it is often believed that John Fothergill (1712-1780) provided the first description of this condition in 1773, a review of the medieval Persian medical writings will show the fact that neuropathic pain was a medieval-originated concept. "Auojae Asab" [Nerve-originated Pain] was used as a medical term in medieval Persian medical literature for pain syndromes which etiologically originated from nerves. Physicians like Rhazes (d. 925 CE), Haly Abbas (d. 982 CE), Avicenna (d. 1037 CE), and Jorjani (d. 1137 CE) have discussed multiple aspects of nerve-originated pain including its classification, etiology, differentiating characteristics, different qualities, and pharmacologic and non-pharmacologic treatments. Recognizing medieval scholars' views on nerve-originated pain can lighten old historical origins of this concept.

Hands of early primates.

Science.gov (United States)

Boyer, Doug M; Yapuncich, Gabriel S; Chester, Stephen G B; Bloch, Jonathan I; Godinot, Marc

2013-12-01

Questions surrounding the origin and early evolution of primates continue to be the subject of debate. Though anatomy of the skull and inferred dietary shifts are often the focus, detailed studies of postcrania and inferred locomotor capabilities can also provide crucial data that advance understanding of transitions in early primate evolution. In particular, the hand skeleton includes characteristics thought to reflect foraging, locomotion, and posture. Here we review what is known about the early evolution of primate hands from a comparative perspective that incorporates data from the fossil record. Additionally, we provide new comparative data and documentation of skeletal morphology for Paleogene plesiadapiforms, notharctines, cercamoniines, adapines, and omomyiforms. Finally, we discuss implications of these data for understanding locomotor transitions during the origin and early evolutionary history of primates. Known plesiadapiform species cannot be differentiated from extant primates based on either intrinsic hand proportions or hand-to-body size proportions. Nonetheless, the presence of claws and a different metacarpophalangeal [corrected] joint form in plesiadapiforms indicate different grasping mechanics. Notharctines and cercamoniines have intrinsic hand proportions with extremely elongated proximal phalanges and digit rays relative to metacarpals, resembling tarsiers and galagos. But their hand-to-body size proportions are typical of many extant primates (unlike those of tarsiers, and possibly Teilhardina, which have extremely large hands). Non-adapine adapiforms and omomyids exhibit additional carpal features suggesting more limited dorsiflexion, greater ulnar deviation, and a more habitually divergent pollex than observed plesiadapiforms. Together, features differentiating adapiforms and omomyiforms from plesiadapiforms indicate increased reliance on vertical prehensile-clinging and grasp-leaping, possibly in combination with predatory behaviors in

Revised age estimates of Australopithecus-bearing deposits at Sterkfontein, South Africa.

Science.gov (United States)

Berger, Lee R; Lacruz, Rodrigo; De Ruiter, Darryl J

2002-10-01

The Sterkfontein fossil site in South Africa has produced the largest concentration of early hominin fossils from a single locality. Recent reports suggest that Australopithecus from this site is found within a broad paleontological age of between 2.5-3.5 Ma (Partridge [2000] The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 100-125; Partridge et al. [2000a], The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 129-130; Kuman and Clarke [2000] J Hum Evol 38:827-847). Specifically, the hominin fossil commonly referred to as the "Little Foot" skeleton from Member 2, which is arguably the most complete early hominin skeleton yet discovered, has been magnetostratigraphically dated to 3.30-3.33 Ma (Partridge [2000] The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 100-125; Partridge et al. [2000a], The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 129-130). More recent claims suggest that hominin fossils from the Jacovec Cavern are even older, being dated to approximately 3.5 Ma. Our interpretation of the fauna, the archeometric results, and the magnetostratigraphy of Sterkfontein indicate that it is unlikely that any Members yet described from Sterkfontein are in excess of 3.04 Ma in age. We estimate that Member 2, including the Little Foot skeleton, is younger than 3.0 Ma, and that Member 4, previously dated to between 2.4-2.8 Ma, is more likely to fall between 1.5-2.5 Ma. Our results suggest that Australopithecus africanus should not be considered as a temporal contemporary of Australopithecus afarensis, Australopithecus bahrelghazali, and Kenyanthropus platyops. Copyright 2002 Wiley-Liss, Inc.

Denan Depression controlled by northeast-directed Olongbulak Thrust Zone in northeastern Qaidam basin: Implications for growth of northern Tibetan Plateau

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Yu, Xiangjiang; Guo, Zhaojie; Zhang, Qiquan; Cheng, Xiang; Du, Wei; Wang, Zhendong; Bian, Qing

2017-10-01

The Denan Depression is a unique depression in the northeastern Qaidam basin, with a maximum Cenozoic sedimentary thickness of 5 km. Detailed field work, interpretation of seismic profiles and analyzation of well data were conducted to define the Cenozoic tectonic evolution of the northeastern Qaidam basin. All geological evidences indicate that the Denan Depression is controlled by the northeast-directed Olongbulak Thrust at its southern boundary. The Denan Depression grew in concert with the development of the northeast-directed Olongbulak Thrust at least since it began to accept the Xiaganchaigou Formation, supporting the early Cenozoic growth of the northern Tibetan Plateau. Surface and subsurface data both point to enhanced tectonic activity since the Quaternary in the northeastern Qaidam basin, leading to a more individual Denan Depression relative to the main Qaidam basin. The northern boundary of the Denan Depression is a passive boundary, and no foreland developed at the northern slope of the Denan Depression.

Universal Temporal Profile of Replication Origin Activation in Eukaryotes

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Goldar, Arach

2011-03-01

The complete and faithful transmission of eukaryotic genome to daughter cells involves the timely duplication of mother cell's DNA. DNA replication starts at multiple chromosomal positions called replication origin. From each activated replication origin two replication forks progress in opposite direction and duplicate the mother cell's DNA. While it is widely accepted that in eukaryotic organisms replication origins are activated in a stochastic manner, little is known on the sources of the observed stochasticity. It is often associated to the population variability to enter S phase. We extract from a growing Saccharomyces cerevisiae population the average rate of origin activation in a single cell by combining single molecule measurements and a numerical deconvolution technique. We show that the temporal profile of the rate of origin activation in a single cell is similar to the one extracted from a replicating cell population. Taking into account this observation we exclude the population variability as the origin of observed stochasticity in origin activation. We confirm that the rate of origin activation increases in the early stage of S phase and decreases at the latter stage. The population average activation rate extracted from single molecule analysis is in prefect accordance with the activation rate extracted from published micro-array data, confirming therefore the homogeneity and genome scale invariance of dynamic of replication process. All these observations point toward a possible role of replication fork to control the rate of origin activation.

Early Intervention in Psychosis

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McGorry, Patrick D.

2015-01-01

Abstract Early intervention for potentially serious disorder is a fundamental feature of healthcare across the spectrum of physical illness. It has been a major factor in the reductions in morbidity and mortality that have been achieved in some of the non-communicable diseases, notably cancer and cardiovascular disease. Over the past two decades, an international collaborative effort has been mounted to build the evidence and the capacity for early intervention in the psychotic disorders, notably schizophrenia, where for so long deep pessimism had reigned. The origins and rapid development of early intervention in psychosis are described from a personal and Australian perspective. This uniquely evidence-informed, evidence-building and cost-effective reform provides a blueprint and launch pad to radically change the wider landscape of mental health care and dissolve many of the barriers that have constrained progress for so long. PMID:25919380

Insights on the evolutionary origin of Detarioideae, a clade of ecologically dominant tropical African trees.

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de la Estrella, Manuel; Forest, Félix; Wieringa, Jan J; Fougère-Danezan, Marie; Bruneau, Anne

2017-06-01

African tropical forests are generally considered less diverse than their Neotropical and Asian counterparts. By contrast, the Detarioideae is much more diverse in Africa than in South America and Asia. To better understand the evolution of this contrasting diversity pattern, we investigated the biogeographical and ecological origin of this subfamily, testing whether they originated in dry biomes surrounding the Tethys Seaway as currently hypothesized for many groups of Leguminosae. We constructed the largest time-calibrated phylogeny for the subfamily to date, reconstructed ancestral states for geography and biome/habitat, estimated diversification and extinction rates, and evaluated biome/habitat and geographic shifts in Detarioideae. The ancestral habitat of Detarioideae is postulated to be a primary forest (terra firme) originated in Africa-South America, in the early Palaeocene, after which several biome/habitat and geographic shifts occurred. The origin of Detarioideae is older than previous estimates, which postulated a dry (succulent) biome origin according to the Tethys Seaway hypothesis, and instead we reveal a post Gondwana and terra firme origin for this early branching clade of legumes. Detarioideae include some of the most dominant trees in evergreen forests and have likely played a pivotal role in shaping continental African forest diversity. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Petrochemistry and origin of basalt breccia from Ban Sap Sawat area, Wichian Buri, Phetchabun, central Thailand

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Phisit Limtrakun

2013-08-01

Full Text Available Thailand is usually considered to be controlled by escape tectonics associated with India-Asia collision during theLate Cenozoic, and basaltic volcanism took place in this extensional period. This volcanism generated both subaqueous andsubaerial lava flows with tholeiitic to alkalic basaltic magma. The subaqueous eruptions represented by the studied WichianBuri basalts, Ban Sap Sawat in particular, are constituted by two main types of volcanic lithofacies, including lava flows andbasalt breccias. The lava flows are commonly porphyritic with olivine and plagioclase phenocrysts and microphenocrysts,and are uncommonly seriate textured. The basalt breccias are strongly vitrophyric texture with olivine and plagioclasephenocrysts and microphenocrysts. Chemical analyses indicate that both lava flows and basalt breccias have similar geochemical compositions, signifying that they were solidified from the same magma. Their chondrite normalized REE patternsand N-MORB normalized patterns are closely analogous to the Early to Middle Miocene tholeiites from central Sinkhote-Alinand Sakhalin, northeastern margin of the Eurasian continent which were erupted in a continental rift environment. The originfor the Wichian Buri basalts show similarity of lava flows and basalt breccias, in terms of petrography and chemical compositions, signifying that they have been formed from the same continental within-plate, transitional tholeiitic magma.

Experimental early crystallization of K-feldspar in granitic systems. Implications on the origin of magmatic fabrics in granitic rocks

Energy Technology Data Exchange (ETDEWEB)

Díaz-Alvarado, J.

2017-07-01

One of the most outstanding characteristics of some granodioritic to granitic rocks is the presence of K-feldspar megacrysts. For instance, granodiorites and monzogranites of the Spanish Central System batholith present variable amounts of large (up to 10cm in length) euhedral K-feldspar crystals. The porphyritic textures, the euhedral shape, the alignment of plagioclase and biotite inclusions and the magmatic fabrics point to a magmatic origin for these megacrysts. This work presents a phase equilibria study in a high-K2O granodioritic system. A series of experiments were conducted with a granodioritic composition (GEMbiot) to study the crystallization sequence at the emplacement conditions in the Gredos massif, i.e. 4 H2O wt.% and 0.4GPa. Experimental results show that orthopiroxene is the liquidus phase at 1010ºC, which reacts with the H2O-rich melt to stabilize biotite between 980 and 940ºC. Plagioclase crystallizes at around 910ºC, and K-feldspar crystallizes in the matrix between 750 and 700ºC when the crystal fraction is around 0.5. However, at 850 ºC, a pelite-doped experiment shows euhedral K-feldspar (≈5vol%) in both the reactive xenolith domain together with cordierite and the granodioritic domain, where the K2O wt.% rise from 4.5 in the normal experiment to 5.9 in the doped experiment. These results suggest that the bulk-assimilation process promotes the bulk and heterogeneous K2O enrichment in a huge granodioritic magma volume, which triggers an early crystallization of K-feldspar megacrysts. Because of this early crystallization of the megacrysts, the magmatic foliations defined by K-feldspar megacrysts are formed during and after the emplacement processes and are highly influenced by tectonic kinematics.

Origin of the diffuse background gamma radiation

International Nuclear Information System (INIS)

Stecker, F.W.; Puget, J.L.

1974-05-01

Recent observations have now provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV. There is some evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation were observed which provide evidence for its origin in nuclear processes in the early stages of the big-band cosmology and tie in these processes with galaxy formation theory. A crucial test of the theory may lie in future observations of the background radiation in the 100 MeV to 100 GeV energy range which may be made with large orbiting spark-chamber satellite detectors. A discussion of the theoretical interpretations of present data, their connection with baryon symmetric cosmology and galaxy formation theory, and the need for future observations are given. (U.S.)

Comparative Analysis of WUSCHEL-Related Homeobox Genes Revealed Their Parent-of-Origin and Cell Type-Specific Expression Pattern During Early Embryogenesis in Tobacco

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Xuemei Zhou

2018-03-01

Full Text Available WUSCHEL-related homeobox (WOX gene is a plant-specific clade of homeobox transcription factors. Increasing evidences reveal that WOXs play critical roles in early embryogenesis, which involves zygote development, initiation of zygote division, and apical or basal cell lineage establishment. However, how WOXs regulate these developmental events remains largely unknown, and even detailed expression pattern in gametes and early proembryos is not yet available. Here, 13 WOX family genes were identified in Nicotiana tabacum genome. Comparative analysis of 13 WOX family genes with their homologs in Arabidopsis thaliana reveals relatively conserved expression pattern of WUS and WOX5 in shoot/root apical meristem. Whereas variations were also found, e.g., lacking homolog of WOX8 (a marker for suspensor cell in tobacco genome and the expression of WOX2/WOX9 in both apical cell and basal cell. Transient transcriptional activity analysis revealed that WOXs in WUS clade have repressive activities for their target's transcription, whereas WOXs in ancient and intermediate clade have activation activities, giving a molecular basis for the phylogenetic classification of tobacco WOXs into three major clades. Expression pattern analysis revealed that some WOXs (e.g., WOX 13a expressed in both male and female gametes and some WOXs (e.g., WOX 11 and WOX 13b displayed the characteristics of parent-of-origin genes. Interestingly, some WOXs (e.g., WOX2 and WOX9, which are essential for early embryo patterning, were de novo transcribed in zygote, indicating relevant mechanism for embryo pattern formation is only established in zygote right after fertilization and not carried in by gametes. We also found that most WOXs displayed a stage-specific and cell type-specific expression pattern. Taken together, this work provides a detailed landscape of WOXs in tobacco during fertilization and early embryogenesis, which will facilitate the understanding of their specific roles

Original Research: Metabolic alterations from early life thyroxine replacement therapy in male Ames dwarf mice are transient.

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Darcy, Justin; Fang, Yimin; Hill, Cristal M; McFadden, Sam; Sun, Liou Y; Bartke, Andrzej

2016-10-01

Ames dwarf mice are exceptionally long-lived due to a Prop1 loss of function mutation resulting in deficiency of growth hormone, thyroid-stimulating hormone and prolactin. Deficiency in thyroid-stimulating hormone and growth hormone leads to greatly reduced levels of circulating thyroid hormones and insulin-like growth factor 1, as well as a reduction in insulin secretion. Early life growth hormone replacement therapy in Ames dwarf mice significantly shortens their longevity, while early life thyroxine (T4) replacement therapy does not. Possible mechanisms by which early life growth hormone replacement therapy shortens longevity include deleterious effects on glucose homeostasis and energy metabolism, which are long lasting. A mechanism explaining why early life T4 replacement therapy does not shorten longevity remains elusive. Here, we look for a possible explanation as to why early life T4 replacement therapy does not impact longevity of Ames dwarf mice. We found that early life T4 replacement therapy increased body weight and advanced the age of sexual maturation. We also find that early life T4 replacement therapy does not impact glucose tolerance or insulin sensitivity, and any deleterious effects on oxygen consumption, respiratory quotient and heat production are transient. Lastly, we find that early life T4 replacement therapy has long-lasting effects on bone mineral density and bone mineral content. We suggest that the transient effects on energy metabolism and lack of effects on glucose homeostasis are the reasons why there is no shortening of longevity after early life T4 replacement therapy in Ames dwarf mice. © 2016 by the Society for Experimental Biology and Medicine.

Origin of uranium isotope variations in early solar nebula condensates.

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Tissot, François L H; Dauphas, Nicolas; Grossman, Lawrence

2016-03-01

High-temperature condensates found in meteorites display uranium isotopic variations ((235)U/(238)U), which complicate dating the solar system's formation and whose origin remains mysterious. It is possible that these variations are due to the decay of the short-lived radionuclide (247)Cm (t 1/2 = 15.6 My) into (235)U, but they could also be due to uranium kinetic isotopic fractionation during condensation. We report uranium isotope measurements of meteoritic refractory inclusions that reveal excesses of (235)U reaching ~+6% relative to average solar system composition, which can only be due to the decay of (247)Cm. This allows us to constrain the (247)Cm/(235)U ratio at solar system formation to (1.1 ± 0.3) × 10(-4). This value provides new clues on the universality of the nucleosynthetic r-process of rapid neutron capture.

Cenozoic global sea level, sequences, and the New Jersey transect: Results from coastal plain and continental slope drilling

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Miller, K.G.; Mountain, Gregory S.; Browning, J.V.; Kominz, M.; Sugarman, P.J.; Christie-Blick, N.; Katz, M.E.; Wright, J.D.

1998-01-01

The New Jersey Sea Level Transect was designed to evaluate the relationships among global sea level (eustatic) change, unconformity-bounded sequences, and variations in subsidence, sediment supply, and climate on a passive continental margin. By sampling and dating Cenozoic strata from coastal plain and continental slope locations, we show that sequence boundaries correlate (within ??0.5 myr) regionally (onshore-offshore) and interregionally (New Jersey-Alabama-Bahamas), implicating a global cause. Sequence boundaries correlate with ??18O increases for at least the past 42 myr, consistent with an ice volume (glacioeustatic) control, although a causal relationship is not required because of uncertainties in ages and correlations. Evidence for a causal connection is provided by preliminary Miocene data from slope Site 904 that directly link ??18O increases with sequence boundaries. We conclude that variation in the size of ice sheets has been a primary control on the formation of sequence boundaries since ~42 Ma. We speculate that prior to this, the growth and decay of small ice sheets caused small-amplitude sea level changes (changes on mid-ocean ridges. Although our results are consistent with the general number and timing of Paleocene to middle Miocene sequences published by workers at Exxon Production Research Company, our estimates of sea level amplitudes are substantially lower than theirs. Lithofacies patterns within sequences follow repetitive, predictable patterns: (1) coastal plain sequences consist of basal transgressive sands overlain by regressive highstand silts and quartz sands; and (2) although slope lithofacies variations are subdued, reworked sediments constitute lowstand deposits, causing the strongest, most extensive seismic reflections. Despite a primary eustatic control on sequence boundaries, New Jersey sequences were also influenced by changes in tectonics, sediment supply, and climate. During the early to middle Eocene, low siliciclastic and

The cenozoic strike-slip faults and TTHE regional crust stability of Beishan area

International Nuclear Information System (INIS)

Guo Zhaojie; Zhang Zhicheng; Zhang Chen; Liu Chang; Zhang Yu; Wang Ju; Chen Weiming

2008-01-01

The remote sensing images and geological features of Beishan area indicate that the Altyn Tagh fault, Sanweishan-Shuangta fault, Daquan fault and Hongliuhe fault are distributed in Beishan area from south to north. The faults are all left-lateral strike-slip faults with trending of NE40-50°, displaying similar distribution pattern. The secondary branch faults are developed at the end of each main strike-slip fault with nearly east to west trending form dendritic oblique crossings at the angle of 30-50°. Because of the left-lateral slip of the branch faults, the granites or the blocks exposed within the branch faults rotate clockwisely, forming 'Domino' structures. So the structural style of Beishan area consists of the Altyn Tagh fault, Sanweishan-Shuangta fault, Daquan fault, Hongliuhe fault and their branch faults and rotational structures between different faults. Sedimentary analysis on the fault valleys in the study area and ESR chronological test of fault clay exhibit that the Sanweishan-Shuangta fault form in the late Pliocene (N2), while the Daquan fault displays formation age of l.5-1.2 Ma, and the activity age of the relevant branch faults is Late Pleistocene (400 ka). The ages become younger from the Altyn Tagh fault to the Daquan fault and strike-slip faults display NW trending extension, further revealing the lateral growth process of the strike-slip boundary at the northern margin during the Cenozoic uplift of Tibetan Plateau. The displacement amounts on several secondary faults caused by the activities of the faults are slight due to the above-mentioned structural distribution characteristics of Beishan area, which means that this area is the most stable active area with few seismic activities. We propose the main granitic bodies in Beishan area could be favorable preselected locations for China's high level radioactive waste repository. (authors)

Organic Minerals in the Origin of Life

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Benner, S.; Biondi, E.; Kim, H. J.

2017-12-01

Models for the origin of life are plagued by fundamental problems that, due to their difficulty, are called "paradoxes". One of these, known to anyone who has ever worked in a kitchen, is that organics, when given energy and left to itself, does not generate life. Rather, organics devolve to give tarry mixtures that become increasingly complex and increasingly less likely to support life (like asphalt). However, even if those mixtures escape devolution to create something useful for Darwinism, like building blocks for RNA, the water in which they must work is corrosive, leading to their destruction. Even if RNA is created, it is itself easily degraded. One current trend to manage those paradoxes turns to minerals in environments on early Earth. Inorganic minerals containing borate have now been shown to prevent the destruction of ribose (the R in RNA) and other carbohydrates essential for early Earth. Evaporite desert basins supplied with aqueous runoff from tourmaline-containing basalts are ideal environments for forming borate minerals, especially if they are made alkaline by serpentinizing peridotite. In the evaporite environments, drying cycles mitigate the destructive capability of water. Further, we have shown that phosphate is segregated from calcium (avoiding formation of relatively unreacted apatites) if magnesium and borate are present. Further, a common magnesium borophosphate (luneburgite) not only makes phosphate available for prebiotic synthesis, but selectively phosphorylates RNA building blocks as it releases borate to stabilize them against further degradation. Finally, a variety of minerals bind and stabilize RNA itself. Research in this area has also discovered organic minerals that might have been relevant to the origins of life on Earth. Such minerals are scarce on Earth today, since they are easily consumed by microbial communities. However, on a prebiotic Earth, organic minerals could have stored organic species as intermediates towards our

Extinction vs. Rapid Radiation: The Juxtaposed Evolutionary Histories of Coelotine Spiders Support the Eocene-Oligocene Orogenesis of the Tibetan Plateau.

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Zhao, Zhe; Li, Shuqiang

2017-11-01

Evolutionary biology has long been concerned with how changing environments affect and drive the spatiotemporal development of organisms. Coelotine spiders (Agelenidae: Coelotinae) are common species in the temperate and subtropical areas of the Northern Hemisphere. Their long evolutionary history and the extremely imbalanced distribution of species richness suggest that Eurasian environments, especially since the Cenozoic, are the drivers of their diversification. We use phylogenetics, molecular dating, ancestral area reconstructions, diversity, and ecological niche analyses to investigate the spatiotemporal evolution of 286 coelotine species from throughout the region. Based on eight genes (6.5 kb) and 2323 de novo DNA sequences, analyses suggest an Eocene South China origin for them. Most extant, widespread species belong to the southern (SCG) or northern (NCG) clades. The origin of coelotine spiders appears to associate with either the Paleocene-Eocene Thermal Maximum or the hot period in early Eocene. Tibetan uplifting events influenced the current diversity patterns of coelotines. The origin of SCG lies outside of the Tibetan Plateau. Uplifting in the southeastern area of the plateau blocked dispersal since the Late Eocene. Continuous orogenesis appears to have created localized vicariant events, which drove rapid radiation in SCG. North-central Tibet is the likely location of origin for NCG and many lineages likely experienced extinction owing to uplifting since early Oligocene. Their evolutionary histories correspond with recent geological evidence that high-elevation orographical features existed in the Tibetan region as early as 40-35 Ma. Our discoveries may be the first empirical evidence that links the evolution of organisms to the Eocene-Oligocene uplifting of the Tibetan Plateau. [Tibet; biogeography; ecology; molecular clock; diversification.]. © The Author(s) 2017. Published by Oxford University Press, on behalf of the Society of Systematic

Genome-wide identification and characterisation of human DNA replication origins by initiation site sequencing (ini-seq).

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Langley, Alexander R; Gräf, Stefan; Smith, James C; Krude, Torsten

2016-12-01

Next-generation sequencing has enabled the genome-wide identification of human DNA replication origins. However, different approaches to mapping replication origins, namely (i) sequencing isolated small nascent DNA strands (SNS-seq); (ii) sequencing replication bubbles (bubble-seq) and (iii) sequencing Okazaki fragments (OK-seq), show only limited concordance. To address this controversy, we describe here an independent high-resolution origin mapping technique that we call initiation site sequencing (ini-seq). In this approach, newly replicated DNA is directly labelled with digoxigenin-dUTP near the sites of its initiation in a cell-free system. The labelled DNA is then immunoprecipitated and genomic locations are determined by DNA sequencing. Using this technique we identify >25,000 discrete origin sites at sub-kilobase resolution on the human genome, with high concordance between biological replicates. Most activated origins identified by ini-seq are found at transcriptional start sites and contain G-quadruplex (G4) motifs. They tend to cluster in early-replicating domains, providing a correlation between early replication timing and local density of activated origins. Origins identified by ini-seq show highest concordance with sites identified by SNS-seq, followed by OK-seq and bubble-seq. Furthermore, germline origins identified by positive nucleotide distribution skew jumps overlap with origins identified by ini-seq and OK-seq more frequently and more specifically than do sites identified by either SNS-seq or bubble-seq. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Active Magmatic Underplating in Western Eger Rift, Central Europe

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Hrubcová, Pavla; Geissler, Wolfram H.; Bräuer, Karin; Vavryčuk, Václav; Tomek, Čestmír.; Kämpf, Horst

2017-12-01

The Eger Rift is an active element of the European Cenozoic Rift System associated with intense Cenozoic intraplate alkaline volcanism and system of sedimentary basins. The intracontinental Cheb Basin at its western part displays geodynamic activity with fluid emanations, persistent seismicity, Cenozoic volcanism, and neotectonic crustal movements at the intersections of major intraplate faults. In this paper, we study detailed geometry of the crust/mantle boundary and its possible origin in the western Eger Rift. We review existing seismic and seismological studies, provide new interpretation of the reflection profile 9HR, and supplement it by new results from local seismicity. We identify significant lateral variations of the high-velocity lower crust and relate them to the distribution and chemical status of mantle-derived fluids and to xenolith studies from corresponding depths. New interpretation based on combined seismic and isotope study points to a local-scale magmatic emplacement at the base of the continental crust within a new rift environment. This concept of magmatic underplating is supported by detecting two types of the lower crust: a high-velocity lower crust with pronounced reflectivity and a high-velocity reflection-free lower crust. The character of the underplated material enables to differentiate timing and tectonic setting of two episodes with different times of origin of underplating events. The lower crust with high reflectivity evidences magmatic underplating west of the Eger Rift of the Late Variscan age. The reflection-free lower crust together with a strong reflector at its top at depths of 28-30 km forms a magma body indicating magmatic underplating of the late Cenozoic (middle and upper Miocene) to recent. Spatial and temporal relations to recent geodynamic processes suggest active magmatic underplating in the intracontinental setting.

Bone-eating Osedax worms lived on Mesozoic marine reptile deadfalls.

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Danise, Silvia; Higgs, Nicholas D

2015-04-01

We report fossil traces of Osedax, a genus of siboglinid annelids that consume the skeletons of sunken vertebrates on the ocean floor, from early-Late Cretaceous (approx. 100 Myr) plesiosaur and sea turtle bones. Although plesiosaurs went extinct at the end-Cretaceous mass extinction (66 Myr), chelonioids survived the event and diversified, and thus provided sustenance for Osedax in the 20 Myr gap preceding the radiation of cetaceans, their main modern food source. This finding shows that marine reptile carcasses, before whales, played a key role in the evolution and dispersal of Osedax and confirms that its generalist ability of colonizing different vertebrate substrates, like fishes and marine birds, besides whale bones, is an ancestral trait. A Cretaceous age for unequivocal Osedax trace fossils also dates back to the Mesozoic the origin of the entire siboglinid family, which includes chemosynthetic tubeworms living at hydrothermal vents and seeps, contrary to phylogenetic estimations of a Late Mesozoic-Cenozoic origin (approx. 50-100 Myr). © 2015 The Author(s) Published by the Royal Society. All rights reserved.

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.

Origin of the use of the word magma in Earth Sciences

Science.gov (United States)

Gohau, , G.

1998-05-01

The word magma was originally used in pharmacy (1694), and then in chemistry (1773).It took its modern geological significance only during the XIXth century.Although it is generally considered to have been first used in geology in 1879 (Roches eruptives, by Fouque and Michel-Levy), the word was already used by Fournet as early as 1838, and soon by Durocher (1845).Both supported an igneous origin of the granite, and were opposed to the metamorphic origin interpretation which, at that time, was dominant in France.Le mot magma, issu de la pharmacie (1694), et utilise par les chimistes des 1773, ne prend son sens moderne, en geologie, qu'au XIX^e siecle.Quoiqu'on retienne habituellement la date de 1879 (Roches eruptives, par Fouque et Michel-Levy), le terme apparait en fait des 1838, chez Fournet, puis chez Durocher a partir de 1845.Partisans de l'origine ignee du granite, ces deux auteurs s'opposent a la these dominante, en France, de l'origine metamorphique.

In the Beginning was a Mutualism - On the Origin of Translation

Science.gov (United States)

Vitas, Marko; Dobovišek, Andrej

2018-04-01

The origin of translation is critical for understanding the evolution of life, including the origins of life. The canonical genetic code is one of the most dominant aspects of life on this planet, while the origin of heredity is one of the key evolutionary transitions in living world. Why the translation apparatus evolved is one of the enduring mysteries of molecular biology. Assuming the hypothesis, that during the emergence of life evolution had to first involve autocatalytic systems which only subsequently acquired the capacity of genetic heredity, we propose and discuss possible mechanisms, basic aspects of the emergence and subsequent molecular evolution of translation and ribosomes, as well as enzymes as we know them today. It is possible, in this sense, to view the ribosome as a digital-to-analogue information converter. The proposed mechanism is based on the abilities and tendencies of short RNA and polypeptides to fold and to catalyse biochemical reactions. The proposed mechanism is in concordance with the hypothesis of a possible chemical co-evolution of RNA and proteins in the origin of the genetic code or even more generally at the early evolution of life on Earth. The possible abundance and availability of monomers at prebiotic conditions are considered in the mechanism. The hypothesis that early polypeptides were folding on the RNA scaffold is also considered and mutualism in molecular evolutionary development of RNA and peptides is favoured.

A fossil unicorn crestfish (Teleostei, Lampridiformes, Lophotidae from the Eocene of Iran

Directory of Open Access Journals (Sweden)

Donald Davesne

2017-06-01

Full Text Available Lophotidae, or crestfishes, is a family of rare deep-sea teleosts characterised by an enlarged horn-like crest on the forehead. They are poorly represented in the fossil record, by only three described taxa. One specimen attributed to Lophotidae has been described from the pelagic fauna of the middle-late Eocene Zagros Basin, Iran. Originally considered as a specimen of the fossil lophotid †Protolophotus, it is proposed hereby as a new genus and species †Babelichthys olneyi, gen. et sp. nov., differs from the other fossil lophotids by its relatively long and strongly projecting crest, suggesting a close relationship with the modern unicorn crestfish, Eumecichthys. This new taxon increases the diversity of the deep-sea teleost fauna to which it belongs, improving our understanding of the taxonomic composition of the early Cenozoic mesopelagic ecosystems.

Trojan Tour and Rendezvous (TTR): A New Frontiers Mission to Explore the Origin and Evolution of the Early Solar System

Science.gov (United States)

Bell, J. F., III; Olkin, C.; Castillo, J. C.

2015-12-01

The orbital properties, compositions, and physical properties of the diverse populations of small outer solar system bodies provide a forensic map of how our solar system formed and evolved. Perhaps the most potentially diagnostic, but least explored, of those populations are the Jupiter Trojan asteroids, which orbit at ~5 AU in the L4 and L5 Lagrange points of Jupiter. More than 6200 Jupiter Trojans are presently known, but these are predicted to be only a small fraction of the 500,000 to 1 million Trojans >1 km in size. The Trojans are hypothesized to be either former Kuiper Belt Objects (KBOs) that were scattered into the inner solar system by early giant planet migration and then trapped in the 1:1 Jupiter mean motion resonance, or bodies formed near 5 AU in a much more quiescent early solar system, and then trapped at L4 and L5. The 2011 Planetary Science Decadal Survey identified important questions about the origin and evolution of the solar system that can be addressed by studying of the Trojan asteroids, including: (a) How did the giant planets and their satellite systems accrete, and is there evidence that they migrated to new orbital positions? (b) What is the relationship between large and small KBOs? Is the small population derived by impact disruption of the large one? (c) What kinds of surface evolution, radiation chemistry, and surface-atmosphere interactions occur on distant icy primitive bodies? And (d) What are the sources of asteroid groups (Trojans and Centaurs) that remain to be explored by spacecraft? The Trojan Tour and Rendezvous (TTR) is a New Frontiers-class mission designed to answer these questions, and to test hypotheses for early giant planet migration and solar system evolution. Via close flybys of a large number of these objects,, and orbital characterization of at least one large Trojan, TTR will enable the first-time exploration of this population. Our primary mission goals are to characterize the overall surface geology

Origin of the chemical elements

Energy Technology Data Exchange (ETDEWEB)

Tayler, R J

1984-05-01

The subject is discussed in relation to the composition of initially created matter and changes which have occurred during the life history of the universe, with particular reference to our galaxy and nearby galaxies. Headings are: observations of element abundances (stars, gas clouds in our own and nearby galaxies, hot gas in galaxy clusters, the solar system); the originally created matter (Big Bang theory and early nuclear reactions); processes changing observed composition (galactic evolution; nuclear fusion reactions in stellar interiors; chemical composition of a highly evolved massive star); supernovae (production of heavy elements); chemical evolution of the galaxy; production of very heavy elements (s process, r process).

Familial ethnic socialization, gender role attitudes, and ethnic identity development in Mexican-origin early adolescents.

Science.gov (United States)

Sanchez, Delida; Whittaker, Tiffany A; Hamilton, Emma; Arango, Sarah

2017-07-01

This study examined the relations between familial ethnic socialization and ethnic identity development in 438 Mexican-origin (n = 242 boys and n = 196 girls) preadolescents. In addition, machismo and marianismo gender role attitudes were examined as potential mediators in this link. Confirmatory factor analyses (CFA) of the Familial Ethnic Socialization Scale (FES), Machismo Measure (MM), Marianismo Beliefs Scale (MBS), and the Ethnic Identity Brief Scale (EISB) were conducted to test the factor structure with a preadolescent Mexican-origin sample. Separate path analyses of analytic models were then performed on boys and girls. Results of the CFAs for survey measures revealed that for the FES, a 1-factor version indicated acceptable fit; for the MM, the original 2-factor structure indicated acceptable model fit; for the MBS, a revised 3-factor version indicated acceptable model fit; and, for the EISB, the affirmation and resolution dimensions showed acceptable fit. Among boys, FES was significantly and positively linked to caballerismo, and EISB affirmation and resolution; furthermore, the links between FES and EISB affirmation and resolution were indirectly connected by caballerismo. In addition, traditional machismo was negatively linked to EISB affirmation, and caballerismo was positively linked to EISB affirmation and resolution. Among girls, FES was significantly and positively related to the MBS-virtuous/chaste pillar, and EISB affirmation and resolution. The MBS-subordinate to others pillar was negatively linked to EISB affirmation. This study underscores the importance of FES and positive gender role attitudes in the link to ethnic identity development among Mexican-origin preadolescents. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Early Microbial Evolution: The Age of Anaerobes.

Science.gov (United States)

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.

Evidence for and implications of an Early Archean terrestrial impact record

International Nuclear Information System (INIS)

Lowe, D.R.; Byerly, G.R.

1988-01-01

Early Archean, 3.5 to 3.2 Ga, greenstone sequences in South Africa and Western Australia contain a well-preserved record of early terrestrial meteorite impacts. The main impact-produced deposits are layers, 10 cm to over 1 m thick, composed largely of sand-sized spherules, 0.1 to 4 mm in diameter. The beds studied to date show an assemblage of features indicating formation by the fall of debris from impact-generated ejecta clouds. Some presented data effectively rule out normal magmatic or sedimentary processes in the origin of these units and provide substantial support for an origin by large impacts on the early earth. The presence of at least four, remarkably thick, nearly pure spherule layers suggests that smaller-scale impact deposits may be even more abundant in these sequences. The existence of a well-preserved Archean terrestrial impact record suggests that a direct source of evidence is available regarding a number of important aspects of early earth history

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).

The origins of originality: the neural bases of creative thinking and originality.

Science.gov (United States)

Shamay-Tsoory, S G; Adler, N; Aharon-Peretz, J; Perry, D; Mayseless, N

2011-01-01

Although creativity has been related to prefrontal activity, recent neurological case studies postulate that patients who have left frontal and temporal degeneration involving deterioration of language abilities may actually develop de novo artistic abilities. In this study, we propose a neural and cognitive model according to which a balance between the two hemispheres affects a major aspect of creative cognition, namely, originality. In order to examine the neural basis of originality, that is, the ability to produce statistically infrequent ideas, patients with localized lesions in the medial prefrontal cortex (mPFC), inferior frontal gyrus (IFG), and posterior parietal and temporal cortex (PC), were assessed by two tasks involving divergent thinking and originality. Results indicate that lesions in the mPFC involved the most profound impairment in originality. Furthermore, precise anatomical mapping of lesions indicated that while the extent of lesion in the right mPFC was associated with impaired originality, lesions in the left PC were associated with somewhat elevated levels of originality. A positive correlation between creativity scores and left PC lesions indicated that the larger the lesion is in this area the greater the originality. On the other hand, a negative correlation was observed between originality scores and lesions in the right mPFC. It is concluded that the right mPFC is part of a right fronto-parietal network which is responsible for producing original ideas. It is possible that more linear cognitive processing such as language, mediated by left hemisphere structures interferes with creative cognition. Therefore, lesions in the left hemisphere may be associated with elevated levels of originality. Copyright © 2010 Elsevier Ltd. All rights reserved.

Andean Basin Evolution Associated with Hybrid Thick- and Thin-Skinned Deformation in the Malargüe Fold-Thrust Belt, Western Argentina

Science.gov (United States)

Horton, B. K.; Fuentes, F.

2015-12-01

Andean deformation and basin evolution in the Malargüe fold-thrust belt of western Argentina (34-36°S) has been dominated by basement faults influenced by pre-existing Mesozoic rift structures of the hydrocarbon-rich Neuquen basin. However, the basement structures diverge from classic inversion structures, and the associated retroarc basin system shows a complex Mesozoic-Cenozoic history of mixed extension and contraction, along with an enigmatic early Cenozoic stratigraphic hiatus. New results from balanced structural cross sections (supported by industry seismic, well data, and surface maps), U-Pb geochronology, and foreland deposystem analyses provide improved resolution to examine the duration and kinematic evolution of Andean mixed-mode deformation. The basement structures form large anticlines with steep forelimbs and up to >5 km of structural relief. Once the propagating tips of the deeper basement faults reached cover strata, they fed slip to shallow thrust systems that were transported in piggyback fashion by newly formed basement structures, producing complex structural relationships. Detrital zircon U-Pb ages for the 5-7 km-thick basin fill succession reveal shifts in sedimentation pathways and accumulation rates consistent with (1) local basement sources during Early-Middle Jurassic back-arc extension, (2) variable cratonic and magmatic arc sources during Late Jurassic-Cretaceous postrift thermal subsidence, and (3) Andean arc and thrust-belt sources during irregular Late Cretaceous-Cenozoic shortening. Although pulses of flexural subsidence can be attributed to periods of fault reactivation (inversion) and geometrically linked thin-skinned thrusting, fully developed foreland basin conditions were only achieved in Late Cretaceous and Neogene time. Separating these two contractional episodes is an Eocene-lower Miocene (roughly 40-20 Ma) depositional hiatus within the Cenozoic succession, potentially signifying forebulge passage or neutral to

Zircon (U-Th)/He Thermochronometric Constraints on Himalayan Thrust Belt Exhumation, Bedrock Weathering, and Cenozoic Seawater Chemistry

Science.gov (United States)

Colleps, Cody L.; McKenzie, N. Ryan; Stockli, Daniel F.; Hughes, Nigel C.; Singh, Birendra P.; Webb, A. Alexander G.; Myrow, Paul M.; Planavsky, Noah J.; Horton, Brian K.

2018-01-01

Shifts in global seawater 187Os/188Os and 87Sr/86Sr are often utilized as proxies to track global weathering processes responsible for CO2 fluctuations in Earth history, particularly climatic cooling during the Cenozoic. It has been proposed, however, that these isotopic records instead reflect the weathering of chemically distinctive Himalayan lithologies exposed at the surface. We present new zircon (U-Th)/He thermochronometric and detrital zircon U-Pb geochronologic evidence from the Himalaya of northwest India to explore these contrasting interpretations concerning the driving mechanisms responsible for these seawater records. Our data demonstrate in-sequence southward thrust propagation with rapid exhumation of Lesser Himalayan strata enriched in labile 187Os and relatively less in radiogenic 87Sr at ˜16 Ma, which directly corresponds with coeval shifts in seawater 187Os/188Os and 87Sr/86Sr. Results presented here provide substantial evidence that the onset of exhumation of 187Os-enriched Lesser Himalayan strata could have significantly impacted the marine 187Os/188Os record at 16 Ma. These results support the hypothesis that regional weathering of isotopically unique source rocks can drive seawater records independently from shifts in global-scale weathering rates, hindering the utility of these records as reliable proxies to track global weathering processes and climate in deep geologic time.

Partial axillary dissection in early breast cancer

African Journals Online (AJOL)

Tarek Abdel Halim El-Fayoumi

ORIGINAL ARTICLE. Partial axillary dissection in early breast cancer. Tarek Abdel Halim El-Fayoumi *. Department of General Surgery, Faculty of Medicine, Alexandria University, Egypt. Received 16 October 2012; accepted 7 January 2013. Available online 7 March 2013. KEYWORDS. Breast cancer;. Axillary lymph nodes.

Energy sources, self-organization, and the origin of life.

Science.gov (United States)

Boiteau, Laurent; Pascal, Robert

2011-02-01

The emergence and early developments of life are considered from the point of view that contingent events that inevitably marked evolution were accompanied by deterministic driving forces governing the selection between different alternatives. Accordingly, potential energy sources are considered for their propensity to induce self-organization within the scope of the chemical approach to the origin of life. Requirements in terms of quality of energy locate thermal or photochemical activation in the atmosphere as highly likely processes for the formation of activated low-molecular weight organic compounds prone to induce biomolecular self-organization through their ability to deliver quanta of energy matching the needs of early biochemical pathways or the reproduction of self-replicating entities. These lines of reasoning suggest the existence of a direct connection between the free energy content of intermediates of early pathways and the quanta of energy delivered by available sources of energy.

Efficient Identification of miRNAs for Classification of Tumor Origin

DEFF Research Database (Denmark)

Søkilde, Rolf; Vincent, Martin; Møller, Anne K

2014-01-01

Carcinomas of unknown primary origin constitute 3% to 5% of all newly diagnosed metastatic cancers, with the primary source difficult to classify with current histological methods. Effective cancer treatment depends on early and accurate identification of the tumor; patients with metastases...... of unknown origin have poor prognosis and short survival. Because miRNA expression is highly tissue specific, the miRNA profile of a metastasis may be used to identify its origin. We therefore evaluated the potential of miRNA profiling to identify the primary tumor of known metastases. Two hundred eight...... formalin-fixed, paraffin-embedded samples, representing 15 different histologies, were profiled on a locked nucleic acid-enhanced microarray platform, which allows for highly sensitive and specific detection of miRNA. On the basis of these data, we developed and cross-validated a novel classification...

Gristhorpe Man: an Early Bronze Age log-coffin burial scientifically defined

DEFF Research Database (Denmark)

Melton, Nigel; Montgomery, Janet; Knüsel, Christopher J.

2010-01-01

A log-coffin excavated in the early nineteenth century proved to be well enough preserved in the early twenty-first century for the full armoury of modern scientific investigation to give its occupants and contents new identity, new origins and a new date. In many ways the interpretation is much ...

Hot origin of the Little Bang

Energy Technology Data Exchange (ETDEWEB)

Akkelin, S.V. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, ExtreMe Matter Institute EMMI, Darmstadt (Germany)

2017-12-15

Ultrarelativistic heavy ion collisions produce a quark-gluon matter which lies in the future light cone originating from given points on the t = z = 0 plane of the Minkowski spacetime manifold. We show that in a weak coupling regime the Minkowski vacuum of massless fields presents itself in the ''Little Bang'' region as a thermal state of low p{sub T} particles, in close analogy to the Unruh effect for uniformly accelerated observers which are causally restricted to a Rindler wedge. It can shed some light on the mechanisms of early time thermalization in ultrarelativistic heavy ion collisions. (orig.)

Thermodynamic inversion origin of living systems

CERN Document Server

Kompanichenko, Vladimir N

2017-01-01

This book discusses the theory, general principles, and energy source conditions allowing for the emergence of life in planetary systems. The author examines the material conditions found in natural hydrothermal sites, the appropriate analogs of prebiotic environments on early Earth. He provides an overview of current laboratory experiments in prebiotic materials chemistry and substantiation of a new direction for the experiments in the origin of life field. Describes thermodynamic inversion and how it relates to the living cell; Examines the current direction of experiments on prebiotic materials chemistry; Introduces and substantiates necessary conditions for the emergence of life.

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.

Complementary feeding and the early origins of obesity risk: a study protocol

OpenAIRE

Muniandy, Naleena Devi; Allotey, Pascale A; Soyiri, Ireneous N; Reidpath, Daniel D

2016-01-01

Introduction The rise in the prevalence of childhood obesity worldwide calls for an intervention earlier in the life cycle. Studies show that nutrition during early infancy may contribute to later obesity. Hence, this study is designed to determine if the variation in complementary feeding practices poses a risk for the development of obesity later in life. A mixed methods approach will be used in conducting this study. Methods and analysis The target participants are infants born from Januar...

Correlation and origin of carnotite occurrences in the southern Nevada region

International Nuclear Information System (INIS)

Johnson, C.L.

1982-01-01

Carnotite [K 2 (UO 2 ) 2 (VO 4 ) 2 .3H 2 O] is recognized at seven localities in the southern Nevada region. These general areas of occurrence are the Jean-Sloan Calcrete, Hidden Valley Calcrete, Hualapai Limestone, Boulder City ''fossil water table'', Horse Spring Formation type locality, Mormon Mesa Caliche, and exposures of the Willow Tank thrust fault. The carnotite occurrences pre-date the 3.80 MY (million years before present) basalt at Sandy Pint, post-date an 8.66 MY tuff that underlies the Hualapai Limestone, and are approximately coeval with the 5.84 MY Fortification Basalt. Analysis of the Th/U ratios from 2045 dry stream sediment samples collected during the National Uranium Resource Evaluation (NURE) Program indicates uranium depletion in Precambrian terrain of the region and enrichment in areas where carnotite is observed. Anomalous vanadium in dry stream sediment samples is associated with intermediate and mafic Cenozoic volcanic rocks of pre-Colorado River age, and to a lesser extent with uratic Precambrian rocks. Correlation of the Jean-Sloan Calcrete, Hidden Valley Calcrete, Mormon Mesa Caliche, Hualapai Limestone, and Boulder City ''fossil water table'' is proposed based on elevation, relief, and inferred common age and origin. Carnotite studies have provided recognition criteria for facies of a regional geomorphic surface that formed in association with sluggish shallow groundwater flow in axial drainage systems in the Late Miocene. Carnotite and gypsum were deposited in disrupted by normal faulting and climatic conditions become increasingly arid 5-6 MY ago. Major geologic events that approximately coincide with the formation of the carnotite occurrences include the Messinian Crisis, opening of the Gulf of California, and uplift of the Sierra Nevada

Multiple determinants controlling activation of yeast replication origins late in S phase.

Science.gov (United States)

Friedman, K L; Diller, J D; Ferguson, B M; Nyland, S V; Brewer, B J; Fangman, W L

1996-07-01

Analysis of a 131-kb segment of the left arm of yeast chromosome XIV beginning 157 kb from the telomere reveals four highly active origins of replication that initiate replication late in S phase. Previous work has shown that telomeres act as determinants for late origin activation. However, at least two of the chromosome XIV origins maintain their late activation time when located on large circular plasmids, indicating that late replication is independent of telomeres. Analysis of the replication time of plasmid derivatives containing varying amounts of chromosome XIV DNA show that a minimum of three chromosomal elements, distinct from each tested origin, contribute to late activation time. These late determinants are functionally equivalent, because duplication of one set of contributing sequences can compensate for the removal of another set. Furthermore, insertion of an origin that is normally early activated into this domain results in a shift to late activation, suggesting that the chromosome XIV origins are not unique in their ability to respond to the late determinants.

The pre-Cenozoic evolution of the Apuseni Mountains (Romania) in the light of new (thermo)geochronological data

Science.gov (United States)

Reiser, Martin; Schuster, Ralf; Spikings, Richard; Tropper, Peter; Fügenschuh, Bernhard

2013-04-01

, although a possible minor influence of later normal faulting on the age distribution cannot be fully excluded and needs further evaluation. In contrast, fission track data show only minor differences between these two units (see Kounov and Schmid, 2012) and point to their mutual evolution since the late Upper Cretaceous. The known and exclusively brittle Cenozoic tectonic evolution did not substantially modify the pre-Cenozoic age (and thermal) pattern of the Tisza and Dacia units. References: Dallmeyer, R.D., Paná, D.I., Neubauer, F., & Erdmer, P. (1999): Tectonothermal Evolution of the Apuseni Mountains, Romania: Resolution of Variscan versus Alpine Events with 40Ar/39Ar Ages. Journal of Geology, 107: 329-352. Kounov, A and Schmid, S.M. (2012): Fission-track constraints on the thermal and tectonic evolution of the Apuseni Mountains (Romania). International Journal of Earth Sciences, DOI: 10.1007/s00531-012-0800-5. Schmid, S. M., D. Bernoulli, B. Fügenschuh, L. Matenco, S. Schaefer, R. Schuster, M. Tischler and K. Ustaszewski (2008): The Alps-Carpathians-Dinaridic orogenic system: correlation and evolution of tectonic units. Swiss Journal of Geosciences, 101, 139-18.

Possible evolutionary origins of cognitive brain lateralization.

Science.gov (United States)

Vallortigara, G; Rogers, L J; Bisazza, A

1999-08-01

Despite the substantial literature on the functional architecture of the asymmetries of the human brain, which has been accumulating for more than 130 years since Dax and Broca's early reports, the biological foundations of cerebral asymmetries are still poorly understood. Recent advances in comparative cognitive neurosciences have made available new animal models that have started to provide unexpected insights into the evolutionary origins and neuronal mechanisms of cerebral asymmetries. Animal model-systems, particularly those provided by the avian brain, highlight the interrelations of genetic, hormonal and environmental events to produce neural and behavioural asymmetries. Novel evidences showing that functional and structural lateralization of the brain is widespread among vertebrates (including fish, reptiles and amphibians) have accumulated rapidly. Perceptual asymmetries, in particular, seem to be ubiquitous in everyday behaviour of most species of animals with laterally placed eyes; in organisms with wider binocular overlap (e.g., amphibians), they appear to be retained for initial detection of stimuli in the extreme lateral fields. We speculate that adjustment of head position and eye movements may play a similar role in mammals with frontal vision as does the choice for right or left lateral visual fields in animals with laterally placed eyes. A first attempt to trace back the origins of brain asymmetry to early vertebrates is presented, based on the hypothesis that functional incompatibility between the logical demands associated with very basic cognitive functions is central to the phenomenon of cerebral lateralization.

Origin and implications of a thrust-bound gypsiferous unit along the western edge of Jabal Sumeini, northern Oman Mountains

Science.gov (United States)

Cooper, David J. W.; Ali, Mohammed Y.; Searle, Michael P.

2018-04-01

The Oman Mountains comprise a series of thrust sheets of Neo-Tethyan oceanic rocks that were emplaced onto the Arabian continental margin during obduction of the Semail Ophiolite during the Late Cretaceous. Three separate groups of anomalous gypsiferous bodies intrude the allochthonous units along faults over a distance of about 150 km in the Hawasina Window, Jabal Qumayrah and Jabal Sumeini. The bodies at Jabal Sumeini form a band about 4 km long and up to 100 m wide along a late-stage thrust that restacks the allochthon over a post-emplacement Maastrichtian-Palaeogene sedimentary succession. The gypsum shows evidence of flow-folding and contains numerous clasts and rafts of a range of quartzose sandstones, but with only a minor component from carbonates from the Neo-Tethyan Sumeini Group in the hanging-wall. Palaeogene limestones from the footwall succession are essentially absent. Strontium isotope ratios are high and intersect with the open ocean-water reference curve for the Late Cambrian-Ordovician and Late Miocene-Pliocene. They are also noticeably higher than the ratios from the two other gypsiferous outcrop areas in the Oman Mountains and from outcrops of Ediacaran-Early Cambrian salt domes in central Oman. However, the regional stratigraphy points towards a source of the gypsum from either an Ediacaran-Early Cambrian Ara Group salt basin or from the Lower Fars Formation (Early-Middle Miocene), and derivation of the sandstone clasts and rafts from thick Lower Palaeozoic clastic sequences. The discrepancy with the ages inferred from the strontium isotope data can be attributed to deposition of the gypsum in restricted conditions not in equilibrium with the prevailing ocean water. Two models are presented, for an Ediacaran-Early Cambrian and an Early-Middle Miocene source. While the latter cannot be wholly discounted, the stratigraphic and structural context point more strongly towards an Ediacaran-Early Cambrian Ara Group source of the gypsum. This was

Evidence for Late Triassic provenance areas and Early Jurassic sediment supply turnover in the Barents Sea Basin of northern Pangea

Czech Academy of Sciences Publication Activity Database

Klausen, T. G.; Müller, R.; Sláma, Jiří; Helland-Hansen, W.

2017-01-01

Roč. 9, č. 1 (2017), s. 14-28 ISSN 1941-8264 Institutional support: RVO:67985831 Keywords : U-Pb geochronology * detrial zircon * Cenozoic evolution * rocks * metamorphism Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 2.662, year: 2016

Origin and radiation of the earliest vascular land plants.

Science.gov (United States)

Steemans, Philippe; Hérissé, Alain Le; Melvin, John; Miller, Merrell A; Paris, Florentin; Verniers, Jacques; Wellman, Charles H

2009-04-17

Colonization of the land by plants most likely occurred in a stepwise fashion starting in the Mid-Ordovician. The earliest flora of bryophyte-like plants appears to have been cosmopolitan and dominated the planet, relatively unchanged, for some 30 million years. It is represented by fossilized dispersed cryptospores and fragmentary plant remains. In the Early Silurian, cryptospore abundance and diversity diminished abruptly as trilete spores appeared, became abundant, and underwent rapid diversification. This change coincides approximately with the appearance of vascular plant megafossils and probably represents the origin and adaptive radiation of vascular plants. We have obtained a diverse trilete spore occurrence from the Late Ordovician that suggests that vascular plants originated and diversified earlier than previously hypothesized, in Gondwana, before migrating elsewhere and secondarily diversifying.

Himalayan origin and evolution of Myricaria (Tamaricaeae in the neogene.

Directory of Open Access Journals (Sweden)

Ming-Li Zhang

Full Text Available BACKGROUND: Myricaria consists of about twelve-thirteen species and occurs in Eurasian North Temperate zone, most species in the Qinghai-Tibet Plateau (QTP and adjacent areas. METHODOLOGY/PRINCIPAL FINDINGS: Twelve species of Myricaria plus two other genera Tamarix and Reaumuria in Tamaricaceae, were sampled, and four markers, ITS, rps16, psbB-psbH, and trnL-trnF were sequenced. The relaxed Bayesian molecular clock BEAST method was used to perform phylogenetic analysis and molecular dating, and Diva, S-Diva, and maximum likelihood Lagrange were used to estimate the ancestral area. The results indicated that Myricaria could be divided into four phylogenetic clades, which correspond to four sections within the genus, of them two are newly described in this paper. The crown age of Myricaria was dated to early Miocene ca. 20 Ma, at the probable early uplifting time of the Himalayas. The Himalayas were also shown as the center of origin for Myricaria from the optimization of ancestral distribution. Migration and dispersal of Myricaria were indicated to have taken place along the Asian Mountains, including the Himalayas, Kunlun, Altun, Hendukosh, Tianshan, Altai, and Caucasus etc., westward to Europe, eastward to Central China, and northward to the Mongolian Plateau. CONCLUSIONS/SIGNIFICANCE: Myricaria spatiotemporal evolution presented here, especially the Himalayan origin at early Miocene ca. 20 Ma, and then migrated westward and eastward along the Asian mountains, offers a significant evolutionary case for QTP and Central Asian biogeography.

The origin of diverse α-element abundances in galaxy discs

Science.gov (United States)

Mackereth, J. Ted; Crain, Robert A.; Schiavon, Ricardo P.; Schaye, Joop; Theuns, Tom; Schaller, Matthieu

2018-04-01

Spectroscopic surveys of the Galaxy reveal that its disc stars exhibit a spread in [α/Fe] at fixed [Fe/H], manifest at some locations as a bimodality. The origin of these diverse, and possibly distinct, stellar populations in the Galactic disc is not well understood. We examine the Fe and α-element evolution of 133 Milky Way-like galaxies from the EAGLE simulation, to investigate the origin and diversity of their [α/Fe]-[Fe/H] distributions. We find that bimodal [α/Fe] distributions arise in galaxies whose gas accretion histories exhibit episodes of significant infall at both early and late times, with the former fostering more intense star formation than the latter. The shorter characteristic consumption timescale of gas accreted in the earlier episode suppresses its enrichment with iron synthesised by Type Ia SNe, resulting in the formation of a high-[α/Fe] sequence. We find that bimodality in [α/Fe] similar to that seen in the Galaxy is rare, appearing in approximately 5 percent of galaxies in our sample. We posit that this is a consequence of an early gas accretion episode requiring the mass accretion history of a galaxy's dark matter halo to exhibit a phase of atypically-rapid growth at early epochs. The scarcity of EAGLE galaxies exhibiting distinct sequences in the [α/Fe]-[Fe/H] plane may therefore indicate that the Milky Way's elemental abundance patterns, and its accretion history, are not representative of the broader population of ˜L⋆ disc galaxies.

The evolution and ascent paths of mantle xenolith-bearing magma: Observations and insights from Cenozoic basalts in Southeast China

Science.gov (United States)

Sun, Pu; Niu, Yaoling; Guo, Pengyuan; Cui, Huixia; Ye, Lei; Liu, Jinju

2018-06-01

Studies have shown that mantle xenolith-bearing magmas must ascend rapidly to carry mantle xenoliths to the surface. It has thus been inferred inadvertently that such rapid ascending melt must have undergone little crystallization or evolution. However, this inference is apparently inconsistent with the widespread observation that xenolith-bearing alkali basalts are variably evolved with Mg# ≤72. In this paper, we discuss this important, yet overlooked, petrological problem and offer new perspectives with evidence. We analyzed the Cenozoic mantle xenolith-bearing alkali basalts from several locations in Southeast China that have experienced varying degrees of fractional crystallization (Mg# = 48-67). The variably evolved composition of host alkali basalts is not in contradiction with rapid ascent, but rather reflects inevitability of crystallization during ascent. Thermometry calculations for clinopyroxene (Cpx) megacrysts give equilibrium temperatures of 1238-1390 °C, which is consistent with the effect of conductive cooling and melt crystallization during ascent because TMelt > TLithosphere. The equilibrium pressure (18-27 kbar) of these Cpx megacrysts suggests that the crystallization takes place under lithospheric mantle conditions. The host melt must have experienced limited low-pressure residence in the shallower levels of lithospheric mantle and crust. This is in fact consistent with the rapid ascent of the host melt to bring mantle xenoliths to the surface.

A Review of Ideas Concerning Life Origin

Science.gov (United States)

Gindilis, L. M.

2014-10-01

Since the times of Antiquity the and for a long time the idea of self-origination of life was the dominant one. It reappeared again after microorganisms were discovered (XVII century). The possibility of abiogenesis at microbial level was discussed for more than a century. Pateur demonstrated that spontaneous origination of microorganisms in sterile broth was due to those same microorganisms transported by dust particles. Thus proving that every form of life originates from the parental life form. So the question arises: how did the first microorganisms appear on the Earth. There are three possible versions: 1) accidental origination of a viable form; 2) primal organisms were transported to the Earth from outer space; 3) they were formed on the Earth in the process of prebiotic chemical evolution. We discuss the problems of prebiotic evolution from simple monomers up to living cells. An important item of nowadays conceptions of life origination is the hypothesis of the ancient world of RNA as possible precursor of life on Earth. The discovery in carbonaceous chondrites of traces of bacterial life evidences the existence of life in the Solar System even before the formation of the Earth. The idea of life as brought to the Earth out of Cosmos originated under the impression of self-origination hypothesis downfall. It went through several stages (Helmholtz, W. Thompson, XIX century; Arrhenius, early XX century; Hoyle and Wickramasinghe, second half of XX century) and presently evokes constantly growing interest. The panspermia theory does not solve the problem of origination of life, only moves it onto other planets. According to V.A. Mazur, the probability of accidental formation of RNA molecule is negligible not only on the Earth, but in the whole Universe over all the time span of its existence. But it is practically equal to unit in the domain formed at the inflation stage of the evolution of the Universe. A.D.Panov considered panspermia in the Galaxy at the level

The ACS LCID Project: On the Origin of Dwarf Galaxy Types—A Manifestation of the Halo Assembly Bias?

NARCIS (Netherlands)

Gallart, Carme; Monelli, Matteo; Mayer, Lucio; Aparicio, Antonio; Battaglia, Giuseppina; Bernard, Edouard J.; Cassisi, Santi; Cole, Andrew A.; Dolphin, Andrew E.; Drozdovsky, Igor; Hidalgo, Sebastian L.; Navarro, Julio F.; Salvadori, Stefania; Skillman, Evan D.; Stetson, Peter B.; Weisz, Daniel R.

2015-01-01

We discuss how knowledge of the whole evolutionary history of dwarf galaxies, including details on the early star formation events, can provide insight on the origin of the different dwarf galaxy types. We suggest that these types may be imprinted by the early conditions of formation rather than

Charles Darwin and the origin of life.

Science.gov (United States)

Peretó, Juli; Bada, Jeffrey L; Lazcano, Antonio

2009-10-01

When Charles Darwin published The Origin of Species 150 years ago he consciously avoided discussing the origin of life. However, analysis of some other texts written by Darwin, and of the correspondence he exchanged with friends and colleagues demonstrates that he took for granted the possibility of a natural emergence of the first life forms. As shown by notes from the pages he excised from his private notebooks, as early as 1837 Darwin was convinced that "the intimate relation of Life with laws of chemical combination, & the universality of latter render spontaneous generation not improbable". Like many of his contemporaries, Darwin rejected the idea that putrefaction of preexisting organic compounds could lead to the appearance of organisms. Although he favored the possibility that life could appear by natural processes from simple inorganic compounds, his reluctance to discuss the issue resulted from his recognition that at the time it was possible to undertake the experimental study of the emergence of life.

Geographical origin: meaningful reference or marketing tool?

DEFF Research Database (Denmark)

Hedegaard, Liselotte

2015-01-01

dimensions of local culture. The French label served as inspiration for the European PDO/PGI-labels, but even if these labels are known in Denmark only five products are PDO-branded The data-collection in Denmark indicated little trust in increased sales through PDO-labelling. This was contrary to data...... of production can be positioned on a map, but there is no precise standard for the rootedness of the product in this place. Origin means to be from a place in the sense that natural factors, cultural practices and historical links contribute to the understanding of the link between food and place...... origin was the result of a crisis in French wine-production in the early 20th century. Labelling was intended to protect the reputation of a product in terms of quality and taste by referring to parcels of land where specific traditions are maintained and the resulting products embedded in collective...

Identification and origin of a subsurface ridge on the continental margin of western India

Digital Repository Service at National Institute of Oceanography (India)

Krishna, K.S.; Murty, G.P.S.; Rao, D.G.

of magnetic polarity reversals is marked along 15~'10'N. Further it is conjectured that these ridges probably originated because of the movement of the Indian Plate over the Reunion hotspot, during the Late Cretaceous and Early Tertiary...

The origin of the chemical elements

International Nuclear Information System (INIS)

Tayler, R.J.

1984-01-01

The subject is discussed in relation to the composition of initially created matter and changes which have occurred during the life history of the universe, with particular reference to our galaxy and nearby galaxies. Headings are: observations of element abundances (stars, gas clouds in our own and nearby galaxies, hot gas in galaxy clusters, the solar system); the originally created matter (Big Bang theory and early nuclear reactions); processes changing observed composition (galactic evolution; nuclear fusion reactions in stellar interiors; chemical composition of a highly evolved massive star); supernovae (production of heavy elements); chemical evolution of the galaxy; production of very heavy elements (s process, r process). (U.K.)

Acceptable losses: the debatable origins of loss aversion.

Science.gov (United States)

Yechiam, Eldad

2018-04-16

It is often claimed that negative events carry a larger weight than positive events. Loss aversion is the manifestation of this argument in monetary outcomes. In this review, we examine early studies of the utility function of gains and losses, and in particular the original evidence for loss aversion reported by Kahneman and Tversky (Econometrica  47:263-291, 1979). We suggest that loss aversion proponents have over-interpreted these findings. Specifically, the early studies of utility functions have shown that while very large losses are overweighted, smaller losses are often not. In addition, the findings of some of these studies have been systematically misrepresented to reflect loss aversion, though they did not find it. These findings shed light both on the inability of modern studies to reproduce loss aversion as well as a second literature arguing strongly for it.

The origin of early age expansions induced in cementitious materials containing shrinkage reducing admixtures

International Nuclear Information System (INIS)

Sant, Gaurav; Lothenbach, Barbara; Juilland, Patrick; Le Saout, Gwenn; Weiss, Jason; Scrivener, Karen

2011-01-01

Studies on the early-age shrinkage behavior of cement pastes, mortars, and concretes containing shrinkage reducing admixtures (SRAs) have indicated these mixtures frequently exhibit an expansion shortly after setting. While the magnitude of the expansion has been noted to be a function of the chemistry of the cement and the admixture dosage; the cause of the expansion is not clearly understood. This investigation uses measurements of autogenous deformation, X-ray diffraction, pore solution analysis, thermogravimetry, and scanning electron microscopy to study the early-age properties and describe the mechanism of the expansion in OPC pastes made with and without SRA. The composition of the pore solution indicates that the presence of the SRA increases the portlandite oversaturation level in solution which can result in higher crystallization stresses which could lead to an expansion. This observation is supported by deformation calculations for the systems examined.

Developmental origins of adult health and disease: the role of periconceptional and foetal nutrition.

Science.gov (United States)

McMillen, I Caroline; MacLaughlin, Severence M; Muhlhausler, Beverly S; Gentili, Sheridan; Duffield, Jaime L; Morrison, Janna L

2008-02-01

The 'developmental origins of adult health and disease' hypothesis stated that environmental factors, particularly maternal undernutrition, act in early life to programme the risks for adverse health outcomes, such as cardiovascular disease, obesity and the metabolic syndrome in adult life. Early physiological tradeoffs, including activation of the foetal hypothalamo-pituitary-adrenal (HPA) axis, confer an early fitness advantage such as foetal survival, while incurring delayed health costs. We review the evidence that such tradeoffs are anticipated from conception and that the periconceptional nutritional environment can programme the developmental trajectory of the stress axis and the systems that maintain and regulate arterial blood pressure. There is also evidence that restriction of placental growth and function, results in an increased dependence of the maintenance of arterial blood pressure on the sequential recruitment of the sympathetic nervous system and HPA axis. While the 'early origins of adult disease' hypothesis has focussed on the impact of maternal undernutrition, an increase in maternal nutritional intake and in maternal body mass intake has become more prevalent in developed countries. Exposure to overnutrition in foetal life results in a series of central and peripheral neuroendocrine responses that in turn programme development of the fat cell and of the central appetite regulatory system. While the physiological responses to foetal undernutrition result in the physiological trade off between foetal survival and poor health outcomes that emerge after reproductive senescence, exposure to early overnutrition results in poor health outcomes that emerge in childhood and adolescence. Thus, the effects of early overnutrition can directly impact on reproductive fitness and on the health of the next generation. In this context, the physiological responses to relative overnutrition in early life may directly contribute to an intergenerational cycle of

The Origin of Dust in the Early Universe: Probing the Star Formation History of Galaxies by Their Dust Content

Science.gov (United States)

Dwek, Eli; Cherchneff, Isabelle

2010-01-01

Two distinct scenarios for the origin of the approximately 4 x 10(exp 8) Solar Mass of dust observed in the high-redshift (z = 6.4) quasar J1148+5251 have been proposed. The first assumes that this galaxy is much younger than the age of the universe at that epoch so that only supernovae, could have produced this dust. The second scenario assumes a significantly older galactic age, so that the dust could have formed in lower-mass AGB stars. Presenting new integral solutions for the chemical evolution of metals and dust in galaxies, we offer a critical evaluation of these two scenarios. ^N;"(,, show that the AGB scenario is sensitive to the details of the galaxy's star formation history (SFH), which must consist of an early intense starburst followed by a period of low stellar activity. The presence or absence of massive amounts of dust in high-redshift galaxies can therefore be used to infer their SFH. However, a problem with the AGB scenario is that it produces a stellar mass that is significantly larger than the inferred dynamical mass of J1148+5251, an yet unresolved discrepancy. If this problem persists, then additional sites for the growth or formation of dust, such as molecular clouds or dense clouds around active galactic nuclei, must be considered.

Astrobiology and the Chemistry of the Early Solar System

Science.gov (United States)

Cook, Jamie Elsila

2011-01-01

The field of astrochemistry investigates the origin of the chemicals necessary for the formation of life. Astrochemists use remote observations, laboratory simulations, and analysis of extraterrestrial samples to understand the inventory of pre biotic chemicals present on the early Earth. Among the problems investigated by astrochemists is the origin of homo chirality in terrestrial life. Analysis of meteorites shows that they may have delivered an excess of L-amino acids to the Earth's surface, perhaps leading to homochirality.

An analysis of silver candlesticks from a casting point of view: originals,copies, forgeries

Directory of Open Access Journals (Sweden)

Jaromir Audy

2010-02-01

Full Text Available Collecting silver artefacts has traditionally been a very popular hobby. Silver is addictive, therefore the number of potential collectors and investors appears to grow each year. Unfortunately, increases in the interest and buying potentials resulted in a number of forgeries manufactured and introduced to the open antique market. The items such as early silver candlesticks dictate a very high price, for many high quality fakes show very good appearances and matching similarities with originals. Such copies are traditionally manufactured by casting using the original items as patterns. Small details and variances in design features, position and shape of hallmarks, including the final surface quality are usual features to distinguish the fakes from the originals. This paper presents results of a study conducted on several silver candlesticks, including two artefacts bearing features of those produced in the mid 18th century, one original Italian candelabrum from Fascist era, and small candlesticks made in the early 20th century. Also, the paper presents some interesting contemporary coins ?replicas of many those produced in different countries. The coins were offered for sale by unscrupulous dealers via auctions and e-bays. Finally the main results and findings from this study are discussed from a manufacturing point of view, such as fabrication technology, surface quality and hallmarks, which will help the collectors, dealers and investors to detect and avoid forgeries.

Djebelemur, a tiny pre-tooth-combed primate from the Eocene of Tunisia: a glimpse into the origin of crown strepsirhines.

Directory of Open Access Journals (Sweden)

Laurent Marivaux

Full Text Available BACKGROUND: Molecular clock estimates of crown strepsirhine origins generally advocate an ancient antiquity for Malagasy lemuriforms and Afro-Asian lorisiforms, near the onset of the Tertiary but most often extending back to the Late Cretaceous. Despite their inferred early origin, the subsequent evolutionary histories of both groups (except for the Malagasy aye-aye lineage exhibit a vacuum of lineage diversification during most part of the Eocene, followed by a relative acceleration in diversification from the late Middle Eocene. This early evolutionary stasis was tentatively explained by the possibility of unrecorded lineage extinctions during the early Tertiary. However, this prevailing molecular view regarding the ancient origin and early diversification of crown strepsirhines must be viewed with skepticism due to the new but still scarce paleontological evidence gathered in recent years. METHODOLOGICAL/PRINCIPAL FINDINGS: Here, we describe new fossils attributable to Djebelemur martinezi, a≈50 Ma primate from Tunisia (Djebel Chambi. This taxon was originally interpreted as a cercamoniine adapiform based on limited information from its lower dentition. The new fossils provide anatomical evidence demonstrating that Djebelemur was not an adapiform but clearly a distant relative of lemurs, lorises and galagos. Cranial, dental and postcranial remains indicate that this diminutive primate was likely nocturnal, predatory (primarily insectivorous, and engaged in a form of generalized arboreal quadrupedalism with frequent horizontal leaping. Djebelemur did not have an anterior lower dentition as specialized as that characterizing most crown strepsirhines (i.e., tooth-comb, but it clearly exhibited a transformed antemolar pattern representing an early stage of a crown strepsirhine-like adaptation ("pre-tooth-comb". CONCLUSIONS/SIGNIFICANCE: These new fossil data suggest that the differentiation of the tooth-comb must postdate the djebelemurid

Djebelemur, a Tiny Pre-Tooth-Combed Primate from the Eocene of Tunisia: A Glimpse into the Origin of Crown Strepsirhines

Science.gov (United States)

Marivaux, Laurent; Ramdarshan, Anusha; Essid, El Mabrouk; Marzougui, Wissem; Ammar, Hayet Khayati; Lebrun, Renaud; Marandat, Bernard; Merzeraud, Gilles; Tabuce, Rodolphe; Vianey-Liaud, Monique

2013-01-01

Background Molecular clock estimates of crown strepsirhine origins generally advocate an ancient antiquity for Malagasy lemuriforms and Afro-Asian lorisiforms, near the onset of the Tertiary but most often extending back to the Late Cretaceous. Despite their inferred early origin, the subsequent evolutionary histories of both groups (except for the Malagasy aye-aye lineage) exhibit a vacuum of lineage diversification during most part of the Eocene, followed by a relative acceleration in diversification from the late Middle Eocene. This early evolutionary stasis was tentatively explained by the possibility of unrecorded lineage extinctions during the early Tertiary. However, this prevailing molecular view regarding the ancient origin and early diversification of crown strepsirhines must be viewed with skepticism due to the new but still scarce paleontological evidence gathered in recent years. Methodological/Principal Findings Here, we describe new fossils attributable to Djebelemur martinezi, a≈50 Ma primate from Tunisia (Djebel Chambi). This taxon was originally interpreted as a cercamoniine adapiform based on limited information from its lower dentition. The new fossils provide anatomical evidence demonstrating that Djebelemur was not an adapiform but clearly a distant relative of lemurs, lorises and galagos. Cranial, dental and postcranial remains indicate that this diminutive primate was likely nocturnal, predatory (primarily insectivorous), and engaged in a form of generalized arboreal quadrupedalism with frequent horizontal leaping. Djebelemur did not have an anterior lower dentition as specialized as that characterizing most crown strepsirhines (i.e., tooth-comb), but it clearly exhibited a transformed antemolar pattern representing an early stage of a crown strepsirhine-like adaptation (“pre-tooth-comb”). Conclusions/Significance These new fossil data suggest that the differentiation of the tooth-comb must postdate the djebelemurid divergence, a view

The origins of American health libertarianism.

Science.gov (United States)

Grossman, Lewis A

2013-01-01

This Article examines Americans' enduring demand for freedom of therapeutic choice as a popular constitutional movement originating in the United States' early years. In exploring extrajudicial advocacy for therapeutic choice between the American Revolution and the Civil War, this piece illustrates how multiple concepts of freedom in addition to bodily freedom bolstered the concept of a constitutional right to medical liberty. There is a deep current of belief in the United States that people have a right to choose their preferred treatments without government interference. Modern American history has given rise to movements for access to abortion, life-ending drugs, unapproved cancer treatments, and medical marijuana. Recently, cries of "Death Panels" have routinely been directed against health care reform proposals that citizens believe would limit the products and procedures covered by government health insurance. Some of the most prominent contemporary struggles for health freedom have been waged in court. But other important recent battles for freedom of therapeutic choice have taken place in other forums, from legislative hearings to Food and Drug Administration advisory committee meetings to public demonstrations. This attitude of therapeutic libertarianism is not new. Drawing mainly on primary historical sources, this Article examines arguments in favor of freedom of therapeutic choice voiced in antebellum America in the context of battles against state licensing regimes. After considering some anti-licensing arguments made before independence, it discusses the views and statements of Benjamin Rush, an influential founding father who was also the most prominent American physician of the early national period. The Article then analyzes the Jacksonian-era battle against medical licensing laws waged by the practitioners and supporters of a school of botanical medicine known as Thomsonianism. This triumphant struggle was waged in explicitly constitutional terms

Transactional relations between caregiving stress, executive functioning, and problem behavior from early childhood to early adolescence

Science.gov (United States)

LaGasse, Linda L.; Conradt, Elisabeth; Karalunas, Sarah L.; Dansereau, Lynne M.; Butner, Jonathan E.; Shankaran, Seetha; Bada, Henrietta; Bauer, Charles R.; Whitaker, Toni M.; Lester, Barry M.

2016-01-01

Developmental psychopathologists face the difficult task of identifying the environmental conditions that may contribute to early childhood behavior problems. Highly stressed caregivers can exacerbate behavior problems, while children with behavior problems may make parenting more difficult and increase caregiver stress. Unknown is: (1) how these transactions originate, (2) whether they persist over time to contribute to the development of problem behavior and (3) what role resilience factors, such as child executive functioning, may play in mitigating the development of problem behavior. In the present study, transactional relations between caregiving stress, executive functioning, and behavior problems were examined in a sample of 1,388 children with prenatal drug exposures at three developmental time points: early childhood (birth-age 5), middle childhood (ages 6 to 9), and early adolescence (ages 10 to 13). Transactional relations differed between caregiving stress and internalizing versus externalizing behavior. Targeting executive functioning in evidence-based interventions for children with prenatal substance exposure who present with internalizing problems and treating caregiving psychopathology, depression, and parenting stress in early childhood may be particularly important for children presenting with internalizing behavior. PMID:27427803

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.

Luncheon address: Early days of CANDU fuel

International Nuclear Information System (INIS)

Page, R.D.

1997-01-01

I will briefly describe how the original dimensions of the fuel bundle were defined and how that early designs of fuel evolved. I will also touch on some of the historical events of the materials and experiments which effected the fuel programme. Also how I became with Canada's Nuclear Fuel programme. (author)

Filming, faking and propaganda: The origins of the war film, 1897-1902

NARCIS (Netherlands)

Bottomore, S.

2007-01-01

The origins of the war film, 1897-1902 In this thesis I present the first detailed treatment of war and early cinema, describing the representation of conflicts in film from the Greco-Turkish War of 1897 through the Spanish-American War, Boer War, and others up to about 1902. I show that in

Developmental Origins of Rumination in Middle Childhood: The Roles of Early Temperament and Positive Parenting.

Science.gov (United States)

Schweizer, Tina H; Olino, Thomas M; Dyson, Margaret W; Laptook, Rebecca S; Klein, Daniel N

2017-09-08

Rumination, a thinking style characterized by a repetitive inward focus on negative cognitions, has been linked to internalizing disorders, particularly depression. Moreover, research suggests that rumination may be a cognitive vulnerability that predisposes individuals to psychopathology. Surprisingly little is known, however, about the etiology and development of rumination. The present study examined the role of specific components of child temperamental negative emotionality (sadness, fear, anger) and effortful control (inhibition), as well as parenting behaviors during early childhood on the development of rumination in middle childhood. Early childhood (age 3) temperament and parenting behaviors were assessed observationally and rumination was self-reported in middle childhood (age 9) in a large community sample (N = 425; 47.1% female). Two significant interactions emerged. First, temperamental anger interacted with inhibitory control (IC) such that high anger and low IC predicted higher levels of rumination, whereas low anger and low IC predicted lower levels of rumination. Second, IC interacted with parenting such that children with low IC and positive parenting had lower levels of rumination. In contrast, children with high IC reported similar levels of rumination regardless of parenting quality. Overall, these findings highlight the interplay of early IC with temperamental anger and positive parenting in the development of ruminative tendencies in middle childhood.

Supernovae and the origin of the solar system

International Nuclear Information System (INIS)

Clayton, D.D.

1979-01-01

This review concentrates on recent ideas involving a relationship between the early solar system and supernovae explosions. It summarizes briefly the data that has helped inspire those ideas. Because the true relationship is still unknown and generates controversy, the distinct ideas are introduced singly in the historical context of their origins, and the active sense of surprise and controversy is visible. Quotations from pivotal papers are used as part of the exposition. The subject involves equally the isotopic anomalies detected in meteorites and the dynamic events of galactic evolution, nucleosynthesis, and protosolar collapse. Whatever the correct situation is, new connections have been found between the origin of the elements and the formation of the solar system. The objective of this review is to enable interested space scientists to quickly identify the competing points of view and the experiments and theories that have led to them. (Auth.)

Early fractionation methods and the origins of the NSD concept

International Nuclear Information System (INIS)

Thames, H.D. Jr.

1988-01-01

The concept of the time factor in radiotherapy originated in the controversy surrounding single-dose and fractionated treatments during the first 20 years of this century. The success of Coutard's fractionated treatments of larynx tumors was an important factor in the abandonment of single-dose treatments. There was considerable research afterwards into the influence of dose rate and overall time of treatment on the responses of normal tissues. Recovery was modeled in terms of the Schwarzschild law of photochemistry, as exemplified by the analysis of Strandqvist in log dose-log time coordinates. Different conventions were followed in defining the time for a single-dose treatment. Subsequently the concept arose that the slopes of isoeffect lines relating dose and treatment time for normal tissues and tumors were different and moreover that the effects of fraction number and overall time could be separated; these developments constituted the foundation of the Ellis NSD model. It had an important influence on clinical practice and was reasonably successful in predicting isoeffective regimens for acute effects. It failed to predict severe late effects after large dose fractions. The dissociation between acute and late effects with altered fractionation led to recognition of the importance of the ratio α/β in characterizing the fractionation sensitivity of tissues. (orig.) With 125 refs

Origin of sapphirine- and garnet-bearing clinopyroxenite xenoliths entrained in the Jiande basalts, SE China

Science.gov (United States)

Xiao, Yan; Zhang, Hong-Fu; Liang, Zi; Su, Ben-Xun; Zhu, Bin; Sakyi, Patrick Asamoah

2018-04-01

We present petrological and geochemical data of sapphirine- and garnet-bearing clinopyroxenite xenoliths entrained in the Jiande Cenozoic basalts, SE China, to investigate their igneous and metamorphic history, and reconstruct of the thermal-tectonic evolution of the lithospheric mantle. These xenoliths have an unusual mineral association consisting of clinopyroxene + garnet/kelyphite + spinel (±sapphirine). Clinopyroxene has high Mg# (89-93) and displays convex-upward REE pattern. Garnet, partially to completely kelyphitized, is rich in pyrope end-member. It usually includes relics of spinel, suggesting that garnet was formed at the expense of spinel. The spinel has high MgO (20.8-22.9 wt%) and Al2O3 (64.8-67.9 wt%) contents. Sapphirine, forming a rim on spinel, has homogeneous SiO2 (14.5-14.9 wt%), Al2O3 (60.9-61.7 wt%) and MgO (19.7-20.1 wt%) contents, interpreted to be of metamorphic origin. The subsolidus reaction for the formation of sapphirine is as follows: spinel + garnet = sapphirine + clinopyroxene + orthopyroxene. Thus, the earliest mineral assemblage recorded in these xenoliths was spinel + clinopyroxene. The clinopyroxene in the Jiande clinopyroxenite xenoliths has Li abundances (1.04-1.63 ppm) similar to high-P mafic cumulate but much lower than those in crustal eclogite. In addition, the clinopyroxene and garnet do not show positive Eu anomalies. Therefore, the protolith of these three clinopyroxenite xenoliths was most likely a pyroxenite, originating as clinopyroxene + spinel cumulates from mafic melts percolating through the mantle. Many reaction textures such as formation of garnet and sapphirine were developed during decompression possibly coupled with cooling and melt percolation. During this process, the earlier composition of clinopyroxene and spinel also changed. The latest P-T conditions recorded in these xenoliths were at pressure of 8-10 kbar and temperatures of 1069-1094 °C. These observations imply that these rocks have been

Archean greenstone-tonalite duality: Thermochemical mantle convection models or plate tectonics in the early Earth global dynamics?

Science.gov (United States)

Kerrich, Robert; Polat, Ali

2006-03-01

Mantle convection and plate tectonics are one system, because oceanic plates are cold upper thermal boundary layers of the convection cells. As a corollary, Phanerozoic-style of plate tectonics or more likely a different version of it (i.e. a larger number of slowly moving plates, or similar number of faster plates) is expected to have operated in the hotter, vigorously convecting early Earth. Despite the recent advances in understanding the origin of Archean greenstone-granitoid terranes, the question regarding the operation of plate tectonics in the early Earth remains still controversial. Numerical model outputs for the Archean Earth range from predominantly shallow to flat subduction between 4.0 and 2.5 Ga and well-established steep subduction since 2.5 Ga [Abbott, D., Drury, R., Smith, W.H.F., 1994. Flat to steep transition in subduction style. Geology 22, 937-940], to no plate tectonics but rather foundering of 1000 km sectors of basaltic crust, then "resurfaced" by upper asthenospheric mantle basaltic melts that generate the observed duality of basalts and tonalities [van Thienen, P., van den Berg, A.P., Vlaar, N.J., 2004a. Production and recycling of oceanic crust in the early earth. Tectonophysics 386, 41-65; van Thienen, P., Van den Berg, A.P., Vlaar, N.J., 2004b. On the formation of continental silicic melts in thermochemical mantle convection models: implications for early Earth. Tectonophysics 394, 111-124]. These model outputs can be tested against the geological record. Greenstone belt volcanics are composites of komatiite-basalt plateau sequences erupted from deep mantle plumes and bimodal basalt-dacite sequences having the geochemical signatures of convergent margins; i.e. horizontally imbricated plateau and island arc crust. Greenstone belts from 3.8 to 2.5 Ga include volcanic types reported from Cenozoic convergent margins including: boninites; arc picrites; and the association of adakites-Mg andesites- and Nb-enriched basalts. Archean cratons

Is There any Relationship Between the Santa Elena Depression and Chicxulub Impact Crater, Northwestern Yucatan Peninsula, Mexico?

Science.gov (United States)

Lefticariu, L.

2005-05-01

The Terminal Cretaceous Chicxulub Impact Crater had a strong control on the depositional and diagenetic history of the northern Yucatan Platform during most of the Cenozoic Era. The Chicxulub Sedimentary Basin (henceforth Basin), which approximately coincides with the impact crater, is circumscribed by a concentration of karstic sinkholes known as the Ring of Cenotes. Santa Elena Depression (henceforth Depression) is the name proposed for the bowl-shaped buried feature, first contoured by geophysical studies, immediately south of the Basin, in the area where the Ticul 1 and UNAM 5 wells were drilled. Lithologic, petrographic, and biostratigraphic data on PEMEX, UNAM, and ICDP cores show that: 1) Cenozoic deposits are much thicker inside the Basin than inside the Depression, 2) in general, the Cenozoic formations from inside the Depression are the thickest among those outside the Basin, 3) variably dolomitized pelagic or outer-platform wackestone or mudstone occur both inside the Basin and Depression, 4) the age of the deeper-water sedimentary carbonate rocks is Paleocene-Eocene inside the Basin and Paleocene?-Early Eocene inside the Depression, 5) the oldest formations that crop out are of Middle Eocene age at the edge of the Basin and Early-Middle Eocene age inside the Depression, 6) saline lake deposits, that consist chiefly of anhydrite, gypsum, and fine carbonate, and also contain quartz, chert, clay, zeolite, potassium feldspar, pyrite, and fragments of wood, are present in the Cenozoic section of the UNAM 5 core between 282 and 198 m below the present land surface, 7) the dolomite, subaerial exposure features (subaerial crusts, vugs, karst, dedolomite), and vug-filling cement from the Eocene formations are more abundant inside the Depression than inside the Basin. The depositional environments that are proposed for explaining the Cenozoic facies succession within the Santa Elena Depression are: 1) deeper marine water (Paleocene?-Early Eocene), 2) relatively

Generating original ideas: The neural underpinning of originality.

Science.gov (United States)

Mayseless, Naama; Eran, Ayelet; Shamay-Tsoory, Simone G

2015-08-01

One of the key aspects of creativity is the ability to produce original ideas. Originality is defined in terms of the novelty and rarity of an idea and is measured by the infrequency of the idea compared to other ideas. In the current study we focused on divergent thinking (DT) - the ability to produce many alternate ideas - and assessed the neural pathways associated with originality. Considering that generation of original ideas involves both the ability to generate new associations and the ability to overcome automatic common responses, we hypothesized that originality would be associated with activations in regions related to associative thinking, including areas of the default mode network (DMN) such as medial prefrontal areas, as well as with areas involved in cognitive control and inhibition. Thirty participants were scanned while performing a DT task that required the generation of original uses for common objects. The results indicate that the ability to produce original ideas is mediated by activity in several regions that are part of the DMN including the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC). Furthermore, individuals who are more original exhibited enhanced activation in the ventral anterior cingulate cortex (vACC), which was also positively coupled with activity in the left occipital-temporal area. These results are in line with the dual model of creativity, according to which original ideas are a product of the interaction between a system that generates ideas and a control system that evaluates these ideas. Copyright © 2015 Elsevier Inc. All rights reserved.

Luncheon address: Early days of CANDU fuel

Energy Technology Data Exchange (ETDEWEB)

Page, R.D. [Atomic Energy of Canada Limited (Canada)

1997-07-01

This will briefly describe how the original dimensions of the fuel bundle were defined and how that early designs of fuel evolved. I will also touch on some of the historical events of the materials and experiments which effected the fuel programme. Also how I became with Canada's Nuclear Fuel programme. (author)

Early life nutritional programming of health and disease in The Gambia.

Science.gov (United States)

Moore, S E

2016-04-01

Exposures during the early life (periconceptional, prenatal and early postnatal) period are increasingly recognized as playing an important role in the aetiology of chronic non-communicable diseases (NCD), including coronary heart disease, stroke, hypertension, Type 2 diabetes and osteoporosis. The 'Developmental Origins of Health and Disease' (DOHaD) hypothesis states that these disorders originate through unbalanced nutrition early in life and risk is highest when there is a 'mismatch' between the early- and later-life environments. Thus, the DOHaD hypothesis would predict highest risk in countries where an excess of infants are born with low birth weight and where there is a rapid transition to nutritional adequacy or excess in adulthood. Here, I will review data from work conducted in rural Gambia, West Africa. Using demographic data dating back to the 1940s, the follow-up of randomized controlled trials of nutritional supplementation in pregnancy and the 'experiment of nature' that seasonality in this region provides, we have investigated the DOHaD hypothesis in a population with high rates of maternal and infant under-nutrition, a high burden from infectious disease, and an emerging risk of NCDs.

Origin of the RNA world: The fate of nucleobases in warm little ponds

Science.gov (United States)

Pearce, Ben K. D.; Pudritz, Ralph E.; Semenov, Dmitry A.; Henning, Thomas K.

2017-10-01

Before the origin of simple cellular life, the building blocks of RNA (nucleotides) had to form and polymerize in favorable environments on early Earth. At this time, meteorites and interplanetary dust particles delivered organics such as nucleobases (the characteristic molecules of nucleotides) to warm little ponds whose wet–dry cycles promoted rapid polymerization. We build a comprehensive numerical model for the evolution of nucleobases in warm little ponds leading to the emergence of the first nucleotides and RNA. We couple Earth's early evolution with complex prebiotic chemistry in these environments. We find that RNA polymers must have emerged very quickly after the deposition of meteorites (less than a few years). Their constituent nucleobases were primarily meteoritic in origin and not from interplanetary dust particles. Ponds appeared as continents rose out of the early global ocean, but this increasing availability of “targets” for meteorites was offset by declining meteorite bombardment rates. Moreover, the rapid losses of nucleobases to pond seepage during wet periods, and to UV photodissociation during dry periods, mean that the synthesis of nucleotides and their polymerization into RNA occurred in just one to a few wet–dry cycles. Under these conditions, RNA polymers likely appeared before 4.17 billion years ago.

Origin of the RNA world: The fate of nucleobases in warm little ponds.

Science.gov (United States)

Pearce, Ben K D; Pudritz, Ralph E; Semenov, Dmitry A; Henning, Thomas K

2017-10-24

Before the origin of simple cellular life, the building blocks of RNA (nucleotides) had to form and polymerize in favorable environments on early Earth. At this time, meteorites and interplanetary dust particles delivered organics such as nucleobases (the characteristic molecules of nucleotides) to warm little ponds whose wet-dry cycles promoted rapid polymerization. We build a comprehensive numerical model for the evolution of nucleobases in warm little ponds leading to the emergence of the first nucleotides and RNA. We couple Earth's early evolution with complex prebiotic chemistry in these environments. We find that RNA polymers must have emerged very quickly after the deposition of meteorites (less than a few years). Their constituent nucleobases were primarily meteoritic in origin and not from interplanetary dust particles. Ponds appeared as continents rose out of the early global ocean, but this increasing availability of "targets" for meteorites was offset by declining meteorite bombardment rates. Moreover, the rapid losses of nucleobases to pond seepage during wet periods, and to UV photodissociation during dry periods, mean that the synthesis of nucleotides and their polymerization into RNA occurred in just one to a few wet-dry cycles. Under these conditions, RNA polymers likely appeared before 4.17 billion years ago.

Early Childhood Education for Sustainability: Origins and Inspirations in the Work of John Dewey

Science.gov (United States)

Luff, Paulette

2018-01-01

In this article, the work of John Dewey is recontextualised and proposed as a basis for contemporary early childhood education for sustainability (ECEfS). Five key themes are explored: experiential learning; curiosity and critical thinking; children's experiences in nature; democracy and participation and classroom as community. In each case,…

Planck early results. XVII. Origin of the submillimetre excess dust emission in the Magellanic Clouds

DEFF Research Database (Denmark)

Lähteenmäki, A.; Poutanen, T.; Natoli, P.

2011-01-01

The integrated spectral energy distributions (SED) of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) appear significantly flatter than expected from dust models based on their far-infrared and radio emission. The still unexplained origin of this millimetre excess is investigate...

Arc magmatism as a window to plate kinematics and subduction polarity: Example from the eastern Pontides belt, NE Turkey

Directory of Open Access Journals (Sweden)

Yener Eyuboglu

2011-01-01

Full Text Available The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on recent information from this belt. We infer a southward subduction for the origin of the Eastern Pontides orogenic belt and its associated late Mesozoic–Cenozoic magmatism based on clear spatial and temporal variations in Late Cretaceous and Cenozoic arc magmatism, together with the existence of a prominent south-dipping reverse fault system along the entire southern coast of the Black Sea. Our model is at variance with some recent proposals favoring a northward subduction polarity, and illustrates the importance of arc magmatism in evaluating the geodynamic milieu associated with convergent margin processes.

Onshore-offshore relationships along the Norwegian margin

DEFF Research Database (Denmark)

Gołędowski, Bartosz

2011-01-01

set (Paper 1) and the interpreted horizons have been correlated with age estimates from numerous exploration wells. From this, an overview of Cenozoic sediment production from Scandinavia emerged forming the basis for a discussion on the factors controlling the erosion and deposition. As climate...... observations. It has revealed a close relationship between a coastlineoutbuilding event documented by steeply prograding clinoforms (seismics), coarsening-upwards sequences (well logs) and occurrence of the cold-water dinocyst Svalbardella(micropaleontology).This provides further evidence for a strong impact......, the age determination of this surface varies from one location to another. Paper 4 investigates whether the MMU is in fact a chronostratigraphic event of uniform origin or maybe just an overused cliché. The onshore part of the Cenozoic Scandinavian source-to-sink system has been approached by quantitative...

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.

Influence of contemporary carbon originating from the 2003 Siberian forest fire on organic carbon in PM2.5 in Nagoya, Japan.

Science.gov (United States)

Ikemori, Fumikazu; Honjyo, Koji; Yamagami, Makiko; Nakamura, Toshio

2015-10-15

In May 2003, high concentrations of organic carbon (OC) in PM2.5 were measured in Nagoya, a representative metropolitan area in Japan. To investigate the influence of possible forest fires on PM2.5 in Japan via long-range aerosol transport, the radiocarbon ((14)C) concentrations of PM2.5 samples from April 2003 to March 2004 were measured. (14)C concentrations in total carbon (TC) from May to early June showed higher values than those in other periods. The OC/elemental carbon (EC) ratios from May to early June were also significantly higher than the ones in other periods. In addition, OC concentrations from May to early June were typically high. These results indicate that the abundant OC fraction from May to early June in Nagoya consisted predominantly of contemporary carbon. Furthermore, simulations of diffusion and transport of organic matter (OM) in East Asia showed that abundant OM originating from East Siberia spread over East Asia and Japan in May and early June. Backward air mass trajectories from this time frame indicate that the air mass in Nagoya likely first passed through East Siberia where fire events were prevalent. However, the backward trajectories showed that the air mass after early June did not originate mainly from Siberia, and correspondingly, the (14)C and OC concentrations showed lower values than those from May to early June. Therefore, the authors conclude that contemporary carbon originating from the forest fire in East Siberia was transported to Nagoya, where it significantly contributed to the high observed concentrations of both OC and (14)C. Copyright © 2015 Elsevier B.V. All rights reserved.

The Vienna Conventions on Early Notification and Assistance

International Nuclear Information System (INIS)

Cameron, P.

1988-01-01

Following the Chernobyl accident, the IAEA established and opened for signature on 26th September 1986 two Conventions, on Early Notification of a Nuclear Accident and on Assistance in Case of a Nuclear Accident or Radiological Emergency respectively. This chapter describes the Conventions and their origins (NEA) [fr

The origins of the birth control movement in England in the early nineteenth century.

Science.gov (United States)

Langer, W L

1975-01-01

The origins of the birth control movement in England in the 19th cen tury are discussed. The impact of Malthus's "Essay on the Principle of Population" and the activities of such thinkers and reformers as Jermy Bentham, James and John Stuart Mill, Francis Plance, Richard Carlile, Robert Dale Owen, and Charles Knowlton are discussed. The social debate that arose during the century is discussed.

A Developmental-Contextual Model of Depressive Symptoms in Mexican-Origin Female Adolescents

Science.gov (United States)

Bámaca-Colbert, Mayra Y.; Umaña-Taylor, Adriana J.; Gayles, Jochebed G.

2011-01-01

The current study tested a developmental-contextual model of depressive symptomatology among early and middle adolescent Mexican-origin females and their mothers. The final sample was comprised of 271 dyads. We examined the interrelations among cultural (i.e., acculturation dissonance), developmental (i.e., pubertal development and autonomy expectation discrepancies), and interpersonal (i.e., mother-daughter conflict and maternal supportive parenting) factors in predicting adolescents’ depressive symptoms. For both early and middle adolescents, maternal support was negatively associated with mother-daughter conflict and depressive symptoms. Importantly, mother-daughter autonomy expectation discrepancies were positively associated with mother-daughter conflict, but this association was found only among early adolescents. Further, mother-daughter acculturation dissonance was positively associated with mother-daughter conflict, but only among middle adolescents. Findings call for concurrently examining the interface of developmental, relational, and cultural factors in predicting female adolescents’ depressive symptomatology and the potential differences by developmental stage (e.g., early vs. middle adolescence) PMID:21967564

A Middle Triassic thoracopterid from China highlights the evolutionary origin of overwater gliding in early ray-finned fishes.

Science.gov (United States)

Xu, Guang-Hui; Zhao, Li-Jun; Shen, Chen-Chen

2015-01-01

Gliding adaptations in thoracopterid flying fishes represent a remarkable case of convergent evolution of overwater gliding strategy with modern exocoetid flying fishes, but the evolutionary origin of this strategy was poorly known in the thoracopterids because of lack of transitional forms. Until recently, all thoracopterids, from the Late Triassic of Austria and Italy and the Middle Triassic of South China, were highly specialized 'four-winged' gliders in having wing-like paired fins and an asymmetrical caudal fin with the lower caudal lobe notably larger than the upper lobe. Here, we show that the new genus Wushaichthys and the previously alleged 'peltopleurid' Peripeltopleurus, from the Middle Triassic (Ladinian, 235-242 Ma) of South China and near the Ladinian/Anisian boundary of southern Switzerland and northern Italy, respectively, represent the most primitive and oldest known thoracopterids. Wushaichthys, the most basal thoracopterid, shows certain derived features of this group in the skull. Peripeltopleurus shows a condition intermediate between Wushaichthys and Thoracopterus in having a slightly asymmetrical caudal fin but still lacking wing-like paired fins. Phylogenetic studies suggest that the evolution of overwater gliding of thoracopterids was gradual in nature; a four-stage adaption following the 'cranial specialization-asymmetrical caudal fin-enlarged paired fins-scale reduction' sequence has been recognized in thoracopterid evolution. Moreover, Wushaichthys and Peripeltopleurus bear hooklets on the anal fin of supposed males, resembling those of modern viviparious teleosts. Early thoracopterids probably had evolved a live-bearing reproductive strategy. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Homochirality and the origin of life

Science.gov (United States)

Pohl, Robert; Leitner, J. J.; Firneis, M. G.

2012-05-01

Homochirality is generally considered a crucial signature for life on Earth, which uses left-handed amino acids and right-handed sugars. A mirror-image life, using right-handed amino acids and left- handed sugars, is perfectly conceivable and might have developed on another planet. Life which would simultaneously use both right- and left-handed forms of the same biological molecules is unlikely for geometrical reasons. Secondary peptide structures are not possible without one-handedness. Various theories try to explain the origin of homochirality. Physicists used as argument the phenomenon of parity violation discovered on 60Co, which does not explain homochirality on prebiotic substances. Astrophysicists suggested that the observed enantiomeric excesses could have been induced by circularly polarized light arising from dust scattering in regions of high mass star formations or even due to super nova remnants or pulsars. An extraterrestrial origin of homochiral substances is discusses as well as catalytic processes on early Earth using different mineral surfaces. Thermodynamics i.e. its 2nd law is considered to explain homochirality as consequence of increasing entropy. There are many questions not yet answered. The author looks forward to discuss some of them with interested scientists.

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

On the possibility of life on early Mars

Science.gov (United States)

Oberbeck, V. R.; Fogleman, G.

1990-01-01

Prebiotic reactants, liquid water, and temperatures low enough for organic compounds to be stable are requirements for the origination of life as we know it. Prebiotic reactants and sufficiently low temperatures were present on Mars before liquid water vanished. Early in this time period, however, large planetesimal impacts may have periodically sterilized Mars, pyrolyzed organic compounds, and interrupted chemical origination of life. However, the calculated time interval between such impacts on Mars was larger just before liquid water vanished 3.8 Gyr (billion years) ago than it was on earth just before life originated. Therefore, there should have been sufficient time for life to originate on Mars. Ideal sites to search for microfossils are in the heavily cratered terrain of Upper Noachian age. Craters and channels in this terrain may have been the sites of ancient lakes and streams that could have provided habitats for the first microorganisms.

Fever of unknown origin

International Nuclear Information System (INIS)

Misaki, Takashi; Matsui, Akira; Tanaka, Fumiko; Okuno, Yoshishige; Mitsumori, Michihide; Torizuka, Tatsurou; Dokoh, Shigeharu; Hayakawa, Katsumi; Shimbo, Shin-ichirou

1990-01-01

Gallium-67 scintigraphy is a commonly performed imaging modality in deteting pyrogenic lesions in cases of long-standing inexplainable fever. To re-evaluate the significance of gallium imaging in such cases, a retrospective review was made of 56 scans performed in febrile patients in whom sufficient clinical and laboratory findings were obtained. Gallium scans were true positive in 30 patients, false positive in 3, true negative in 19, and false negative in 4. In the group of true positive, local inflammatory lesions were detected in 23 patients with a final diagnosis of lung tuberculosis, urinary tract infection, and inflammatory joint disease. Abnormal gallium accumulation, as shown in the other 7 patients, provided clues to the diagnosis of generalized disorders, such as hematological malignancies (n=3), systemic autoimmune diseases (n=3), and severe infectious mononucleosis (n=one). In the group of false positive, gallium imaging revealed intestinal excretion of gallium in 2 patients and physiological pulmonary hilar accumulation in one. In the true negative group of 19 patients, fever of unknown origin was resolved spontaneously in 12 patients, and with antibiotics and corticosteroids in 2 and 5 patients, respectively. Four patients having false negative scans were finally diagnosed as having urinary tract infection (n=2), bacterial meningitis (n=one), and polyarteritis (n=one). Gallium imaging would remain the technique of choice in searching for origin of unknown fever. It may also be useful for early diagnosis of systemic disease, as well as focal inflammation. (N.K.)

On the origin of alkali metals in Europa exosphere

Science.gov (United States)

Ozgurel, Ozge; Pauzat, Françoise; Ellinger, Yves; Markovits, Alexis; Mousis, Olivier; LCT, LAM

2016-10-01

At a time when Europa is considered as a plausible habitat for the development of an early form of life, of particular concern is the origin of neutral sodium and potassium atoms already detected in its exosphere (together with magnesium though in smaller abundance), since these atoms are known to be crucial for building the necessary bricks of prebiotic species. However their origin and history are still poorly understood. The most likely sources could be exogenous and result from the contamination produced by Io's intense volcanism and/or by meteoritic bombardment. These sources could also be endogenous if these volatile elements originate directly from Europa's icy mantle. Here we explore the possibility that neutral sodium and potassium atoms were delivered to the satellite's surface via the upwelling of ices formed in contact with the hidden ocean. These metallic elements would have been transferred as ions to the ocean at early epochs after Europa's formation, by direct contact of water with the rocky core. During Europa's subsequent cooling, the icy layers formed at the top of the ocean would have kept trapped the sodium and potassium, allowing their future progression to the surface and final identification in the exosphere of the satellite. To support this scenario, we have used chemistry numerical models based on first principle periodic density functional theory (DFT). These models are shown to be well adapted to the description of compact ice and are capable to describe the trapping and neutralization of the initial ions in the ice matrix. The process is found relevant for all the elements considered, alkali metals like Na and K, as well as for Mg and probably for Ca, their respective abundances depending essentially of their solubility and chemical capabilities to blend with water ices.

Cancer of unknown primary origin: a case report

Directory of Open Access Journals (Sweden)

Elisa De Carlo

2013-03-01

Full Text Available Carcinoma of unknown primary origin (CUP accounts for 2-10% of all malignancies. The apparent absence of the primary tumour, the development of early, uncommon systemic metastases and the resistance to therapy and poor prognosis are hallmarks of this heterogeneous clinical entity and are a challenge for physicians. The diagnostic workup of patients with CUP includes a large amount of histopathological examination, as well as the use of imaging techniques that often fail to identify the primary tumour. Therefore, the optimal workup and treatment for these patients remains to be determined. Molecular diagnostic tools, such as DNA microarray analysis, could help in the search for "lost" CUP origin and guide the further treatment approach. We report the case of a 66-year-old man, with mediastinal lymph nodes metastasis of carcinoma and neurological syndrome with diplopia and balance disorders, in which many exams have been performed without finding the primary tumour.

Guia para los padres sobre educacion preescolar (A Parents' Guide to Early Childhood Education).

Science.gov (United States)

Dodge, Diane Trister; Phinney, Joanna

This handbook, entirely in Spanish, was originally intended for parents whose children attend programs which use "The Creative Curriculum for Early Childhood" (CCEC), but the information is also useful to parents whose children attend early childhood programs using other curriculum models based on child development theories. The purpose…

Early life insults as determinants of chronic obstructive pulmonary disease in adult life

DEFF Research Database (Denmark)

Savran, Osman; Ulrik, Charlotte Suppli

2018-01-01

Background: Early life events may predispose to the development of chronic lung disease in adulthood. Aim: To provide an update on current knowledge of early nongenetic origins of COPD. Materials and methods: Systematic literature review was performed according to the Preferred Reporting Items...... in utero and early life is a risk factor for subsequent development of COPD. Furthermore, low birth weight, lower respiratory tract infections and asthma, including wheezy bronchitis, in childhood also seem to be important determinants for later development of COPD. Early life insults may, therefore...

From early days of elitism to earning a wider respect.

Science.gov (United States)

Stammer, T

1979-07-20

Gone are those early elitist days in the life of the Association of NHS Supplies Officers. It has widened its umbrella and its ambitions. Author traces the association's origins and ruminates on what lies in store for it.

Immune-mediated diseases and microbial exposure in early life

DEFF Research Database (Denmark)

Bisgaard, H; Bønnelykke, K; Stokholm, Jacob

2014-01-01

The non-communicable disease pandemic includes immune-mediated diseases such as asthma and allergy, which are likely originating in early life where the immature immune system is prone to alterations caused by the exposome. The timing of exposure seems critical for the developing immune system...

Electrical energy sources for organic synthesis on the early earth

Science.gov (United States)

Chyba, Christopher; Sagan, Carl

1991-01-01

It is pointed out that much of the contemporary origin-of-life research uses the original estimates of Miller and Urey (1959) for terrestrial energy dissipation by lightning and coronal discharges being equal to 2 x 10 to the 19th J/yr and 6 x 10 to the 19th J/yr, respectively. However, data from experiments that provide analogues to naturally-occurring lightning and coronal discharges indicate that lightning energy yields for organic synthesis (nmole/J) are about one order of magnitude higher than the coronal discharge yields. This suggests that, on early earth, organic production by lightning may have dominated that due to coronal emission. New values are recommended for lightning and coronal discharge dissipation rates on the early earth, 1 x 10 to the 18th J/yr and 5 x 10 to the 17th J/yr, respectively.

Neogene palaeochannel deposits in Sudan - Remnants of a trans-Saharan river system?

Science.gov (United States)

Bussert, Robert; Eisawi, Ali A. M.; Hamed, Basher; Babikir, Ibrahim A. A.

2018-05-01

The start of Nile-type trans-Saharan drainage systems in NE Africa during the Cenozoic is disputed. Stratigraphical and sedimentological data in Egypt are partly in conflict with the uplift history of potential source areas of water and sediment in East Africa. Here, we investigate outcrops of the Wadi Awatib Conglomerate in Sudan that provide the first evidence of northerly flowing Neogene rivers in the region. Dimension and relief of basal erosion surfaces, overall geometry of deposits and palaeocurrent indicators demonstrate that the deposits represent the fill of northward-oriented incised valleys. The conglomerates were deposited in deep gravel-bed rivers, by hyperconcentrated flows, tractions carpets and gravel bars, primarily during heavily sediment-laden floods of probably monsoonal origin. Stratigraphical and geomorphological relationships show that the deposits are between Eocene and Pliocene in age. Considering the structural history of the region and periods in the Cenozoic with palaeoclimatic conditions suitable for the production and transport of gravels, we hypothesize that the dramatic base-level fall during the Late Miocene Messinian salinity crisis in combination with a favorable palaeoclimate caused the incision of valleys and their subsequent filling with conglomerates. Sea-level change in the Mediterranean Sea and headward erosion of streams that were connected to the Egyptian Nile might have been the primary cause of valley incision and deposition of conglomerates, despite a location far inland from the coastline. We suggest that the deposits document a relatively young Neogene (Messinian to early Pliocene) trans-Saharan river system unrelated to uplift of the Ethiopian Plateau.

Tracing the Origin of Black Hole Accretion Through Numerical Hydrodynamic Simulations

Science.gov (United States)

Spicer, Sandy; Somerville, Rachel; Choi, Ena; Brennan, Ryan

2018-01-01

It is now widely accepted that supermassive black holes co-evolve with galaxies, and may play an important role in galaxy evolution. However, the origin of the gas that fuels black hole accretion, and the resulting observable radiation, is not well understood or quantified. We use high-resolution "zoom-in" cosmological numerical hydrodynamic simulations including modeling of black hole accretion and feedback to trace the inflow and outflow of gas within galaxies from the early formation period up to present day. We track gas particles that black holes interact with over time to trace the origin of the gas that feeds supermassive black holes. These gas particles can come from satellite galaxies, cosmological accretion, or be a result of stellar evolution. We aim to track the origin of the gas particles that accrete onto the central black hole as a function of halo mass and cosmic time. Answering these questions will help us understand the connection between galaxy and black hole evolution.

On a chaotic early universe

International Nuclear Information System (INIS)

Tomita, Kenji.

1974-11-01

The theories regarding the origin of galaxies and elements are reviewed in this paper, and the assumptions made for these theories are discussed. It has been assumed that the universe has always been isotropic and homogeneous from the beginning of cosmic expansion. At the stage of very high density that any local irregularities such as galaxies cannot exist, the admissible deviation in this case from the mean value is only the statistical or quantum fluctuation of matter density, spatial curvature or their growth. It should be considered that the chemical composition of matters at the earliest stage consisted of most fundamental particles. However, if the fluctuation of matter density is statistical, the present values are too small. As for the origin of elements, it depends strongly on the period when cosmic radiation appeared. The final mass ratios of elements are given from the present baryon mass density, and are in agreement with observed values. The assumption of hot universe seems good. However, the time-independent ratio of photon number to baryon number is hardly understood. It is reasonable to assume for the early universe an inhomogeneous model whose space-time curvature is of turbulent character, according to weak cosmological principle. The inhomogeneous models to be considered are weakly non-linear perturbation theory, anti-Newtonian approximation and post anti-Newtonian approximation. Smoothing-out process, the origin of cosmic microwave radiation, the origin of galaxies and the origin of chemical elements are discussed. (Kato, T.)

The origin of art according to Karl von den Steinen

Directory of Open Access Journals (Sweden)

Pierre Déléage

2015-06-01

Full Text Available Based on a study of the custom, adopted by ethnologists in the early 20th century, of asking Amerindians of Lowland South America to do drawings in pencil in their notebooks, I explore three forgotten fragments of the history of thinking: the intense debates on the origin of ornaments, opposing an evolutionist and a materialist approach at the end of the 19th century; the theories on the origin of figuration, which I show date back to the important work of Karl von den Steinen regarding the populations of central Brazil; and the publications of ethnologists’ portraits drawn by Indians of the lowlands of South America, a little-known tradition of reverse anthropology serving as a counterpoint to the study of the reception of Amerindian art in Western ethnological literature.

Until the sun dies. [Book on origin of universe, life and intelligence on earth

Science.gov (United States)

Jastrow, R.

1977-01-01

This book gives a popular account of the forces that have shaped human beings into their present form and created the power of human intelligence, and considers the prospects for intelligent life on other planets in the solar system and elsewhere in the universe. The chain of events leading from the big bang to the origin of life on earth is reviewed together with the observations that established the expansion of the universe. Philosophical difficulties with the concept of a universe that has both a beginning and an end are pondered, steady-state cosmology is briefly explained, and the discovery of the relict microwave background is discussed. The formation of the solar system is recounted along with the scientific view of the origin of terrestrial life. Attention is given to the origin of cells and the evolution of oxygen-breathing life, multicelled creatures, armored animals, fishes, amphibians, early reptiles, dinosaurs, and mammals. The development of mammalian intelligence is traced from the early tree dwellers through monkeys, apes, ape men, humanoid tool makers, and primitive members of the genus Homo, to Homo sapiens. Possible evidence for the existence of life on Mars is evaluated together with prospects for communication or other contact with extraterrestrial intelligence.

Study of southern CHAONAN sag lower continental slope basin deposition character in Northern South China Sea

Science.gov (United States)

Tang, Y.

2009-12-01

Northern South China Sea Margin locates in Eurasian plate,Indian-Australia plate,Pacific Plates.The South China Sea had underwent a complicated tectonic evolution in Cenozoic.During rifting,the continental shelf and slope forms a series of Cenozoic sedimentary basins,including Qiongdongnan basin,Pearl River Mouth basin,Taixinan basin.These basins fill in thick Cenozoic fluviolacustrine facies,transitional facies,marine facies,abyssal facies sediment,recording the evolution history of South China Sea Margin rifting and ocean basin extending.The studies of tectonics and deposition of depression in the Southern Chaonan Sag of lower continental slope in the Norther South China Sea were dealt with,based on the sequence stratigraphy and depositional facies interpretation of seismic profiles acquired by cruises of“China and Germany Joint Study on Marine Geosciences in the South China Sea”and“The formation,evolution and key issues of important resources in China marginal sea",and combining with ODP 1148 cole and LW33-1-1 well.The free-air gravity anomaly of the break up of the continental and ocean appears comparatively low negative anomaly traps which extended in EW,it is the reflection of passive margin gravitational effect.Bouguer gravity anomaly is comparatively low which is gradient zone extended NE-SW.Magnetic anomaly lies in Magnetic Quiet Zone at the Northern Continental Margin of the South China Sea.The Cenozoic sediments of lower continental slope in Southern Chaonan Sag can be divided into five stratum interface:SB5.5,SB10.5,SB16.5,SB23.8 and Hg,their ages are of Pliocene-Quaternary,late Miocene,middle Miocene,early Miocene,paleogene.The tectonic evolution of low continental slope depressions can be divided into rifting,rifting-depression transitional and depression stages,while their depositional environments change from river to shallow marine and abyssa1,which results in different topography in different stages.The topographic evolvement in the study

Dinetah: An Early History of the Navajo People.

Science.gov (United States)

Sundberg, Lawrence D.

Originally written for Navajo elementary school students, this book chronicles the history of the Navajo people from prehistory to 1868. The book presents a sympathetic history of a people who depended on their tenacity and creative adaptability to survive troubled times. Chapters examine how Navajo culture changed from that of an early hunting…

A bottom-up perspective on ecosystem change in Mesozoic oceans.

Science.gov (United States)

Knoll, Andrew H; Follows, Michael J

2016-10-26

Mesozoic and Early Cenozoic marine animals across multiple phyla record secular trends in morphology, environmental distribution, and inferred behaviour that are parsimoniously explained in terms of increased selection pressure from durophagous predators. Another systemic change in Mesozoic marine ecosystems, less widely appreciated than the first, may help to explain the observed animal record. Fossils, biomarker molecules, and molecular clocks indicate a major shift in phytoplankton composition, as mixotrophic dinoflagellates, coccolithophorids and, later, diatoms radiated across shelves. Models originally developed to probe the ecology and biogeography of modern phytoplankton enable us to evaluate the ecosystem consequences of these phytoplankton radiations. In particular, our models suggest that the radiation of mixotrophic dinoflagellates and the subsequent diversification of marine diatoms would have accelerated the transfer of primary production upward into larger size classes and higher trophic levels. Thus, phytoplankton evolution provides a mechanism capable of facilitating the observed evolutionary shift in Mesozoic marine animals. © 2016 The Authors.

ORIGIN: Metal Creation and Evolution from the Cosmic Dawn

CERN Document Server

Herder, Jan-Willem den; Ohashi, Takaya; Kouveliotou, Chryssa; Hartmann, Dieter H.; Kaastra, Jelle S.; Amati, L.; Andersen, M.I.; Arnaud, M.; Attéia, J.-L.; Bandler, S.; Barbera, M.; Barcons, X.; Barthelmy, S.; Basa, S.; Basso, S.; Boer, M.; Branchini, E.; Branduardi-Raymont, G.; Borgani, S.; Boyarsky, A.; Brunetti, G.; Budtz-Jorgensen, C.; Burrows, D.; Butler, N.; Campana, S.; Caroli, E.; Ceballos, M.; Christensen, F.; Churazov, E.; Comastri, A.; Colasanti, L.; Cole, R.; Content, R.; Corsi, A.; Costantini, E.; Conconi, P.; Cusumano, G.; de Plaa, J.; De Rosa, A.; Del Santo, M.; Di Cosimo, S.; De Pasquale, M.; Doriese, R.; Ettori, S.; Evans, P.; Ezoe, Y.; Ferrari, L.; Finger, H.; Figueroa-Feliciano, T.; Friedrich, P.; Fujimoto, R.; Furuzawa, A.; Fynbo, J.; Gatti, F.; Galeazzi, M.; Gehrels, N.; Gendre, B.; Ghirlanda, G.; Ghisellini, G.; Gilfanov, M.; Giommi, P.; Girardi, M.; Grindlay, J.; Cocchi, M.; Godet, O.; Guedel, M.; Haardt, F.; den Hartog, R.; Hepburn, I.; Hermsen, W.; Hjorth, J.; Hoekstra, H.; Holland, A.; Hornstrup, A.; van der Horst, A.; Hoshino, A.; in 't Zand, J.; Irwin, K.; Ishisaki, Y.; Jonker, P.; Kitayama, T.; Kawahara, H.; Kawai, N.; Kelley, R.; Kilbourne, C.; de Korte, P.; Kusenko, A.; Kuvvetli, I.; Labanti, M.; Macculi, C.; Maiolino, R.; Hesse, M. Mas; Matsushita, K.; Mazzotta, P.; McCammon, D.; Méndez, M.; Mignani, R.; Mineo, T.; Mitsuda, K.; Mushotzky, R.; Molendi, S.; Moscardini, L.; Natalucci, L.; Nicastro, F.; O'Brien, P.; Osborne, J.; Paerels, F.; Page, M.; Paltani, S.; Pedersen, K.; Perinati, E.; Ponman, T.; Pointecouteau, E.; Predehl, P.; Porter, S.; Rasmussen, A.; Rauw, G.; Röttgering, H.; Roncarelli, M.; Rosati, P.; Quadrini, E.; Ruchayskiy, O.; Salvaterra, R.; Sasaki, S.; Sato, K.; Savaglio, S.; Schaye, J.; Sciortino, S.; Shaposhnikov, M.; Sharples, R.; Shinozaki, K.; Spiga, D.; Sunyaev, R.; Suto, Y.; Takei, Y.; Tanvir, N.; Tashiro, M.; Tamura, T.; Tawara, Y.; Troja, E.; Tsujimoto, M.; Tsuru, T.; Ubertini, P.; Ullom, J.; Ursino, E.; Verbunt, F.; van de Voort, F.; Viel, M.; Wachter, S.; Watson, D.; Weisskopf, M.; Werner, N.; White, N.; Willingale, R.; Wijers, R.; Yamasaki, N.; Yoshikawa, K.; Zane, S.

2011-01-01

ORIGIN is a proposal for the M3 mission call of ESA aimed at the study of metal creation from the epoch of cosmic dawn. Using high-spectral resolution in the soft X-ray band, ORIGIN will be able to identify the physical conditions of all abundant elements between C and Ni to red-shifts of z=10, and beyond. The mission will answer questions such as: When were the first metals created? How does the cosmic metal content evolve? Where do most of the metals reside in the Universe? What is the role of metals in structure formation and evolution? To reach out to the early Universe ORIGIN will use Gamma-Ray Bursts (GRBs) to study their local environments in their host galaxies. This requires the capability to slew the satellite in less than a minute to the GRB location. By studying the chemical composition and properties of clusters of galaxies we can extend the range of exploration to lower redshifts (z ~ 0.2). For this task we need a high-resolution spectral imaging instrument with a large field of view. Using the ...

Early executive function predicts reasoning development.

Science.gov (United States)

Richland, Lindsey E; Burchinal, Margaret R

2013-01-01

Analogical reasoning is a core cognitive skill that distinguishes humans from all other species and contributes to general fluid intelligence, creativity, and adaptive learning capacities. Yet its origins are not well understood. In the study reported here, we analyzed large-scale longitudinal data from the Study of Early Child Care and Youth Development to test predictors of growth in analogical-reasoning skill from third grade to adolescence. Our results suggest an integrative resolution to the theoretical debate regarding contributory factors arising from smaller-scale, cross-sectional experiments on analogy development. Children with greater executive-function skills (both composite and inhibitory control) and vocabulary knowledge in early elementary school displayed higher scores on a verbal analogies task at age 15 years, even after adjusting for key covariates. We posit that knowledge is a prerequisite to analogy performance, but strong executive-functioning resources during early childhood are related to long-term gains in fundamental reasoning skills.

Formal Semantics: Origins, Issues, Early Impact

Directory of Open Access Journals (Sweden)

Barbara H. Partee

2010-12-01

Full Text Available Formal semantics and pragmatics as they have developed since the late 1960's have been shaped by fruitful interdisciplinary collaboration among linguists, philosophers, and logicians, among others, and in turn have had noticeable effects on developments in syntax, philosophy of language, computational linguistics, and cognitive science.In this paper I describe the environment in which formal semantics was born and took root, highlighting the differences in ways of thinking about natural language semantics in linguistics and in philosophy and logic. With Montague as a central but not solo player in the story, I reflect on crucial developments in the 1960's and 70's in linguistics and philosophy, and the growth of formal semantics and formal pragmatics from there. I discuss innovations, key players, and leading ideas that shaped the development of formal semantics and its relation to syntax, to pragmatics, and to the philosophy of language in its early years, and some central aspects of its early impact on those fields.ReferencesAbbott, B. 1999. ‘The formal approach to meaning: Formal semantics and its recent developments’. Journal of Foreign Languages (Shanghai119, no. 1: 2–20. https://www.msu.edu/~abbottb/formal.htm.Ajdukiewicz, K. 1960. Je¸zyk i Poznanie (Language and Knowledge. Warsaw.Bach, E. 1968. ‘Nouns and Noun Phrases’. In E. Bach & R.T. Harms (eds. ‘Universals in Linguistic Theory’, 90–122. NY: Holt, Rinehart & Winston.Bach, E. 1989. Informal Lectures on Formal Semantics. New York: State University of New York Press.Bar-Hillel, Y. 1954a. ‘Logical syntax and semantics’. Language 30: 230–237.http://dx.doi.org/10.2307/410265Bar-Hillel, Y. 1954b. ‘Indexical Expressions’. Mind 63: 359–379.http://dx.doi.org/10.1093/mind/LXIII.251.359Bar-Hillel, Y. 1963. ‘Remarks on Carnap’s Logical Syntax of Language’. In P. A. Schilpp (ed. ‘The Philosophy of Rudolf Carnap’, 519–543. LaSalle, Illinois / London: Open

Geologic strip map along the Hines Creek Fault showing evidence for Cenozoic displacement in the western Mount Hayes and northeastern Healy quadrangles, eastern Alaska Range, Alaska

Science.gov (United States)

Nokleberg, Warren J.; Aleinikoff, John N.; Bundtzen, Thomas K.; Hanshaw, Maiana N.

2013-01-01

Geologic mapping of the Hines Creek Fault and the adjacent Trident Glacier and McGinnis Glacier Faults to the north in the eastern Alaska Range, Alaska, reveals that these faults were active during the Cenozoic. Previously, the Hines Creek Fault, which is considered to be part of the strike-slip Denali Fault system (Ridgway and others, 2002; Nokleberg and Richter, 2007), was interpreted to have been welded shut during the intrusion of the Upper Cretaceous Buchanan Creek pluton (Wahrhaftig and others, 1975; Gilbert, 1977; Sherwood and Craddock, 1979; Csejtey and others, 1992). Our geologic mapping along the west- to west-northwest-striking Hines Creek Fault in the northeastern Healy quadrangle and central to northwestern Mount Hayes quadrangle reveals that (1) the Buchanan Creek pluton is truncated by the Hines Creek Fault and (2) a tectonic collage of fault-bounded slices of various granitic plutons, metagabbro, metabasalt, and sedimentary rock of the Pingston terrane occurs south of the Hines Creek Fault.

A Hot Spring Origin of Life and Early Adaptive Pathway from Woese Progenotes to Marine Stromatolites

Science.gov (United States)

Norkus, R.; Damer, B. F.; Deamer, D. W.

2017-07-01

An origin of life on land is visualized as: organic compounds accumulating in hydrothermal pools, wet-dry cycling of protocells encapsulating synthesized polymers, arising of a Woese progenote and its evolution into living microbial communities.

Towards a High-resolution Time Scale for the Early Devonian

Science.gov (United States)

Dekkers, M. J.; da Silva, A. C.

2017-12-01

High-resolution time scales are crucial to understand Earth's history in detail. The construction of a robust geological time scale, however, inevitably becomes increasingly harder further back in time. Uncertainties associated with anchor radiometric ages increase in size, not speaking of the mere presence of suitable datable strata. However, durations of stages can be tightly constrained by making use of cyclic expressions in sediments, an approach that revolutionized the Cenozoic time scale. When precisely determined durations are stitched together, ultimately, a very precise time scale is the result. For the Mesozoic and Paleozoic an astronomical solution as a tuning target is not available but the dominant periods of eccentricity, obliquity and precession are reasonably well constrained for the entire Phanerozoic which enables their detection by means of spectral analysis. Eccentricity is time-invariant and is used as the prime building block. Here we focus on the Early Devonian, on its lowermost three stages: the Lochkovian, Pragian and Emsian. The uncertainties on the Devonian stage boundaries are currently in the order of several millions of years. The preservation of climatic cycles in diagenetically or even anchimetamorphically affected successions, however, is essential. The fit of spectral peak ratios with those calculated for orbital cycles, is classically used as a strong argument for a preserved climatic signal. Here we use primarily the low field magnetic susceptibility (MS) as proxy parameter, supported by gamma-ray spectrometry to test for consistency. Continuous Wavelet Transform, Evolutive Harmonic Analysis, Multitaper Method, and Average Spectral Misfit are used to reach an optimal astronomical interpretation. We report on classic Early Devonian sections from the Czech Republic: the Pozar-CS (Lochkovian and Pragian), Pod Barrandovem (Pragian and Lower Emsian), and Zlichov (Middle-Upper Emsian). Also a Middle-Upper Emsian section from the US

Trans-Amazon Drilling Project (TADP): origins and evolution of the forests, climate, and hydrology of the South American tropics

Science.gov (United States)

Baker, P. A.; Fritz, S. C.; Silva, C. G.; Rigsby, C. A.; Absy, M. L.; Almeida, R. P.; Caputo, M.; Chiessi, C. M.; Cruz, F. W.; Dick, C. W.; Feakins, S. J.; Figueiredo, J.; Freeman, K. H.; Hoorn, C.; Jaramillo, C.; Kern, A. K.; Latrubesse, E. M.; Ledru, M. P.; Marzoli, A.; Myrbo, A.; Noren, A.; Piller, W. E.; Ramos, M. I. F.; Ribas, C. C.; Trnadade, R.; West, A. J.; Wahnfried, I.; Willard, D. A.

2015-12-01

This article presents the scientific rationale for an ambitious ICDP drilling project to continuously sample Late Cretaceous to modern sediment in four different sedimentary basins that transect the equatorial Amazon of Brazil, from the Andean foreland to the Atlantic Ocean. The goals of this project are to document the evolution of plant biodiversity in the Amazon forests and to relate biotic diversification to changes in the physical environment, including climate, tectonism, and the surface landscape. These goals require long sedimentary records from each of the major sedimentary basins across the heart of the Brazilian Amazon, which can only be obtained by drilling because of the scarcity of Cenozoic outcrops. The proposed drilling will provide the first long, nearly continuous regional records of the Cenozoic history of the forests, their plant diversity, and the associated changes in climate and environment. It also will address fundamental questions about landscape evolution, including the history of Andean uplift and erosion as recorded in Andean foreland basins and the development of west-to-east hydrologic continuity between the Andes, the Amazon lowlands, and the equatorial Atlantic. Because many modern rivers of the Amazon basin flow along the major axes of the old sedimentary basins, we plan to locate drill sites on the margin of large rivers and to access the targeted drill sites by navigation along these rivers.

Trans-Amazon Drilling Project (TADP): origins and evolution of the forests, climate, and hydrology of the South American tropics

Science.gov (United States)

Baker, P.A.; Fritz, S.C.; Silva, C.G.; Rigsby, C.A.; Absy, M.L.; Almeida, R.P.; Caputo, Maria C.; Chiessi, C.M.; Cruz, F.W.; Dick, C.W.; Feakins, S.J.; Figueiredo, J.; Freeman, K.H.; Hoorn, C.; Jaramillo, C.A.; Kern, A.; Latrubesse, E.M.; Ledru, M.P.; Marzoli, A.; Myrbo, A.; Noren, A.; Piller, W.E.; Ramos, M.I.F.; Ribas, C.C.; Trinadade, R.; West, A.J.; Wahnfried, I.; Willard, Debra A.

2015-01-01

This article presents the scientific rationale for an ambitious ICDP drilling project to continuously sample Late Cretaceous to modern sediment in four different sedimentary basins that transect the equatorial Amazon of Brazil, from the Andean foreland to the Atlantic Ocean. The goals of this project are to document the evolution of plant biodiversity in the Amazon forests and to relate biotic diversification to changes in the physical environment, including climate, tectonism, and the surface landscape. These goals require long sedimentary records from each of the major sedimentary basins across the heart of the Brazilian Amazon, which can only be obtained by drilling because of the scarcity of Cenozoic outcrops. The proposed drilling will provide the first long, nearly continuous regional records of the Cenozoic history of the forests, their plant diversity, and the associated changes in climate and environment. It also will address fundamental questions about landscape evolution, including the history of Andean uplift and erosion as recorded in Andean foreland basins and the development of west-to-east hydrologic continuity between the Andes, the Amazon lowlands, and the equatorial Atlantic. Because many modern rivers of the Amazon basin flow along the major axes of the old sedimentary basins, we plan to locate drill sites on the margin of large rivers and to access the targeted drill sites by navigation along these rivers.

Apatite fission-track thermochronometric constraints on the exhumation and evolution of the southeastern Indian (Tamil Nadu) passive margin and the role of structural inheritance

Science.gov (United States)

De Grave, Johan; Glorie, Stijn; Singh, Tejpal; Van Ranst, Gerben; Nachtergaele, Simon

2017-04-01

After rifting from Gondwana in the Late Jurassic - Early Cretaceous, and subsequent opening of the Indian Ocean basin, the continental margins of India developed into typical passive margins. Extensional tectonic forces and thermal subsidence gave rise to the formation of both on-shore and off-shore basins along the southeastern passive margin of the Indian continent, along the Tamil Nadu coast. There, basins such as the Cauvery and Krishna-Godavari basin, accumulated Meso- and Cenozoic (Early Cretaceous to recent) detrital sediments coming off the rifted blocks and the Tamil Nadu hinterland. In places, deep rift basins have accumulated up to over 3000 m of sediments. The continental basement of Tamil Nadu is chiefly composed of metamorphic rocks of the Archean to Palaeoproterozoic Eastern Dharwar Craton and the coeval Southern Granulite Terrane (e.g. Peucat et al., 2013). Several crustal scale shear zones crosscut this assemblage and at least some are considered to represent Gondwanan sutures (Santosh et al., 2012). Smaller, younger granitoid plutons intrude the basement at several locations and most of these are of Late Neoproterozoic age (Glorie et al., 2014). In this work metamorphic basements rocks and the younger granitoids were sampled for a apatite fission-track (AFT) thermochronometric study. A North-South profile from Chennai to Thanjavur mainly transects the Salem block of the Southern Granulite Terrane, and crosscuts several crustal scale shear zones, such as the Cauvery, Salem-Attur and Gangavalli shear zones. Apatites from over 30 samples were used in this study. AFT ages all range between about 190 and 120 Ma (Jurassic - Early Cretaceous). These mainly represent the slow, shallow exhumation of the basement during the rift and early drift phase of the Indian plate from Gondwana. AFT mean track lengths vary between 11 and 13 µm and are typical of slowly exhumed basement. Thermal history modelling (using the QTQt software by Gallagher, 2012) confirms

Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets.

Science.gov (United States)

Antonelli, Michael A; Kim, Sang-Tae; Peters, Marc; Labidi, Jabrane; Cartigny, Pierre; Walker, Richard J; Lyons, James R; Hoek, Joost; Farquhar, James

2014-12-16

Achondrite meteorites have anomalous enrichments in (33)S, relative to chondrites, which have been attributed to photochemistry in the solar nebula. However, the putative photochemical reactions remain elusive, and predicted accompanying (33)S depletions have not previously been found, which could indicate an erroneous assumption regarding the origins of the (33)S anomalies, or of the bulk solar system S-isotope composition. Here, we report well-resolved anomalous (33)S depletions in IIIF iron meteorites (solar system (solar system S-isotope composition was chondritic (consistent with IAB iron meteorites, Earth, Moon, and Mars). The range of mass-independent sulfur isotope compositions may reflect spatial or temporal changes influenced by photochemical processes. A tentative correlation between S isotopes and Hf-W core segregation ages suggests that the two systems may be influenced by common factors, such as nebular location and volatile content.

Palaeoecology of triassic stem turtles sheds new light on turtle origins.

OpenAIRE

Joyce, Walter G.; Gauthier, Jacques A.

2004-01-01

Competing hypotheses of early turtle evolution contrast sharply in implying very different ecological settings-aquatic versus terrestrial-for the origin of turtles. We investigate the palaeoecology of extinct turtles by first demonstrating that the forelimbs of extant turtles faithfully reflect habitat preferences, with short-handed turtles being terrestrial and long-handed turtles being aquatic. We apply this metric to the two successive outgroups to all living turtles with forelimbs preserv...

The amniote temporal roof and the diapsid origin of the turtle skull.

Science.gov (United States)

Bever, G S; Lyson, Tyler R; Field, Daniel J; Bhullar, Bhart-Anjan S

2016-12-01

Fossils provide a glimpse into the architecturally complex origins of modern vertebrate body plans. One such origin that has been long debated is that of turtles. Although much attention has been directed toward the origin of the shell, the enigmatic evolution of the turtle skull and its anapsid temporal region has long clouded our understanding of reptile phylogeny. Two taxa, Eunotosaurus africanus and Pappochelys rosinae, were recently and independently described as long-anticipated stem turtles whose diapsid skulls would cement the evolutionary link between turtles and other modern reptile lineages. Detailed μCT analysis of the stratigraphically older and phylogenetically stemward of the two, Eunotosaurus, provides empirical insight into changing developmental trajectories that may have produced the anapsid cranial form of modern turtles and sets the stage for more comprehensive studies of early amniote cranial evolution. Copyright © 2016 Elsevier GmbH. All rights reserved.

Mitogenomic perspectives on the origin and phylogeny of living amphibians.

Science.gov (United States)

Zhang, Peng; Zhou, Hui; Chen, Yue-Qin; Liu, Yi-Fei; Qu, Liang-Hu

2005-06-01

Establishing the relationships among modern amphibians (lissamphibians) and their ancient relatives is necessary for our understanding of early tetrapod evolution. However, the phylogeny is still intractable because of the highly specialized anatomy and poor fossil record of lissamphibians. Paleobiologists are still not sure whether lissamphibians are monophyletic or polyphyletic, and which ancient group (temnospondyls or lepospondyls) is most closely related to them. In an attempt to address these problems, eight mitochondrial genomes of living amphibians were determined and compared with previously published amphibian sequences. A comprehensive molecular phylogenetic analysis of nucleotide sequences yields a highly resolved tree congruent with the traditional hypotheses (Batrachia). By using a molecular clock-independent approach for inferring dating information from molecular phylogenies, we present here the first molecular timescale for lissamphibian evolution, which suggests that lissamphibians first emerged about 330 million years ago. By observing the fit between molecular and fossil times, we suggest that the temnospondyl-origin hypothesis for lissamphibians is more credible than other hypotheses. Moreover, under this timescale, the potential geographic origins of the main living amphibian groups are discussed: (i) advanced frogs (neobatrachians) may possess an Africa-India origin; (ii) salamanders may have originated in east Asia; (iii) the tropic forest of the Triassic Pangaea may be the place of origin for the ancient caecilians. An accurate phylogeny with divergence times can be also helpful to direct the search for "missing" fossils, and can benefit comparative studies of amphibian evolution.

Unguja Ukuu on Zanzibar : An archaeological study of early urbanism

OpenAIRE

Juma, Abdurahman

2004-01-01

This study describes archaeological excavations carried out at Unguja Ukuu on the main island of Zanzibar, Tanzania. The site has long remained obscure, oral histories do not mention it and no particular group among the living community of the island describes its origin from the site. A stone well at Unguja Ukuu together with several other early monuments of the east African coast that survive on the site have been attributed to the Wadebuli, suspected by early scholars to be people of Arab ...

The Early History of UC Santa Cruz's Farm and Garden

OpenAIRE

Lee, Paul; Norris, Phyllis; Martin, Orin; Tamura, Dennis; Hagege, Maya; Jarrell, Randall; Regional History Project, UCSC Library

2002-01-01

The Early History of UCSC's Farm and Garden documents the emergence of the organic gardening and farming movement in Santa Cruz. It includes interviews with Paul Lee, Phyllis Norris, Orin Martin, and Dennis Tamura, who were involved in the early years of the Garden. Maya Hagege, a former Farm and Garden apprentice and UCSC alumna, conducted the interviews, which were edited by Jarrell. Established in 1967 by master gardener Alan Chadwick, the original site was a neglected 4-acre plot...

Early Birds in Korea: Exporting Defense AT and L Has Far Reaching Impact

Science.gov (United States)

2015-11-01

51 Defense AT&L: November–December 2015 Early Birds in Korea ”Exporting” Defense AT&L Has Far-Reaching Impact DT Tripp n Hwa Yu Tripp is...Defense Acquisition Program Administration. “The early bird catches the worm.” Who doesn’t know this proverb? A study club in the Republic of Korea (ROK...name originated from that tenet as the “Early Birds Study”—or the EBS, for short. This year, the EBS will celebrate the 10th anniversary of its

Cenozoic landforms and post-orogenic landscape evolution of the Balkanide orogen: Evidence for alternatives to the tectonic denudation narrative in southern Bulgaria

Science.gov (United States)

Gunnell, Y.; Calvet, M.; Meyer, B.; Pinna-Jamme, R.; Bour, I.; Gautheron, C.; Carter, A.; Dimitrov, D.

2017-01-01

Continental denudation is the mass transfer of rock from source areas to sedimentary depocentres, and is typically the result of Earth surface processes. However, a process known as tectonic denudation is also understood to expose deep-seated rocks in short periods of geological time by displacing large masses of continental crust along shallow-angle faults, and without requiring major contributions from surface erosion. Some parts of the world, such as the Basin and Range in the USA or the Aegean province in Europe, have been showcased for their Cenozoic tectonic denudation features, commonly described as metamorphic core-complexes or as supradetachment faults. Based on 22 new apatite fission-track (AFT) and 21 helium (AHe) cooling ages among rock samples collected widely from plateau summits and their adjacent valley floors, and elaborating on inconsistencies between the regional stratigraphic, topographic and denudational records, this study frames a revised perspective on the prevailing tectonic denudation narrative for southern Bulgaria. We conclude that conspicuous landforms in this region, such as erosion surfaces on basement-cored mountain ranges, are not primarily the result of Paleogene to Neogene core-complex formation. They result instead from "ordinary" erosion-driven, subaerial denudation. Rock cooling, each time suggesting at least 2 km of crustal denudation, has exposed shallow Paleogene granitic plutons and documents a 3-stage wave of erosional denudation which progressed from north to south during the Middle Eocene, Oligocene, Early to Middle Miocene, and Late Miocene. Denudation initially prevailed during the Paleogene under a syn-orogenic compressional regime involving piggyback extensional basins (Phase 1), but subsequently migrated southward in response to post-orogenic upper-plate extension driven by trench rollback of the Hellenic subduction slab (Phase 2). Rare insight given by the denudation pattern indicates that trench rollback

The palaeobiology of high latitude birds from the early Eocene greenhouse of Ellesmere Island, Arctic Canada.

Science.gov (United States)

Stidham, Thomas A; Eberle, Jaelyn J

2016-02-12

Fossils attributable to the extinct waterfowl clade Presbyornithidae and the large flightless Gastornithidae from the early Eocene (~52-53 Ma) of Ellesmere Island, in northernmost Canada are the oldest Cenozoic avian fossils from the Arctic. Except for its slightly larger size, the Arctic presbyornithid humerus is not distinguishable from fossils of Presbyornis pervetus from the western United States, and the Gastornis phalanx is within the known size range of mid-latitude individuals. The occurrence of Presbyornis above the Arctic Circle in the Eocene could be the result of annual migration like that of its living duck and geese relatives, or it may have been a year-round resident similar to some Eocene mammals on Ellesmere and some extant species of sea ducks. Gastornis, along with some of the mammalian and reptilian members of the Eocene Arctic fauna, likely over-wintered in the Arctic. Despite the milder (above freezing) Eocene climate on Ellesmere Island, prolonged periods of darkness occurred during the winter. Presence of these extinct birds at both mid and high latitudes on the northern continents provides evidence that future increases in climatic warming (closer to Eocene levels) could lead to the establishment of new migratory or resident populations within the Arctic Circle.

Do Martian Blueberries Have Pits? -- Artifacts of an Early Wet Mars

Science.gov (United States)

Lerman, L.

2005-03-01

Early Martian weather cycles would have supported organic chemical self-organization, the assumed predecessor to an independent "origin" of Martian life. Artifacts of these processes are discussed, including the possibility that Martian blueberries nucleated around organic cores.

An evaluation of the Triage Early Warning Score in an urban ...

African Journals Online (AJOL)

2013-12-03

Dec 3, 2013 ... Original Research: An evaluation of the Triage Early Warning Score in an urban accident and emergency department. 69 ... This can potentially improve the gap .... were defined as “discharge within 24 hours of admission,.