Penis morphology in a Burmese amber harvestman

Science.gov (United States)

Dunlop, Jason A.; Selden, Paul A.; Giribet, Gonzalo

2016-02-01

A unique specimen of the fossil harvestman Halitherses grimaldii Giribet and Dunlop, 2005 (Arachnida: Opiliones) from the Cretaceous (ca. 99 Ma) Burmese amber of Myanmar reveals a fully extended penis. This is the first record of a male copulatory organ of this nature preserved in amber and is of special importance due to the age of the deposit. The penis has a slender, distally flattened truncus, a spatulate heart-shaped glans and a short distal stylus, twisted at the tip. In living harvestmen, the penis yields crucial characters for their systematics. Male genital morphology in H. grimaldii appears to be unique among the wider Dyspnoi clade to which this fossil belongs. The large eyes in the fossil differ markedly from other members of the subfamily Ortholasmatinae to which H. grimaldii was originally referred. Based on recent data, it has been argued that large eyes may be plesiomorphic for Palpatores (i.e. the suborders Eupnoi and Dyspnoi), potentially rendering this character plesiomorphic for the fossil too. Thus, the unique structure of the penis seen here, and the probable lack of diaphanous teeth, present in all other extant non-acropsopilionid Dyspnoi, suggest that H. grimaldii represents a new, extinct family of large-eyed dyspnoid harvestmen, Halithersidae fam. nov.; a higher taxon in amber diagnosed here on both somatic and genital characters.

Bridging the gap between chewing and sucking in the hemipteroid insects: new insights from Cretaceous amber.

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Yoshizawa, Kazunori; Lienhard, Charles

2016-02-11

The diversity of feeding apparatuses in insects far exceeds that observed in any other animal group. Consequently, tracking mouthpart innovation in insects is one of the keys toward understanding their diversification. In hemipteroid insects (clade Paraneoptera or Acercaria: lice, thrips, aphids, cicadas, bugs, etc.), the transition from chewing to piercing-and-sucking mouthparts is widely regarded as the turning point that enabled hyperdiversification of the Hemiptera, the fifth largest insect order. However, the transitional process from chewing to piercing-and-sucking in the Paraneoptera was hitherto completely unknown. In this paper, we report a well preserved mid Cretaceous amber fossil of the paraneopteran insect family Archipsyllidae and describe it as Mydiognathus eviohlhoffae gen. et sp. n. This species has elongate mandibles and styliform laciniae similar to Hemiptera but retains functional chewing mouthparts. A number of morphological characters place the Archipsyllidae as the sister group of the thrips plus hemipterans, which strongly suggests that the mouthparts of M. eviohlhoffae represent a transitional condition from primitive chewing to derived piercing-and-sucking mouthparts. The clade composed of Archipsyllidae, thrips, and hemipterans is here named Pancondylognatha, a new supra-ordinal taxon. Based on newly obtained information, we also assess the monophyly of the Paraneoptera, which was called into question by recent phylogenomic analyses. A phylogenetic analysis that includes Mydiognathus strongly supports the monophyly of the Paraneoptera.

Ca2+-Signal Transduction Inhibitors, Kujiol A and Kujigamberol B, Isolated from Kuji Amber Using a Mutant Yeast.

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Uchida, Takeshi; Koshino, Hiroyuki; Takahashi, Shunya; Shimizu, Eisaku; Takahashi, Honoka; Yoshida, Jun; Shinden, Hisao; Tsujimura, Maiko; Kofujita, Hisayoshi; Uesugi, Shota; Kimura, Ken-Ichi

2018-04-27

A podocarpatriene and a labdatriene derivative, named kujiol A [13-methyl-8,11,13-podocarpatrien-19-ol (1)] and kujigamberol B [15,20-dinor-5,7,9-labdatrien-13-ol (2)], respectively, were isolated from Kuji amber through detection with the aid of their growth-restoring activity against a mutant yeast strain ( zds1Δ erg3Δ pdr1Δ pdr3Δ), which is known to be hypersensitive with respect to Ca 2+ -signal transduction. The structures were elucidated by spectroscopic data analysis. Compounds 1 and 2 are rare organic compounds from Late Cretaceous amber, and the mutant yeast used seems useful for elucidating a variety of new compounds from Kuji amber specimens, produced before the K-Pg boundary.

The trace fossil Lepidenteron lewesiensis (Mantell, 1822) from the Upper Cretaceous of southern Poland

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Jurkowska, Agata; Uchman, Alfred

2013-12-01

Jurkowska, A. and Uchman, A. 2013. The trace fossil Lepidenteron lewesiensis (Mantell, 1822) from the Upper Cretaceous of southern Poland. Acta Geologica Polonica, 63(4), 611-623. Warszawa. Lepidenteron lewesiensis (Mantell, 1822) is an unbranched trace fossil lined with small fish scales and bones, without a constructed wall. It is characteristic of the Upper Cretaceous epicontinental, mostly marly sediments in Europe. In the Miechow Segment of the Szczecin-Miechow Synclinorium in southern Poland, it occurs in the Upper Campanian-Lower Maastrichtian deeper shelf sediments, which were deposited below wave base and are characterized by total bioturbation and a trace fossil assemblage comprising Planolites, Palaeophycus, Thalassinoides , Trichichnus, Phycosiphon, Zoophycos and Helicodromites that is typical of the transition from the distal Cruziana to the Zoophycos ichnofacies. L. lewesiensis was produced by a burrowing predator or scavenger of fishes. The tracemaker candidates could be eunicid polychaetes or anguillid fishes.

New genus and species of the extinct aphid family Szelegiewicziidae and their implications for aphid evolution

DEFF Research Database (Denmark)

Wegierek, Piotr; Zyła, Dagmara Maria; Homan, Agnieszka

2017-01-01

of the extinct groups. The extinct aphid family Szelegiewicziidae is supposed to be one of the oviparous lineages in aphid evolution. New material from the rock fossil deposits of Shar Teg (Upper Jurassic of Mongolia), Baissa (Lower Cretaceous of Siberia-Russia), and Burmese amber (Upper Cretaceous of Myanmar...

Palaeoenvironments and facies on a progressively flooded rocky island (Upper Cenomanian – Lower Turonian, Bohemian Cretaceous Basin)

Czech Academy of Sciences Publication Activity Database

Žítt, Jiří; Vodrážka, R.; Hradecká, L.; Svobodová, Marcela

2010-01-01

Roč. 179, - (2010), s. 223-234 ISSN 1802-6842 Institutional research plan: CEZ:AV0Z30130516 Keywords : Cretaceous island * weathering * geomorphology * sedimentary environments * biostratigraphy * Upper Cenomanian-Lower Turonian * Bohemian Cretaceous Basin Subject RIV: DB - Geology ; Mineralogy http://www.nm.cz/publikace/archiv-en.php?id=1&rok=179&f_=Show

Geologic models and evaluation of undiscovered conventional and continuous oil and gas resources: Upper Cretaceous Austin Chalk

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Pearson, Krystal

2012-01-01

The Upper Cretaceous Austin Chalk forms a low-permeability, onshore Gulf of Mexico reservoir that produces oil and gas from major fractures oriented parallel to the underlying Lower Cretaceous shelf edge. Horizontal drilling links these fracture systems to create an interconnected network that drains the reservoir. Field and well locations along the production trend are controlled by fracture networks. Highly fractured chalk is present along both regional and local fault zones. Fractures are also genetically linked to movement of the underlying Jurassic Louann Salt with tensile fractures forming downdip of salt-related structures creating the most effective reservoirs. Undiscovered accumulations should also be associated with structure-controlled fracture systems because much of the Austin that overlies the Lower Cretaceous shelf edge remains unexplored. The Upper Cretaceous Eagle Ford Shale is the primary source rock for Austin Chalk hydrocarbons. This transgressive marine shale varies in thickness and lithology across the study area and contains both oil- and gas-prone kerogen. The Eagle Ford began generating oil and gas in the early Miocene, and vertical migration through fractures was sufficient to charge the Austin reservoirs.

Review of the Upper Jurassic-Lower Cretaceous stratigraphy in Western Cameros basin, Northern Spain

DEFF Research Database (Denmark)

Vidal, Maria del Pilar Clemente

2010-01-01

The Upper Jurassic-Lower Cretaceous stratigraphy of the Cameros basin has been reviewed. In Western Cameros the stratigraphic sections are condensed but they have a parallel development with the basin depocentre and the same groups have been identified. The Tera Group consists of two formations: ...

The Amber Industry: Development Сhallenges and Combating Amber Trafficking in the Baltic Region

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Volchetskaya Т. S.

2017-12-01

Full Text Available This article considers the current state and prospective development of the amber industry in the Baltic Sea region. The authors identify the main obstacles to the industry’s development in Russia — poor pricing mechanisms for raw amber, an imbalance between supply and demand, a slow pace of technological modernisation, and a delayed introduction of new technologies and processing techniques. The authors identify gaps in the regulatory framework and highlight problems of legal regulation and law enforcement as regards the amber industry. Combating illegal amber extraction and trafficking is a pressing problem in the Kaliningrad region (Russia and other Baltic region states. The article explores theoretical aspects of the legislative policy on combating illegal amber extraction and trafficking. The authors focus on the relevant law enforcement practices and hold that administrative sanctions for unauthorised amber extraction and trade are not fully effective in Russia. The authors stress the need for introducing criminal liability for a repeated offence and outline opportunities for using forensic gemological examination of amber and amber products.

Reworked Middle Jurassic sandstones as a marker for Upper Cretaceous basin inversion in Central Europe—a case study for the U-Pb detrital zircon record of the Upper Cretaceous Schmilka section and their implication for the sedimentary cover of the Lausitz Block (Saxony, Germany)

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Hofmann, Mandy; Voigt, Thomas; Bittner, Lucas; Gärtner, Andreas; Zieger, Johannes; Linnemann, Ulf

2018-04-01

The Saxonian-Bohemian Cretaceous Basin (Elbsandsteingebirge, E Germany and Czech Republic, Elbtal Group) comprises Upper Cretaceous sedimentary rocks from Upper Cenomanian to Santonian age. These sandstones were deposited in a narrow strait of the sea linking the northern Boreal shelf to the southern Tethyan areas. They were situated between the West Sudetic Island in the north and the Mid-European Island in the south. As known by former studies (e.g. Tröger, Geologie 6/7:717-730, 1964; Tröger, Geologie von Sachsen, Schweizerbart, 311-358, 2008; Voigt and Tröger, Proceedings of the 4th International Cretaceous Symposium, 275-290, 1996; Voigt, Dissertation, TU Bergakademie Freiberg, 1-130, 1995; Voigt, Zeitschrift der geologischen Wissenschaften 37(1-2): 15-39, 2009; Wilmsen et al., Freiberger Forschungshefte C540: 27-45, 2011) the main sedimentary input came from the north (Lausitz Block, southern West-Sudetic Island). A section of Turonian to Coniacian sandstones was sampled in the Elbsandsteingebirge near Schmilka (Elbtal Group, Saxony, Germany). The samples were analysed for their U-Pb age record of detrital zircon using LA-ICP-MS techniques. The results show main age clusters typical for the Bohemian Massif (local material) and are interpreted to reflect the erosion of uniform quartz-dominated sediments and basement rocks. Surprisingly, these rocks lack an expected Upper Proterozoic to Lower Palaeozoic age peak, which would be typical for the basement of the adjacent Lausitz Block (c. 540-c. 560 Ma). Therefore, the Lausitz Block basement must have been covered by younger sediments that acted as source rocks during deposition of the Elbtal Group. The sandstones of the Elbe valley (Elbtal Group, Schmilka section) represent the re-deposited sedimentary cover of the Lausitz Block in inverse order. This cover comprised Permian, Triassic, Jurassic and Lower Cretaceous deposits, which are eroded already today and cannot be investigated. Within the samples of the

Preliminary vitrinite and bitumen reflectance, total organic carbon, and pyrolysis data for samples from Upper and Lower Cretaceous strata, Maverick Basin, south Texas

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Hackley, Paul C.; Dennen, Kristin O.; Gesserman, Rachel M.; Ridgley, Jennie L.

2009-01-01

The Lower Cretaceous Pearsall Formation, a regionally occurring limestone and shale interval of 500-600-ft maximum thickness (Rose, 1986), is being evaluated as part of an ongoing U.S. Geological Survey (USGS) assessment of undiscovered hydrocarbon resources in onshore Lower Cretaceous strata of the northern Gulf of Mexico. The purpose of this report is to release preliminary vitrinite and bitumen reflectance, total organic carbon, and pyrolysis data for Pearsall Formation, Glen Rose Formation, Hosston Formation, Austin Group, and Eagle Ford Group samples from the Maverick Basin in south Texas in order to aid in the characterization of these strata in this area. The preliminary nature of this report and the data contained herein reflect that the assessment and characterization of these samples is a work currently in progress. Pearsall Formation subdivisions are, in ascending stratigraphic order, the Pine Island Shale, James Limestone, and Bexar Shale Members (Loucks, 2002). The Lower Cretaceous Glen Rose Formation is also part of the USGS Lower Cretaceous assessment and produces oil in the Maverick Basin (Loucks and Kerans, 2003). The Hosston Formation was assessed by the USGS for undiscovered oil and gas resources in 2006 (Dyman and Condon, 2006), but not in south Texas. The Upper Cretaceous Austin Group is being assessed as part of the USGS assessment of undiscovered hydrocarbon resources in the Upper Cretaceous strata of the northern Gulf of Mexico and, along with the Upper Cretaceous Eagle Ford Group, is considered to be an important source rock in the Smackover-Austin-Eagleford Total Petroleum System (Condon and Dyman, 2006). Both the Austin Group and the Eagle Ford Group are present in the Maverick Basin in south Texas (Rose, 1986).

The occurrence of amber and sub-amber (copal) in Costa Rica: the case of San Cristobal de Savegre

International Nuclear Information System (INIS)

Alvarado, Guillermo E.; Brenes, Jorge; Brenes, Jose

2013-01-01

In Costa Rica, small fragments of amber are found in the Miocene shallow marine clastic sedimentary rocks, such as Formacion Punta Judas (Middle Miocene), Formacion Santa Teresa (Middle Miocene), and Formacion Curre (Middle-Upper Miocene). Sub-amber or copal is found in relative abundance in certain localities in the residual soils in the mountains near San Cristobal de Savegre (Aguirre, Puntarenas). The copal samples have sub-rounded or pearly (21.3%), tabular or laminar (29.6%) and troncoidal (30.4%) forms, but some are intermediate or indefinite (18.7%). Its color varies between orange / red (57.4%), followed by yellow (31.0%) and less frequently light yellow to whitish (11.6%); some samples have insects incorporated. The age of the copal is in the age range of 1670-1780 A.D., based on a calibrated 14 C dating. Although these samples of copal seem to have no commercial value, they could be used by local artisans. (author) [es

Geochemistry and environmental isotope of groundwater from the upper Cretaceous aquifer of Orontes basin (Syria)

International Nuclear Information System (INIS)

Al-Charideh, A.

2010-03-01

Chemical and environmental isotopes have been used for studying the Upper Cretaceous aquifer systems in the Middle Orontes basin. The results indicate that the salinity of groundwater (0.2 to 2 g/l) reveals the dissolution of evaporate rocks is the main factor of high salinity especially in the Homes depression. The degree of salinity and its spaces distribution are basically related to the pattern of groundwater movement in the Upper cretaceous aquifer. The stable isotopes composition of groundwater in the Homes depression are more depleted by -2.5% and -17.0% for δ 18 O and δ 2 H respectively, than the groundwater from Hama elevation, suggested different origin and recharge time between this two groundwater groups. Estimates of their mean subsurface residence times have been constrained on the basis of 14 C D IC. The corrected ages of groundwater are recent and less to 10 thousand years in Hama uplift. However, the corrected age of groundwater in the Homs depression range between 10 to 25 thousand years indicate late Pleistocene recharge period. (author)

A large parasitengonid mite (Acari, Erythraeoidea from the Early Cretaceous Crato Formation of Brazil

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J. A. Dunlop

2007-08-01

Full Text Available A new large, fossil mite (Arachnida: Acari, Pararainbowia martilli n. gen. n. sp., is described from the Early Cretaceous (Aptian Crato Formation from Ceará State, Brazil. It is assigned to the Cohort Parasitengona and the superfamily Erythraeoidea, some extant members of which can reach up to seven millimetres in body length. Given that doubts have been raised about the identity of putative Crato feather mite eggs, this new fossil represents the first unequivocal record of Acari from the Crato Formation, the first non-amber record of an erythraeoid mite and the oldest named example of this superfamily. Fossil erythraeoids from Mesozoic and Tertiary ambers are briefly reviewed – including a widely overlooked Late Cretaceous species – with comments on Mesozoic mites in general. Thirteen Baltic amber erythraeoids have been formally described, but much unstudied material from various amber sources remains. Ein neues großes Milbenfossil (Arachnida: Acari, Pararainbowia martilli n. gen. n. sp., wird aus der Crato Formation (Unterkreide, Aptium des Ceará Gebietes in Brasilien beschrieben. Es wird der Kohorte Parasitengona und der Überfamilie Erythraeoidea zugeordnet; die modernen Vertreter erreichen eine Körperlänge bis zu sieben mm. Weil die Identität von Federmilbeneiern aus der Crato Formation in Frage gestellt wurde, ist dieser Neufund der erste klare Hinweis von Acari aus der Crato Formation. Es ist die erste erythraeoide Milbe, die nicht aus dem Bernstein stammt sowie das älteste genannte Beispiel dieser Überfamilie. Fossile erythraeoide Milben aus dem Bernstein des Mesozoikum und des Tertiärs werden kurz zusammengefasst – u. a. eine weitgehend übersehene Art aus der Oberkreide – mit allgemeinen Anmerkungen zu den mesozoischen Milben. Dreizehn erythraeoide Milbenarten sind aus dem baltischen Bernstein genannt und beschrieben worden, aber weiteres unbearbeitetes Material von verschiedenen Bernstein-Fundpunkten liegt noch vor

A new genus and species of micro bee fly from the Earliest Eocene French amber (Diptera: Mythicomyiidae: Psiloderoidinae).

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Myskowiak, Justine; Garrouste, Romain; Nel, Andre

2016-05-26

Mythicomyiidae, or micro bee flies, are tiny flies (0.5-5.0 mm) that are found throughout most parts of the world except the highest altitudes and latitudes (Greathead & Evenhuis 2001). Including all extinct and extant taxa, the Mythicomyiidae currently comprise more than 380 valid taxonomic species distributed among 30 genera. The subfamily Psiloderoidinae is especially well represented among the fossil Mythicomyiidae by seven Cretaceous or Cenozoic genera. We here describe a new genus and a new species of this subfamily based on fossils from the Earliest Eocene of Oise (France). A Psiloderoidinae, Proplatypygus matilei Nel & DePloëg, 2004, is already described in this amber. Another mythicomyiid, Eurodoliopteryx inexpectatus Nel, 2006, is the most frequent bombylioid in this amber (Nel & DePloëg, 2004; Nel, 2006).

Foraminiferal biostratigraphy of Upper Cretaceous (Campanian - Maastrichtian) sequences in the Peri-Tethys basin; Moghan area, NW Iran

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Omidvar, Mahboobeh; Safari, Amrollah; Vaziri-Moghaddam, Hossain; Ghalavand, Hormoz

2018-04-01

The Upper Cretaceous sediments in the Moghan area, NW Iran, contain diverse planktonic and benthic foraminifera, with a total of 33 genera and 53 species (17 genera and 38 species of planktonic foraminifera and 16 genera and 15 species from benthic foraminifera), which led to the identification of six biozones spanning the middle Campanian to late Maastrichtian. A detailed paleontological study and biostratigraphic zonation of these sequences has been carried out in four surface sections. This study shows that there are two different facies in the Moghan area, based on the faunal content. A deep open marine condition exists in the Molok, Selenchai and Nasirkandi sections. In these sections, Upper Cretaceous sequences have diverse planktonic foraminiferal species including the Globotruncana ventricosa (middle to late Campanian), Globotruncanella havanensis (late Campanian), Globotruncana aegyptiaca (latest Campanian), Gansserina gansseri (latest Campanian to early Maastrichtian), Contusotruncana contusa- Racemiguembelina fructicosa (early to late Maastrichtian) and Abathomphalus mayaroensis (late Maastrichtian) zones. This deep open marine setting grades laterally into shallower marine condition dominated by large benthic foraminifera such as Orbitoides media, Orbitoides gruenbachensis, Orbitoides cf. apiculata, Lepidorbitoides minor, Pseudosiderolites sp., Siderolites praecalcitrapoides, Siderolites aff. calcitrapoides and Siderolites calcitrapoides. This facies is mainly recorded in the Hovay section. A detailed biostratigraphic zonation scheme is presented for the studied sections and correlated with the results of other studies in the Tethyan realm. This is the first biozonation scheme for Upper Cretaceous sequences of the Moghan area that can be used as a basis for ongoing studies in this area and other parts of Tethys basin.

Evidence for marine microfossils from amber.

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Girard, Vincent; Schmidt, Alexander R; Saint Martin, Simona; Struwe, Steffi; Perrichot, Vincent; Saint Martin, Jean-Paul; Grosheny, Danièle; Breton, Gérard; Néraudeau, Didier

2008-11-11

Amber usually contains inclusions of terrestrial and rarely limnetic organisms that were embedded in the places were they lived in the amber forests. Therefore, it has been supposed that amber could not have preserved marine organisms. Here, we report the discovery amber-preserved marine microfossils. Diverse marine diatoms as well as radiolarians, sponge spicules, a foraminifer, and a spine of a larval echinoderm were found in Late Albian and Early Cenomanian amber samples of southwestern France. The highly fossiliferous resin samples solidified approximately 100 million years ago on the floor of coastal mixed forests dominated by conifers. The amber forests of southwestern France grew directly along the coast of the Atlantic Ocean and were influenced by the nearby sea: shells and remnants of marine organisms were probably introduced by wind, spray, or high tide from the beach or the sea onto the resin flows.

Biostratigraphy of the Upper Cretaceous deposits in north of Birjand, (Shushud section

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farah jalili

2014-11-01

Full Text Available Introduction: One of the first works about Cretaceous deposits in eastern part of the Lut Block is done by Stocklin et al. (1972. They reported Orbitolina limestones in Shah Kuh area and Maasterichtian siliciclastic and limestone beds which have overlaid the older deposits with a gap. In geological maps of the east of Iran, Upper Cretaceous deposits have been reported (Berthiaux et al., 1990; Eftekharnejad, 1991; Berberian and Soheili, 1992; Alvai Naini, 1983; Guillou et al., 1981 that they have been mostly referred to shallow and relatively deep facies. Moreover, Gorgich (2002, Gorgich et al. (2009 and Motie (2010 reported Maastrichtian deposits in the east of Iran. The study area is located at Geological Quadrangle Map of Qayen (Berthiaux et al., 1990 and Geological Sheet Map of Roum (Shahidi et al., 2000. The measured section is geographically situated at 33o 05′ north latitude and 59o 02′ east longitude. Aims and Method: This paper aims to study lithostratigraphy, identification of foraminifera assemblage, age determination, and biostratigraphy and biozonation of the measured section. The authors hope this research lead to a better understanding of the regional geology and distribution of Cretaceous foraminifera that might describe the degree of lithostratigraphic and biostratigraphic precision. In this research 160 samples have been collected which 130 samples were cut and thin sections were prepared. The other samples were disaggregated in dilute H2O2 (10% vol. and washed. The washed residues were dried and picked the isolated forams. Thin sections studied under Olympus microscope and the foraminifera were identified and photographed. The isolated forms were photographed with Scanning Electronic Microscope (SEM device model XL30 Philips in Technical Faculty of Tehran University. Discussion and results (Lithostratigraphy and biostratigraphy: From point of view of lithostratigraphy, the lower contact of the succession is faulted and the

Scaphitid ammonites from the Upper Cretaceous of KwaZulu-Natal and Eastern Cape Province, South Africa

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Kennedy, William James; Klinger, Herbert Christian

2013-12-01

Kennedy, W.J. and Klinger, H.C. 2013. Scaphitid ammonites from the Upper Cretaceous of KwaZulu-Natal and Eastern Cape Province, South Africa. Acta Geologica Polonica, 63 (4), 527-543. Warszawa. Scaphitid ammonites are described and illustrated from the Upper Cretaceous of the coastal region of north-eastern South Africa. Scaphites kieslingswaldensis Langenhan and Grundey, 1891, Scaphites manasoaensis Collignon, 1965, and Yezoites concinna sp. nov. occur in the Coniacian part of the St Lucia Formation in northern KwaZulu-Natal. A further Yezoites sp. may also be from this level. Argentoscaphites corrugatus sp. nov. occurs in the Santonian to Lower Campanian Mzamba Formation on the northernmost coast of Eastern Cape Province. Yezoites australis sp. nov. occurs in the Upper Santonian part of the St Lucia and Mzamba formations of these areas, and Scaphites reesidei Collignon, 1969, is recorded from the Lower Campanian part of the Mzamba Formation. The scaphitid assemblage includes species previously described from Western Europe and Madagascar, together with Argentoscaphites, previously known only from Patagonia (and possibly South India). Dimorphism is recognised in Scaphites reesidei, Yezoites concinna sp. nov. and Y. australis sp. nov. Argentoscaphites corrugatus sp. nov. and Yezoites sp. are represented by microconchs only. Dimorphism has not been recognised in Scaphites kieslingswaldensis.

Debris-carrying camouflage among diverse lineages of Cretaceous insects.

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Wang, Bo; Xia, Fangyuan; Engel, Michael S; Perrichot, Vincent; Shi, Gongle; Zhang, Haichun; Chen, Jun; Jarzembowski, Edmund A; Wappler, Torsten; Rust, Jes

2016-06-01

Insects have evolved diverse methods of camouflage that have played an important role in their evolutionary success. Debris-carrying, a behavior of actively harvesting and carrying exogenous materials, is among the most fascinating and complex behaviors because it requires not only an ability to recognize, collect, and carry materials but also evolutionary adaptations in related morphological characteristics. However, the fossil record of such behavior is extremely scarce, and only a single Mesozoic example from Spanish amber has been recorded; therefore, little is known about the early evolution of this complicated behavior and its underlying anatomy. We report a diverse insect assemblage of exceptionally preserved debris carriers from Cretaceous Burmese, French, and Lebanese ambers, including the earliest known chrysopoid larvae (green lacewings), myrmeleontoid larvae (split-footed lacewings and owlflies), and reduviids (assassin bugs). These ancient insects used a variety of debris material, including insect exoskeletons, sand grains, soil dust, leaf trichomes of gleicheniacean ferns, wood fibers, and other vegetal debris. They convergently evolved their debris-carrying behavior through multiple pathways, which expressed a high degree of evolutionary plasticity. We demonstrate that the behavioral repertoire, which is associated with considerable morphological adaptations, was already widespread among insects by at least the Mid-Cretaceous. Together with the previously known Spanish specimen, these fossils are the oldest direct evidence of camouflaging behavior in the fossil record. Our findings provide a novel insight into early evolution of camouflage in insects and ancient ecological associations among plants and insects.

A diverse ant fauna from the mid-cretaceous of Myanmar (Hymenoptera: Formicidae.

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Phillip Barden

Full Text Available A new collection of 24 wingless ant specimens from mid-Cretaceous Burmese amber (Albian-Cenomanian, 99 Ma comprises nine new species belonging to the genus Sphecomyrmodes Engel and Grimaldi. Described taxa vary considerably with regard to total size, head and body proportion, cuticular sculpturing, and petiole structure while all species are unified by a distinct shared character. The assemblage represents the largest known diversification of closely related Cretaceous ants with respect to species number. These stem-group ants exhibit some characteristics previously known only from their extant counterparts along with presumed plesiomorphic morphology. Consequently, their morphology may inform hypotheses relating to basal relationships and general patterns of ant evolution. These and other uncovered Cretaceous species indicate that stem-group ants are not simply wasp-like, transitional formicids, but rather a group of considerable adaptive diversity, exhibiting innovations analogous to what crown-group ants would echo 100 million years later.

The bivalve Anopaea (Inoceramidae) from the Upper Jurassic-lowermost Cretaceous of Mexico

Science.gov (United States)

Zell, Patrick; Crame, J. Alistair; Stinnesbeck, Wolfgang; Beckmann, Seija

2015-07-01

In Mexico, the Upper Jurassic to lowermost Cretaceous La Casita and coeval La Caja and La Pimienta formations are well-known for their abundant and well-preserved marine vertebrates and invertebrates. The latter include conspicuous inoceramid bivalves of the genus Anopaea not formally described previously from Mexico. Anopaea bassei (Lecolle de Cantú, 1967), Anopaea cf. stoliczkai (Holdhaus, 1913), Anopaea cf. callistoensis Crame and Kelly, 1995 and Anopaea sp. are rare constituents in distinctive Tithonian-lower Berriasian levels of the La Caja Formation and one Tithonian horizon of the La Pimienta Formation. Anopaea bassei was previously documented from the Tithonian of central Mexico and Cuba, while most other members of Anopaea described here are only known from southern high latitudes. The Mexican assemblage also includes taxa which closely resemble Anopaea stoliczkai from the Tithonian of India, Indonesia and the Antarctic Peninsula, and Anopaea callistoensis from the late Tithonian to ?early Berriasian of the Antarctic Peninsula. Our new data expand the palaeogeographical distribution of the high latitude Anopaea to the Gulf of Mexico region and substantiate faunal exchange, in the Late Jurassic-earliest Cretaceous, between Mexico and the Antarctic Realm.

Facies analysis and paleoenvironmental reconstruction of Upper Cretaceous sequences in the eastern Para-Tethys Basin, NW Iran

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Omidvar, M.; Safari, A.; Vaziri-Moghaddam, H.; Ghalavand, H.

2016-07-01

Upper Cretaceous mixed carbonate-siliciclastic sequences are among the most important targets for hydrocarbon exploration in the Moghan area, located in the eastern Para-Tethys Basin. Despite of their significance, little is known about their facies characteristics and depositional environments. Detailed facies analysis and paleoenvironmental reconstruction of these sequences have been carried out in eight surface sections. Accordingly, four siliciclastic facies, eight carbonate facies and one volcanic facies have been recognized. Detailed facies descriptions and interpretations, together with the results of facies frequency analysis, standard facies models and Upper Cretaceous depositional models of Para-Tethys Basin, have been integrated and a non-rimmed carbonate platform is presented. This platform was affected by siliciclastic influx, in the form of coastal fan delta and submarine fans in the shallow- to deep-marine parts, respectively. This model is interpreted to be shallower in the central and northeastern parts of the Moghan area. Toward the southeast and southwest, this shallow platform turns into deep marine settings along steep slopes without remarkable marginal barriers. (Author)

Vertebrate paleontological exploration of the Upper Cretaceous succession in the Dakhla and Kharga Oases, Western Desert, Egypt

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Sallam, Hesham M.; O'Connor, Patrick M.; Kora, Mahmoud; Sertich, Joseph J. W.; Seiffert, Erik R.; Faris, Mahmoud; Ouda, Khaled; El-Dawoudi, Iman; Saber, Sara; El-Sayed, Sanaa

2016-05-01

The Campanian and Maastrichtian stages are very poorly documented time intervals in Africa's record of terrestrial vertebrate evolution. Upper Cretaceous deposits exposed in southern Egypt, near the Dakhla and Kharga Oases in the Western Desert, preserve abundant vertebrate fossils in nearshore marine environments, but have not yet been the focus of intensive collection and description. Our recent paleontological work in these areas has resulted in the discovery of numerous new vertebrate fossil-bearing localities within the middle Campanian Qusier Formation and the upper Campanian-lower Maastrichtian Duwi Formation. Fossil remains recovered from the Campanian-aged Quseir Formation include sharks, rays, actinopterygian and sarcopterygian fishes, turtles, and rare terrestrial archosaurians, including some of the only dinosaurs known from this interval on continental Africa. The upper Campanian/lower Maastrichtian Duwi Formation preserves sharks, sawfish, actinopterygians, and marine reptiles (mosasaurs and plesiosaurs). Notably absent from these collections are representatives of Mammalia and Avialae, both of which remain effectively undocumented in the Upper Cretaceous rocks of Africa and Arabia. New age constraints on the examined rock units is provided by 23 nannofossil taxa, some of which are reported from the Duwi Formation for the first time. Fossil discoveries from rock units of this age are essential for characterizing the degree of endemism that may have developed as the continent became increasingly tectonically isolated from the rest of Gondwana, not to mention for fully evaluating origin and diversification hypotheses of major modern groups of vertebrates (e.g., crown birds, placental mammals).

Crown Group Lejeuneaceae and Pleurocarpous Mosses in Early Eocene (Ypresian Indian Amber.

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Jochen Heinrichs

Full Text Available Cambay amber originates from the warmest period of the Eocene, which is also well known for the appearance of early angiosperm-dominated megathermal forests. The humid climate of these forests may have triggered the evolution of epiphytic lineages of bryophytes; however, early Eocene fossils of bryophytes are rare. Here, we present evidence for lejeuneoid liverworts and pleurocarpous mosses in Cambay amber. The preserved morphology of the moss fossil is inconclusive for a detailed taxonomic treatment. The liverwort fossil is, however, distinctive; its zig-zagged stems, suberect complicate-bilobed leaves, large leaf lobules, and small, deeply bifid underleaves suggest a member of Lejeuneaceae subtribe Lejeuneinae (Harpalejeunea, Lejeunea, Microlejeunea. We tested alternative classification possibilities by conducting divergence time estimates based on DNA sequence variation of Lejeuneinae using the age of the fossil for corresponding age constraints. Consideration of the fossil as a stem group member of Microlejeunea or Lejeunea resulted in an Eocene to Late Cretaceous age of the Lejeuneinae crown group. This reconstruction is in good accordance with published divergence time estimates generated without the newly presented fossil evidence. Balancing available evidence, we describe the liverwort fossil as the extinct species Microlejeunea nyiahae, representing the oldest crown group fossil of Lejeuneaceae.

Crown Group Lejeuneaceae and Pleurocarpous Mosses in Early Eocene (Ypresian) Indian Amber.

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Heinrichs, Jochen; Scheben, Armin; Bechteler, Julia; Lee, Gaik Ee; Schäfer-Verwimp, Alfons; Hedenäs, Lars; Singh, Hukam; Pócs, Tamás; Nascimbene, Paul C; Peralta, Denilson F; Renner, Matt; Schmidt, Alexander R

2016-01-01

Cambay amber originates from the warmest period of the Eocene, which is also well known for the appearance of early angiosperm-dominated megathermal forests. The humid climate of these forests may have triggered the evolution of epiphytic lineages of bryophytes; however, early Eocene fossils of bryophytes are rare. Here, we present evidence for lejeuneoid liverworts and pleurocarpous mosses in Cambay amber. The preserved morphology of the moss fossil is inconclusive for a detailed taxonomic treatment. The liverwort fossil is, however, distinctive; its zig-zagged stems, suberect complicate-bilobed leaves, large leaf lobules, and small, deeply bifid underleaves suggest a member of Lejeuneaceae subtribe Lejeuneinae (Harpalejeunea, Lejeunea, Microlejeunea). We tested alternative classification possibilities by conducting divergence time estimates based on DNA sequence variation of Lejeuneinae using the age of the fossil for corresponding age constraints. Consideration of the fossil as a stem group member of Microlejeunea or Lejeunea resulted in an Eocene to Late Cretaceous age of the Lejeuneinae crown group. This reconstruction is in good accordance with published divergence time estimates generated without the newly presented fossil evidence. Balancing available evidence, we describe the liverwort fossil as the extinct species Microlejeunea nyiahae, representing the oldest crown group fossil of Lejeuneaceae.

Early Cretaceous greenhouse pumped higher taxa diversification in spiders.

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Shao, Lili; Li, Shuqiang

2018-05-24

The Cretaceous experienced one of the most remarkable greenhouse periods in geological history. During this time, ecosystem reorganizations significantly impacted the diversification of many groups of organisms. The rise of angiosperms marked a major biome turnover. Notwithstanding, relatively little remains known about how the Cretaceous global ecosystem impacted the evolution of spiders, which constitute one of the most abundant groups of predators. Herein, we evaluate the transcriptomes of 91 taxa representing more than half of the spider families. We add 23 newly sequenced taxa to the existing database to obtain a robust phylogenomic assessment. Phylogenetic reconstructions using different datasets and methods obtain novel placements of some groups, especially in the Synspermiata and the group having a retrolateral tibial apophysis (RTA). Molecular analyses indicate an expansion of the RTA clade at the Early Cretaceous with a hunting predatory strategy shift. Fossil analyses show a 7-fold increase of diversification rate at the same period, but this likely owes to the first occurrences spider in amber deposits. Additional analyses of fossil abundance show an accumulation of spider lineages in the Early Cretaceous. We speculate that the establishment of a warm greenhouse climate pumped the diversification of spiders, in particular among webless forms tracking the abundance of insect prey. Our study offers a new pathway for future investigations of spider phylogeny and diversification. Copyright © 2018. Published by Elsevier Inc.

Uranium distribution and sandstone depositional environments: oligocene and upper Cretaceous sediments, Cheyenne basin, Colorado

International Nuclear Information System (INIS)

Nibbelink, K.A.; Ethridge, F.G.

1984-01-01

Wyoming-type roll-front uranium deposits occur in the Upper Cretaceous Laramie and Fox Hills sandstones in the Cheyenne basin of northeastern Colorado. The location, geometry, and trend of specific depositional environments of the Oligocene White River and the Upper Cretaceous Laramie and Fox Hills formations are important factors that control the distribution of uranium in these sandstones. The Fox Hills Sandstone consists of up to 450 ft (140 m) of nearshore marine wave-dominated delta and barrier island-tidal channel sandstones which overlie offshore deposits of the Pierre Shale and which are overlain by delta-plain and fluvial deposits of the Laramie Formation. Uranium, which probably originated from volcanic ash in the White River Formation, was transported by groundwater through the fluvial-channel deposits of the White River into the sandstones of the Laramie and Fox Hills formations where it was precipitated. Two favorable depositional settings for uranium mineralization in the Fox Hills Sandstone are: (1) the landward side of barrier-island deposits where barrier sandstones thin and interfinger with back-barrier organic mudstones, and (2) the intersection of barrier-island and tidal channel sandstones. In both settings, sandstones were probably reduced during early burial by diagenesis of contained and adjacent organic matter. The change in permeability trends between the depositional strike-oriented barrier sandstones and the dip-oriented tidal-channel sandstones provided sites for dispersed groundwater flow and, as demonstrated in similar settings in other depositional systems, sites for uranium mineralization

Cretaceous Crocodyliforms from the Sahara

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Paul Sereno

2009-11-01

Full Text Available Diverse crocodyliforms have been discovered in recent years in Cretaceous rocks on southern landmasses formerly composing Gondwana.  We report here on six species from the Sahara with an array of trophic adaptations that significantly deepen our current understanding of African crocodyliform diversity during the Cretaceous period.  We describe two of these species (Anatosuchus minor, Araripesuchus wegeneri from nearly complete skulls and partial articulated skeletons from the Lower Cretaceous Elrhaz Formation (Aptian-Albian of Niger. The remaining four species (Araripesuchus rattoides sp. n., Kaprosuchus saharicus gen. n. sp. n., Laganosuchus thaumastos gen. n. sp. n., Laganosuchus maghrebensis gen. n. sp. n. come from contemporaneous Upper Cretaceous formations (Cenomanian in Niger and Morocco.

Assessment of undiscovered continuous oil and gas resources of Upper Cretaceous Shales in the Songliao Basin of China, 2017

Science.gov (United States)

Potter, Christopher J.; Schenk, Christopher J.; Pitman, Janet K.; Klett, Timothy R.; Tennyson, Marilyn E.; Gaswirth, Stephanie B.; Leathers-Miller, Heidi M.; Finn, Thomas M.; Brownfield, Michael E.; Mercier, Tracey J.; Marra, Kristen R.; Woodall, Cheryl A.

2018-05-03

Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered, technically recoverable resources of 3.3 billion barrels of oil and 887 billion cubic feet of gas in shale reservoirs of the Upper Cretaceous Qingshankou and Nenjiang Formations in the Songliao Basin of northeastern China.

New biostratigraphic evidence (texanitid ammonites, inoceramids and calcareous nannofossils) for the Upper and the uppermost Coniacian in the Bohemian Cretaceous Basin

Czech Academy of Sciences Publication Activity Database

Svobodová, Andrea; Košťák, M.; Čech, S.; Švábenická, L.

2014-01-01

Roč. 165, č. 4 (2014), s. 577-589 ISSN 1860-1804 Institutional support: RVO:67985831 Keywords : Bohemian Cretaceous Basin * Upper Coniacian * biostratigraphy * ammonites * inoceramids * calcareous nannofossils Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.569, year: 2014

Tropical and Holarctic Ants in Late Eocene Ambers

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Perkovsky E. E.

2016-04-01

Full Text Available Based on representative collections, the ratio of tropical and Holarctic ant species in Priabonian (Late Eocene Baltic, Bitterfeld (Saxonian, Danish and Rovno ambers is analyzed for the first time. In surveyed representative collections of Baltic amber, the ratios of Holarctic and tropical ant species are from 1.1 to 1.5; with 10 Holarctic and 9 tropical species (out of 31 in the PIN-964 collection, and 9 and 5 species (out of 29 in the Giecewicz collection; the ratio in the representative collection of Saxonian amber is 0.9, 11 Holarctic species vs. 12 tropical species (out of 55; in the representative collection of Rovno amber it is 0.65, 15 vs. 23 species (out of 79; and in the representative collection of Danish amber it is 0.64, 7 vs. 11 species (out of 36. Hence, in representative collections of Baltic amber, Holarctic species clearly prevail not just in terms of the share of their specimens (by 9.8 to 19.6 times, but also by the number of species. In Bitterfeld amber, Holarctic species are somewhat less numerous than tropical ones, but their specimens are 6 times greater. In representative collections of Rovno and Danish ambers, the number of Holarctic species is 1.5 to 1.7 times smaller than that of tropical species, but the number of their specimens is 4.9 to 6.9 times greater. The numbers of tropical and Holarctic species represented by more than one specimen is similar in Priabonian ambers, 25 versus 22, but Holarctic species include four dominants or subdominants. The abundance of temperate elements in the Priabonian amber ant fauna along with the relatively small number of tropical elements greatly distinguishes it from the Middle European Lutetian ant faunas of Messel and Eckfeld in shale, which do not have temperate elements at all. Formica phaethusa Wheeler, Glaphyromyrmex oligocenicus Wheeler, Plagiolepis squamifera Mayr, Proceratium eocenicum Dlussky, Hypoponera atavia (Mayr, Ponera lobulifera Dlussky, Aphaenogaster mersa

A new pterosaur (Pterodactyloidea: Azhdarchidae from the Upper Cretaceous of Morocco.

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Nizar Ibrahim

Full Text Available The Kem Kem beds in South Eastern Morocco contain a rich early Upper (or possibly late Lower Cretaceous vertebrate assemblage. Fragmentary remains, predominantly teeth and jaw tips, represent several kinds of pterosaur although only one species, the ornithocheirid Coloborhynchus moroccensis, has been named. Here, we describe a new azhdarchid pterosaur, Alanqa saharica nov. gen. nov. sp., based on an almost complete well preserved mandibular symphysis from Aferdou N'Chaft. We assign additional fragmentary jaw remains, some of which have been tentatively identified as azhdarchid and pteranodontid, to this new taxon which is distinguished from other azhdarchids by a remarkably straight, elongate, lance-shaped mandibular symphysis that bears a pronounced dorsal eminence near the posterior end of its dorsal (occlusal surface. Most remains, including the holotype, represent individuals of approximately three to four meters in wingspan, but a fragment of a large cervical vertebra, that probably also belongs to A. saharica, suggests that wingspans of six meters were achieved in this species. The Kem Kem beds have yielded the most diverse pterosaur assemblage yet reported from Africa and provide the first clear evidence for the presence of azhdarchids in Gondwana at the start of the Late Cretaceous. This, the relatively large size achieved by Alanqa, and the additional evidence of variable jaw morphology in azhdarchids provided by this taxon, indicates a longer and more complex history for this clade than previously suspected.

Upper cretaceous ammonite succession (Cenomanian - Coniacian) related to the upper Hondita and Loma Gorda Formations along the Bambuca creek, Aipe, Huila (Colombia, S.A.)

International Nuclear Information System (INIS)

Patarroyo, Pedro

2011-01-01

The Bambuca creek section (Aipe - Huila) shows a very good exposition of the upper Magdalena valley cretaceous deposits. To the upper part of the Hondita Formation were recollected acanthoceras sp. and rhynchostreon sp. of the upper Cenomanian. Related to the lower segment of the Loma Gorda Formation were found choffaticeras (c.) cf. segne, fagesia cf. catinus, neoptychites cf. andinus, mitonia gracilis, morrowitessp., nannovascoceras ? sp., quitmaniceras ? sp., benueites ? sp., paramammites ? sp. together with mytiloideskossmati, m. goppelnensis and anomia sp. of the lower Turonian. Following by hoplitoides sp. h. ingens,h. cf. lagiraldae, codazziceras ospinae, allocrioceras sp. that can be representing between the lower and middle Turonian. To the upper part of this segment were collected prionocycloceras sp. p. guayabanum, reesidites subtuberculatum, subprionotropis colombianus, mytiloides scupini, dydimotis sp., gauthiericerassp, anagaudryceras ? sp., eulophoceras jacobi, paralenticeras sieversi, hauericeras cf. madagascarensis, peroniceras (p.) subtricarinatum, forresteria (f.) sp, barroisiceras cf. onilahyense, ankinatsytes venezolanus, with upper Turonian to Coniacian. According to the related fauna it is not possible to establish the Cenomanian/Turonian and Turonian/Coniacian boundaries.

Further AMBER and Ecolego Intercomparisons

International Nuclear Information System (INIS)

Maul, Philip; Robinson, Peter; Broed, Robert

2004-01-01

The AMBER compartmental modelling software is used by Quintessa in undertaking Performance Assessment (PA) calculations for SKI. SSI and NRPA are supporting the development of Ecolego which is based on the Matlab/Simulink general purpose modelling software for undertaking PA calculations. Intercomparison calculations using AMBER and Ecolego have been undertaken based on calculation cases considered in SKB's SR97 assessment. The reasons for undertaking such intercomparisons included: 1. to give confidence in the use of AMBER and Ecolego for whole system PA calculations for a deep repository; and 2. to provide SKI and SSI with an understanding of some of the technical issues raised by seeking to repeat the SR97 calculations with different models and software. Conclusions drawn from these intercomparisons included: 1. Both modelling packages successfully reproduced SKB's SR97 calculations for the near field, geosphere and biosphere. 2. AMBER and Ecolego calculations were typically in agreement to within one significant figure, but in several instances the SR97 documentation was not sufficiently clear to enable the implementation of the models in AMBER and Ecolego to be unambiguous. In order to gain more information on the comparisons between the two codes, additional intercomparisons have been undertaken using input data from the Vault Safety Case originally undertaken as part of an IAEA research project (ISAM). The comparisons between the AMBER and Ecolego calculations for the ISAM vault safety case have shown excellent agreement. Calculations at specified times generally agree to around three significant figures, and calculations of peak radionuclide fluxes and concentrations agree to two significant figures. This agreement is particularly good given the large number of model compartments and the inclusion of decay changes of up to six members. The most important situation where agreement may not be as good as that generally found is where radionuclides have been

Dinosaur ichnofauna of the Upper Jurassic/Lower Cretaceous of the Paraná Basin (Brazil and Uruguay)

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Francischini, H.; Dentzien–Dias, P. C.; Fernandes, M. A.; Schultz, C. L.

2015-11-01

Upper Jurassic and Lower Cretaceous sedimentary layers are represented in the Brazilian Paraná Basin by the fluvio-aeolian Guará Formation and the Botucatu Formation palaeoerg, respectively, overlapped by the volcanic Serra Geral Formation. In Uruguay, the corresponding sedimentary units are named Batoví and Rivera Members (both from the Tacuarembó Formation), and the lava flows constitute the Arapey Formation (also in Paraná Basin). Despite the lack of body fossils in the mentioned Brazilian formations, Guará/Batoví dinosaur fauna is composed of theropod, ornithopod and wide-gauge sauropod tracks and isolated footprints, as well as theropod teeth. In turn, the Botucatu/Rivera dinosaur fauna is represented by theropod and ornithopod ichnofossils smaller than those from the underlying units. The analysis of these dinosaur ichnological records and comparisons with other global Mesozoic ichnofauna indicates that there is a size reduction in dinosaur fauna in the more arid Botucatu/Rivera environment, which is dominated by aeolian dunes. The absence of sauropod trackways in the Botucatu Sandstone fits with the increasingly arid conditions because it is difficult for heavy animals to walk on sandy dunes, as well as to obtain the required amount of food resources. This comparison between the Upper Jurassic and Lower Cretaceous dinosaur fauna in south Brazil and Uruguay demonstrates the influence of aridization on the size of animals occupying each habitat.

The first freshwater mosasauroid (Upper Cretaceous, Hungary and a new clade of basal mosasauroids.

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László Makádi

Full Text Available Mosasauroids are conventionally conceived of as gigantic, obligatorily aquatic marine lizards (1000s of specimens from marine deposited rocks with a cosmopolitan distribution in the Late Cretaceous (90-65 million years ago [mya] oceans and seas of the world. Here we report on the fossilized remains of numerous individuals (small juveniles to large adults of a new taxon, Pannoniasaurus inexpectatus gen. et sp. nov. from the Csehbánya Formation, Hungary (Santonian, Upper Cretaceous, 85.3-83.5 mya that represent the first known mosasauroid that lived in freshwater environments. Previous to this find, only one specimen of a marine mosasauroid, cf. Plioplatecarpus sp., is known from non-marine rocks in Western Canada. Pannoniasaurus inexpectatus gen. et sp. nov. uniquely possesses a plesiomorphic pelvic anatomy, a non-mosasauroid but pontosaur-like tail osteology, possibly limbs like a terrestrial lizard, and a flattened, crocodile-like skull. Cladistic analysis reconstructs P. inexpectatus in a new clade of mosasauroids: (Pannoniasaurus (Tethysaurus (Yaguarasaurus, Russellosaurus. P. inexpectatus is part of a mixed terrestrial and freshwater faunal assemblage that includes fishes, amphibians turtles, terrestrial lizards, crocodiles, pterosaurs, dinosaurs and birds.

Phosphatic intraclasts in shallow-water hemipelagic strata: a source of palaeoecological, taphonomic and biostratigraphic data (Upper Turonian, Bohemian Cretaceous Basin)

Czech Academy of Sciences Publication Activity Database

Vodrážka, R.; Sklenář, J.; Čech, S.; Laurin, Jiří; Hradecká, L.

2009-01-01

Roč. 30, č. 1 (2009), s. 204-222 ISSN 0195-6671 Grant - others:GA ČR(CZ) GA205/06/0842 Program:GA Institutional research plan: CEZ:AV0Z30120515 Keywords : Upper Cretaceous * Turonian * Bohemia * condensed sedimentation * palaeoecology * sponges * biostratigraphy Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.221, year: 2009

Lygistorrhinidae (Diptera: Bibionomorpha: Sciaroidea in early Eocene Cambay amber

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Frauke Stebner

2017-05-01

Full Text Available One new genus and three new species of Lygistorrhinidae in early Eocene Cambay amber from India are described, which significantly increases our knowledge about this group in the Eocene. Lygistorrhina indica n. sp. is the oldest fossil known from this extant genus. Indorrhina sahnii n. gen. et sp. shows morphological similarities to each of the two extant genera Lygistorrhina and Asiorrhina. Palaeognoriste orientale is the third species known from a group that has only been recorded from Eocene Baltic amber before. The latter finding reveals faunal links between Cambay amber and the probably slightly younger Baltic amber, adding further evidence that faunal exchange between Europe/Asia and India took place before the formation of Cambay amber.

Lygistorrhinidae (Diptera: Bibionomorpha: Sciaroidea) in early Eocene Cambay amber.

Science.gov (United States)

Stebner, Frauke; Singh, Hukam; Rust, Jes; Grimaldi, David A

2017-01-01

One new genus and three new species of Lygistorrhinidae in early Eocene Cambay amber from India are described, which significantly increases our knowledge about this group in the Eocene. Lygistorrhina indica n. sp. is the oldest fossil known from this extant genus. Indorrhina sahnii n. gen. et sp. shows morphological similarities to each of the two extant genera Lygistorrhina and Asiorrhina . Palaeognoriste orientale is the third species known from a group that has only been recorded from Eocene Baltic amber before. The latter finding reveals faunal links between Cambay amber and the probably slightly younger Baltic amber, adding further evidence that faunal exchange between Europe/Asia and India took place before the formation of Cambay amber.

Leucine insertion caused by a yeast amber suppressor

Energy Technology Data Exchange (ETDEWEB)

Liebman, S W [Univ. of Rochester School of Medicine and Dentistry, NY; Stewart, J W; Parker, J H; Sherman, F

1977-01-01

The amber suppressor SUP52 can cause the production of approximately 15 to 20% of the normal amount of iso-l-cytochrome c when coupled to the amber (UAG) mutant cyc1-76. The suppressed iso-l-cytochrome c contains a residue of leucine at the position corresponding to the site of the amber codon. SUP52 also supresses another amber allele cyc1-179, but only with a low efficiency of approximately 2%. It does not appear to act at all on ochre (UAA) mutants. SUP52 was found to be on the left arm of chromosome X closely linked to the centromere.

Visualization of normal pleural sinuses with AMBER

International Nuclear Information System (INIS)

Aarts, N.J.; Kool, L.J.S.; Oestmann, J.W.

1991-01-01

This paper reports that ventral and dorsal pleural sinuses are frequently better appreciated with advanced modulated beam equalization radiography (AMBER) than with standard chest radiography. The visualization of the sinuses with both techniques was compared and their typical configuration studied. Four hundred patients without known chest disease were evaluated. Two groups of 200 patients were studied with either AMBER or standard chest radiography. Visualization was evaluated by three radiologists using a four-point scale. The shape of the sinus was traced if sufficiently visible. A significantly larger segment of the respective sinuses was seen with the AMBER technique. The dorsal sinus was significantly easier to trace than the ventral. Various sinus configurations were noted. AMBER improves the visibility of the pleural sinuses. Knowledge of their normal configuration is the precondition for correctly diagnosing lesions hitherto frequently overlooked

Microfacies characteristics, sedimentary environments and sequence stratigraphy of Upper Cretaceous deposits in northwest of Nehbandan (Basiran section

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Mohammad nabi Gorgij

2015-10-01

Full Text Available Introduction   The Basiran stratigraphic section is located about 160 km northwest of Nehbandan.The section was measured in detail at 59 06 30 N and 31 52 50 E. Nehbandan area with respect to fourfold geological subdivision of Iran is part of Central Iran that is located in the eastern flank of Lut Block which first time are studied by Stocklin et al.in 1972. Gorgij (2001 stratigraphically and paleontologically investigate Upper Cretaceous deposits in Mighan and Basiran sections. Upper Cretaceous deposits in in this area consists of 275m conglomerate,alternation of conglomerate-sandstone, sandy limestone -marl and limy marl, marl with intercalation of limestone-sandy limestone thin beds and medium-bedded to massive limestone. Microfacies analysis led to the recognition of 9 microfacies that are related to 5 belts; Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. Main part of the section are deposited in the open marine environment that consist of marl,marly limestone and limestone. The doals of this study are : (1 describing and determining main carbonate and siliciclastic microfacies of late Cretaceous deposits (2 interpreting and providing depositional model for reconstruction of its paleoenvironmental setting based on microfacies characteristics (3 dividing the section based on lithostratigraphic principles and (4 recognizing a sequence stratigraphic model of this successions based on the vertical variation of facies,stratal key beds and stratal packing pattern.       Material and Method   The Basiran section as a complete stratigraphic section was measured and described. Up to 68 samples (indicated by KB1 to KB68 were collected and 170 thin sections are prepared. Based on field observations, sedimentological characteristics, parasequence stacking patterns, sequence boundary types and other key stratigraphical surfaces are identified and were obtained. Scheme of Dunham (1962 and Embry and Klovan

Microfacies characteristics, sedimentary environments and sequence stratigraphy of Upper Cretaceous deposits in northwest of Nehbandan (Basiran section

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Azadeh Bordbar

2015-09-01

Full Text Available   Introduction   The Basiran stratigraphic section is located about 160 km northwest of Nehbandan.The section was measured in detail at 59 06 30 N and 31 52 50 E. Nehbandan area with respect to fourfold geological subdivision of Iran is part of Central Iran that is located in the eastern flank of Lut Block which first time are studied by Stocklin et al.in 1972. Gorgij (2001 stratigraphically and paleontologically investigate Upper Cretaceous deposits in Mighan and Basiran sections. Upper Cretaceous deposits in in this area consists of 275m conglomerate,alternation of conglomerate-sandstone, sandy limestone -marl and limy marl, marl with intercalation of limestone-sandy limestone thin beds and medium-bedded to massive limestone. Microfacies analysis led to the recognition of 9 microfacies that are related to 5 belts Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. Main part of the section are deposited in the open marine environment that consist of marl,marly limestone and limestone. The doals of this study are : (1 describing and determining main carbonate and siliciclastic microfacies of late Cretaceous deposits (2 interpreting and providing depositional model for reconstruction of its paleoenvironmental setting based on microfacies characteristics (3 dividing the section based on lithostratigraphic principles and (4 recognizing a sequence stratigraphic model of this successions based on the vertical variation of facies,stratal key beds and stratal packing pattern.       Material and Method   The Basiran section as a complete stratigraphic section was measured and described. Up to 68 samples (indicated by KB1 to KB68 were collected and 170 thin sections are prepared. Based on field observations, sedimentological characteristics, parasequence stacking patterns, sequence boundary types and other key stratigraphical surfaces are identified and were obtained. Scheme of Dunham (1962 and Embry

Current oil and gas production from North American Upper Cretaceous chalks

Science.gov (United States)

Scholle, Peter A.

1977-01-01

Production of oil and natural gas from North American chalks has increased significantly during the past five years, spurred by the prolific production from North Sea chalks, as well as by higher prices and improved production technology. Chalk reservoirs have been discovered in the Gulf Coast in the Austin Group, Saratoga and Annona Chalks, Ozan Formation, Selma Group, Monroe gas rock (an informal unit of Navarro age), and other Upper Cretaceous units. In the Western Interior, production has been obtained from the Cretaceous Niobrara and Greenhorn Formations. Significant, though subcommercial, discoveries of natural gas and gas condensate also have been made in the Upper Cretaceous Wyandot Formation on the Scotian Shelf of eastern Canada. All North American chalk units share a similar depositional and diagenetic history. The chalks consist primarily of whole and fragmented coccoliths with subordinate planktonic and benthonic Foraminifera, inoceramid prisms, oysters, and other skeletal grains. Most have between 10 and 35 percent HCl-insoluble residue, predominantly clay. Deposition was principally below wave base in tens to hundreds of meters of water. The diagenetic history of a chalk is critical in determining its reservoir potential. All chalk has a stable composition (low-Mg calcite) and very high primary porosity. With subsequent burial, mechanical and chemical (solution-transfer) compaction can reduce or completely eliminate pore space. The degree of loss of primary porosity in chalk sections is normally a direct function of the maximum depth to which it has been buried. Pore-water chemistry, pore-fluid pressures, and tectonic stresses also influence rates of cementation. Oil or gas reservoirs of North American chalk fall into three main groups: 1. Areas with thin overburden and significant primary porosity retention (for example, Niobrara Formation of Kansas and eastern Colorado). 2. Areas with thicker overburden but considerable fracturing. Here primary

Inoceramid and foraminiferal record and biozonation of the Turonian and Coniacian (Upper Cretaceous) of the Mangyshlak Mts., western Kazakhstan

Science.gov (United States)

Walaszczyk, Ireneusz; Kopaevich, Ludmila F.; Beniamovski, Vladimir N.

2013-12-01

Walaszczyk, I., Kopaevich, L.F. and Beniamovski, V.N. 2013. Inoceramid and foraminiferal record and biozonation of the Turonian and Coniacian (Upper Cretaceous) of the Mangyshlak Mts., western Kazakhstan. Acta Geologica Polonica, 63 (4), 469-487. Warszawa. The Turonian and Coniacian (Upper Cretaceous) of the Mangyshlak Mts., western Kazakhstan, yielded a rich and relatively complete inoceramid bivalve record. The faunas and their succession correspond to those known from central and eastern Europe, allowing the zonation established in the latter areas to be applied in a virtually identical form. The gaps in the record of the group in Mangyshlak stem from the regional hiatuses in the geological record in the area and do not reflect any biogeographical differences between eastern and central-western Europe. Planktonic foraminifera are rare. Four successive interval range zones can be distinguished: in ascending stratigraphic order, the Helvetoglobotrunaca helvetica, Marginotruncaca pseudolinneiana, Marginotruncana coronata, and Concavotruncana concavata zones. Their correlation with the inoceramid zonation and, consequently, with the chronostratigraphic scheme, is demonstrated. The zonation and chronostratigraphic subdivision as applied in Mangyshlak may easily be applied to other areas of the peri-Caspian region (Caucasus, Tuarkyr, Kopet-Dagh, SE margin of the East-European Craton).

Provenance and U-Pb geochronology of the Upper Cretaceous El Chanate Group, northwest Sonora, Mexico, and its tectonic significance

Science.gov (United States)

Jacques-Ayala, C.; Barth, A.P.; Wooden, J.L.; Jacobson, C.E.

2009-01-01

The Upper Cretaceous El Chanate Group, northwest Sonora, Mexico, is a 2.8km thick clastic sedimentary sequence deposited in a continental basin closely related to volcanic activity. It consists of three formations: the Pozo Duro (oldest), the Anita, and the Escalante (youngest). Petrographic study, conglomerate pebble counts, and U-Pb geochronology of detrital zircons were performed to determine the source and age of this sequence, and to interpret its tectonic setting. In the sandstones of all three formations, the most abundant grains are those of volcanic composition (Q38F22L 40, Q35F19L46, and Q 31F22L47, respectively). The Pozo Duro Formation includes well-rounded quartz-arenite clast conglomerates, whereas conglomerates of the two upper units have clasts predominantly of andesitic and rhyolitic composition. The most likely source for these sediments was the Jurassic volcanic arc exposed in northern Sonora and southern Arizona. Zircons from five sandstone samples define two main age groups, Proterozoic and Mesozoic. The first ranges mostly from 1000 to 1800Ma, which suggests the influence of a cratonic source. This zircon suite is interpreted to be recycled and derived from the same source area as the quartz-rich sandstone clasts in the basal part of the section. Mesozoic zircons range from Triassic to Late Cretaceous, which confirms the proposed Late Cretaceous age for the sequence, and also corroborates Jurassic felsic source rocks. Another possible source was the Alisitos volcanic arc, exposed along the western margin of the Baja California Peninsula. Of regional significance is the great similarity between the El Chanate Group and the McCoy Mountains Formation of southeastern California and southwestern Arizona. Both are Cretaceous, were deposited in continental environments, and have similar zircon-age patterns. Also, both exhibit intense deformation and locally display penetrative foliation. These features strongly suggest that both units underwent

Upper Cretaceous molluscan record along a transect from Virden, New Mexico, to Del Rio, Texas

Science.gov (United States)

Cobban, W.A.; Hook, S.C.; McKinney, K.C.

2008-01-01

Updated age assignments and new collections of molluscan fossils from lower Cenomanian through upper Campanian strata in Texas permit a much refined biostratigraphic correlation with the rocks of New Mexico and the Western Interior. Generic names of many Late Cretaceous ammonites and inoceramid bivalves from Texas are updated to permit this correlation. Strata correlated in the west-to-east transect include the lower Cenomanian Beartooth Quartzite and Sarten Sandstone of southwest New Mexico, and the Eagle Mountains Formation, Del Rio Clay, Buda Limestone, and. basal beds of the Chispa Summit, Ojinaga, and Boquillas Formations of the Texas-Mexico border area. Middle Cenomanian strata are lacking in southwestern New Mexico but are present in the lower parts of the Chispa Summit and Boquillas Formations in southwest Texas. Upper Cenomanian and lower Turonian rocks are present at many localities in New Mexico and Texas in the Mancos Shale and Chispa Summit, Ojinaga, and Boquillas Formations. Middle Turonian and younger rocks seem to be entirely nonmarine in southwestern New Mexico, but they are marine in the Rio Grande area in the Chispa. Summit, Ojinaga, and Boquillas Formations. The upper part of the Chispa Summit and Boquillas contain late Turonian fossils. Rocks of Coniacian and Santonian age are present high in the Chispa Summit, Ojinaga, and Boquillas Formations, and in the lower part of the Austin. The San Carlos, Aguja, Pen, and Austin Formations contain fossils of Campanian age. Fossils representing at least 38 Upper Cretaceous ammonite zones are present along the transect. Collections made in recent years in southwestern New Mexico and at Sierra de Cristo Rey just west of downtown El Paso, Texas, have been well treated and do not need revision. Taxonomic names and zonations published in the pre-1970 literature on the Rio Grande area of Texas have been updated. New fossil collections from the Big Bend National Park, Texas, allow for a much refined correlation

Current status and future of developing Upper Cretaceous oil deposits in the Oktyabrskoye field

Energy Technology Data Exchange (ETDEWEB)

Kamyshnikova, A.I.; Lapshin, M.Ye.

1979-01-01

The Upper Cretaceous deposit at the Oktyabrskoye field was discovered in 1966. Fractured, cavernous limestone, similar to the producing rock of many Upper Cretaceous deposits of the Chechen Ingush ASSR, form the reservoir. The deposit is situated toward a narrow anticlinal fold with angles of rock drop 40-45/sup 0/. Its heighth is 950m; the average capacity of the producing part is 400m; the deposit depth is 4200-5150m; the layer temperature is 150-160/sup 0/C. Exploratory work on the deposit is incomplete. The deposit was brought under industrial development in 1974. The development is conducted based on a refined, technological system, that includes contour flooding to maintain layer pressure in the center to edge part of the deposit at 36.0 MPa. This somewhat increases the pressure of the gas saturated oil, as well as the subsequent increase in layer pressure to 45.9 MPa for assuring wide open well flow during the late stages of development. Currently, the amount of oil obtained somewhat exceeds the planned level but the pumping volume is less than that planned. The deposit has not yet been studied sufficiently. Its boundaries have not been established; the locations of the initial and working water/oil edges are conditional; the structural plan is approximate. Data on the degree of waterflooding in the deposit and the magnitude of the actual oil yield coefficient are lacking inasmuch as the amount of oil already extracted at this time exceeds the calculated reserves. To increase the effectiveness of further development of the deposit and acquisition of the necessary data for calculating oil reserves, the deposit will be studied according to a special plan over a number of new drilling wells.

Applications of diamond crystal ATR FTIR spectroscopy to the characterization of ambers.

Science.gov (United States)

Guiliano, Michel; Asia, Laurence; Onoratini, Gérard; Mille, Gilbert

2007-08-01

Diamond crystal ATR FTIR spectroscopy is a rapid technique with virtually no sample preparation which requires small sample amounts and showed potential in the study of ambers. FTIR spectra of ambers present discriminating patterns and can be used to distinguish amber from immature resins as copal, to determine local or Baltic origin of archaeological ambers and to detect most of the falsifications encountered in the amber commercialisation.

A revised inoceramid biozonation for the Upper Cretaceous based on high-resolution carbon isotope stratigraphy in northwestern Hokkaido, Japan

Science.gov (United States)

Hayakawa, Tatsuya; Hirano, Hiromichi

2013-06-01

Hayakawa, T., Hirano, H. 2013. A revised inoceramid biozonation for the Upper Cretaceous based on high-resolution carbon isotope stratigraphy in northwestern Hokkaido, Japan. Acta Geologica Polonica, 63 (2), 239-263. Warszawa. Biostratigraphic correlations of inoceramid bivalves between the North Pacific and Euramerican provinces have been difficult because the inoceramid biostratigraphy of the Japanese strata has been based on endemic species of the northwest Pacific. In this study, carbon stable isotope fluctuations of terrestrial organic matter are assembled for the Upper Cretaceous Yezo Group in the Haboro and Obira areas, Hokkaido, Japan, in order to revise the chronology of the inoceramid biozonation in Japan. The carbon isotope curves are correlated with those of marine carbonates in English and German sections with the aid of age-diagnostic taxa. According to the correlations of the carbon isotope curves, 11 isotope events are recognised in the sections studied. As a result of these correlations, the chronology of the inoceramid biozones of the Northwest Pacific has been considerably revised. The revised inoceramid biozones suggest that the timing of the origination and extinction of the inoceramids in the North Pacific biotic province is different from the stage/substage boundaries defined by inoceramids, as used in Europe and North America.

Amber Trust on ostmas Tallinna Külmhoone emafirmat / Liis Kängsepp

Index Scriptorium Estoniae

Kängsepp, Liis, 1981-

2005-01-01

Skandinaavia-USA investeerimisfond Amber Trust loodab enne aasta lõppu allkirjastada Tallinna Külmhoone emafirma Kauno Pieno Centras ostulepingu. Diagramm: Tallinna Külmhoone majandusnäitajad. Vt. samas: Amber Trust tahab investeerida üle 2 miljardi krooni; Amber laiendas tegevust Vetteli kaudu Soome

Geologic assessment of undiscovered oil and gas resources—Lower Cretaceous Albian to Upper Cretaceous Cenomanian carbonate rocks of the Fredericksburg and Washita Groups, United States Gulf of Mexico Coastal Plain and State Waters

Science.gov (United States)

Swanson, Sharon M.; Enomoto, Catherine B.; Dennen, Kristin O.; Valentine, Brett J.; Cahan, Steven M.

2017-02-10

In 2010, the U.S. Geological Survey (USGS) assessed Lower Cretaceous Albian to Upper Cretaceous Cenomanian carbonate rocks of the Fredericksburg and Washita Groups and their equivalent units for technically recoverable, undiscovered hydrocarbon resources underlying onshore lands and State Waters of the Gulf Coast region of the United States. This assessment was based on a geologic model that incorporates the Upper Jurassic-Cretaceous-Tertiary Composite Total Petroleum System (TPS) of the Gulf of Mexico basin; the TPS was defined previously by the USGS assessment team in the assessment of undiscovered hydrocarbon resources in Tertiary strata of the Gulf Coast region in 2007. One conventional assessment unit (AU), which extends from south Texas to the Florida panhandle, was defined: the Fredericksburg-Buda Carbonate Platform-Reef Gas and Oil AU. The assessed stratigraphic interval includes the Edwards Limestone of the Fredericksburg Group and the Georgetown and Buda Limestones of the Washita Group. The following factors were evaluated to define the AU and estimate oil and gas resources: potential source rocks, hydrocarbon migration, reservoir porosity and permeability, traps and seals, structural features, paleoenvironments (back-reef lagoon, reef, and fore-reef environments), and the potential for water washing of hydrocarbons near outcrop areas.In Texas and Louisiana, the downdip boundary of the AU was defined as a line that extends 10 miles downdip of the Lower Cretaceous shelf margin to include potential reef-talus hydrocarbon reservoirs. In Mississippi, Alabama, and the panhandle area of Florida, where the Lower Cretaceous shelf margin extends offshore, the downdip boundary was defined by the offshore boundary of State Waters. Updip boundaries of the AU were drawn based on the updip extent of carbonate rocks within the assessed interval, the presence of basin-margin fault zones, and the presence of producing wells. Other factors evaluated were the middle

Isolation and genetic analysis of amber uvrA and uvrB mutants

International Nuclear Information System (INIS)

Morimyo, M.; Shimazu, Y.; Ishii, N.

1976-01-01

Genetic properties of amber uvrA and uvrB mutants of Escherichia coli K-12 are described. The isolation of three amber uvrA and two amber uvrB mutants indicates that the products of these genes are proteins

Optimal geophysical complex and methods for investigation of peleogene and upper cretaceous deposits in search and exploratory wells in the northern areas of Tumen region

International Nuclear Information System (INIS)

Nelepchenko, O.M.; Akhiyarov, V.Kh.

1975-01-01

A number of geophysical studies of the Paleogene and upper Cretaceous deposits in prospecting and exploration boreholes in the northern part of the Tyumen field are described. The studies include, besides the essential ones, neutron logging with thermal neutrons (NKT-50), infrared logging, and lateral logging

AMBER User's Manual

International Nuclear Information System (INIS)

Vay, J.L.; Fawley, W.

2000-01-01

AMBER is a Particle-In-Cell (PIC) code which models the evolution of a representative slice of a relativistic electron beam in a linear accelerator. The beam is modeled as a steady flow and therefore no electromagnetic waves: all the fields (external and self-fields) are electrostatic and magnetostatic fields (for a complete description, see chapter 5). The possible elements describing the accelerator lattice are solenoids, accelerating gaps, pipes and apertures. Several kinds of beam distribution can be loaded: KV, gaussian, semi-gaussian, etc. Alternatively, the user can reconstruct (or load) a distribution from the output of another codefile, for example, an interface generating the beam distribution from output produced from EGUN or LSP codes is available as an option. This documentation first describes in detail the input files needed to run AMBER and the procedure to start the executable. The possible data files and graphical output are explained in the two following chapters. The last chapter describes the physics model and numerical techniques used. An example of input files and the result obtained with these inputs are also given in the Appendix

AMBER: Uma linguagem para o desenvolvimento de sistemas distribuidos

NARCIS (Netherlands)

Ferreira Pires, Luis; Farines, J-M.; Westphall, C.; Guareis de farias, Cléver

2001-01-01

This paper presents the architectural model AMBER for the design of distributed systems developed at the University of Twente. This model allows the specification of distributed systems in terms of structures of functional entities and their corresponding behaviour. AMBER was originally developed to

Using 20-million-year-old amber to test the super-Arrhenius behaviour of glass-forming systems

Science.gov (United States)

Zhao, Jing; Simon, Sindee L.; McKenna, Gregory B.

2013-04-01

Fossil amber offers the opportunity to investigate the dynamics of glass-forming materials far below the nominal glass transition temperature. This is important in the context of classical theory, as well as some new theories that challenge the idea of an ‘ideal’ glass transition. Here we report results from calorimetric and stress relaxation experiments using a 20-million-year-old Dominican amber. By performing the stress relaxation experiments in a step-wise fashion, we measured the relaxation time at each temperature and, above the fictive temperature of this 20-million-year-old glass, this is an upper bound to the equilibrium relaxation time. The results deviate dramatically from the expectation of classical theory and are consistent with some modern ideas, in which the diverging timescale signature of complex fluids disappears below the glass transition temperature.

A new oviraptorid (Dinosauria: Theropoda) from the Upper Cretaceous of southern China.

Science.gov (United States)

Wang, Shuo; Sun, Chengkai; Sullivan, Corwin; Xu, Xing

2013-01-01

This paper describes a new oviraptorid dinosaur taxon, Ganzhousaurus nankangensis gen. et sp. nov., based on a specimen collected from the Upper Cretaceous Nanxiong Formation of Nankang County, Ganzhou City, Jiangxi Province, southern China. This new taxon is distinguishable from other oviraptorids based on the following unique combination of primitive and derived features: relatively shallow dentary; absence of fossa or pneumatopore on lateral surface of dentary; weakly downturned anterior mandibular end; shallow depression immediately surrounding anterior margin of external mandibular fenestra; external mandibular fenestra subdivided by anterior process of surangular; dentary posteroventral process slightly twisted and positioned on mandibular ventrolateral surface; shallow longitudinal groove along medial surface of dentary posteroventral process; angular anterior process wider transversely than deep dorsoventrally; sharp groove along ventrolateral surface of angular anterior process; ventral border of external mandibular fenestra formed mainly by angular; ventral flange along distal half of metatarsal II; and arctometatarsal condition absent. Phylogenetic analysis places Ganzhousaurus nankangensis gen. et sp. nov. in the clade Oviraptoridae, together with Oviraptor, Citipati, Rinchenia and the unnamed Zamyn Khondt oviraptorid.

AMBER and Ecolego Intercomparisons using Calculations from SR 97

International Nuclear Information System (INIS)

Maul, Philip; Robinson, Peter; Avila, Rodolfo; Broed, Robert; Pereira, Antonio

2003-08-01

The AMBER compartmental modelling software has been used by Quintessa in undertaking Performance Assessment (PA) calculations for SKI for the last four years. In particular, it was used in helping to identify key issues in the safety case for SFR 1. SSI and the Norwegian Radiation Protection Authority (NRPA) are supporting the development of Ecolego which is based on the Matlab/Simulink general purpose modelling software and provides a user-friendly Graphical User Interface which is particularly suitable for undertaking PA calculations. At SKI/SSI expert group meetings in September 2002, Quintessa presented some radionuclide transport calculations for a deep repository for spent fuel using AMBER. Comparisons were presented with calculations undertaken by SKB in their SR 97 study. It was agreed that it would be useful to undertake some intercomparison calculations using AMBER and Ecolego based on calculation cases considered in SR 97. The reasons for undertaking such intercomparisons include: 1. to give confidence in the use of AMBER and Ecolego for whole system PA calculations for a deep repository; and 2. to provide SKI and SSI with an understanding of some of the technical issues raised by seeking to repeat the SR 97 calculations with different models and software. This report documents the intercomparison calculations that have been undertaken. The main conclusions that have been drawn are: 1. Both modelling packages could successfully reproduce SKB's SR 97 calculations for the near field, geosphere and biosphere. 2. The results of the deterministic calculations for the near field and both deterministic and probabilistic calculations for the biosphere, where AMBER and Ecolego used compartment models, were typically in agreement to within one significant figure. The identical results for the calculated equilibrium inventories in Bay sediments illustrate that the calculations by AMBER and Ecolego are essentially the same when the compartment models are identical

The taxonomy of a new parvicursorine alvarezsauroid specimen IVPP V20341 (Dinosauria: Theropoda from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia, China

Directory of Open Access Journals (Sweden)

Michael Pittman

2015-06-01

Full Text Available A new parvicursorine alvarezsauroid theropod specimen IVPP V20341 from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia, China is described. IVPP V20341 appears to be distinguishable amongst alvarezsauroids by possible cervical procoely and relatively larger semi-circular caudal neural canals, but these features are not proposed as autapomorphies because current knowledge of alvarezsauroid necks and tails remains sparse. IVPP V20341 is distinguishable from Linhenykus—the sole parvicursorine at Bayan Mandahu—by the location of the origination points of the anterior caudal transverse processes; in IVPP V20341 this is the anterodorsal corner of the centra, whereas in Linhenykus it is the posterior end of the prezygapophyses. A number of additional tentative differences between IVPP V20341 and Linhenykus are also identified, but cannot be confirmed until further details of anatomical variation along the neck and tail are revealed by future finds. Thus, following the study of IVPP V20341 there are still seven parvicursorine species from the Upper Cretaceous Gobi Basin, but future finds could increase this to eight species.

Game Theory Model of Traffic Participants within Amber Time at Signalized Intersection

Directory of Open Access Journals (Sweden)

Weiwei Qi

2014-01-01

Full Text Available The traffic light scheme is composed of red, green, and amber lights, and it has been defined clearly for the traffic access of red and green lights; however, the definition of that for the amber light is indistinct, which leads to the appearance of uncertainty factors and serious traffic conflicts during the amber light. At present, the traffic administrations are faced with the decision of whether to forbid passing or not during the amber light in the cities of China. On one hand, it will go against the purpose of setting amber lights if forbidding passing; on the other hand, it may lead to a mess of traffic flow running if not. And meanwhile the drivers are faced with the decision of passing the intersection or stopping during the amber light as well. So the decision-making behavior of traffic administrations and drivers can be converted into a double game model. And through quantification of their earnings in different choice conditions, the optimum decision-making plan under specific conditions could be solved via the Nash equilibrium solution concept. Thus the results will provide a basis for the formulation of the traffic management strategy.

Game Theory Model of Traffic Participants within Amber Time at Signalized Intersection

Science.gov (United States)

Qi, Weiwei; Wen, Huiying; Fu, Chuanyun; Song, Mo

2014-01-01

The traffic light scheme is composed of red, green, and amber lights, and it has been defined clearly for the traffic access of red and green lights; however, the definition of that for the amber light is indistinct, which leads to the appearance of uncertainty factors and serious traffic conflicts during the amber light. At present, the traffic administrations are faced with the decision of whether to forbid passing or not during the amber light in the cities of China. On one hand, it will go against the purpose of setting amber lights if forbidding passing; on the other hand, it may lead to a mess of traffic flow running if not. And meanwhile the drivers are faced with the decision of passing the intersection or stopping during the amber light as well. So the decision-making behavior of traffic administrations and drivers can be converted into a double game model. And through quantification of their earnings in different choice conditions, the optimum decision-making plan under specific conditions could be solved via the Nash equilibrium solution concept. Thus the results will provide a basis for the formulation of the traffic management strategy. PMID:25580108

Rib fracture in Prognathodon saturator (Mosasauridae, Late Cretaceous)

NARCIS (Netherlands)

Schulp, Anne S.; Walenkamp, G. H I M; Hofman, P.A.M.; Rothschild, B. M.; Jagt, J. W M

2004-01-01

Two unusual bumps occur on the internal surface of a rib of the marine reptile Prognathodon saturator from the Upper Cretaceous (Maastrichtian) of Maastricht, The Netherlands. These bumps are interpreted as stress fractures, possibly related to agonistic behaviour.

Tectonosedimentary framework of Upper Cretaceous -Neogene series in the Gulf of Tunis inferred from subsurface data: implications for petroleum exploration

Science.gov (United States)

Dhraief, Wissem; Dhahri, Ferid; Chalwati, Imen; Boukadi, Noureddine

2017-04-01

The objective and the main contribution of this issue are dedicated to using subsurface data to delineate a basin beneath the Gulf of Tunis and its neighbouring areas, and to investigate the potential of this area in terms of hydrocarbon resources. Available well data provided information about the subsurface geology beneath the Gulf of Tunis. 2D seismic data allowed delineation of the basin shape, strata geometries, and some potential promising subsurface structures in terms of hydrocarbon accumulation. Together with lithostratigraphic data obtained from drilled wells, seismic data permitted the construction of isochron and isobath maps of Upper Cretaceous-Neogene strata. Structural and lithostratigraphic interpretations indicate that the area is tectonically complex, and they highlight the tectonic control of strata deposition during the Cretaceous and Neogene. Tectonic activity related to the geodynamic evolution of the northern African margin appears to have been responsible for several thickness and facies variations, and to have played a significant role in the establishment and evolution of petroleum systems in northeastern Tunisia. As for petroleum systems in the basin, the Cretaceous series of the Bahloul, Mouelha and Fahdene formations are acknowledged to be the main source rocks. In addition, potential reservoirs (Fractured Abiod and Bou Dabbous carbonated formations) sealed by shaly and marly formations (Haria and Souar formations respectively) show favourable geometries of trap structures (anticlines, tilted blocks, unconformities, etc.) which make this area adequate for hydrocarbon accumulations.

Specialized proteinine rove beetles shed light on insect-fungal associations in the Cretaceous.

Science.gov (United States)

Cai, Chenyang; Newton, Alfred F; Thayer, Margaret K; Leschen, Richard A B; Huang, Diying

2016-12-28

Insects and fungi have a long history of association in shared habitats. Fungus-feeding, or mycophagy, is remarkably widespread in beetles (Coleoptera) and appears to be a primitive feeding habit that preceded feeding on plant tissues. Numerous Mesozoic beetles belonging to extant fungus-associated families are known, but direct fossil evidence elucidating mycophagy in insects has remained elusive. Here, we report a remarkable genus and species, Vetuproteinus cretaceus gen. et sp. nov., belonging to a new tribe (Vetuproteinini trib. nov.) of the extant rove beetle subfamily Proteininae (Staphylinidae) in Mid-Cretaceous Burmese amber. The mouthparts of this beetle have a markedly enlarged protruding galea bearing an apparent spore brush, a specialized structure we infer was used to scrape spores off surfaces and direct them into the mouth, as in multiple modern spore-feeding beetles. Considering the long evolutionary history of Fungi, the Mid-Cretaceous beetles likely fed on ancient Basidiomycota and/or Ascomycota fungi or spore-producing organisms such as slime moulds (Myxomycetes). The discovery of the first Mesozoic proteinine illustrates the antiquity of the subfamily, and suggests that ancestral Proteininae were already diverse and widespread in Pangaea before the supercontinent broke up. © 2016 The Author(s).

Experimental analysis of motion artifacts in chest radiographs with the AMBER system

International Nuclear Information System (INIS)

Boetticher, H. von; Hofmann, K.; Luska, G.

1999-01-01

The prerequisites, mechanisms and principles of motion artifacts in AMBER radiographs were analysed. The experiments were performed using metronomes, a moving conventional mammography phantom, and arrangements of oscillating coil spring, spheroid and grid elements. A diagnostic dosimeter and TLDs, respectively, were used to measure exposure times and doses. The deree of distortion in AMBER radiographs depends on the direction of the object movement relative to the AMBER fan beam in a complex manner. The size of the motion artifacts depends on the local exposure time. The maximum value of this time is 75 ms and thus 1.5 times higher than specified by the manufacturer. To interpret AMBER radiographs possible system specific artifacts have to be considered to avoid misinterpretations of potentially significant details. (orig.) [de

Implementation of project Safe in Amber. Verification study for SFR 1 SAR-08

Energy Technology Data Exchange (ETDEWEB)

Thomson, Gavin; Herben, Martin; Lloyd, Pam; Rose, Danny; Smith, Chris; Barraclough, Ian (Enviros Consulting Ltd (GB))

2008-03-15

This report documents an exercise in which AMBER has been used to represent the models used in Project SAFE, a safety assessment undertaken on SFR 1. (AMBER is a flexible, graphical-user-interface based tool that allows users to build their own dynamic compartmental models to represent the migration, degradation and fate of contaminants in an environmental system. AMBER allows the user to assess routine, accidental and long-term contaminant release.) AMBER has been used to undertake assessment calculations on all of the disposal system, including all disposal tunnels and the Silo, the geosphere and several biosphere modules. The near-field conceptual models were implemented with minimal changes to the approach undertaken previously in Project SAFE. Model complexity varied significantly between individual disposal facilities increasing significantly from the BLA to the BTF and BMA tunnels and Silo. Radionuclide transport through the fractured granite geosphere was approximated using a compartment model approach in AMBER. Several biosphere models were implemented in AMBER including reasonable biosphere development, which considered the evolution of the Forsmark area from coastal to lacustrine to agricultural environments in response to land uplift. Parameters were sampled from distributions and simulations were run for 1,000 realisations. In undertaking the comparison of AMBER with the various codes and calculation tools used in Project SAFE it was necessary to undertake a detailed analysis of the modelling approach previously adopted, with particular focus given to the near-field models. As a result some discrepancies in the implementation of the models and documentation were noted. The exercise demonstrates that AMBER is fully capable of representing the features of the SFR 1 disposal system in a safety assessment suitable for SAR-08

Implementation of project Safe in Amber. Verification study for SFR 1 SAR-08

International Nuclear Information System (INIS)

Thomson, Gavin; Herben, Martin; Lloyd, Pam; Rose, Danny; Smith, Chris; Barra clough, Ian

2008-03-01

This report documents an exercise in which AMBER has been used to represent the models used in Project SAFE, a safety assessment undertaken on SFR 1. (AMBER is a flexible, graphical-user-interface based tool that allows users to build their own dynamic compartmental models to represent the migration, degradation and fate of contaminants in an environmental system. AMBER allows the user to assess routine, accidental and long-term contaminant release.) AMBER has been used to undertake assessment calculations on all of the disposal system, including all disposal tunnels and the Silo, the geosphere and several biosphere modules. The near-field conceptual models were implemented with minimal changes to the approach undertaken previously in Project SAFE. Model complexity varied significantly between individual disposal facilities increasing significantly from the BLA to the BTF and BMA tunnels and Silo. Radionuclide transport through the fractured granite geosphere was approximated using a compartment model approach in AMBER. Several biosphere models were implemented in AMBER including reasonable biosphere development, which considered the evolution of the Forsmark area from coastal to lacustrine to agricultural environments in response to land uplift. Parameters were sampled from distributions and simulations were run for 1,000 realisations. In undertaking the comparison of AMBER with the various codes and calculation tools used in Project SAFE it was necessary to undertake a detailed analysis of the modelling approach previously adopted, with particular focus given to the near-field models. As a result some discrepancies in the implementation of the models and documentation were noted. The exercise demonstrates that AMBER is fully capable of representing the features of the SFR 1 disposal system in a safety assessment suitable for SAR-08

IOT Overview: Calibrations of the VLTI Instruments (MIDI and AMBER)

Science.gov (United States)

Morel, S.; Rantakyrö, F.; Rivinius, T.; Stefl, S.; Hummel, C.; Brillant, S.; Schöller, M.; Percheron, I.; Wittkowski, M.; Richichi, A.; Ballester, P.

We present here a short review of the calibration processes that are currently applied to the instruments AMBER and MIDI of the VLTI (Very Large Telescope Interferometer) at Paranal. We first introduce the general principles to calibrate the raw data (the "visibilities") that have been measured by long-baseline optical interferometry. Then, we focus on the specific case of the scientific operation of the VLTI instruments. We explain the criteria that have been used to select calibrator stars for the observations with the VLTI instruments, as well as the routine internal calibration techniques. Among these techniques, the "P2VM" (Pixel-to-Visibility Matrix) in the case of AMBER is explained. Also, the daily monitoring of AMBER and MIDI, that has recently been implemented, is shortly introduced.

Tectonosedimentary framework of Upper Cretaceous –Neogene series in the Gulf of Tunis inferred from subsurface data: implications for petroleum exploration

Directory of Open Access Journals (Sweden)

Dhraief Wissem

2017-04-01

Full Text Available The objective and the main contribution of this issue are dedicated to using subsurface data to delineate a basin beneath the Gulf of Tunis and its neighbouring areas, and to investigate the potential of this area in terms of hydrocarbon resources. Available well data provided information about the subsurface geology beneath the Gulf of Tunis. 2D seismic data allowed delineation of the basin shape, strata geometries, and some potential promising subsurface structures in terms of hydrocarbon accumulation. Together with lithostratigraphic data obtained from drilled wells, seismic data permitted the construction of isochron and isobath maps of Upper Cretaceous-Neogene strata. Structural and lithostratigraphic interpretations indicate that the area is tectonically complex, and they highlight the tectonic control of strata deposition during the Cretaceous and Neogene. Tectonic activity related to the geodynamic evolution of the northern African margin appears to have been responsible for several thickness and facies variations, and to have played a significant role in the establishment and evolution of petroleum systems in northeastern Tunisia. As for petroleum systems in the basin, the Cretaceous series of the Bahloul, Mouelha and Fahdene formations are acknowledged to be the main source rocks. In addition, potential reservoirs (Fractured Abiod and Bou Dabbous carbonated formations sealed by shaly and marly formations (Haria and Souar formations respectively show favourable geometries of trap structures (anticlines, tilted blocks, unconformities, etc. which make this area adequate for hydrocarbon accumulations.

Organic geochemistry of Czech amber

Czech Academy of Sciences Publication Activity Database

Havelcová, Martina; Sýkorová, Ivana; Mach, K.; Dvořák, Z.

2015-01-01

Roč. 11, č. 1 (2015), s. 146 ISSN 1336-7242. [Zjazd chemikov /67./. 07.09.2015-11.09.2015, Horný Smokovec] R&D Projects: GA ČR(CZ) GA13-18482S Institutional research plan: CEZ:AV0Z30460519 Keywords : fossil resin * amber * resinite Subject RIV: DD - Geochemistry

Entrapment bias of arthropods in Miocene amber revealed by trapping experiments in a tropical forest in Chiapas, Mexico.

Science.gov (United States)

Solórzano Kraemer, Mónica M; Kraemer, Mónica M Solórzano; Kraemer, Atahualpa S; Stebner, Frauke; Bickel, Daniel J; Rust, Jes

2015-01-01

All entomological traps have a capturing bias, and amber, viewed as a trap, is no exception. Thus the fauna trapped in amber does not represent the total existing fauna of the former amber forest, rather the fauna living in and around the resin producing tree. In this paper we compare arthropods from a forest very similar to the reconstruction of the Miocene Mexican amber forest, and determine the bias of different trapping methods, including amber. We also show, using cluster analyses, measurements of the trapped arthropods, and guild distribution, that the amber trap is a complex entomological trap not comparable with a single artificial trap. At the order level, the most similar trap to amber is the sticky trap. However, in the case of Diptera, at the family level, the Malaise trap is also very similar to amber. Amber captured a higher diversity of arthropods than each of the artificial traps, based on our study of Mexican amber from the Middle Miocene, a time of climate optimum, where temperature and humidity were probably higher than in modern Central America. We conclude that the size bias is qualitatively independent of the kind of trap for non-extreme values. We suggest that frequent specimens in amber were not necessarily the most frequent arthropods in the former amber forest. Selected taxa with higher numbers of specimens appear in amber because of their ecology and behavior, usually closely related with a tree-inhabiting life. Finally, changes of diversity from the Middle Miocene to Recent time in Central and South America can be analyzed by comparing the rich amber faunas from Mexico and the Dominican Republic with the fauna trapped using sticky and Malaise traps in Central America.

Evidence concerning oxidation as a surface reaction in Baltic amber

DEFF Research Database (Denmark)

Shashoua, Yvonne

2012-01-01

, obtained from pressed amber powder, were subjected to accelerated thermal ageing. Cross-sections of the pellets were analyzed by infrared micro-spectroscopy, in order to identify and quantify changes in chemical properties. The experimental results showed strong oxidation exclusively at the exterior part...... of cross-sections from samples subjected to long-term thermal ageing, confirming that oxidation of Baltic amber starts from the surface....

Lower Cretaceous Puez key-section in the Dolomites - towards the mid-Cretaceous super-greenhouse

Science.gov (United States)

Lukeneder, A.; Halásová, E.; Rehákova, D.; Józsa, Š.; Soták, J.; Kroh, A.; Jovane, L.; Florindo, F.; Sprovieri, M.; Giorgioni, M.; Lukeneder, S.

2012-04-01

�dtirol' in Bozen, Southern Tyrol. Producing major results with a broad impact requires using tools such as facies analysis supported by lithological, sedimentological and chemical characteristics, isotope and magnetic properties as well as fossil record (ammonites, belemnites, brachiopods, echinoids, planktonic foraminiferas, radiolarians, nannofossils, calcareous dinoflagellates, calpionellids). Foraminiferal study provides the zonal subdivision of the Puez section from Valanginian - Hauterivian gorbachikellids and praehedbergelids (Hedbergella semielongata Zone), Barremo-Aptian praehedbergelids (Blesusciana kuznetzove Zone), Aptian hedbergellids of occulta - aptiana - praetrocoidea group, Early Late Aptian pseudo-planispiral foraminifera (Praehedbergella luterbacheri and Globigerinelloides ferreolensis Zones), important marker species of Hedbergella trocoidea and Paraticinella bejaaouaensis for the Late Aptian zone, Early Albian microperforate hedbergellids (Hedbergella planispira Zone), Mid Albian ticinellids (Ticinella primula Zone), advanced ticinellids like Ticinella roberti etc. (Biticinella breggiensis Zone), Latest Albian rotalliporids (Rotalipora appeninica Zone) up to Early Cenonanian appearance of Thalmanninella (Rotalipora) globotruncanoides. Results of this integrated study will be used for both, the precise biostratigraphy of the sequence studied as well as for the paleoenvironmental reconstruction. Lukeneder A. 2012. New biostratigraphic data on an Upper Hauterivian-Upper Barremian ammonite assemblage from the Dolomites (Southern Alps, Italy). Cretaceous Research. doi:10.1016/j.cretres.2011.11.002 Lukeneder A. 2011. The Biancone and Rosso Ammonitico facies of the northern Trento Plateau (Dolomites, Southern Alps; Italy). Annalen des Naturhistorischen Museum Wien, Serie A, 112, 9-33. Lukeneder A. 2010. Lithostratigraphic definition and stratotype for the Puez Formation: formalisation of the Lower Cretaceous in the Dolomites (S. Tyrol, Italy). Austrian Journals

Arthropods in modern resins reveal if amber accurately recorded forest arthropod communities.

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Solórzano Kraemer, Mónica M; Delclòs, Xavier; Clapham, Matthew E; Arillo, Antonio; Peris, David; Jäger, Peter; Stebner, Frauke; Peñalver, Enrique

2018-05-07

Amber is an organic multicompound derivative from the polymerization of resin of diverse higher plants. Compared with other modes of fossil preservation, amber records the anatomy of and ecological interactions between ancient soft-bodied organisms with exceptional fidelity. However, it is currently suggested that ambers do not accurately record the composition of arthropod forest paleocommunities, due to crucial taphonomic biases. We evaluated the effects of taphonomic processes on arthropod entrapment by resin from the plant Hymenaea , one of the most important resin-producing trees and a producer of tropical Cenozoic ambers and Anthropocene (or subfossil) resins. We statistically compared natural entrapment by Hymenaea verrucosa tree resin with the ensemble of arthropods trapped by standardized entomological traps around the same tree species. Our results demonstrate that assemblages in resin are more similar to those from sticky traps than from malaise traps, providing an accurate representation of the arthropod fauna living in or near the resiniferous tree, but not of entire arthropod forest communities. Particularly, arthropod groups such as Lepidoptera, Collembola, and some Diptera are underrepresented in resins. However, resin assemblages differed slightly from sticky traps, perhaps because chemical compounds in the resins attract or repel specific insect groups. Ground-dwelling or flying arthropods that use the tree-trunk habitat for feeding or reproduction are also well represented in the resin assemblages, implying that fossil inclusions in amber can reveal fundamental information about biology of the past. These biases have implications for the paleoecological interpretation of the fossil record, principally of Cenozoic amber with angiosperm origin.

The range of bioinclusions and pseudoinclusions preserved in a new Turonian (~90 ma) amber occurrence from Southern Australia.

Science.gov (United States)

Quinney, Annie; Mays, Chris; Stilwell, Jeffrey D; Zelenitsky, Darla K; Therrien, François

2015-01-01

A new Turonian amber occurrence, representing the oldest in situ amber locality in Australia and the southern-most locality in Gondwana, has recently been discovered in the Otway Basin of Victoria. The amber was collected from petroleum cores and many pieces contain a range of inclusions that can provide information on the depositional history of the resin. To date, one species of fern spore (Cyathidites minor) and one species of lycophyte spore (Kraeuselisporites sp?) have been conclusively identified in the amber, along with filamentous microorganisms and degraded plant matter. Several samples are also rife with pseudoinclusions as reported recently in other ambers. The abundance of preserved particulate debris and wind dispersed spores suggest that the Otway amber formed subaerially. Furthermore, based on the range of bioinclusions and forms of pseudoinclusions preserved within a single piece of amber, the locus of hardening for individual samples is variably interpreted as occurring in the tree tops, on the tree trunk or on the ground surface. Notably, specific inclusion assemblages are associated with certain colours of amber. By extension, and in accordance with recent studies, amber colour may be indicative of depositional environment. Variation in the environment of solidification may, therefore, be sufficient to account for the broad range of morphological characteristics preserved in a single amber deposit.

Geology and sequence stratigraphy of undiscovered oil and gas resources in conventional and continuous petroleum systems in the Upper Cretaceous Eagle Ford Group and related strata, U.S. Gulf Coast Region

Science.gov (United States)

Dubiel, Russell F.; Pearson, Ofori N.; Pitman, Janet K.; Pearson, Krystal M.; Kinney, Scott A.

2012-01-01

The U.S. Geological Survey (USGS) recently assessed the technically recoverable undiscovered oil and gas onshore and in State waters of the Gulf Coast region of the United States. The USGS defined three assessment units (AUs) with potential undiscovered conventional and continuous oil and gas resources in Upper Cretaceous (Cenomanian to Turonian) strata of the Eagle Ford Group and correlative rocks. The assessment is based on geologic elements of a total petroleum system, including hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and traps (formation, timing, and seals). Conventional oil and gas undiscovered resources are in updip sandstone reservoirs in the Upper Cretaceous Tuscaloosa and Woodbine Formations (or Groups) in Louisiana and Texas, respectively, whereas continuous oil and continuous gas undiscovered resources reside in the middip and downdip Upper Cretaceous Eagle Ford Shale in Texas and the Tuscaloosa marine shale in Louisiana. Conventional resources in the Tuscaloosa and Woodbine are included in the Eagle Ford Updip Sandstone Oil and Gas AU, in an area where the Eagle Ford Shale and Tuscaloosa marine shale display vitrinite reflectance (Ro) values less than 0.6%. The continuous Eagle Ford Shale Oil AU lies generally south of the conventional AU, is primarily updip of the Lower Cretaceous shelf edge, and is defined by thermal maturity values within shales of the Eagle Ford and Tuscaloosa that range from 0.6 to 1.2% Ro. Similarly, the Eagle Ford Shale Gas AU is defined downdip of the shelf edge where source rocks have Ro values greater than 1.2%. For undiscovered oil and gas resources, the USGS assessed means of: 1) 141 million barrels of oil (MMBO), 502 billion cubic feet of natural gas (BCFG), and 4 million barrels of natural gas liquids (MMBNGL) in the Eagle Ford Updip Sandstone Oil and Gas AU; 2) 853 MMBO, 1707 BCFG, and 34 MMBNGL in the

GPU acceleration of Dock6's Amber scoring computation.

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Yang, Hailong; Zhou, Qiongqiong; Li, Bo; Wang, Yongjian; Luan, Zhongzhi; Qian, Depei; Li, Hanlu

2010-01-01

Dressing the problem of virtual screening is a long-term goal in the drug discovery field, which if properly solved, can significantly shorten new drugs' R&D cycle. The scoring functionality that evaluates the fitness of the docking result is one of the major challenges in virtual screening. In general, scoring functionality in docking requires a large amount of floating-point calculations, which usually takes several weeks or even months to be finished. This time-consuming procedure is unacceptable, especially when highly fatal and infectious virus arises such as SARS and H1N1, which forces the scoring task to be done in a limited time. This paper presents how to leverage the computational power of GPU to accelerate Dock6's (http://dock.compbio.ucsf.edu/DOCK_6/) Amber (J. Comput. Chem. 25: 1157-1174, 2004) scoring with NVIDIA CUDA (NVIDIA Corporation Technical Staff, Compute Unified Device Architecture - Programming Guide, NVIDIA Corporation, 2008) (Compute Unified Device Architecture) platform. We also discuss many factors that will greatly influence the performance after porting the Amber scoring to GPU, including thread management, data transfer, and divergence hidden. Our experiments show that the GPU-accelerated Amber scoring achieves a 6.5× speedup with respect to the original version running on AMD dual-core CPU for the same problem size. This acceleration makes the Amber scoring more competitive and efficient for large-scale virtual screening problems.

Improving the Efficiency of Free Energy Calculations in the Amber Molecular Dynamics Package.

Science.gov (United States)

Kaus, Joseph W; Pierce, Levi T; Walker, Ross C; McCammont, J Andrew

2013-09-10

Alchemical transformations are widely used methods to calculate free energies. Amber has traditionally included support for alchemical transformations as part of the sander molecular dynamics (MD) engine. Here we describe the implementation of a more efficient approach to alchemical transformations in the Amber MD package. Specifically we have implemented this new approach within the more computational efficient and scalable pmemd MD engine that is included with the Amber MD package. The majority of the gain in efficiency comes from the improved design of the calculation, which includes better parallel scaling and reduction in the calculation of redundant terms. This new implementation is able to reproduce results from equivalent simulations run with the existing functionality, but at 2.5 times greater computational efficiency. This new implementation is also able to run softcore simulations at the λ end states making direct calculation of free energies more accurate, compared to the extrapolation required in the existing implementation. The updated alchemical transformation functionality will be included in the next major release of Amber (scheduled for release in Q1 2014) and will be available at http://ambermd.org, under the Amber license.

Compositional variation of glauconites in Upper Cretaceous-Paleogene sedimentary iron-ore deposits in South-eastern Western Siberia

Science.gov (United States)

Rudmin, Maxim; Banerjee, Santanu; Mazurov, Aleksey

2017-06-01

Glauconite occurs either as unaltered greenish or as altered brownish variety in Upper Cretaceous-Palaeocene sediments in the southeastern corner of Western Siberia. Studied section within the Bakchar iron-ore deposit includes Ipatovo, Slavgorod, Gan'kino and Lyulinvor formations, which are represented by sandstones, siltstones, claystones and oolitic ironstones of coastal-marine facies. The origin of unaltered glauconite is explained by the ;verdissement theory;. Transgressions during Lower Coniacian, Santonian and Campanian favored the formation of unaltered glauconites in dysoxic to anoxic conditions. Subaerial exposure of glauconite resulted in leaching of potassium, oxidation of iron and formation of iron hydroxides in Upper Coniacian, Maastrichtian and Palaeocene. Glauconite ultimately converts to leptochlorite and hydrogoethite by this alteration. Abundant microscopic gold inclusions, besides sulphides, sulphates, oxides and silicates characterize this glauconite. Mineral inclusions include precious, rare metals and non-ferrous metals. The concentration of gold in glauconite may be as high as 42.9 ppb. Abundant inclusions of various compositions in glauconites indicate enrichment of marine sediments in precious and non-precious metals. While major element composition of glauconites is affected by subaerial exposure, the broadly similar micro-inclusions in both altered and unaltered varieties are possibly related to the comparatively immobile nature of REE and trace elements.

ASSESMENT OF FACTORS AFFECTING THE PRODUCTIVITY OF AMBER CHARKHA AND ERGONOMIC EVALUATION OF WORKERS

OpenAIRE

G. V. THAKRE; S. G. PATIL; D. N. AGRAWAL

2011-01-01

Increasing demands of the cotton fabrics, now a day has made it necessary to increase the production of cotton fabrics. To increase the production it is necessary to study the factors affecting the performance of the women workers working on Amber charkha. Most of the Amber charkha in rural areas are hand operated (i.e. they runwith the help of human energy input). There are various medical, technical and environmental factors which affect the productivity of women workers working on Amber ch...

Biostratigraphy of the Cretaceous/Tertiary boundary in the Sirwan Valley (Sulaimani Region, Kurdistan, NE Iraq)

Science.gov (United States)

Sharbazheri, Khalid Mahmood; Ghafor, Imad Mahmood; Muhammed, Qahtan Ahmad

2009-10-01

The Cretaceous/Tertiary (K/T) boundary sequence, which crops out in the studied area is located within the High Folded Zone, in the Sirwan Valley, northeastern Iraq. These units mainly consist of flysch and flysch-type successions of thick clastic beds of Tanjero/Kolosh Formations. A detailed lithostratigraphic study is achieved on the outcropping uppermost part of the Upper Cretaceous successions (upper part of Tanjero Formation) and the lowermost part of the Kolosh Formation. On the basis of the identified planktonic foraminiferal assemblages, five biozones are recorded from the uppermost part of Tanjero Formation and four biozones from the lower part of the Kolosh Formation (Lower Paleocene) in the Sirwan section. The biostratigraphic correlations based on planktonic foraminiferal zonations showed a comparison between the biostratigraphic zones established in this study and other equivalents of the commonly used planktonic zonal scheme around the Cretaceous/Tertiary boundary in and outside Iraq.

A new troodontid theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America.

Directory of Open Access Journals (Sweden)

Lindsay E Zanno

Full Text Available Troodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species--Troodon formosus--presently known from substantial skeletal remains.Here we report a gracile new troodontid theropod--Talos sampsoni gen. et sp. nov.--from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes.Talos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians by bolstering functional interpretations of prey grappling and

A new proposal concerning the botanical origin of Baltic amber.

Science.gov (United States)

Wolfe, Alexander P; Tappert, Ralf; Muehlenbachs, Karlis; Boudreau, Marc; McKellar, Ryan C; Basinger, James F; Garrett, Amber

2009-10-07

Baltic amber constitutes the largest known deposit of fossil plant resin and the richest repository of fossil insects of any age. Despite a remarkable legacy of archaeological, geochemical and palaeobiological investigation, the botanical origin of this exceptional resource remains controversial. Here, we use taxonomically explicit applications of solid-state Fourier-transform infrared (FTIR) microspectroscopy, coupled with multivariate clustering and palaeobotanical observations, to propose that conifers of the family Sciadopityaceae, closely allied to the sole extant representative, Sciadopitys verticillata, were involved in the genesis of Baltic amber. The fidelity of FTIR-based chemotaxonomic inferences is upheld by modern-fossil comparisons of resins from additional conifer families and genera (Cupressaceae: Metasequoia; Pinaceae: Pinus and Pseudolarix). Our conclusions challenge hypotheses advocating members of either of the families Araucariaceae or Pinaceae as the primary amber-producing trees and correlate favourably with the progressive demise of subtropical forest biomes from northern Europe as palaeotemperatures cooled following the Eocene climate optimum.

Upper Cretaceous (Campanian) phosphorites in Jordan: implications for the formation of a south Tethyan phosphorite giant

Science.gov (United States)

Pufahl, Peir K.; Grimm, Kurt A.; Abed, Abdulkader M.; Sadaqah, Rushdi M. Y.

2003-10-01

A record of sedimentary, authigenic, and biological processes are preserved within the Upper Cretaceous (Campanian) Alhisa Phosphorite Formation (AP) in central and northern Jordan. The AP formed near the eastern extremity of the south Tethyan Phosphorite Province (STPP), a carbonate-dominated Upper Cretaceous to Eocene "phosphorite giant" that extends from Colombia, North Africa to the Middle East. Multidisciplinary research of the AP and associated cherts, chalks, and oyster buildups indicate that phosphatic strata formed on a highly productive, storm-dominated, east-west trending epeiric platform along the south Tethyan margin. The onset of phosphogenesis and the accumulation of economic phosphorite coincided with a rise in relative sea level that onlapped peritidal carbonates of the Ajlun Group. Pristine phosphates are associated with well-developed micrite concretionary horizons and contain abundant non-keeled spiral planktic foraminifera and a low diversity benthic assemblage of Buliminacean foraminifera, suggesting that pristine phosphates are a condensed facies and phosphogenesis was stimulated by the effects of a highly productive surface ocean and the suboxic diagenesis of sedimentary organic matter. The bulk sediment composition and absence of Fe-bearing authigenic phases such as glauconite, pyrite (including pyrite molds), siderite, and goethite within pristine phosphates suggests that deposition and authigenesis occurred under conditions of detrital starvation and that "iron-pumping" played a minimal role in phosphogenesis. Authigenic precipitation of phosphate occurred in a broad array of sedimentary environments—herein termed a "phosphorite nursery"—that spanned the entire platform. This is a non-uniformitarian phenomenon reflecting precipitation of sedimentary apatite across a wide depositional spectrum in a variety of depositional settings, wherever the conditions were suitable for phosphogenesis. Sedimentologic data indicate that pristine

Two new fossil species of Cryptocephalus Geoffroy (Coleoptera: Chrysomelidae) from Baltic and Dominican Amber

Science.gov (United States)

Two new species of Cryptocephalus Geoffroy (Coleoptera: Chrysomelidae) are described and illustrated from fossil resin: Cryptocephalus groehni sp. nov (Baltic amber) and Cryptocephalus kheelorum sp. nov. (Dominican amber). These are the first described species of Cryptocephalinae from fossil resin. ...

Subfamily Limoniinae Speiser, 1909 (Diptera, Limoniidae) from Baltic amber (Eocene): the genus Helius Lepeletier & Serville, 1828.

Science.gov (United States)

Kania, Iwona

2014-06-10

A revision of the genus Helius Lepeletier & Serville, 1828 (Diptera: Limoniidae) from Baltic amber (Eocene) is presented. Redescriptions of 5 species, Helius formosus Krzemiński, 1993, Helius linus Podenas, 2002, Helius minutus (Loew, 1850), Helius mutus Podenas, 2002, Helius pulcher (Loew, 1850) of this genus from Baltic amber are given and documented by photographs and drawings. Four new species of the genus Helius from Baltic amber are described: Helius gedanicus sp. nov., Helius hoffeinsorum sp. nov., Helius similis sp. nov., Helius fossilis sp. nov. A key to species of Helius from Baltic amber is provided. Patterns morphological evolution and the aspects evolutionary history of Helius are discussed.

Influence of land-based Kaliningrad (Primorsky) amber mining on coastal zone.

Science.gov (United States)

Krek, Alexander; Ulyanova, Marina; Koschavets, Svetlana

2018-06-01

In this paper, we report on the pollution in the coastal zone of the South-Eastern Baltic Sea (Russian coast). It was studied through a range of methods, including analyses potential water quality indicators (WQIs) and potentially harmful elements (PHEs). A contamination factor and modified degree of contamination were used for describing the contamination of the sediments by toxic substances. Special attention was paid to activity of the Kaliningrad Amber Combine (KAC), the biggest world amber mining company, located onshore close to the coastal zone (Kaliningrad Region). The amber extraction contribution to the ecological state of the coastal zone was estimated. Contamination of the quarry by metals (Cr, Co, Ni, Cu, Pb, Zn) was comparable with contamination of abrasion bench. The pollution of the western coastal zone of the Sambia Peninsula is caused both by land-based anthropogenic developments (including KAC) and natural processes (coastal abrasion). Copyright © 2018 Elsevier Ltd. All rights reserved.

A new squamate lizard from the Upper Cretaceous Adamantina Formation (Bauru Group, São Paulo State, Brazil

Directory of Open Access Journals (Sweden)

William R. Nava

2011-03-01

Full Text Available The record of non-mosasaur squamates (Reptilia, Squamata is sparse in the Cretaceus fossil record of Brazil and include six putative reports, three from the Aptian-Albian of the Araripe Basin (Tijubina pontei Bonfim-Júnior and Marques, Olindalacerta brasiliensis Evans and Yabumoto, and a lizard indet. and three from the Upper Cretaceous of the Bauru Group (Pristiguana brasiliensis Estes and Price, Anilioidae gen. et sp. indet., and Squamata gen. et sp. indet.. In this contribution, a new genus and species of lizard, Brasiliguana prudentis gen. et sp. nov., is described based on an isolated left maxilla with teeth. The material was discovered in an outcrop of the Upper Cretaceous Adamantina Formation (Bauru Group located in the proximity of Presidente Prudente Municipality, São Paulo State, Brazil. The new taxon is considered a basal non-Priscagamidae+Acrodonta iguanian based on the presence of a weakly inclined anterior margin of the maxillary nasal process and maxillary tooth shape and tooth implantation similar to that of iguanians rather than of other lizard groups (e.g. teiids. This finding significantly increases the squamate lizard diversity of South America, which is still poorly understood and sparsely represented in the fossil record.Os achados de escamados (Reptilia, Squamata são escassos no Cretáceo do Brasil, incluindo cinco registros pontuais, dois do Aptiano-Albiano da Bacia do Araripe (Tijubina pontei Bonfim-Júnior e Marques e Olindalacerta brasiliensis Evans e Yabumoto, e três do Cretáceo Superior do Grupo Bauru (Pristiguana brasiliensis Estes and Price, Anilioidae gen. et sp. indet., Squamata gen. et sp. indet.. Nesta contribuição apresentamos um novo gênero e espécie de lagarto, Brasiliguana prudentis, baseado numa maxila esquerda com dentição. O material provém de depósitos da Formação Adamantina aflorantes próximos a cidade de Presidente Prudente, Estado de São Paulo, Brasil. O novo táxon é considerado um

Heavy mineral delineation of the Cretaceous, Paleocene, and Eocene stratigraphic sections at the Savannah River Site, Upper Coastal Plain of South Carolina

International Nuclear Information System (INIS)

Cathcart, E.M.; Sargent, K.A.

1994-01-01

The Upper Atlantic Coastal Plain of South Carolina consists of a fluvial-deltaic and shallow marine complex of unconsolidated sediments overlying the crystalline basement rocks of the North American continent. Because of the lateral and vertical variability of these sediments, stratigraphic boundaries have been difficult to distinguish. Portions of the Cretaceous, Paleocene, and eocene stratigraphic sections from cores recovered during the construction of two monitoring wells at the Savannah River Site were studied to determine if heavy mineral suites could be utilized to distinguish boundaries. The stratigraphic sections include: the Late Cretaceous Middendorf, Black Creek, and Steel Creek Formations, the Paleocene Snapp Formation, the late Paleocene-Early Eocene Fourmile Branch Formation, and the Early Eocene Congaree formation. In previous studies composite samples were taken over 2.5 ft. intervals along the cores and processed using a heavy liquid for heavy mineral recovery. During this study, heavy mineral distributions were determined by binocular microscope and the mineral identifications confirmed by x-ray diffraction analysis of hand-picked samples. The heavy mineral concentration data and grain size data were then compared to the stratigraphic boundary positions determined by other workers using more classical methods. These comparisons were used to establish the utility of this method for delineating the stratigraphic boundaries in the area of study

The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA).

Science.gov (United States)

Farke, Andrew A; Phillips, George E

2017-01-01

Ceratopsids ("horned dinosaurs") are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian) of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA

Directory of Open Access Journals (Sweden)

Andrew A. Farke

2017-05-01

Full Text Available Ceratopsids (“horned dinosaurs” are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

The Jurassic-Cretaceous basaltic magmatism of the Oued El-Abid syncline (High Atlas, Morocco): Physical volcanology, geochemistry and geodynamic implications

Science.gov (United States)

Bensalah, Mohamed Khalil; Youbi, Nasrrddine; Mata, João; Madeira, José; Martins, Línia; El Hachimi, Hind; Bertrand, Hervé; Marzoli, Andrea; Bellieni, Giuliano; Doblas, Miguel; Font, Eric; Medina, Fida; Mahmoudi, Abdelkader; Beraâouz, El Hassane; Miranda, Rui; Verati, Chrystèle; De Min, Angelo; Ben Abbou, Mohamed; Zayane, Rachid

2013-05-01

Basaltic lava flows, dykes and sills, interbedded within red clastic continental sedimentary sequences (the so called "Couches Rouges") are widespread in the Oued El-Abid syncline. They represent the best candidates to study the Jurassic-Cretaceous magmatism in the Moroccan High Atlas. The volcanic successions were formed during two pulses of volcanic activity, represented by the Middle to Upper Jurassic basaltic sequence B1 (1-4 eruptions) and the Lower Cretaceous basaltic sequence B2 (three eruptions). Whether belonging to the B1 or B2, the lava flows present morphology and internal structures typical of inflated pahoehoe. Our geochemical data show that, at least for Jurassic magmatism, the dykes, and sills cannot be considered as strictly representing the feeders of the sampled lava flows. The Middle to Upper Jurassic pulse is moderately alkaline in character, while the Lower Cretaceous one is transitional. Crustal contamination plays a minor role in the petrogenesis of these magmas, which were generated by variable partial melting degrees of a garnet-bearing mantle source. Magmatism location was controlled by pre-existing Hercynian fault systems reactivated during a Middle to Upper Jurassic-Cretaceous rifting event. The associated lithospheric stretching induced melting, by adiabatic decompression, of enriched low-solidus infra-lithospheric domains.

Mid-infrared spectroscopy for characterization of Baltic amber (succinite)

Science.gov (United States)

Wagner-Wysiecka, Ewa

2018-05-01

Natural Baltic amber (succinite) is the most appreciated fossil resin of the rich cultural traditions dating back to prehistoric times. Its unequivocal identification is extremely important in many branches of science and trades including archeology, paleontology, chemistry and finally mineralogical and gemological societies. Current methods of modification of natural succinite are more and more sophisticated making the identification of natural Baltic amber often challenging. In article the systematic analytical approach for identification of natural and modified under different conditions succinite, using mid-infrared spectroscopy (transmission, Drifts and ATR techniques) is presented. The correlation between spectral characteristics and properties of succinite is discussed pointing that the understanding of the nature of changes is the key of identification of this precious material.

First record of lobed trace fossils in Brazil's Upper Cretaceous paleosols: Rhizoliths or evidence of insects and their social behavior?

Science.gov (United States)

Luciano do Nascimento, Diego; Batezelli, Alessandro; Bernardes Ladeira, Francisco Sérgio

2017-11-01

This is the first report of trace fossils potentially associated with insect social behavior in sandy and well-drained paleosols of the Upper Cretaceous continental sequence of Brazil. The trace fossils consist of dozens of lobed and vertical structures cemented by CaCO3 and preserved mainly in full relief in paleosols of the Marilia Formation (Bauru Basin) in the state of Minas Gerais. The described ichnofossils are predominantly vertical, up to 2 m long, and are composed of horizontal lobed structures connected by vertical tunnel-like structures that intersect in the center and at the edges. The lobed structures range from 3 to 15 cm long and 2-6 cm thick. Two different hypotheses are analyzed to explain the origin of the trace fossils; the less probable one is that the structures are laminar calcretes associated with rhizoliths and rhizoconcretions. The hypothesis involving social insects was considered because the trace fossils described herein partially resemble a modern ant nest and the ichnofossil Daimoniobarax. The micromorphological analysis of the lobed and tunnel-like structures indicates modifications of the walls, such as the presence of inorganic fluidized linings, dark linings and oriented grains, supporting the hypothesis that they are chambers and shafts. The architecture and size of the reported nests suggest the possibility that social insect colonies existed during the Maastrichtian and are direct evidence of the social behavior and reproductive strategies of the Cretaceous pedofauna.

Vibrational spectroscopy with chromatographic methods in molecular analyses of Moravian amber samples (Czech Republic)

Czech Academy of Sciences Publication Activity Database

Havelcová, Martina; Machovič, Vladimír; Linhartová, M.; Lapčák, L.; Přichystal, A.; Dvořák, Z.

2016-01-01

Roč. 128, SEP (2016), 153-160 ISSN 0026-265X R&D Projects: GA ČR(CZ) GA13-18482S Grant - others:OPPK(XE) CZ.2.16/3.1.00/21538 Program:OPPK Institutional support: RVO:67985891 Keywords : studlovite * valchovite * amber * fossil resin * Baltic amber Subject RIV: DD - Geochemistry Impact factor: 3.034, year: 2016

Analysis and Provenience of Minoan and Mycenaean Amber, I

Directory of Open Access Journals (Sweden)

Curt W. Beck

2003-02-01

Full Text Available Spectroscopic analysis of amber artifacts excavated in Greece, chiefly of the Bronze Age, can clarify the geographical origins of the material (chiefly Balkan and add to our understanding of trade routes.

Crocodyliform feeding traces on juvenile ornithischian dinosaurs from the Upper Cretaceous (Campanian Kaiparowits Formation, Utah.

Directory of Open Access Journals (Sweden)

Clint A Boyd

Full Text Available Crocodyliforms serve as important taphonomic agents, accumulating and modifying vertebrate remains. Previous discussions of Mesozoic crocodyliform feeding in terrestrial and riverine ecosystems have often focused on larger taxa and their interactions with equally large dinosaurian prey. However, recent evidence suggests that the impact of smaller crocodyliforms on their environments should not be discounted. Here we present direct evidence of feeding by a small crocodyliform on juvenile specimens of a 'hypsilophodontid' dinosaur from the Upper Cretaceous (Campanian Kaiparowits Formation of southern Utah. Diagnostic crocodyliform bite marks present on a left scapula and a right femur, as well as a partial probable crocodyliform tooth crown (ovoid in cross-section preserved within a puncture on the right femur, comprise the bulk of the feeding evidence. Computed tomography scans of the femoral puncture reveal impact damage to the surrounding bone and that the distal tip of the embedded tooth was missing prior to the biting event. This is only the second reported incidence of a fossil crocodyliform tooth being found embedded directly into prey bone. These bite marks provide insight into the trophic interactions of the ecosystem preserved in the Kaiparowits Formation. The high diversity of crocodyliforms within this formation may have led to accentuated niche partitioning, which seems to have included juvenile dinosaurian prey.

Palaeontology of the upper Turonian paralic deposits of the Sainte-Mondane Formation, Aquitaine Basin, France

Energy Technology Data Exchange (ETDEWEB)

Neraudenau, D.; Saint Martin, S.; Battern, D.J.; Colin, J.P.; Daviero-Gomez, V.; Girard, V.; Gomez, B.; Nohra, Y.A.; Polette, F.; Platel, J.P.; Saint Martin, J.P.; Vullo, R.

2016-07-01

The upper Turonian lignite deposits of Sainte-Mondane, Dordogne (Aquitaine Basin, SW France), consist of clays bearing translucent, orange to red, amber micrograins. The amber exhibits different types of microbial inclusions. The clays contain several conifers including the genera Brachyphyllum, Frenelopsis and Glenrosa, and a few leaf fragments of eudicot angiosperms. Among the plant meso-fossils the occurrence of Costatheca, Spermatites and abundant, diverse, megaspores, including species of Ariadnaesporites, Bacutriletes, Echitriletes, Erlansonisporites, Maexisporites, Minerisporites and Verrutriletes, is noteworthy. Pollen grains of the Normapolles group are important components of the palynomorph assemblage. The clays were deposited in a calm, estuarine or lagoonal, muddy environment. The overlying lignitic sands contain large fossil wood pieces of the conifer Agathoxylon, small solitary corals, fragmentary oysters and pectinids, echinoid spines, a few teeth of marine selachians and bony fishes, but no amber is present. These sands were deposited in a high-energy coastal marine environment. (Author)

Sedimentary processes and architecture of Upper Cretaceous deep-sea channel deposits: a case from the Skole Nappe, Polish Outer Carpathians

Science.gov (United States)

Łapcik, Piotr

2018-02-01

Deep-sea channels are one of the architectonic elements, forming the main conduits for sand and gravel material in the turbidite depositional systems. Deep-sea channel facies are mostly represented by stacking of thick-bedded massive sandstones with abundant coarse-grained material, ripped-up clasts, amalgamation and large scale erosional structures. The Manasterz Quarry of the Ropianka Formation (Upper Cretaceous, Skole Nappe, Carpathians) contains a succession of at least 31 m of thick-bedded high-density turbidites alternated with clast-rich sandy debrites, which are interpreted as axial deposits of a deep-sea channel. The section studied includes 5 or 6 storeys with debrite basal lag deposits covered by amalgamated turbidite fills. The thickness of particular storeys varies from 2.5 to 13 m. Vertical stacking of similar facies through the whole thickness of the section suggest a hierarchically higher channel-fill or a channel complex set, with an aggradation rate higher than its lateral migration. Such channel axis facies cannot aggrade without simultaneous aggradation of levee confinement, which was distinguished in an associated section located to the NW from the Manasterz Quarry. Lateral offset of channel axis facies into channel margin or channel levee facies is estimated at less than 800 m. The Manasterz Quarry section represents mostly the filling and amalgamation stage of channel formation. The described channel architectural elements of the Ropianka Formation are located within the so-called Łańcut Channel Zone, which was previously thought to be Oligocene but may have been present already in the Late Cretaceous.

Microplastics in sea coastal zone: Lessons learned from the Baltic amber.

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Chubarenko, Irina; Stepanova, Natalia

2017-05-01

Baltic amber, adored for its beauty already in Homer's Odyssey (ca. 800 B.C.E), has its material density close to that of wide-spread plastics like polyamide, polystyrene, or acrylic. Migrations of amber stones in the sea and their massive washing ashore have been monitored by Baltic citizens for ages. Based on the collected information, we present the hypothesis on the behaviour of microplastic particles in sea coastal zone. Fresh-to-strong winds generate surface waves, currents and roll-structures, whose joint effect washes ashore from the underwater slope both amber stones and plastics - and carries them back to the sea in a few days. Analysis of underlying hydrophysical processes suggests that sea coastal zone under stormy winds plays a role of a mill for plastics, and negatively buoyant pieces seem to repeatedly migrate between beaches and underwater slopes until they are broken into small enough fragments that can be transported by currents to deeper areas and deposited out of reach of stormy waves. Direct observations on microplastics migrations are urged to prove the hypothesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Blue ghosts: a new method for isolating amber mutants defective in essential genes of Escherichia coli

DEFF Research Database (Denmark)

Brown, S; Brickman, E R; Beckwith, J

1981-01-01

We describe a technique which permits an easy screening for amber mutants defective in essential genes of Escherichia coli. Using this approach, we have isolated three amber mutants defective in the rho gene. An extension of the technique allows the detection of ochre mutants and transposon inser...

Efficiency enhancement of InGaN amber MQWs using nanopillar structures

KAUST Repository

Ou, Yiyu

2017-09-09

We have investigated the use of nanopillar structures on high indium content InGaN amber multiple quantum well (MQW) samples to enhance the emission efficiency. A significant emission enhancement was observed which can be attributed to the enhancement of internal quantum efficiency and light extraction efficiency. The size-dependent strain relaxation effect was characterized by photoluminescence, Raman spectroscopy and time-resolved photoluminescence measurements. In addition, the light extraction efficiency of different MQW samples was studied by finite-different time-domain simulations. Compared to the as-grown sample, the nanopillar amber MQW sample with a diameter of 300 nm has demonstrated an emission enhancement by a factor of 23.8.

Efficiency enhancement of InGaN amber MQWs using nanopillar structures

KAUST Repository

Ou, Yiyu; Iida, Daisuke; Liu, Jin; Wu, Kaiyu; Ohkawa, Kazuhiro; Boisen, Anja; Petersen, Paul Michael; Ou, Haiyan

2017-01-01

We have investigated the use of nanopillar structures on high indium content InGaN amber multiple quantum well (MQW) samples to enhance the emission efficiency. A significant emission enhancement was observed which can be attributed to the enhancement of internal quantum efficiency and light extraction efficiency. The size-dependent strain relaxation effect was characterized by photoluminescence, Raman spectroscopy and time-resolved photoluminescence measurements. In addition, the light extraction efficiency of different MQW samples was studied by finite-different time-domain simulations. Compared to the as-grown sample, the nanopillar amber MQW sample with a diameter of 300 nm has demonstrated an emission enhancement by a factor of 23.8.

Dinosaur Footprints and Other Ichnofauna from the Cretaceous Kem Kem Beds of Morocco

Science.gov (United States)

Ibrahim, Nizar; Varricchio, David J.; Sereno, Paul C.; Wilson, Jeff A.; Dutheil, Didier B.; Martill, David M.; Baidder, Lahssen; Zouhri, Samir

2014-01-01

We describe an extensive ichnofossil assemblage from the likely Cenomanian-age ‘lower’ and ‘upper’ units of the ‘Kem Kem beds’ in southeastern Morocco. In the lower unit, trace fossils include narrow vertical burrows in cross-bedded sandstones and borings in dinosaur bone, with the latter identified as the insect ichnotaxon Cubiculum ornatus. In the upper unit, several horizons preserve abundant footprints from theropod dinosaurs. Sauropod and ornithischian footprints are much rarer, similar to the record for fossil bone and teeth in the Kem Kem assemblage. The upper unit also preserves a variety of invertebrate traces including Conichnus (the resting trace of a sea-anemone), Scolicia (a gastropod trace), Beaconites (a probable annelid burrow), and subvertical burrows likely created by crabs for residence and detrital feeding on a tidal flat. The ichnofossil assemblage from the Upper Cretaceous Kem Kem beds contributes evidence for a transition from predominantly terrestrial to marine deposition. Body fossil and ichnofossil records together provide a detailed view of faunal diversity and local conditions within a fluvial and deltaic depositional setting on the northwestern coast of Africa toward the end of the Cretaceous. PMID:24603467

Are glendonites reliable indicators of cold conditions? Evidence from the Lower Cretaceous of Spitsbergen

Science.gov (United States)

Vickers, Madeleine; Price, Gregory; Watkinson, Matthew; Jerrett, Rhodri

2017-04-01

Glendonites are pseudomorphs after the mineral ikaite, and have been found in marine sediments throughout geological time. Ikaite is a metastable, hydrated form of calcium carbonate, which is only stable under specific conditions: between -2 and +5 °C, and with high alkalinity and phosphate concentrations. Glendonites are often associated with cold climates due to the strong temperature control on ikaite growth, and the coincidence in the geological record with episodes of global cooling. Glendonites are found in the Lower Cretaceous succession in Spitsbergen. During the Early Cretaceous, Spitsbergen was at a palaeolatitude of 60°N, and was part of a shallow epicontinental sea that formed during the Mesozoic as Atlantic rifting propagated northwards. Though the Early Cretaceous was generally characterised by greenhouse climate conditions, episodic cold snaps occurred during the Valanginian (the "Weissert Event") and during Aptian-Albian. Using high resolution carbon-isotope stratigraphy, we show that the first occurrences of glendonites are in the upper Lower Hauterivian and in the very upper Upper Hauterivian, stratigraphically higher than the Valanginian cooling event. Glendonites are also found in horizons in the Upper Aptian, coincident with the Aptian-Albian cold snap. Petrological analysis of the glendonite structure reveals differences between the Hauterivian and Aptian glendonites, with evidence for multiple diagenetic phases of growth in the Hauterivian glendonites, suggesting oscillating chemical conditions. This evidence suggests that local environmental conditions may have a stronger control on glendonite formation and preservation than global climate. We present a new model for ikaite growth and slow transformation to glendonite in marine sediments, which points to a more complex suite of diagenetic transformations than previously modelled. Furthermore, we critically assess whether such pseudomorphs after marine sedimentary ikaite may be indicators

Hydrocarbon migration and accumulation in the Upper Cretaceous Qingshankou Formation, Changling Sag, southern Songliao Basin: Insights from integrated analyses of fluid inclusion, oil source correlation and basin modelling

Science.gov (United States)

Dong, Tian; He, Sheng; Wang, Dexi; Hou, Yuguang

2014-08-01

The Upper Cretaceous Qingshankou Formation acts as both the source and reservoir sequence in the Changling Sag, situated in the southern end of the Songliao Basin, northeast China. An integrated approach involving determination of hydrocarbon charging history, oil source correlation and hydrocarbon generation dynamic modeling was used to investigate hydrocarbon migration processes and further predict the favorable targets of hydrocarbon accumulations in the Qingshankou Formation. The hydrocarbon generation and charge history was investigated using fluid inclusion analysis, in combination with stratigraphic burial and thermal modeling. The source rocks began to generate hydrocarbons at around 82 Ma and the hydrocarbon charge event occurred from approximately 78 Ma to the end of Cretaceous (65.5 Ma) when a large tectonic uplift took place. Correlation of stable carbon isotopes of oils and extracts of source rocks indicates that oil was generated mainly from the first member of Qingshankou Formation (K2qn1), suggesting that hydrocarbon may have migrated vertically. Three dimensional (3D) petroleum system modeling was used to evaluate the processes of secondary hydrocarbon migration in the Qingshankou Formation since the latest Cretaceous. During the Late Cretaceous, hydrocarbon, mainly originated from the Qianan depression, migrated laterally to adjacent structural highs. Subsequent tectonic inversion, defined as the late Yanshan Orogeny, significantly changed hydrocarbon migration patterns, probably causing redistribution of primary hydrocarbon reservoirs. In the Tertiary, the Heidimiao depression was buried much deeper than the Qianan depression and became the main source kitchen. Hydrocarbon migration was primarily controlled by fluid potential and generally migrated from relatively high potential areas to low potential areas. Structural highs and lithologic transitions are potential traps for current oil and gas exploration. Finally, several preferred hydrocarbon

Lower Cretaceous Source Rock and its Implication for the Gulf of Guinea Petroleum System

International Nuclear Information System (INIS)

Frost, B.R.; Griffith, R.C.

2002-01-01

Current petroleum system models for the Gulf of Guinea propose Tertiary-age deltaic organic material as the principal source for the hydrocarbons found there. Although previous workers recognized numerous difficulties and inconsistencies, no alternative model has been resented to adequately explain the complete petroleum system. We propose that the principal source rock for the Gulf of Guinea system occurs in upper lower Cretaceous-age shales at the rift-drift transition. Tertiary loading and the consequent maturation of this lower Cretaceous source rock can explain the controls on tap formation, reservoir distribution and hydrocarbon types found in the Gulf of Guinea

Efficiency enhancement of InGaN amber MQWs using nanopillar structures

Directory of Open Access Journals (Sweden)

Ou Yiyu

2018-01-01

Full Text Available We have investigated the use of nanopillar structures on high indium content InGaN amber multiple quantum well (MQW samples to enhance the emission efficiency. A significant emission enhancement was observed which can be attributed to the enhancement of internal quantum efficiency and light extraction efficiency. The size-dependent strain relaxation effect was characterized by photoluminescence, Raman spectroscopy and time-resolved photoluminescence measurements. In addition, the light extraction efficiency of different MQW samples was studied by finite-different time-domain simulations. Compared to the as-grown sample, the nanopillar amber MQW sample with a diameter of 300 nm has demonstrated an emission enhancement by a factor of 23.8.

A comparative Study between GoldSim and AMBER Based Biosphere Assessment Models for an HLW Repository

International Nuclear Information System (INIS)

Lee, Youn-Myoung; Hwang, Yong-Soo

2007-01-01

To demonstrate the performance of a repository, the dose exposure rate to human being due to long-term nuclide releases from a high-level waste repository (HLW) should be evaluated and the results compared to the dose limit presented by the regulatory bodies. To evaluate such a dose rate to an individual, biosphere assessment models have been developed and implemented for a practical calculation with the aid of such commercial tools as AMBER and GoldSim, both of which are capable of probabilistic and deterministic calculation. AMBER is a general purpose compartment modeling tool and GoldSim is another multipurpose simulation tool for dynamically modeling complex systems, supporting a higher graphical user interface than AMBER and a postprocessing feature. And also unlike AMBER, any kind of compartment scheme can be rather simply constructed with an appropriate transition rate between compartments, GoldSim is designed to facilitate the object-oriented modules to address any specialized programs, similar to solving jig saw puzzles. During the last couple of years a compartment modeling approach for a biosphere has been mainly carried out with AMBER in KAERI in order to conservatively or rather roughly provide dose conversion factors to get the final exposure rate due to a nuclide flux into biosphere over various geosphere-biosphere interfaces (GBIs) calculated through nuclide transport modules. This caused a necessity for a newly devised biosphere model that could be coupled to a nuclide transport model with less conservatism in the frame of the development of a total system performance assessment modeling tool, which could be successfully done with the aid of GoldSim. Therefore, through the current study, some comparison results of the AMBER and the GoldSim approaches for the same case of a biosphere modeling without any consideration of geosphere transport are introduced by extending a previous study

Petrological-geochemical characteristics of coarse-grained clastic sedimentary rocks of Quantou Formation, Cretaceous in Songliao basin and their geological significance

International Nuclear Information System (INIS)

Wang Gan; Zhang Bangtong

2005-01-01

Clastic sedimentary rocks of Quantou Formation, Cretaceous in Qing-an area, Songliao basin are mainly composed of sandstone, mudstone and siltstone. The petrological-chemical analysis of clastic sedimentary rocks from Quantou Formation, Cretaceous indicates that their lithology mainly consists of arkose, shale and minor rock debris sandstone and greywacke by chemical classification of bulk elements. REE distribution pattern displays the apparent enrichment of LREE and negative anomaly of Eu and is similar to that of NASC and PAAS. The ratio of trace-element in sedimentary rocks to that of upper crust shows gentle character. All the above features indicate that these sedimentary rocks were slowly deposited under weakly active tectonic setting. They are sediments typical for passive continental margin and active continental margin. It is suggested that material source of clastic sediments of Quantou Formation, Cretaceous in Qing-an area, Songliao basin was originated from Hercynian granite of Zhangguangchai Mountain, and the granite was originated from upper crust. (authors)

Structural changes in amber due to uranium mineralization

Czech Academy of Sciences Publication Activity Database

Havelcová, M.; Machovič, V.; Mizera, Jiří; Sýkorová, I.; Rene, M.; Borecká, L.; Lapčák, L.; Bičáková, O.; Janeček, O.; Dvořák, Z.

2016-01-01

Roč. 158, JUL (2016), s. 89-101 ISSN 0265-931X R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : fossil resin * amber * Uranium * radiolytic alteration * micro-FTIR * mapping * SEM/EDX Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.310, year: 2016

New genus and species of the extinct aphid family Szelegiewicziidae and their implications for aphid evolution.

Science.gov (United States)

Wegierek, Piotr; Żyła, Dagmara; Homan, Agnieszka; Cai, Chenyang; Huang, Diying

2017-10-24

Recently, we are witnessing an increased appreciation for the importance of the fossil record in phylogenetics and testing various evolutionary hypotheses. However, this approach brings many challenges, especially for such a complex group as aphids and requires a thorough morphological analysis of the extinct groups. The extinct aphid family Szelegiewicziidae is supposed to be one of the oviparous lineages in aphid evolution. New material from the rock fossil deposits of Shar Teg (Upper Jurassic of Mongolia), Baissa (Lower Cretaceous of Siberia-Russia), and Burmese amber (Upper Cretaceous of Myanmar) allowed us to undertake a more detailed examination of the morphological features and carry out an analysis of the taxonomical composition and evolution of the family. This led us to the conclusion that evolution of the body plan and wing structure was similar in different, often not closely related groups, probably as a result of convergence. Additionally, we present a description of a new genus and two species (Tinaphis mongolica Żyła &Wegierek, sp. nov., and Feroorbis burmensis Wegierek & Huang, gen. et sp. nov.) that belong to this family.

New genus and species of the extinct aphid family Szelegiewicziidae and their implications for aphid evolution

Science.gov (United States)

Wegierek, Piotr; Żyła, Dagmara; Homan, Agnieszka; Cai, Chenyang; Huang, Diying

2017-12-01

Recently, we are witnessing an increased appreciation for the importance of the fossil record in phylogenetics and testing various evolutionary hypotheses. However, this approach brings many challenges, especially for such a complex group as aphids and requires a thorough morphological analysis of the extinct groups. The extinct aphid family Szelegiewicziidae is supposed to be one of the oviparous lineages in aphid evolution. New material from the rock fossil deposits of Shar Teg (Upper Jurassic of Mongolia), Baissa (Lower Cretaceous of Siberia-Russia), and Burmese amber (Upper Cretaceous of Myanmar) allowed us to undertake a more detailed examination of the morphological features and carry out an analysis of the taxonomical composition and evolution of the family. This led us to the conclusion that evolution of the body plan and wing structure was similar in different, often not closely related groups, probably as a result of convergence. Additionally, we present a description of a new genus and two species ( Tinaphis mongolica Żyła &Wegierek, sp. nov., and Feroorbis burmensis Wegierek & Huang, gen. et sp. nov.) that belong to this family.

Dinosaur footprint assemblage from the Lower Cretaceous Khok Kruat Formation, Khorat Group, northeastern Thailand

Directory of Open Access Journals (Sweden)

Shohei Kozu

2017-11-01

Full Text Available The Khok Kruat Formation is the upper part of the Khorat Group, which consists of upper Lower Cretaceous non-marine sedimentary rocks in northeastern Thailand. Many dinosaur footprints have been known from the upper Lower Cretaceous (Aptian–Albian Khok Kruat Formation at the Huai Dam Chum (Tha Uthen site, northeastern Thailand. Approximately 600 tracks occur in thin mudstone layer of the northern part of the outcrop at the Huai Dam Chum track site. Two types of footprints, small-sized theropod and crocodylomorph are imprinted with mud cracks and ripple marks on the thin mud layer. Most of footprints are referred to cf. Asianopodus, and are imprinted by small-sized theropoda, probably ornithomimosauria. Theropod tracks are mainly separated into two groups, Group A and Group B. From ichnological viewpoints, the small-sized theropod track assemblage indicates the herd behaviour and its idiosyncratic group composition. In particular, the histogram of size-frequency measurements of Group A shows the anomalous bimodal distribution. We consider that there are two hypotheses; the first one is due to the male-female difference, and the second is a result of the different growing stage.

Biting Midges (Diptera: Ceratopogonidae) from Cambay Amber Indicate that the Eocene Fauna of the Indian Subcontinent Was Not Isolated.

Science.gov (United States)

Stebner, Frauke; Szadziewski, Ryszard; Singh, Hukam; Gunkel, Simon; Rust, Jes

2017-01-01

India's unique and highly diverse biota combined with its unique geodynamical history has generated significant interest in the patterns and processes that have shaped the current distribution of India's flora and fauna and their biogeographical relationships. Fifty four million year old Cambay amber from northwestern India provides the opportunity to address questions relating to endemism and biogeographic history by studying fossil insects. Within the present study seven extant and three fossil genera of biting midges are recorded from Cambay amber and five new species are described: Eohelea indica Stebner & Szadziewski n. sp., Gedanohelea gerdesorum Stebner & Szadziewski n. sp., Meunierohelea cambayana Stebner & Szadziewski n. sp., Meunierohelea borkenti Stebner & Szadziewski n. sp., and Meunierohelea orientalis Stebner & Szadziewski n. sp. Fossils of species in the genera Leptoconops Skuse, 1889, Forcipomyia Meigen, 1818, Brachypogon Kieffer, 1899, Stilobezzia Kieffer, 1911, Serromyia Meigen, 1818, and Mantohelea Szadziewski, 1988 are recorded without formal description. Furthermore, one fossil belonging to the genus Camptopterohelea Wirth & Hubert, 1960 is included in the present study. Our study reveals faunal links among Ceratopogonidae from Cambay amber and contemporaneous amber from Fushun, China, Eocene Baltic amber from Europe, as well as the modern Australasian and the Oriental regions. These findings imply that faunal exchange between Europe, Asia and India took place before the formation of Cambay amber in the early Eocene.

Geologic framework for the assessment of undiscovered oil and gas resources in sandstone reservoirs of the Upper Jurassic-Lower Cretaceous Cotton Valley Group, U.S. Gulf of Mexico region

Science.gov (United States)

Eoff, Jennifer D.; Dubiel, Russell F.; Pearson, Ofori N.; Whidden, Katherine J.

2015-01-01

The U.S. Geological Survey (USGS) is assessing the undiscovered oil and gas resources in sandstone reservoirs of the Upper Jurassic–Lower Cretaceous Cotton Valley Group in onshore areas and State waters of the U.S. Gulf of Mexico region. The assessment is based on geologic elements of a total petroleum system. Four assessment units (AUs) are defined based on characterization of hydrocarbon source and reservoir rocks, seals, traps, and the geohistory of the hydrocarbon products. Strata in each AU share similar stratigraphic, structural, and hydrocarbon-charge histories.

Invertebrate ichnofossils and rhizoliths associated with rhizomorphs from the Marília Formation (Echaporã Member), Bauru Group, Upper Cretaceous, Brazil

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Mineiro, Adriano Santos; Santucci, Rodrigo Miloni; da Rocha, Dulce Maria Sucena; de Andrade, Marco Brandalise; Nava, William Roberto

2017-12-01

The Marília Formation (Bauru Group, Upper Cretaceous, Brazil) has furnished a large array of vertebrate fossils. However, its ichnological and botanical contents are poorly explored to date. Here we report findings of invertebrate trace fossils (Beaconites isp., Skolithos isp., and Taenidium barretti), rhizoliths associated with rhizomorphs with preserved hyphae, and fossil roots from the Echaporã Member, Marília Formation, São Paulo State, Brazil. The association of trace fossils suggest they can be regarded to the Scoyenia Ichnofacies. The rhizoliths indicate that at least two types of herbaceous/arbustive plants inhabited the area, one of them living in the vadose zone and the other one with roots closer to the water table, under arid/semiarid conditions. Sedimentological analyses suggest the studied outcrop comprises fluvial deposits, with predominance of sand bars that underwent different and relatively long periods of subaerial exposure.

Depositional and palaeoenvironmental variation of lower Turonian nearshore facies in the Bohemian Cretaceous Basin, Czech Republic

Czech Academy of Sciences Publication Activity Database

Žítt, Jiří; Vodrážka, R.; Hradecká, L.; Svobodová, Marcela; Šťastný, Martin; Švábenická, L.

2015-01-01

Roč. 56, September/December (2015), s. 293-315 ISSN 0195-6671 Institutional support: RVO:67985831 Keywords : phosphatic particle accumulations * organic matter * micropalaeontology * biostratigraphy * condensed sedimentation * Upper Cretaceous Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.196, year: 2015

Detrital zircon U-Pb and (U-Th)/He double-dating of Upper Cretaceous-Cenozoic Zagros foreland basin strata in the Kurdistan Region of northern Iraq

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Barber, D. E.; Stockli, D. F.; Koshnaw, R. I.; Horton, B. K.; Tamar-Agha, M. Y.; Kendall, J. J.

2014-12-01

The NW Zagros orogen is the result of the multistage collisional history associated with Late Cretaceous-Cenozoic convergence of the Arabian and Eurasian continents and final closure of Neotethys. Siliciclastic strata preserved within a ~400 km segment of the NW Zagros fold-thrust belt and foreland basin in the Iraqi Kurdistan Region (IKR) provide a widespread record of exhumation and sedimentation. As a means of assessing NW Zagros foreland basin evolution and chronostratigraphy, we present coupled detrital zircon (DZ) U-Pb and (U-Th)/He geo-thermochronometric data of Upper Cretaceous to Pliocene siliciclastic strata from the Duhok, Erbil, and Suleimaniyah provinces of IKR. LA-ICP-MS U-Pb age analyses reveal that the foreland basin fill in IKR in general was dominantly derived from Pan-African/Arabian-Nubian, Peri-Gondwandan, Eurasian, and Cretaceous volcanic arc terrenes. However, the provenance of these strata varies systematically along strike and through time, with an overall increase in complexity upsection. DZ age distribution of Paleocene-Eocene strata is dominated by a ~95 Ma grain age population, likely sourced from the Late Cretaceous Hassanbag-Bitlis volcanic arc complex along the northern margin of Arabia. In contrast, DZ U-Pb age distributions of Neogene strata show a major contribution derived from various Eurasian (e.g., Iranian, Tauride, Pontide; ~45, 150, 300 Ma) and Pan-African (~550, 950 Ma) sources. The introduction of Eurasian DZ ages at the Paleogene-Neogene transition likely records the onset of Arabian-Eurasian collision. Along strike to the southeast, the DZ U-Pb spectra of Neogene strata show a decreased percentage of Pan-African, Peri-Gondwandan, Tauride, and Ordovician ages, coupled with a dramatic increase in 40-50 Ma DZ ages that correspond to Urumieh-Dokhtar magmatic rocks in Iran. Combined with paleocurrent data, this suggests that Neogene sediments were transported longitudinally southeastward through an unbroken foreland basin

Structural changes in amber due to uranium mineralization

Czech Academy of Sciences Publication Activity Database

Havelcová, Martina; Machovič, Vladimír; Mizera, Jiří; Sýkorová, Ivana; René, Miloš; Borecká, Lenka; Lapčák, L.; Bičáková, Olga; Janeček, O.; Dvořák, Z.

158-159, JUL (2016), s. 89-101 ISSN 0265-931X R&D Projects: GA ČR(CZ) GA13-18482S Grant - others:OPPK(XE) CZ.2.16/3.1.00/21538 Program:OPPK Institutional support: RVO:67985891 Keywords : fossil resin * amber * uranium * radiolytic alteration * micro-FTIR * mapping * SEM/EDX Subject RIV: DD - Geochemistry Impact factor: 2.310, year: 2016

Calcareous nannofossils from the Boreal upper Campanian-Maastrichtian Chalk of Denmark

DEFF Research Database (Denmark)

Thibault, Nicolas Rudolph

2010-01-01

Boreal calcareous nannofossil assemblages have been documented from three sections in Denmark. from the Upper Campanian to Upper Maastrichtian (nannofossil zones UC16a(BP) to UC20d(BP)): the Stevns-1 borehole, next to the Cretaceous/Palaeogene boundary section of Stevns Klint, eastern Sjaelland...

Growing with dinosaurs: natural products from the Cretaceous relict Metasequoia glyptostroboides Hu & Cheng-a molecular reservoir from the ancient world with potential in modern medicine.

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Juvik, Ole Johan; Nguyen, Xuan Hong Thy; Andersen, Heidi Lie; Fossen, Torgils

2016-01-01

After the sensational rediscovery of living exemplars of the Cretaceous relict Metasequoia glyptostroboides -a tree previously known exclusively from fossils from various locations in the northern hemisphere, there has been an increasing interest in discovery of novel natural products from this unique plant source. This article includes the first complete compilation of natural products reported from M. glyptostroboides during the entire period in which the tree has been investigated (1954-2014) with main focus on the compounds specific to this plant source. Studies on the biological activity of pure compounds and extracts derived from M. glyptostroboides are reviewed for the first time. The unique potential of M. glyptostroboides as a source of bioactive constituents is founded on the fact that the tree seems to have survived unchanged since the Cretaceous era. Since then, its molecular defense system has resisted the attacks of millions of generations of pathogens. In line with this, some recent landmarks in Metasequoia paleobotany are covered. Initial spectral analysis of recently discovered intact 53 million year old wood and amber of Metasequoia strongly indicate that the tree has remained unchanged for millions of years at the molecular level.

Late Cenomanian - Early Turonian Hardgrounds and nearshore Depositional Environments (Bohemian Cretaceous Basin)

Czech Academy of Sciences Publication Activity Database

Žítt, Jiří; Bosák, Pavel; Hradecká, L.; Svobodová, Marcela

Colloque sur le Cénomanien/Colloquium on the Cenomanian Stage, - (2001), s. 105-107 ISSN 0766-5946. [Colloque sur le Cénomanien/Colloquium on the Cenomanian Stage. Rouen, 20.10.2001-21.10.2001] R&D Projects: GA ČR GA205/99/1315 Institutional research plan: CEZ:AV0Z3013912 Keywords : Upper Cretaceous * Hardgrounds Subject RIV: DB - Geology ; Mineralogy

A review and phylogeny of Scarabaeine dung beetle fossils (Coleoptera: Scarabaeidae: Scarabaeinae, with the description of two Canthochilum species from Dominican amber

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Sergei Tarasov

2016-05-01

Full Text Available Despite the increasing rate of systematic research on scarabaeine dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae, their fossil record has remained largely unrevised. In this paper, we review all 33 named scarabaeine fossils and describe two new species from Dominican amber (Canthochilum alleni sp.n., Canthochilum philipsivieorum sp.n.. We provide a catalogue of all fossil Scarabaeinae and evaluate their assignment to this subfamily, based primarily on the original descriptions but also, where possible, by examining the type specimens. We suggest that only 21 fossil taxa can be reliably assigned to the Scarabaeinae, while the remaining 14 should be treated as doubtful Scarabaeinae. The doubtful scarabaeines include the two oldest dung beetle fossils known from the Cretaceous and we suggest excluding them from any assessments of the minimum age of scarabaeine dung beetles. The earliest reliably described scarabaeine fossil appears to be Lobateuchus parisii, known from Oise amber (France, which shifts the minimum age of the Scarabaeinae to the Eocene (53 Ma. We scored the best-preserved fossils, namely Lobateuchus and the two Canthochilum species described herein, into the character matrix used in a recent morphology-based study of dung beetles, and then inferred their phylogenetic relationships with Bayesian and parsimony methods. All analyses yielded consistent phylogenies where the two fossil Canthochilum are placed in a clade with the extant species of Canthochilum, and Lobateuchus is recovered in a clade with the extant genera Ateuchus and Aphengium. Additionally, we evaluated the distribution of dung beetle fossils in the light of current global dung beetle phylogenetic hypotheses, geological time and biogeography. The presence of only extant genera in the late Oligocene and all later records suggests that the main present-day dung beetle lineages had already been established by the late Oligocene–mid Miocene.

The upper cretaceous snake Dinilysia patagonica Smith-Woodward, 1901, and the crista circumfenestralis of snakes.

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Palci, Alessandro; Caldwell, Michael W

2014-10-01

Studies on the phylogenetic relationships of snakes and lizards are plagued by problematic characterizations of anatomy that are then used to define characters and states in taxon-character matrices. State assignments and character descriptions must be clear characterizations of observable anatomy and topological relationships if homologies are to be hypothesized. A supposed homology among snakes, not observed in lizards, is the presence of a crista circumfenestralis (CCF), a system of bony crests surrounding the fenestra ovalis and lateral aperture of the recessus scalae tympani. We note that there are some fossil and extant snakes that lack a CCF, and some extant lizards that possess a morphological equivalent. The phylogenetically important upper Cretaceous fossil snake Dinilysia patagonica has been interpreted by different authors as either having or lacking a CCF. These conflicting results for Dinilysia were tested by re-examining the morphology of the otic region in a large sample of snakes and lizards. An unambiguous criterion arising from the test of topology is used to define the presence of a CCF: the enclosure of the ventral margin of the juxtastapedial recess by flanges of the otoccipital (crista tuberalis and crista interfenestralis) that extend forward to contact the posterior margin of the prootic. According to this criterion D. patagonica does not possess a CCF, therefore, this anatomical feature must have arisen later during the evolution of snakes. Copyright © 2014 Wiley Periodicals, Inc.

Hydrothermal dolomitization of the Bekhme formation (Upper Cretaceous), Zagros Basin, Kurdistan Region of Iraq: Record of oil migration and degradation

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Mansurbeg, Howri; Morad, Daniel; Othman, Rushdy; Morad, Sadoon; Ceriani, Andrea; Al-Aasm, Ihsan; Kolo, Kamal; Spirov, Pavel; Proust, Jean Noel; Preat, Alain; Koyi, Hemin

2016-07-01

The common presence of oil seepages in dolostones is widespread in Cretaceous carbonate successions of the Kurdistan Region of Iraq. This integrated field, petrographic, chemical, stable C, O and Sr isotopes, and fluid inclusion study aims to link dolomitization to the origin and geochemical evolution of fluids and oil migration in the Upper Cretaceous Bekhme carbonates. Flux of hot basinal (hydrothermal) brines, which is suggested to have occurred during the Zagros Orogeny, resulted in dolomitization and cementation of vugs and fractures by coarse-crystalline saddle dolomite, equant calcite and anhydrite. The saddle dolomite and host dolostones have similar stable isotopic composition and formed prior to oil migration from hot (81-115 °C) basinal NaCl-MgCl2-H2O brines with salinities of 18-22 wt.% NaCl eq. The equant calcite cement, which surrounds and hence postdates saddle dolomite, has precipitated during oil migration from cooler (60-110 °C) NaCl-CaCl2-H2O brines (14-18 wt.% NaCl eq). The yellowish fluorescence color of oil inclusions in the equant calcite indicates that the oil had API gravity of 15-25° composition, which is lighter than present-day oil in the reservoirs (API of 10-17°). This difference in oil composition is attributed to oil degradation by the flux of meteoric water, which is evidenced by the low δ13C values (- 8.5‰ to - 3.9‰ VPDB) as well as by nil salinity and low temperature in fluid inclusions of late columnar calcite cement. This study demonstrates that linking fluid flux history and related diagenesis to the tectonic evolution of the basin provides important clues to the timing of oil migration, degradation and reservoir evolution.

Highly derived eutherian mammals from the earliest Cretaceous of southern Britain

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Steven C. Sweetman

2017-11-01

Full Text Available Eutherian mammals (Placentalia and all mammals phylogenetically closer to placentals than to marsupials comprise the vast majority of extant Mammalia. Among these there is a phenomenal range of forms and sizes, but the origins of crown group placentals are obscure. They lie within the generally tiny mammals of the Mesozoic, represented for the most part by isolated teeth and jaws, and there is strongly conflicting evidence from phenomic and molecular data as to the date of origin of both Eutheria and Placentalia. The oldest purported eutherians are Juramaia from the Upper Jurassic of China, and Eomaia and Acristatherium from the Lower Cretaceous, also of China. Based on dental characters and analyses of other morphological and molecular data, doubt has recently been cast on the eutherian affinities of the Chinese taxa and consequently on the date of emergence of Eutheria. Until now, the only tribosphenic mammal recorded from the earliest Cretaceous (Berriasian Purbeck Group of Britain was the stem tribosphenidan Tribactonodon. Here we document two new tribosphenic mammals from the Purbeck Group, Durlstotherium gen. nov. and Durlstodon gen. nov., showing highly derived eutherian molar characters that support the early emergence of this clade, prior to the Cretaceous.

Early Miocene amber inclusions from Mexico reveal antiquity of mangrove-associated copepods.

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Huys, Rony; Suárez-Morales, Eduardo; Serrano-Sánchez, María de Lourdes; Centeno-García, Elena; Vega, Francisco J

2016-10-12

Copepods are aquatic microcrustaceans and represent the most abundant metazoans on Earth, outnumbering insects and nematode worms. Their position of numerical world predominance can be attributed to three principal radiation events, i.e. their major habitat shift into the marine plankton, the colonization of freshwater and semiterrestrial environments, and the evolution of parasitism. Their variety of life strategies has generated an incredible morphological plasticity and disparity in body form and shape that are arguably unrivalled among the Crustacea. Although their chitinous exoskeleton is largely resistant to chemical degradation copepods are exceedingly scarce in the geological record with limited body fossil evidence being available for only three of the eight currently recognized orders. The preservation of aquatic arthropods in amber is unusual but offers a unique insight into ancient subtropical and tropical ecosystems. Here we report the first discovery of amber-preserved harpacticoid copepods, represented by ten putative species belonging to five families, based on Early Miocene (22.8 million years ago) samples from Chiapas, southeast Mexico. Their close resemblance to Recent mangrove-associated copepods highlights the antiquity of the specialized harpacticoid fauna living in this habitat. With the taxa reported herein, the Mexican amber holds the greatest diversity of fossil copepods worldwide.

Ichnofabric and substrate consistency in Upper Turonian carbonates of the Bohemian Cretaceous Basin (Czech Republic)

Czech Academy of Sciences Publication Activity Database

Mikuláš, Radek

2006-01-01

Roč. 57, č. 2 (2006), s. 79-90 ISSN 1335-0552 R&D Projects: GA ČR GA205/04/0151 Institutional research plan: CEZ:AV0Z30130516 Keywords : Cretaceous * ichnofossils * firmground Subject RIV: EG - Zoology Impact factor: 0.364, year: 2006 http://www.geologicacarpathica.sk/src/main.php

Microbe-like inclusions in tree resins and implications for the fossil record of protists in amber.

Science.gov (United States)

Thiel, V; Lausmaa, J; Sjövall, P; Ragazzi, E; Seyfullah, L J; Schmidt, A R

2016-07-01

During the past two decades, a plethora of fossil micro-organisms have been described from various Triassic to Miocene ambers. However, in addition to entrapped microbes, ambers commonly contain microscopic inclusions that sometimes resemble amoebae, ciliates, microfungi, and unicellular algae in size and shape, but do not provide further diagnostic features thereof. For a better assessment of the actual fossil record of unicellular eukaryotes in amber, we studied equivalent inclusions in modern resin of the Araucariaceae; this conifer family comprises important amber-producers in Earth history. Using time-of-flight secondary ion mass spectrometry (ToF-SIMS), we investigated the chemical nature of the inclusion matter and the resin matrix. Whereas the matrix, as expected, showed a more hydrocarbon/aromatic-dominated composition, the inclusions contain abundant salt ions and polar organics. However, the absence of signals characteristic for cellular biomass, namely distinctive proteinaceous amino acids and lipid moieties, indicates that the inclusions do not contain microbial cellular matter but salts and hydrophilic organic substances that probably derived from the plant itself. Rather than representing protists or their remains, these microbe-like inclusions, for which we propose the term 'pseudoinclusions', consist of compounds that are immiscible with the terpenoid resin matrix and were probably secreted in small amounts together with the actual resin by the plant tissue. Consequently, reports of protists from amber that are only based on the similarity of the overall shape and size to extant taxa, but do not provide relevant features at light-microscopical and ultrastructural level, cannot be accepted as unambiguous fossil evidence for these particular groups. © 2016 John Wiley & Sons Ltd.

Source rock potential of the organic rich Turonian - Upper Campanian carbonates of northern Lebanon

Energy Technology Data Exchange (ETDEWEB)

Daher, S. Bou; Littke, R. [RWTH Aachen Univ. (Germany). Energy and Mineral Resources Group (EMR); Nader, F.H. [IFP Energies nouvelles, Paris (France). Dept. of Sedimentology-Stratigraphy

2013-08-01

Upper Cretaceous chalks, marls, and shales are arguably the most prolific petroleum source rocks in the eastern Mediterranean region. 209 core samples from the Turonian - Upper Campanian rock succession in north Lebanon were collected and analyzed for their organic matter (OM) content, quality, and maturity. The total organic carbon (TOC) measurements revealed a very good source rock potential for a 150 m interval within the Upper Santonian - Upper Campanian, with an average of 2% TOC. High HI values (average 707 mg/g TOC) characterize these source rocks as type I kerogen and reflect a very good preservation of the organic matter. T{sub max} values (average 421 C) match the other maturity parameters such as vitrinite reflectance (average 0.35%), and all point towards immature organic matter. The equivalent Upper Cretaceous in the offshore Levant basin has enough overburden to have reached maturity. However, the accurate extrapolation of the organic matter quality and quantity to the offshore is yet a challenge with the data at hand. (orig.)

Revival and Identification of Bacterial Spores in 25- to 40-Million-Year-Old Dominican Amber

Science.gov (United States)

Cano, Raul J.; Borucki, Monica K.

1995-05-01

A bacterial spore was revived, cultured, and identified from the abdominal contents of extinct bees preserved for 25 to 40 million years in buried Dominican amber. Rigorous surface decontamination of the amber and aseptic procedures were used during the recovery of the bacterium. Several lines of evidence indicated that the isolated bacterium was of ancient origin and not an extant contaminant. The characteristic enzymatic, biochemical, and 16S ribosomal DNA profiles indicated that the ancient bacterium is most closely related to extant Bacillus sphaericus.

Detailed measured sections, cross sections, and paleogeographic reconstructions of the upper cretaceous and lower tertiary nonmarine interval, Wind River Basin, Wyoming: Chapter 10 in Petroleum systems and geologic assessment of oil and gas resources in the Wind River Basin Province, Wyoming

Science.gov (United States)

Johnson, Ronald C.

2007-01-01

Detailed measured sections and regional stratigraphic cross sections are used to reconstruct facies maps and interpret paleogeographic settings for the interval from the base of Upper Cretaceous Mesaverde Formation to top of lower member of the Paleocene Fort Union Formation in the Wind River Basin, Wyoming. The Mesaverde Formation spans the time during which the Upper Cretaceous seaway retreated eastward out of central Wyoming in Campanian time and the initial stages of the Lewis transgression in earliest Maastrichtian time. This retreat stalled for a considerable period of time during deposition of the lower part of the Mesaverde, creating a thick buildup of marginal marine sandstones and coaly coastal plain deposits across the western part of the basin. The Lewis sea transgressed into the northeast part of Wind River Basin, beginning in early Maastrichtian time during deposition of the Teapot Sandstone Member of the Mesaverde Formation. The Meeteetse Formation, which overlies the Teapot, was deposited in a poorly-drained coastal plain setting southwest of the Lewis seaway. The Lewis seaway, at maximum transgression, covered much of the northeast half of the Wind River Basin area but was clearly deflected around the present site of the Wind River Range, southwest of the basin, providing the first direct evidence of Laramide uplift on that range. Uplift of the Wind River Range continued during deposition of the overlying Maastrichtian Lance Formation. The Granite Mountains south of the basin also became a positive feature during this time. A rapidly subsiding trough during the Maastrichtian time formed near the presentday trough of the Wind River Basin in which more than 6,000 feet of Lance was deposited. The development of this trough appears to have begun before the adjacent Owl Creek Mountains to the north started to rise; however, a muddy facies in the upper part of Lance in the deep subsurface, just to the south, might be interpreted to indicate that the

High diversity in cretaceous ichthyosaurs from Europe prior to their extinction.

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Valentin Fischer

Full Text Available BACKGROUND: Ichthyosaurs are reptiles that inhabited the marine realm during most of the Mesozoic. Their Cretaceous representatives have traditionally been considered as the last survivors of a group declining since the Jurassic. Recently, however, an unexpected diversity has been described in Upper Jurassic-Lower Cretaceous deposits, but is widely spread across time and space, giving small clues on the adaptive potential and ecosystem control of the last ichthyosaurs. The famous but little studied English Gault Formation and 'greensands' deposits (the Upper Greensand Formation and the Cambridge Greensand Member of the Lower Chalk Formation offer an unprecedented opportunity to investigate this topic, containing thousands of ichthyosaur remains spanning the Early-Late Cretaceous boundary. METHODOLOGY/PRINCIPAL FINDINGS: To assess the diversity of the ichthyosaur assemblage from these sedimentary bodies, we recognized morphotypes within each type of bones. We grouped these morphotypes together, when possible, by using articulated specimens from the same formations and from new localities in the Vocontian Basin (France; a revised taxonomic scheme is proposed. We recognize the following taxa in the 'greensands': the platypterygiines 'Platypterygius' sp. and Sisteronia seeleyi gen. et sp. nov., indeterminate ophthalmosaurines and the rare incertae sedis Cetarthrosaurus walkeri. The taxonomic diversity of late Albian ichthyosaurs now matches that of older, well-known intervals such as the Toarcian or the Tithonian. Contrasting tooth shapes and wear patterns suggest that these ichthyosaurs colonized three distinct feeding guilds, despite the presence of numerous plesiosaur taxa. CONCLUSION/SIGNIFICANCE: Western Europe was a diversity hot-spot for ichthyosaurs a few million years prior to their final extinction. By contrast, the low diversity in Australia and U.S.A. suggests strong geographical disparities in the diversity pattern of Albian

Sedimentology and Reservoir Characteristics of Early Cretaceous Fluvio-Deltaic and Lacustrine Deposits, Upper Abu Gabra Formation, Sufyan Sub-basin, Muglad Rift Basin, Sudan

Science.gov (United States)

Yassin, Mohamed; Abdullatif, Osman; Hariri, Mustafa

2017-04-01

Sufyan Sub-basin is an East-West trending Sub-basin located in the northwestern part of the Muglad Basin (Sudan), in the eastern extension of the West and Central Africa Rift System (WCARS). The Early Cretaceous Abu Gabra Formation considered as the main source rock in the Muglad Basin. In Sufyan Sub-basin the Early Cretaceous Upper Abu Gabra Formation is the main oil-producing reservoir. It is dominated by sandstone and shales deposited in fluvio-deltaic and lacustrine environment during the first rift cycle in the basin. Depositional and post-depositional processes highly influenced the reservoir quality and architecture. This study investigates different scales of reservoir heterogeneities from macro to micro scale. Subsurface facies analysis was analyzed based on the description of six conventional cores from two wells. Approaches include well log analysis, thin sections and scanning electron microscope (SEM) investigations, grain-size, and X-ray diffraction (XRD) analysis of the Abu Gabra sandstone. The cores and well logs analyses revealed six lithofacies representing fluvio-deltaic and lacustrine depositional environment. The sandstone is medium to coarse-grained, poorly to moderately sorted and sub-angular to subrounded, Sub-feldspathic arenite to quartz arenite. On macro-scale, reservoir quality varies within Abu Gabra reservoir where it shows progressive coarsening upward tendencies with different degrees of connectivity. The upper part of the reservoir showed well connected and amalgamated sandstone bodies, the middle to lower parts, however, have moderate to low sandstone bodies' connectivity and amalgamation. On micro-scale, sandstone reservoir quality is directly affected by textures and diagenesis.The XRD and SEM analyses show that kaolinite and chlorite clay are the common clay minerals in the studied samples. Clay matrix and quartz overgrowth have significantly reduced the reservoir porosity and permeability, while the dissolution of feldspars

TRANSITION FROM CARBONATE PLATFORM TO PELAGIC DEPOSITION (MID JURASSIC- LATE CRETACEOUS, VOURINOS MASSIF, NORTHERN GREECE

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NICOLAOS CARRAS

2004-03-01

Full Text Available A Jurassic- Cretaceous carbonate succession crops out along the Zyghosti Rema, Kozani (Northern Greece. The substratum consists of the ophiolitic succession of the Vourinos Massif (Pelagonian Domain: serpentinites tectonically overlain by basalts, with thin lenses of radiolarian cherts of middle Bathonian age. The contact with the overlying Jurassic limestones is tectonic. Eight informal units have been distinguished within the Mesozoic limestones, from the base upwards. (A bioclastic, intraclastic and oolitic packstone (Callovian- Oxfordian. (B bioclastic packstone and coral boundstone (Oxfordian . (C bioclastic and oncoidal wackestone with Clypeina jurassica (Oxfordian- Upper Kimmeridgian. (D (Upper Kimmeridgian- Portlandian: oncoidal packstone and rudstone (facies D1; intraclastic and bioclastic grainstone and packstone (facies D2; neptunian dykes with intraclastic and bioclastic wackestone and packstone filling (facies D3; neptunian dykes with Fe-Mn rich laterite filling and with pink silty filling of early Late Cretaceous age. An unconformity surface, due to emersion and erosion of the platform during the latest Jurassic- Early Cretaceous, is overlain by (E intraclastic, bioclastic packstone and grainstone (Cenomanian. (F massive body of debrites with coral, echinoderm, algae and rudist large clasts (facies F1 (Cenomanian; turbiditic beds of bioclastic, intraclastic and lithoclastic rudstone and grainstone (facies F2. (G thin bedded bioclastic mudstone and wackestone with planktonic foraminifers and radiolarians, alternating with turbiditic beds of bioclastic, intraclastic packstone and rudstone and with conglomeratic levels and slumped beds of the previous turbidites (upper Santonian- lower Campanian. (H: bioclastic packstone with planktonic foraminifers (facies H1 (lower Campanian - ?Maastrichtian; amalgamated turbiditic beds of bioclastic wackestone and packstone with planktonic foraminifers (facies H2; turbiditic beds of bioclastic

Meteoric diagenesis of Upper Cretaceous and Paleocene-Eocene shallow-water carbonates in the Kruja Platform (Albania): geochemical evidence

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Heba, Grigor; Prichonnet, Gilbert; El Albani, Abderrazak

2009-04-01

In the central part of the Kruja Platform (Albania) located in the Apulian passive margin, geochemical analyses (calcimetry, Sr, REE and isotopic, δ13C and δ18O) coupled with sedimentological and sequence stratigraphic study were carried out on Upper Cretaceous (CsB4, CsB5, CsB6 Biozones) and Paleocene to Middle Eocene shallow-water carbonates that crop out in the Kruje-Dajt massif (L'Escalier section) and Makareshi massif (La Route section). The lower values in Sr contents, the homogeneous δ18O values in both sections and the covariance between δ13C and δ18O values (La Route section) are attributed to diagenesis influence by a meteoric water-buffer system, supported by petrographic observations. Moreover, a new exposure surface during the Late Cretaceous time (between CsB5 and CsB6 Biozones) may be proposed according to the low or negative excursions of Sr values, the negative excursions of isotopic values in both sections and a positive peak of normalized REE values (La Route section). These variations correlate with the geochemical signal reported by the decreasing strontium isotope values of rudist shells in the Island of Brač carbonate platform (Apulia domain) during the late Middle Campanian (77.3 Ma). Also, this continental exposure is consistent with the global sea-level fall reported from the Boreal Realm, North Atlantic, and the southern Tethyan margin. This geochemical evidence is a complementary tool for the sedimentological analysis and suggests a maximum regression (a sea-level fall) at the transition between the CsB5 and CsB6 Biozones. The high values of Sr content in Middle Eocene carbonates (L'Escalier section) reflect changes in depositional environment from restricted to open marine conditions. REE values increase through transgressive systems tract, characterized by small increase of detrital input. However, anomalies of certain values in both sections suggest disturbances linked either to the changes in clay input and to diagenetic

Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge, Danish North Sea

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Finn Surlyk

2011-12-01

Full Text Available The 331 m long core from the Mona-1 well in the Danish North Sea spans almost the entire Upper Cretaceous Chalk Group but only about 10% of Late Cretaceous time is represented. The succession comprises 14 facies representing pelagic deposition, turbidity flow, and mass-transport processes, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab¬sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites, and the resultant deposits were thoroughly bioturbated if deposited during normal oxygenation at the sea floor. Periodic benthic dysoxia resulted in the preservation of primary structures, as represented by laminated chalk which consists of thin pelagic laminae alternating with thin turbidites. In addition to the thin turbidites in the laminated chalk, four dif¬ferent turbidite facies are interpreted as representing high- to low-energy flows. Clast-supported chalk conglomerates have previously not been differentiated from other turbidites, but are here interpreted to be directly related to the down-slope evolution of debris flows. Debris flows are rep¬resented by matrix-supported conglomerates, which form one of the most common facies in the succession. High-concentration, gravity-driven suspension flows passed into dilute visco-plastic flows during the final stages of deposition and resulted in the deposition of structureless chalks. Limited shear deformation produced distinct quasi-facies from which the precursor facies can be deduced, whereas intense or continued shear deformation produced a shear-banded quasi-facies from which the precursor facies cannot be deduced in all cases. A series of major slump packages (14–18 in total are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in

Microfloral assemblage, age and paleoenvironment of the Upper ...

African Journals Online (AJOL)

Microfloral assemblage, age and paleoenvironment of the Upper Cretaceous Patti Formation, southeastern Bida Basin, Nigeria. OJ Ojo, SO Akande. Abstract. No Abstract. Journal of Mining and Geology Vol. 44 (1) 2008: pp. 71-82. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

Late Cretaceous paleosols as paleoclimate proxies of high-latitude Southern Hemisphere: Mata Amarilla Formation, Patagonia, Argentina

Science.gov (United States)

Varela, Augusto N.; Raigemborn, M. Sol; Richiano, Sebastián; White, Tim; Poiré, Daniel G.; Lizzoli, Sabrina

2018-01-01

Although there is general consensus that a global greenhouse climate characterized the mid-Cretaceous, details of the climate state of the mid-Cretaceous Southern Hemisphere are less clearly understood. In particular, continental paleoclimate reconstructions are scarce and exclusively derived from paleontological records. Using paleosol-derived climofunction studies of the mid- to Upper Cretaceous Mata Amarilla Formation, southern Patagonia, Argentina, we present a reconstruction of the mid-Cretaceous climate of southern South America. Our results indicate that at 60° south paleolatitude during the Cenomanian-Santonian stages, the climate was subtropical temperate-warm (12 °C ± 2.1 °C) and humid (1404 ± 108 mm/yr) with marked rainfall seasonality. These results are consistent with both previous estimations from the fossil floras of the Mata Amarilla Formation and other units of the Southern Hemisphere, and with the previous observations of the displacement of tropical and subtropical floras towards the poles in both hemispheres. The data presented here show a more marked seasonality and slightly lower mean annual precipitation and mean annual temperature values than those recorded at the same paleolatitudes in the Northern Hemisphere.

A Kepler Workflow Tool for Reproducible AMBER GPU Molecular Dynamics.

Science.gov (United States)

Purawat, Shweta; Ieong, Pek U; Malmstrom, Robert D; Chan, Garrett J; Yeung, Alan K; Walker, Ross C; Altintas, Ilkay; Amaro, Rommie E

2017-06-20

With the drive toward high throughput molecular dynamics (MD) simulations involving ever-greater numbers of simulation replicates run for longer, biologically relevant timescales (microseconds), the need for improved computational methods that facilitate fully automated MD workflows gains more importance. Here we report the development of an automated workflow tool to perform AMBER GPU MD simulations. Our workflow tool capitalizes on the capabilities of the Kepler platform to deliver a flexible, intuitive, and user-friendly environment and the AMBER GPU code for a robust and high-performance simulation engine. Additionally, the workflow tool reduces user input time by automating repetitive processes and facilitates access to GPU clusters, whose high-performance processing power makes simulations of large numerical scale possible. The presented workflow tool facilitates the management and deployment of large sets of MD simulations on heterogeneous computing resources. The workflow tool also performs systematic analysis on the simulation outputs and enhances simulation reproducibility, execution scalability, and MD method development including benchmarking and validation. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Efficiency enhancement of InGaN amber MQWs using nanopillar structures

DEFF Research Database (Denmark)

Ou, Yiyu; Iida, Daisuke; Liu, Jin

2018-01-01

We have investigated the use of nanopillar structures on high indium content InGaN amber multiple quantum well (MQW) samples to enhance the emission efficiency. A significant emission enhancement was observed which can be attributed to the enhancement of internal quantum efficiency and light extr...

Quantifying opening-mode fracture spatial organization in horizontal wellbore image logs, core and outcrop: Application to Upper Cretaceous Frontier Formation tight gas sandstones, USA

Science.gov (United States)

Li, J. Z.; Laubach, S. E.; Gale, J. F. W.; Marrett, R. A.

2018-03-01

The Upper Cretaceous Frontier Formation is a naturally fractured gas-producing sandstone in Wyoming. Regionally, random and statistically more clustered than random patterns exist in the same upper to lower shoreface depositional facies. East-west- and north-south-striking regional fractures sampled using image logs and cores from three horizontal wells exhibit clustered patterns, whereas data collected from east-west-striking fractures in outcrop have patterns that are indistinguishable from random. Image log data analyzed with the correlation count method shows clusters ∼35 m wide and spaced ∼50 to 90 m apart as well as clusters up to 12 m wide with periodic inter-cluster spacings. A hierarchy of cluster sizes exists; organization within clusters is likely fractal. These rocks have markedly different structural and burial histories, so regional differences in degree of clustering are unsurprising. Clustered patterns correspond to fractures having core quartz deposition contemporaneous with fracture opening, circumstances that some models suggest might affect spacing patterns by interfering with fracture growth. Our results show that quantifying and identifying patterns as statistically more or less clustered than random delineates differences in fracture patterns that are not otherwise apparent but that may influence gas and water production, and therefore may be economically important.

Paleoenvironmental reconstruction and evolution of an Upper Cretaceous lacustrine-fluvial-deltaic sequence in the Parecis Basin, Brazil

Science.gov (United States)

Rubert, Rogerio R.; Mizusaki, Ana Maria Pimentel; Martinelli, Agustín G.; Urban, Camile

2017-12-01

The Cretaceous in the Brazilian Platform records events of magmatism, tectonism and sedimentation coupled to the Gondwana breakup. Some of these events are registered as sedimentary sequences in interior basins, such as in the Cretaceous sequence of the Alto Xingu Sub-basin, Parecis Basin, Central Brazil. This article proposes the faciologic characterization and paleoenvironmental reconstruction of the Cretaceous sequence of the eastern portion of the Parecis Basin and its relation with some reactivated structures as, for instance, the Serra Formosa Arch. Based on both data from outcrops and core drillings a paleoenvironmental and evolutionary reconstruction of the sequence is herein presented. The base of the studied section is characterized by chemical and low energy clastic sedimentation of Lake Bottom and Shoreline, in a context of fast initial subsidence and low sedimentation rate. As the subsidence process decreased, a deltaic progradation became dominant with deposition in a prodelta environment, followed by a deltaic front and deltaic plain interbedded with fluvial plain, and aeolian deposition completing the sequence. The inferred Coniacian-Santonian age is based on vertebrate (fishes and notosuchians) and ostracod fossils with regional chrono-correlates in the Adamantina (Bauru Group), Capacete (Sanfranciscana Basin), and Bajo de la Carpa (Neuquén Group, in Argentina) formations. The formation of a Coniacian depocenter in the Alto Xingu Sub-basin is associated to the Turonian-Coniacian reactivation event in the Peruvian Orogenic Phase of the Andean Orogeny, with the transference of stresses to interplate setting, reactivating Proterozoic structures of the basement.

Petrophysical characterization of the Dolomitic Member of the Boñar Formation (Upper Cretaceous; Duero Basin, Spain) as a potential CO2 reservoir

Energy Technology Data Exchange (ETDEWEB)

Suarez-Gonzalez, A.; Kovacs, C.; Herrero-Hernandez, A.; Gomez-Fernandez, F.

2016-07-01

Boñar Formation (Upper Cretaceous) is a mainly carbonate succession, which outcrops in the North of Duero Basin (Spain). According to the existing data, the Dolomitic Member of this formation appears to be the most suitable for geological storage of CO2. The main objective of this study is to find evidence to support, clarify and specify –at an initial level– the potential of the Dolomitic Member of the Boñar Formation as a geological reservoir. The study covers density, porosity and permeability tests on samples obtained from the outcrop of the succession near the village of Boñar (León). According to the analysis and interpretation of the mentioned petrophysical properties, the porosity of the Dolomitic Member is within the acceptable range for CO2 geological storage, but the permeability values are far too low. This minimizes the possibilities of the Dolomitic Member –and probably of the whole Boñar Formation– to become an appropriate CO2 reservoir. (Author)

Preliminary study of uranium favorability of upper cretaceous, paleocene, and lower eocene rocks of the Bighorn Basin, Wyoming and Montana

International Nuclear Information System (INIS)

Hesse, S.L.; Dunagan, J.F. Jr.

1978-02-01

This report presents an evaluation of the uranium favorability of continental sediments of the Upper Cretaceous Lance, Paleocene Polecat Bench, and lower Eocene Willwood Formations in the Bighorn Basin of Wyoming and Montana, an intermontane structural basin of Laramide age. Previous work dealing with the Bighorn Basin was reviewed, and field investigations were carried out in the spring and summer of 1976. Subsurface data were collected and results of surface and subsurface investigations were evaluated with respect to uranium favorability. Precambrian plutonic and metamorphic rocks and Tertiary tuffaceous rocks in the Bighorn Basin and bordering uplifts are considered insignificant as source rocks, although the Wiggins Formation (White River equivalent) cannot be evaluated as a possible source because of a lack of data. Potential host rocks locally show only limited favorability. Lithology of strata exposed along the western and southern basin margins is more favorable than that of rocks in the central and eastern parts of the basin, but there is little organic material, pyrite, or other reducing agents in these rocks. Strata of the Lance, Polecat Bench, and Willwood Formations in the Bighorn Basin are considered generally unfavorable for sandstone uranium deposits

Comparative analysis of the calcretization process in the Marilia formations (Bauru group - Brasil) and Mercedes ( Paysandu group - Uruguay), Upper Cretaceous of the Parana basin

International Nuclear Information System (INIS)

Veroslavsky, G.; Etchebehere, M.; Sad, A.; Fulfaro, J.

1998-01-01

Pedogenic and non-pedogenic calcrete facies are very common feature of Marilia (Brazil) and Mercedes (Uruguay) formations in the Parana Basin. The non-pedogenic ones constitute massive limestone facies that have been recently interpreted as groundwater calcretes. These limestones are exploited in both countries to supply raw materials to Portland cement and soil conditioner in origin and age of calcretization phenomena. In Uruguay, the calcretization process seens to be band formation. Field relationships and fossil assemblage point to a Paleocene (or later) age for the calcretization. In Brazilian territory, the groundwater calcretes aresupposed to be of Upper Cretaceous age due to the presence of dinosaurs scattered through the Bauru Group, including siliciclastic beds below and above the calcretes. The authors assume that calcretization processes are similar in both countries (host rocks, intensity, size, textures, geometries and economic potential). The main difference is in age of the calcretization. (author)

A community intervention: AMBER: Arab American breast cancer education and referral program.

Science.gov (United States)

Ayash, Claudia; Axelrod, Deborah; Nejmeh-Khoury, Sana; Aziz, Arwa; Yusr, Afrah; Gany, Francesca M

2011-12-01

Although the number of Arab Americans is growing in the United States, there is very little data available on this population's cancer incidence and screening practices. Moreover, there are few interventions addressing their unique needs. This study aims to determine effective strategies for increasing breast cancer screening in at-risk underserved Arab American women. AMBER utilizes a community based participatory approach to conduct formative research and program interventions, including culturally appropriate Arabic language breast cancer education, screening coordination, and cultural competency training for healthcare professionals in New York City. In 2 years, 597 women were educated, 189 underserved women were identified as being in need of assistance, 68 were screened, one new case of breast cancer was detected, and four active cases in need of follow-up reconnected with care. The AMBER model is an important intervention for breast cancer screening and care in the underserved Arab American community.

Stratigraphy, provenance, and diagenesis of the Cretaceous Horse Range Formation, east Otago, New Zealand

International Nuclear Information System (INIS)

Mitchell, M.; Craw, D.; Landis, C.A.; Frew, R.

2009-01-01

The Horse Range Formation is a structurally controlled late Early Cretaceous to early Late Cretaceous nonmarine unit in east Otago, South Island, New Zealand, containing immature lithic debris. Clasts are generally rounded, with only minor subangular material. The formation contains clasts derived from two principal basement sources: schist and greywacke. Schist debris is most abundant at the base of the described section, and this material is dominated (>60%) by quartz from the greenschist facies core of the Otago Schist belt. Conglomerates with >70% greywacke clasts constitute most of the upper part of the Horse Range Formation. These greywacke conglomerates have a matrix of sand derived mainly from schist. A 60 m thick wedge of quartz-rich, locally carbonaceous sand occurs interlayered with greywacke conglomerates. The Horse Range Formation rests on sub-greenschist facies semischist, which forms only a small proportion ( 18 O SMOW near +24 permil and δ 13 C PDB near -2 permil, and was partly dissolved and redeposited from the immature basement debris (metamorphic calcite) and partly introduced from overlying Late Cretaceous and Teriary marine sediments by groundwater. (author). 43 refs., 11 figs., 1 tab.

Webspinners in Early Eocene amber from western India (Insecta, Embiodea

Directory of Open Access Journals (Sweden)

Michael Engel

2011-11-01

Full Text Available The family Scelembiidae (Neoembiodea: Embiomorpha: Archembioidea is recorded from Asia for the first time, based on two individuals preserved in Early Eocene amber from the Cambay Basin, western India. Kumarembia hurleyi Engel & Grimaldi, gen. n. et sp. n., is described, figured, and distinguished from other archembioid genera. The genus shares male genitalic features with scelembiids, otherwise known from South America and Africa.

A potential amber-emitting KCaVO4:Sm3+ nanophosphor for near-UV LEDs

Science.gov (United States)

Biswas, Pankaj; Kumar, Vinay

2018-05-01

The Sm3+ doped KCaVO4 phosphor powders were synthesized via combustion route. The powder X-ray diffraction (pXRD) analysis established the crystalline structure and phase of the phosphor material. Williamson-Hall technique was employed to approximate the mean grain size and lattice micro-strain. The transmission electron microscope (TEM) studies were carried out to confirm the nano-sized grain formation. On 405 nm excitation, the phosphor gave amber emission which was assigned to 4G5/2 → 6HJ/2 (J = 7/2, 9/2) transitions of the Sm3+ ion. The concentration quenching mechanism was studied and the optimum dopant concentration in the phosphor was obtained as 2.0 mol%. The diffuse reflectance (DR) studies were carried out to obtain optical band gap (Eg) and Urbach energy (Ec) of the KCaVO4 phosphor which were estimated as 3.63 eV and 98.6 meV, respectively. The color coordinates (x = 0.61, y = 0.39) of the nanophosphor signified the amber shade in the color gamut. The high luminescent properties of KCaVO4:Sm3+ phosphor suggests that the material can be explored as a potential phosphor to be profitably excited by near-UV LEDs to bridge the amber gap in light emitting diodes (LEDs) for solid state lighting (SSL) applications.

Constraints on deformation of the Southern Andes since the Cretaceous from anisotropy of magnetic susceptibility

Science.gov (United States)

Maffione, Marco; Hernandez-Moreno, Catalina; Ghiglione, Matias C.; Speranza, Fabio; van Hinsbergen, Douwe J. J.; Lodolo, Emanuele

2015-12-01

The southernmost segment of the Andean Cordillera underwent a complex deformation history characterized by alternation of contractional, extensional, and strike-slip tectonics. Key elements of southern Andean deformation that remain poorly constrained, include the origin of the orogenic bend known as the Patagonian Orocline (here renamed as Patagonian Arc), and the exhumation mechanism of an upper amphibolite facies metamorphic complex currently exposed in Cordillera Darwin. Here, we present results of anisotropy of magnetic susceptibility (AMS) from 22 sites in Upper Cretaceous to upper Eocene sedimentary rocks within the internal structural domain of the Magallanes fold-and-thrust belt in Tierra del Fuego (Argentina). AMS parameters from most sites reveal a weak tectonic overprint of the original magnetic fabric, which was likely acquired upon layer-parallel shortening soon after sedimentation. Magnetic lineation from 17 sites is interpreted to have formed during compressive tectonic phases associated to a continuous N-S contraction. Our data, combined with the existing AMS database from adjacent areas, show that the Early Cretaceous-late Oligocene tectonic phases in the Southern Andes yielded continuous contraction, variable from E-W in the Patagonian Andes to N-S in the Fuegian Andes, which defined a radial strain field. A direct implication is that the exhumation of the Cordillera Darwin metamorphic complex occurred under compressive, rather than extensional or strike-slip tectonics, as alternatively proposed. If we agree with recent works considering the curved Magallanes fold-and-thrust belt as a primary arc (i.e., no relative vertical-axis rotation of the limbs occurs during its formation), then other mechanisms different from oroclinal bending should be invoked to explain the documented radial strain field. We tentatively propose a kinematic model in which reactivation of variably oriented Jurassic faults at the South American continental margin controlled

The Hunt for Pristine Cretaceous Astronomical Rhythms at Demerara Rise (Cenomanian-Coniacian)

Science.gov (United States)

Ma, C.; Meyers, S. R.

2014-12-01

Rhythmic Upper Cretaceous strata from Demerara Rise (ODP leg 207) preserve a strong astronomical signature, and this attribute has facilitated the development of continuous astrochronologies to refine the geologic time scale and calibrate Late Cretaceous biogeochemical events. While the mere identification of astronomical rhythms is a crucial first step in many deep-time paleoceanographic investigations, accurate evaluation of often subtle amplitude and frequency modulations are required to: (1) robustly constrain the linkage between climate and sedimentation, and (2) evaluate the plausibility of different theoretical astrodynamical models. The availability of a wide range of geophysical, lithologic and geochemical data from multiple sites drilled at Demerara Rise - when coupled with recent innovations in the statistical analysis of cyclostratigraphic data - provides an opportunity to hunt for the most pristine record of Cretaceous astronomical rhythms at a tropical Atlantic location. To do so, a statistical metric is developed to evaluate the "internal" consistency of hypothesized astronomical rhythms observed in each data set, particularly with regard to the expected astronomical amplitude modulations. In this presentation, we focus on how the new analysis yields refinements to the existing astrochronologies, provides constraints on the linkages between climate and sedimentation (including the deposition of organic carbon-rich sediments at Demerara Rise), and allows a quantitative evaluation of the continuity of deposition across sites at multiple temporal scales.

Development of ACBIO: A Biosphere Template Using AMBER for a Potential Radioactive Waste Repository

International Nuclear Information System (INIS)

Lee, Youn Myoung; Hwang, Yong Soo; Kang, Chul Hyung; Hahn, Pil Soo

2005-01-01

Nuclides in radioactive wastes are assumed to be transported in the geosphere by groundwater and probably discharged into the biosphere. Quantitative evaluation of doses to human beings due to nuclide transport in the geosphere and through the various pathways in the biosphere is the final step of safety assessment of the radioactive waste repository. To calculate the flux to dose conversion factors (DCFs) for nuclides appearing at GBIs with their decay chains, a template ACBIO which is an AMBER case file based on mathematical model for the mass transfer coefficients between the compartments has been developed considering material balance among the compartments in biosphere and then implementing to AMBER, a general and flexible software tool that allows to build dynamic compartment models. An illustrative calculation with ACBIO is shown.

Island life in the Cretaceous - faunal composition, biogeography, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago

OpenAIRE

Csiki Sava,Zoltan; Buffetaut,Eric; Ősi,Attila; Pereda-Suberbiola,Xabier; Brusatte,Stephen

2015-01-01

Abstract The Late Cretaceous was a time of tremendous global change, as the final stages of the Age of Dinosaurs were shaped by climate and sea level fluctuations and witness to marked paleogeographic and faunal changes, before the end-Cretaceous bolide impact. The terrestrial fossil record of Late Cretaceous Europe is becoming increasingly better understood, based largely on intensive fieldwork over the past two decades, promising new insights into latest Cretaceous faunal evolution. We revi...

Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge, Danish North Sea: Plate 1

Directory of Open Access Journals (Sweden)

Surlyk, Finn

2011-12-01

Full Text Available The 331 m long core from the Mona-1 well in the Danish North Sea spans almost the entire Upper Cretaceous Chalk Group but only about 10% of Late Cretaceous time is represented. The succession comprises 14 facies representing pelagic deposition, turbidity flow, and mass-transport processes, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab¬sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites, and the resultant deposits were thoroughly bioturbated if deposited during normal oxygenation at the sea floor. Periodic benthic dysoxia resulted in the preservation of primary structures, as represented by laminated chalk which consists of thin pelagic laminae alternating with thin turbidites. In addition to the thin turbidites in the laminated chalk, four dif¬ferent turbidite facies are interpreted as representing high- to low-energy flows. Clast-supported chalk conglomerates have previously not been differentiated from other turbidites, but are here interpreted to be directly related to the down-slope evolution of debris flows. Debris flows are rep¬resented by matrix-supported conglomerates, which form one of the most common facies in the succession. High-concentration, gravity-driven suspension flows passed into dilute visco-plastic flows during the final stages of deposition and resulted in the deposition of structureless chalks. Limited shear deformation produced distinct quasi-facies from which the precursor facies can be deduced, whereas intense or continued shear deformation produced a shear-banded quasi-facies from which the precursor facies cannot be deduced in all cases. A series of major slump packages (14–18 in total are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in

Dinosaurs and the Cretaceous Terrestrial Revolution

Science.gov (United States)

Lloyd, Graeme T; Davis, Katie E; Pisani, Davide; Tarver, James E; Ruta, Marcello; Sakamoto, Manabu; Hone, David W.E; Jennings, Rachel; Benton, Michael J

2008-01-01

The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125–80 Myr ago, when flowering plants, herbivorous and social insects, squamates, birds and mammals all underwent a rapid expansion. Although an apparent explosion of dinosaur diversity occurred in the mid-Cretaceous, coinciding with the emergence of new groups (e.g. neoceratopsians, ankylosaurid ankylosaurs, hadrosaurids and pachycephalosaurs), results from the first quantitative study of diversification applied to a new supertree of dinosaurs show that this apparent burst in dinosaurian diversity in the last 18 Myr of the Cretaceous is a sampling artefact. Indeed, major diversification shifts occurred largely in the first one-third of the group's history. Despite the appearance of new clades of medium to large herbivores and carnivores later in dinosaur history, these new originations do not correspond to significant diversification shifts. Instead, the overall geometry of the Cretaceous part of the dinosaur tree does not depart from the null hypothesis of an equal rates model of lineage branching. Furthermore, we conclude that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR. PMID:18647715

Maaqwi cascadensis: A large, marine diving bird (Avialae: Ornithurae from the Upper Cretaceous of British Columbia, Canada.

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Sandy M S McLachlan

Full Text Available Mesozoic bird fossils from the Pacific Coast of North America are rare, but small numbers are known from the Late Cretaceous aged sediments of Hornby Island, British Columbia. Most are unassociated fragments that offer little information, but additional preparation of a large coracoid has revealed more details of its structure, as well as three associated wing bones. Phylogenetic analysis suggests that Maaqwi cascadensis, gen. et sp. nov. represents a derived crown or near-crown member of Ornithurae, and specifically suggests affinities with Vegaviidae. M. cascadensis is characterized by large size, and regressions based on dimensions of the coracoid suggest a large bird, with an estimated body mass of approximately 1.5 kilograms. The bones are robust, with thick walls, suggesting that M. cascadensis was a bird adapted for diving, similar to modern loons and grebes. The wings are short, while the coracoid is unusually short and broad, similar to modern loons. Along with the Ichthyornithes and Hesperornithes, M. cascadensis and Vegaviidae appear to represent a third clade of bird that evolved to exploit marine habitats in the Late Cretaceous, one specialized for foot-propelled diving and rapid cruising flight over water.

Dinosaur Census Reveals Abundant Tyrannosaurus and Rare Ontogenetic Stages in the Upper Cretaceous Hell Creek Formation (Maastrichtian), Montana, USA

Science.gov (United States)

Horner, John R.; Goodwin, Mark B.; Myhrvold, Nathan

2011-01-01

Background A dinosaur census recorded during the Hell Creek Project (1999–2009) incorporates multiple lines of evidence from geography, taphohistory, stratigraphy, phylogeny and ontogeny to investigate the relative abundance of large dinosaurs preserved in the Upper Cretaceous Hell Creek Formation of northeastern Montana, USA. Overall, the dinosaur skeletal assemblages in the Hell Creek Formation (excluding lag-influenced records) consist primarily of subadult or small adult size individuals. Small juveniles and large adults are both extremely rare, whereas subadult individuals are relatively common. We propose that mature individuals of at least some dinosaur taxa either lived in a separate geographic locale analogous to younger individuals inhabiting an upland environment where sedimentation rates were relatively less, or these taxa experienced high mortality before reaching terminal size where late stage and often extreme cranial morphology is expressed. Methodology/Principal Findings Tyrannosaurus skeletons are as abundant as Edmontosaurus, an herbivore, in the upper Hell Creek Formation and nearly twice as common in the lower third of the formation. Smaller, predatory dinosaurs (e.g., Troodon and dromaeosaurids) are primarily represented by teeth found in microvertebrate localities and their skeletons or identifiable lag specimens were conspicuously absent. This relative abundance suggests Tyrannosaurus was not a typical predator and likely benefited from much wider food choice opportunities than exclusively live prey and/or specific taxa. Tyrannosaurus adults may not have competed with Tyrannosaurus juveniles if the potential for selecting carrion increased with size during ontogeny. Conclusions/Significance Triceratops is the most common dinosaur and isolated skulls contribute to a significant portion of this census. Associated specimens of Triceratops consisting of both cranial and postcranial elements remain relatively rare. This rarity may be explained

Physical behaviour of Cretaceous calcareous nannofossil ooze

DEFF Research Database (Denmark)

Buls, Toms; Anderskouv, Kresten; Friend, Patrick L.

2017-01-01

Geomorphic features such as drifts, sediment waves and channels have been documented in the Upper Cretaceous of north-west Europe. These features are interpreted to result from bottom currents and have been used to refine chalk depositional models and quantify palaeocirculation patterns. Chalk...... was first deposited as calcareous nannofossil ooze and geomorphic features are the result of sediment reworking after deposition. There is limited knowledge on the processes that govern nannofossil ooze mobility, thus forcing uncertainty onto numerical models based on sedimentological observations...... of deposition thresholds (τcd) from ca 0·04 to 0·13 Pa reflects the influence of variable suspended sediment concentration and τ0 on settling particle size due to the identified potential for chalk ooze aggregation and flocculation. Additionally, deposition thresholds seem to be affected by the size of eroded...

Morphometry, Microstructure, and Wear Pattern of Neornithischian Dinosaur Teeth From the Upper Cretaceous Iharkút Locality (Hungary).

Science.gov (United States)

Virág, Attila; Ősi, Attila

2017-08-01

Teeth of iguanodontian ornithopods and ceratopsians could be remarkably similar, thus the referral of isolated dental material to particular neornithischian clades can be highly problematic. These groups are represented by the rhabdodontid Mochlodon vorosi and the basal coronosaurian Ajkaceratops kozmai in the Upper Cretaceous Csehbánya Formation at Iharkút (western Hungary). Whereas teeth of Mochlodon are common elements at the locality, no dental material belonging to Ajkaceratops was identified until now. Here we used mathematical statistical approaches, as well as tooth wear and dental microstructure analysis in order to decide whether the teeth previously referred to Mochlodon can be treated as a homogenous sample, or some remains belong rather to Ajkaceratops. According to our results, there was a striking morphological and structural convergence between the teeth of both taxa. However, the wear study revealed the existence of two different patterns within the sample. One is characterized by straight and parallel microstriations that suggest orthal movements during the jaw closure. This pattern was associated with Mochlodon. The other pattern appeared only on a few teeth, and it can be differentiated by its distinctive curved microstriations that indicate circumpalinal chewing. Because curved striations have never been described in ornithopods, but are found in several neoceratopsians, this pattern was associated here with Ajkaceratops. Here we present the first teeth that can provisionally be referred to the latter genus. We believe that the methodology discussed in this article will facilitate distinguishing ceratopsian and ornithopod teeth in other localities as well. Anat Rec, 300:1439-1463, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Lower Cretaceous Luscar group (revised) of the northern and north-central foothills of Alberta

Energy Technology Data Exchange (ETDEWEB)

Langenberg, C W; McMechan, M E

1985-03-01

Lower Cretaceous coal-bearing strata exposed in the northern and north-central foothills of Alberta form part of a predominantly nonmarine succession that extends from Montana to northeastern British Columbia. The Luscar Group (revised) forms the sequence of coal bearing Lower Cretaceous strata that disconformably overlies marine and nonmarine strata of the Nikanassin Formation or Minnes Group and disconformably underlies marine shales of the Blackstone or Shaftesbury formations. It includes a thin, basal conglomerate, a predominantly nonmarine sandstone and shale unit that locally contains coal; a marine shale and sandstone unit, and an upper nonmarine sandstone and shale unit that contains thick commercial coal seams. These units form the Cadomin, Gladstone, Moosebar and Gates formations, respectively. The Luscar Group is exposed from Kakwa River to Clearwater River in the Foothills of Alberta. It represents a slight modification, by the inclusion of the thin basal conglomerate, from the previous usage of the term Luscar in the northern Foothills of Alberta. 25 references.

Inversion of the Erlian Basin (NE China) in the early Late Cretaceous: Implications for the collision of the Okhotomorsk Block with East Asia

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Guo, Zhi-Xin; Shi, Yuan-Peng; Yang, Yong-Tai; Jiang, Shuan-Qi; Li, Lin-Bo; Zhao, Zhi-Gang

2018-04-01

A significant transition in tectonic regime from extension to compression occurred throughout East Asia during the mid-Cretaceous and has stimulated much attention. However, the timing and driving mechanisms of the transition remain disputed. The Erlian Basin, a giant late Mesozoic intracontinental petroliferous basin located in the Inner Mongolia, Northeast China, contains important sedimentary and structural records related to the mid-Cretaceous compressional event. The stratigraphical, sedimentological and structural analyses reveal that a NW-SE compressional inversion occurred in the Erlian Basin between the depositions of the Lower Cretaceous Saihan and Upper Cretaceous Erlian formations, causing intense folding of the Saihan Formation and underlying strata, and the northwestward migration of the depocenters of the Erlian Formation. Based on the newly obtained detrital zircon U-Pb data and previously published paleomagnetism- and fossil-based ages, the Saihan and Erlian formations are suggested as latest Aptian-Albian and post-early Cenomanian in age, respectively, implying that the inversion in the Erlian Basin occurred in the early Late Cretaceous (Cenomanian time). Apatite fission-track thermochronological data record an early Late Cretaceous cooling/exhuming event in the basin, corresponding well with the aforementioned sedimentary, structural and chronological analyses. Combining with the tectono-sedimentary evolutions of the neighboring basins of the Erlian Basin, we suggest that the early Late Cretaceous inversional event in the Erlian Basin and the large scale tectonic transition in East Asia shared the common driving mechanism, probably resulting from the Okhotomorsk Block-East Asia collisional event at about 100-89 Ma.

Data for molecular dynamics simulations of B-type cytochrome c oxidase with the Amber force field

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Longhua Yang

2016-09-01

Full Text Available Cytochrome c oxidase (CcO is a vital enzyme that catalyzes the reduction of molecular oxygen to water and pumps protons across mitochondrial and bacterial membranes. This article presents parameters for the cofactors of ba3-type CcO that are compatible with the all-atom Amber ff12SB and ff14SB force fields. Specifically, parameters were developed for the CuA pair, heme b, and the dinuclear center that consists of heme a3 and CuB bridged by a hydroperoxo group. The data includes geometries in XYZ coordinate format for cluster models that were employed to compute proton transfer energies and derive bond parameters and point charges for the force field using density functional theory. Also included are the final parameter files that can be employed with the Amber leap program to generate input files for molecular dynamics simulations with the Amber software package. Based on the high resolution (1.8 Å X-ray crystal structure of the ba3-type CcO from Thermus thermophilus (Protein Data Bank ID number PDB: 3S8F, we built a model that is embedded in a POPC lipid bilayer membrane and solvated with TIP3P water molecules and counterions. We provide PDB data files of the initial model and the equilibrated model that can be used for further studies.

A study on uranium metallogenetic prospects of ground water oxidation zone type in the lower cretaceous, north Shanganning basin

International Nuclear Information System (INIS)

Wang Jinping

2000-01-01

Lower Cretaceous is developed well in the north part of Shanganning basin. The area was widely uplifting vertically after their deposited. Based on the features of lithology, lithophase and Neotectonic forms, two main periods of oxidation-erosion of K2-E1 and N1-present can be distinguished. During these two periods, large scale horizontal oxidation were occurred. It is significant that the ground water oxidation related to the uranium mineralization and has been proved by the field investigation and the data of γ-logging in drill hole for oil. Meanwhile, according to the hydrodynamic features of present Shanganning plateau type artesian basin, it seems that uranium mineralization main related to the ground water oxidation the upper parts of the Lower Cretaceous

Early cretaceous dinosaurs from the sahara.

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Sereno, P C; Wilson, J A; Larsson, H C; Dutheil, D B; Sues, H D

1994-10-14

A major question in Mesozoic biogeography is how the land-based dinosaurian radiation responded to fragmentation of Pangaea. A rich fossil record has been uncovered on northern continents that spans the Cretaceous, when continental isolation reached its peak. In contrast, dinosaur remains on southern continents are scarce. The discovery of dinosaurian skeletons from Lower Cretaceous beds in the southern Sahara shows that several lineages of tetanuran theropods and broad-toothed sauropods had a cosmopolitan distribution across Pangaea before the onset of continental fragmentation. The distinct dinosaurian faunas of Africa, South America, and Asiamerica arose during the Cretaceous by differential survival of once widespread lineages on land masses that were becoming increasingly isolated from one another.

Microtomography of the Baltic amber tick Ixodes succineus reveals affinities with the modern Asian disease vector Ixodes ovatus

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Dunlop, Jason A.; Apanaskevich, Dmitry A.; Lehmann, Jens; Hoffmann, René; Fusseis, Florian; Ehlke, Moritz; Zachow, Stefan; Xiao, Xianghui

2016-10-10

Background: Fossil ticks are extremely rare, whereby Ixodes succineus Weidner, 1964 from Eocene (ca. 44–49 Ma) Baltic amber is one of the oldest examples of a living hard tick genus (Ixodida: Ixodidae). Previous work suggested it was most closely related to the modern and widespread European sheep tick Ixodes ricinus (Linneaus, 1758). Results: Restudy using phase contrast synchrotron x-ray tomography yielded images of exceptional quality. These confirm the fossil’s referral to Ixodes Latreille, 1795, but the characters resolved here suggest instead affinities with the Asian subgenus Partipalpiger Hoogstraal et al., 1973 and its single living (and medically significant) species Ixodes ovatus Neumann, 1899. We redescribe the amber fossil here as Ixodes (Partipalpiger) succineus. Conclusions: Our data suggest that Ixodes ricinus is unlikely to be directly derived from Weidner’s amber species, but instead reveals that the Partipalpiger lineage was originally more widely distributed across the northern hemisphere. The closeness of Ixodes (P.) succineus to a living vector of a wide range of pathogens offers the potential to correlate its spatial and temporal position (northern Europe, nearly 50 million years ago) with the estimated origination dates of various tick-borne diseases.

CARBONATE FACIES ZONATION OF THE UPPER JURASSIC-LOWER CRETACEOUS APULIA PLATFORM MARGIN (GARGANO PROMONTORY, SOUTHERN ITALY

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MICHELE MORSILLI

1997-07-01

Full Text Available The Late Jurassic-Early Cretaceous Apulia platform margin and the transition to adjacent basinal deposits (inner platform to basin are well exposed in the Gargano Promontory. Detailed field work has allowed to recognize eight main facies associations which reflect various depositional environments, and which document a differentiated zonation, from the inner platform to the basin. A shallow lagoon existed in the internal part of the Gargano Promontory with a transition to tidal flat areas (F1. Oolitic shoals (F2 bordered this internal peritidal area passing seaward to a reef-flat with abundant corals (F3. A reef-front, associated with a coral rubble zone, has been found in some areas (F4. In the external margin zone, massive wackestones with Ellipsactinia occur (F5 and pass gradually to a rudstone facies on the proximal slope (F6. The base-of-slope facies association consists of pelagic sediments interbedded with gravity-displaced deposits (F7 and F8. The depositional profile of the Apulia Platform is typical of the Tethyan Jurassic-Early Cretaceous platforms, with slope declivities in the order of 25°-28°. The remarkable progradation of the platform in the northern tract of the Gargano (Lesina and Varano lakes area and its substantial stability east- and southwards (Mattinata area suggest a possible windward position of the margin in this latter portion and, in contrast, a leeward position of the northern portion.   

Examining the interplay of climate and low amplitude sea-level change on the distribution and volume of massive dolomitization: Zebbag Formation, Cretaceous, Southern Tunisia

DEFF Research Database (Denmark)

Newport, Richard; Hollis, Cathy; Bodin, Stéphane

2017-01-01

During the Cretaceous, a humid global climate, calcitic seas, high relative sea-level and low amplitude changes in relative sea-level largely prevented large-scale dolomitization in many carbonate successions. However, the well-exposed shallow-water carbonate sediments of the Upper Albian–Lower T...

New Australian sauropods shed light on Cretaceous dinosaur palaeobiogeography

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Poropat, Stephen F.; Mannion, Philip D.; Upchurch, Paul; Hocknull, Scott A.; Kear, Benjamin P.; Kundrát, Martin; Tischler, Travis R.; Sloan, Trish; Sinapius, George H. K.; Elliott, Judy A.; Elliott, David A.

2016-01-01

Australian dinosaurs have played a rare but controversial role in the debate surrounding the effect of Gondwanan break-up on Cretaceous dinosaur distribution. Major spatiotemporal gaps in the Gondwanan Cretaceous fossil record, coupled with taxon incompleteness, have hindered research on this effect, especially in Australia. Here we report on two new sauropod specimens from the early Late Cretaceous of Queensland, Australia, that have important implications for Cretaceous dinosaur palaeobiogeography. Savannasaurus elliottorum gen. et sp. nov. comprises one of the most complete Cretaceous sauropod skeletons ever found in Australia, whereas a new specimen of Diamantinasaurus matildae includes the first ever cranial remains of an Australian sauropod. The results of a new phylogenetic analysis, in which both Savannasaurus and Diamantinasaurus are recovered within Titanosauria, were used as the basis for a quantitative palaeobiogeographical analysis of macronarian sauropods. Titanosaurs achieved a worldwide distribution by at least 125 million years ago, suggesting that mid-Cretaceous Australian sauropods represent remnants of clades which were widespread during the Early Cretaceous. These lineages would have entered Australasia via dispersal from South America, presumably across Antarctica. High latitude sauropod dispersal might have been facilitated by Albian–Turonian warming that lifted a palaeoclimatic dispersal barrier between Antarctica and South America. PMID:27763598

Kinematics of Late Cretaceous subduction initiation in the Neo-Tethys Ocean reconstructed from ophiolites of Turkey, Cyprus, and Syria

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Maffione, Marco; van Hinsbergen, Douwe J. J.; de Gelder, Giovanni I. N. O.; van der Goes, Freek C.; Morris, Antony

2017-05-01

Formation of new subduction zones represents one of the cornerstones of plate tectonics, yet both the kinematics and geodynamics governing this process remain enigmatic. A major subduction initiation event occurred in the Late Cretaceous, within the Neo-Tethys Ocean between Gondwana and Eurasia. Suprasubduction zone ophiolites (i.e., emerged fragments of ancient oceanic lithosphere formed at suprasubduction spreading centers) were generated during this subduction event and are today distributed in the eastern Mediterranean region along three E-W trending ophiolitic belts. Several models have been proposed to explain the formation of these ophiolites and the evolution of the associated intra-Neo-Tethyan subduction zone. Here we present new paleospreading directions from six Upper Cretaceous ophiolites of Turkey, Cyprus, and Syria, calculated by using new and published paleomagnetic data from sheeted dyke complexes. Our results show that NNE-SSW subduction zones were formed within the Neo-Tethys during the Late Cretaceous, which we propose were part of a major step-shaped subduction system composed of NNE-SSW and WNW-ESE segments. We infer that this subduction system developed within old (Triassic?) lithosphere, along fracture zones and perpendicular weakness zones, since the Neo-Tethyan spreading ridge formed during Gondwana fragmentation would have already been subducted at the Pontides subduction zone by the Late Cretaceous. Our new results provide an alternative kinematic model of Cretaceous Neo-Tethyan subduction initiation and call for future research on the mechanisms of subduction inception within old (and cold) lithosphere and the formation of metamorphic soles below suprasubduction zone ophiolites in the absence of nearby spreading ridges.

Geochemical and palynological sea-level proxies in hemipelagic sediments: A critical assessment from the Upper Cretaceous of the Czech Republic

Czech Academy of Sciences Publication Activity Database

Olde, K.; Jarvis, I.; Uličný, David; Pearce, M. A.; Trabucho-Alexandre, J.; Čech, S.; Gröcke, D. R.; Laurin, Jiří; Švábenická, L.; Tocher, B. A.

2015-01-01

Roč. 435, October (2015), s. 222-243 ISSN 0031-0182 R&D Projects: GA ČR GAP210/10/1991 Institutional support: RVO:67985530 Keywords : sea - level change * Cretaceous * chemostratigraphy Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.525, year: 2015

New Genus and Species of Gall Midges (Diptera, Cecidomyiidae, Porricondylinae, Holoneurini from the Late Eocene Amber of Olevsk (Zhitomir Region, Ukraine

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Fedotova Z. A.

2017-02-01

Full Text Available Gall midges are reported for the first time in Late Eocene Rovno amber from the Olevsk, Zhitomir Region. This is the second amber locality to yield gall midges in the Zhitomir Region, after Gulyanka. Rovnoholoneurus gen. n. and two new species, Rovnoholoneurus davidi sp. n. and R. miyae sp. n. are described. Bryocrypta laqueata Fedotova, 2005 is transferred to the genus Rovnoholoneurus, and Rovnoholoneurus laqueatus (Fedotova, 2005, comb. n. is established. A key to the species of Rovnoholoneurus is provided.

Paleomagnetic tests for tectonic reconstructions of the Late Jurassic-Early Cretaceous Woyla Group, Sumatra

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Advokaat, Eldert; Bongers, Mayke; van Hinsbergen, Douwe; Rudyawan, Alfend; Marshal, Edo

2017-04-01

-Early Cretaceous Andean margin above a NE dipping subduction zone. We sampled limestones of the Woyla Group, and sediments of the West Sumatra margin for paleomagnetic analyses. Here we present new paleomagnetic data from Upper Jurassic-Lower Cretaceous limestones of the Woyla Arc. Preliminary results suggest that the Woyla Arc was formed near equatorial latitudes. This precludes interpretations that the Woyla arc was derived from Gondwana, near the northern Indian margin. To account for (1) synchronous magmatism at the Woyla Arc and the West Sumatra continental margin, and (2) the juxtaposition of unmetamorphosed units of the Woyla Arc to highly metamorphosed units of the West Sumatra margin, we interpret the Woyla Group to be intra-oceanic arc formed above a SW dipping subduction zone in the Early Cretaceous, which was subsequently thrusted over the West Sumatra margin during the mid-Cretaceous.

The oldest known snakes from the Middle Jurassic-Lower Cretaceous provide insights on snake evolution.

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Caldwell, Michael W; Nydam, Randall L; Palci, Alessandro; Apesteguía, Sebastián

2015-01-27

The previous oldest known fossil snakes date from ~100 million year old sediments (Upper Cretaceous) and are both morphologically and phylogenetically diverse, indicating that snakes underwent a much earlier origin and adaptive radiation. We report here on snake fossils that extend the record backwards in time by an additional ~70 million years (Middle Jurassic-Lower Cretaceous). These ancient snakes share features with fossil and modern snakes (for example, recurved teeth with labial and lingual carinae, long toothed suborbital ramus of maxillae) and with lizards (for example, pronounced subdental shelf/gutter). The paleobiogeography of these early snakes is diverse and complex, suggesting that snakes had undergone habitat differentiation and geographic radiation by the mid-Jurassic. Phylogenetic analysis of squamates recovers these early snakes in a basal polytomy with other fossil and modern snakes, where Najash rionegrina is sister to this clade. Ingroup analysis finds them in a basal position to all other snakes including Najash.

Cretaceous paleogeography and depositional cycles of western South America

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Macellari, C. E.

The western margin of South America was encroached upon by a series of marine advances that increased in extent from the Early Cretaceous to a maximum in the early Late Cretaceous for northern South America (Venezuela to Peru). In southern South America, however, the area covered by the marine advances decreased from a maximum in the Early Cretaceous to a minimum during mid-Cretaceous time, followed by a widespread advance at the end of the period. A series of unconformity-bounded depositional cycles was recognized in these sequences: five cycles in northern South America, and six (but not exactly equivalent) cycles in the Cretaceous back-arc basins of southern South America (Neuquén and Austral, or Magallanes, Basins). Both widespread anoxic facies and maximum flooding of the continent in northern South America coincide in general terms with recognized global trends, but this is not the case in southern South America. Here, anoxic facies are restricted to the Lower Cretaceous and seem to be controlled by local aspects of the basin evolution and configuration. The contrasts observed between northern and southern South America can be explained by differences in tectonic setting and evolution. To the north, sediments were deposited around the tectonically stable Guayana-Brazilian Massifs, and thus registered global "signals" such as anoxic events and major eustatic changes. The southern portion of the continent, on the contrary, developed in an active tectonic setting. Here, the mid-Cretaceous Peruvian Orogeny overprinted, to a large extent, world-wide trends and only the earliest and latest Cretaceous conform to global depositional patterns.

Cretaceous Vertebrate Tracksites - Korean Cretaceous Dinosaur Coast World Heritage Nomination Site

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Huh, M.; Woo, K. S.; Lim, J. D.; Paik, I. S.

2009-04-01

South Korea is one of the best known regions in the world for Cretaceous fossil footprints, which are also world-renowned. Korea has produced more scientifically named bird tracks (ichnotaxa) than any other region in the world. It has also produced the world's largest pterosaur tracks. Dinosaur tracksites also have the highest frequency of vertebrate track-bearing levels currently known in any stratigraphic sequence. Among the areas that have the best track records, and the greatest scientific significance with best documentation, Korea ranks very highly. Objective analysis of important individual tracksites and tracksite regions must be based on multiple criteria including: size of site, number of tracks, trackways and track bearing levels, number of valid named ichnotaxa including types, number of scientific publications, quality of preservation. The unique and distinctive dinosaur tracksites are known as one of the world's most important dinosaur track localities. In particular, the dinosaur track sites in southern coastal area of Korea are very unique. In the sites, we have excavated over 10,000 dinosaur tracks. The Hwasun sites show diverse gaits with unusual walking patterns and postures in some tracks. The pterosaur tracks are the most immense in the world. The longest pterosaur trackway yet known from any track sites suggests that pterosaurs were competent terrestrial locomotors. This ichnofauna contains the first pterosaur tracks reported from Asia. The Haenam Uhangri pterosaur assigns to a new genus Haenamichnus which accomodates the new ichnospecies, Haenamichnus uhangriensis. At least 12 track types have been reported from the Haman and Jindong Formations (probably late Lower Cretaceous). These include the types of bird tracks assigned to Koreanornis, Jindongornipes, Ignotornis and Goseongornipes. In addition the bird tracks Hwangsanipes, Uhangrichnus, the pterosaur track Haenamichnus and the dinosaur tracks, Brontopodus, Caririchnium, Minisauripus and

Adaptive Radiation in Socially Advanced Stem-Group Ants from the Cretaceous.

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Barden, Phillip; Grimaldi, David A

2016-02-22

Across terrestrial ecosystems, modern ants are ubiquitous. As many as 94 out of every 100 individual arthropods in rainforests are ants, and they constitute up to 15% of animal biomass in the Amazon. Moreover, ants are pervasive agents of natural selection as over 10,000 arthropod species are specialized inquilines or myrmecomorphs living among ants or defending themselves through mimicry. Such impact is traditionally explained by sociality: ants are the first major group of ground-dwelling predatory insects to become eusocial, increasing efficiency of tasks and establishing competitive superiority over solitary species. A wealth of specimens from rich deposits of 99 million-year-old Burmese amber resolves ambiguity regarding sociality and diversity in the earliest ants. The stem-group genus Gerontoformica maintained distinct reproductive castes including morphotypes unknown in solitary aculeate (stinging) wasps, providing insight into early behavior. We present rare aggregations of workers, indicating group recruitment as well as an instance of interspecific combat; such aggression is a social feature of modern ants. Two species and an unusual new genus are described, further expanding the remarkable diversity of early ants. Stem-group ants are recovered as a paraphyletic assemblage at the base of modern lineages varying greatly in size, form, and mouthpart structure, interpreted here as an adaptive radiation. Though Cretaceous stem-group ants were eusocial and adaptively diverse, we hypothesize that their extinction resulted from the rise of competitively superior crown-group taxa that today form massive colonies, consistent with Wilson and Hölldobler's concept of "dynastic succession." Copyright © 2016 Elsevier Ltd. All rights reserved.

Evolution of magmatism from the uppermost cretaceous to Oligocene, and its relationship to changing tectonic regime, in the Inca de Oro-El Salvador area (Northern Chile)

International Nuclear Information System (INIS)

Cornejo, Paula; Matthews, Stephen

2001-01-01

We present geochronological and petrological data for extrusive and intrusive rocks in the Inca de Oro and El Salvador sheets (in prep.), and the Potrerillos (Tomlinson et al., 1999) and Salar de Maricunga sheets (Cornejo et al., 1998), III Region, Chile (26 o -27 o S). Most of these data were collected as part of the SERNAGEOMIN regional mapping programme. Additionally, we include published data for El Salvador and Potrerillos districts (Cornejo et al., 1997; Marsh et al., 1997; Gustafson et al., 2001). The dataset includes K/Ar, Ar/Ar and U-Pb mineral ages, which have been carefully selected for quality. The area is underlain by Carboniferous-Permian granitic basement rocks, which are covered by Triassic to Early Upper Cretaceous volcanic and sedimentary successions, including both marine and continental sequences (Cornejo et al., 1993). The period studied in this paper includes extrusive and intrusive rocks of Maastrichtian to Oligocene age, which are of particular interest since they record the 'preparation' of the lithosphere prior to, during, and after the mid-Eocene Incaic deformation and associated porphyry copper event. Shortening in the early-upper Cretaceous (95-85Ma; e.g. Mpodozis and Ramos, 1989; Arevalo and Grocott, 2000) deformed large areas of northen Chile, and marked the transition from the dominance of intra-arc extension to that of shortening punctuated by periods of extension. We recognise seven tectono-magmatic periods from the uppermost Cretaceous to Oligocene, comprising a volcanic sedimentary event contemporaneous with an extensional tectonic regime in the Upper Cretaceous, associated with graben formation, followed by an important compressive event at the beginning of the Tertiary. The middle Paleocene was again dominated by voluminous volcanic activity (collapse calderas) in an extensional regime. During the lowest Eocene the magmatic activity in the area shows a gradual transition from pyroxene-bearing to amphibole-bearing lithologies

Paleomagnetism of Jurassic and Cretaceous rocks in central Patagonia: a key to constrain the timing of rotations during the breakup of southwestern Gondwana?

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Geuna, Silvana E.; Somoza, Rubén; Vizán, Haroldo; Figari, Eduardo G.; Rinaldi, Carlos A.

2000-08-01

A paleomagnetic study in Jurassic and Cretaceous rocks from the Cañadón Asfalto basin, central Patagonia, indicates the occurrence of about 25-30° clockwise rotation in Upper Jurassic-lowermost Cretaceous rocks, whereas the overlying mid-Cretaceous rocks do not show evidence of rotation. This constrains the tectonic rotation to be related to a major regional unconformity in Patagonia, which in turn seems to be close in time with the early opening of the South Atlantic Ocean. The sense and probably the timing of this rotation are similar to those of other paleomagnetically detected rotations in different areas of southwestern Gondwana, suggesting a possible relationship between these and major tectonic processes related with fragmentation of the supercontinent. On the other hand, the mid-Cretaceous rocks in the region yield a paleopole located at Lat. 87° South, Long. 159° East, A95=3.8°. This pole position is consistent with coeval high-quality paleopoles of other plates when transferred to South American coordinates, implying it is an accurate determination of the Aptian (circa 116 Ma) geomagnetic field in South America.

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

Science.gov (United States)

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.

Molecular and Morphological Evidence Challenges the Records of the Extant Liverwort Ptilidium pulcherrimum in Eocene Baltic Amber.

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Heinrichs, Jochen; Scheben, Armin; Lee, Gaik Ee; Váňa, Jiří; Schäfer-Verwimp, Alfons; Krings, Michael; Schmidt, Alexander R

2015-01-01

Preservation of liverworts in amber, a fossilized tree resin, is often exquisite. Twenty-three fossil species of liverworts have been described to date from Eocene (35-50 Ma) Baltic amber. In addition, two inclusions have been assigned to the extant species Ptilidium pulcherrimum (Ptilidiales or Porellales). However, the presence of the boreal P. pulcherrimum in the subtropical or warm-temperate Baltic amber forest challenges the phytogeographical interpretation of the Eocene flora. A re-investigation of one of the fossils believed to be P. pulcherrimum reveals that this specimen in fact represents the first fossil evidence of the genus Tetralophozia, and thus is re-described here as Tetralophozia groehnii sp. nov. A second fossil initially assigned to P. pulcherrimum is apparently lost, and can be reassessed only based on the original description and illustrations. This fossil is morphologically similar to the extant North Pacific endemic Ptilidium californicum, rather than P. pulcherrimum. Divergence time estimates based on chloroplast DNA sequences provide evidence of a Miocene origin of P. pulcherrimum, and thus also argue against the presence of this taxon in the Eocene. Ptilidium californicum originated 25-43 Ma ago. As a result, we cannot rule out that the Eocene fossil belongs to P. californicum. Alternatively, the fossil might represent a stem lineage element of Ptilidium or an early crown group species with morphological similarities to P. californicum.

Zircon U-Pb age of the Pescadero felsite: A late Cretaceous igneous event in the forearc, west-central California Coast Ranges

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Ernst, W.G.; Martens, U.C.; McLaughlin, R.J.; Clark, J.C.; Moore, Diane E.

2011-01-01

Weathered felsite is associated with the late Campanian-Maastrichtian Pigeon Point Formation near Pescadero, California. Poorly exposed, its age and correlation are uncertain. Is it part of the Pigeon Point section west of the San Gregorio-Hosgri fault? Does it rest on Nacimiento block basement? Is it dextrally offset from the Oligocene Cambria Felsite, ~185 km to the southeast? Why is a calc-alkaline hypabyssal igneous rock intrusive into the outboard accretionary prism? To address these questions, we analyzed 43 oscillatory-zoned zircon crystals from three incipiently recrystallized pumpellyite ?? prehnite ?? laumontite-bearing Pescadero felsite samples by sensitive high-resolution ion microprobe-reverse geometry (SHRIMPRG) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) techniques. Thirty-three zircons gave late Mesozoic U-Pb ages, with single-grain values ranging from 81 to 167 Ma; ten have pre-Mesozoic, chiefl y Proterozoic ages. A group of the four youngest Pescadero zircons yielded an apparent maximum igneous age of ca. 86-90 Ma. Refl ecting broad age scatter and presence of partly digested sandstone inclusions, we interpret the rest of the zircons (perhaps all) as xenocrysts. Twenty-three zircons were separated and analyzed from two samples of the similar Cambria Felsite, yielding a unimodal 27 Ma U-Pb age. Clearly, the origin of the Upper Oligocene Cambria Felsite is different from that of the Upper Cretaceous Pescadero felsite; these rocks are not correlated, and do not constrain displacement along the San Gregorio-Hosgri fault. Peak ages differ slightly, but relative probability curves for Mesozoic and pre-Mesozoic Pescadero zircons compare well, for example, with abundant U-Pb age data for detrital zircons from Franciscan metaclastic strata ~100 km to the east in the Diablo Range- San Francisco Bay area, San Joaquin Great Valley Group turbidites, Upper Cretaceous Nacimiento block Franciscan strata, and Upper Cretaceous

Amber light-emitting diode comprising a group III-nitride nanowire active region

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Wang, George T.; Li, Qiming; Wierer, Jr., Jonathan J.; Koleske, Daniel

2014-07-22

A temperature stable (color and efficiency) III-nitride based amber (585 nm) light-emitting diode is based on a novel hybrid nanowire-planar structure. The arrays of GaN nanowires enable radial InGaN/GaN quantum well LED structures with high indium content and high material quality. The high efficiency and temperature stable direct yellow and red phosphor-free emitters enable high efficiency white LEDs based on the RGYB color-mixing approach.

Total petroleum systems of the Pelagian Province, Tunisia, Libya, Italy, and Malta; the Bou Dabbous, Tertiary and Jurassic-Cretaceous composite

Science.gov (United States)

Klett, T.R.

2001-01-01

Undiscovered conventional oil and gas resources were assessed within total petroleum systems of the Pelagian Province (2048) as part of the U.S. Geological Survey World Petroleum Assessment 2000. The Pelagian Province is located mainly in eastern Tunisia and northwestern Libya. Small portions of the province extend into Malta and offshore Italy. Although several petroleum systems may exist, only two ?composite? total petroleum systems were identified. Each total petroleum system comprises a single assessment unit. These total petroleum systems are called the Bou Dabbous?Tertiary and Jurassic-Cretaceous Composite, named after the source-rock intervals and reservoir-rock ages. The main source rocks include mudstone of the Eocene Bou Dabbous Formation; Cretaceous Bahloul, Lower Fahdene, and M?Cherga Formations; and Jurassic Nara Formation. Known reservoirs are in carbonate rocks and sandstone intervals throughout the Upper Jurassic, Cretaceous, and Tertiary sections. Traps for known accumulations include fault blocks, low-amplitude anticlines, high-amplitude anticlines associated with reverse faults, wrench fault structures, and stratigraphic traps. The estimated means of the undiscovered conventional petroleum volumes in total petroleum systems of the Pelagian Province are as follows: [MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids] Total Petroleum System MMBO BCFG MMBNGL Bou Dabbous?Tertiary 667 2,746 64 Jurassic-Cretaceous Composite 403 2,280 27

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.

Vertebrate assemblages from the early Late Cretaceous of southeastern Morocco: An overview

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Cavin, L.; Tong, H.; Boudad, L.; Meister, C.; Piuz, A.; Tabouelle, J.; Aarab, M.; Amiot, R.; Buffetaut, E.; Dyke, G.; Hua, S.; Le Loeuff, J.

2010-07-01

Fossils of vertebrates have been found in great abundance in the continental and marine early Late Cretaceous sediments of Southeastern Morocco for more than 50 years. About 80 vertebrate taxa have so far been recorded from this region, many of which were recognised and diagnosed for the first time based on specimens recovered from these sediments. In this paper, we use published data together with new field data to present an updated overview of Moroccan early Late Cretaceous vertebrate assemblages. The Cretaceous series we have studied encompasses three Formations, the Ifezouane and Aoufous Formations, which are continental and deltaic in origin and are often grouped under the name "Kem Kem beds", and the Akrabou Formation which is marine in origin. New field observations allow us to place four recognised vertebrate clusters, corresponding to one compound assemblage and three assemblages, within a general temporal framework. In particular, two ammonite bioevents characterise the lower part of the Upper Cenomanian ( Calycoceras guerangeri Zone) at the base of the Akrabou Formation and the upper part of the Lower Turonian ( Mammites nodosoides Zone), that may extend into the Middle Turonian within the Akrabou Formation, and allow for more accurate dating of the marine sequence in the study area. We are not yet able to distinguish a specific assemblage that characterises the Ifezouane Formation when compared to the similar Aoufous Formation, and as a result we regard the oldest of the four vertebrate "assemblages" in this region to be the compound assemblage of the "Kem Kem beds". This well-known vertebrate assemblage comprises a mixture of terrestrial (and aerial), freshwater and brackish vertebrates. The archosaur component of this fauna appears to show an intriguingly high proportion of large-bodied carnivorous taxa, which may indicate a peculiar trophic chain, although collecting biases alter this palaeontological signal. A small and restricted assemblage, the

Dinosaur morphological diversity and the end-Cretaceous extinction.

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Brusatte, Stephen L; Butler, Richard J; Prieto-Márquez, Albert; Norell, Mark A

2012-05-01

The extinction of non-avian dinosaurs 65 million years ago is a perpetual topic of fascination, and lasting debate has focused on whether dinosaur biodiversity was in decline before end-Cretaceous volcanism and bolide impact. Here we calculate the morphological disparity (anatomical variability) exhibited by seven major dinosaur subgroups during the latest Cretaceous, at both global and regional scales. Our results demonstrate both geographic and clade-specific heterogeneity. Large-bodied bulk-feeding herbivores (ceratopsids and hadrosauroids) and some North American taxa declined in disparity during the final two stages of the Cretaceous, whereas carnivorous dinosaurs, mid-sized herbivores, and some Asian taxa did not. Late Cretaceous dinosaur evolution, therefore, was complex: there was no universal biodiversity trend and the intensively studied North American record may reveal primarily local patterns. At least some dinosaur groups, however, did endure long-term declines in morphological variability before their extinction.

Photoageing of Baltic amber-influence of daylight radiation behind window glass on surface colour and chemistry

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Shashoua, Yvonne

2011-01-01

The aim of this study was to provide evidence about the interaction between Baltic amber and daylight behind window glass, essential to understanding the mechanisms by which the material degrades in museum environments and to propose techniques for preventive conservation based on the control...

Tribosphenic mammal from the North American Early Cretaceous.

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Cifelli, R L

1999-09-23

The main groups of living mammals, marsupials and eutherians, are presumed to have diverged in the Early Cretaceous, but their early history and biogeography are poorly understood. Dental remains have suggested that the eutherians may have originated in Asia, spreading to North America in the Late Cretaceous, where an endemic radiation of marsupials was already well underway. Here I describe a new tribosphenic mammal (a mammal with lower molar heels that are three-cusped and basined) from the Early Cretaceous of North America, based on an unusually complete specimen. The new taxon bears characteristics (molarized last premolar, reduction to three molars) otherwise known only for Eutheria among the tribosphenic mammals. Morphometric analysis and character comparisons show, however, that its molar structure is primitive (and thus phylogenetically uninformative), emphasizing the need for caution in interpretation of isolated teeth. The new mammal is approximately contemporaneous with the oldest known Eutheria from Asia. If it is a eutherian, as is indicated by the available evidence, then this group was far more widely distributed in the Early Cretaceous than previously appreciated. An early presence of Eutheria in North America offers a potential source for the continent's Late Cretaceous radiations, which have, in part, proven difficult to relate to contemporary taxa in Asia.

Petrographic Evidence of Microbial Mats in the Upper Cretaceous Fish-Bearing, Organic-Rich Limestone, Agua Nueva Formation, Central Mexico

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Blanco, A.; Maurrasse, F. J.; Hernández-Ávila, J.; Ángeles-Trigueros, S. A.; García-Cabrera, M. E.

2013-05-01

We document petrographic evidence of microbial mats in the Upper Cretaceous Agua Nueva Formation in the area of Xilitla (San Luis Potosí, Central Mexico), located in the southern part of the Tampico-Misantla basin. The sequence consists predominantly of alternating decimeter-thick beds of fossiliferous dark laminated limestone (C-org > 1.0wt%), and light gray, bioturbated limestone (C-org Duque-Botero and Maurrasse, 2005; 2008). These structures are also analogous to microbial mats in present environments, and Devonian deposits (Kremer, 2006). In addition, the laminae at Xilitla include filamentous bacterial structures, as thin and segmented red elements. In some thin sections, filaments appear to be embedded within the crinkly laminae and shreds showing the same pattern of folding, suggestive of biomorphic elements that represent the main producers of the organic matter associated with the laminae. Thus, exceptional bacterial activity characterizes sedimentation during the accumulation of the Agua Nueva Formation. Oxygen-deficient conditions related to the microbial mats were an important element in the mass mortality and preservation of the fish assemblages. Absence of bioturbation, pervasive framboidal pyrite, and the high concentration of organic matter (TOC ranges from 1.2% to 8wt%) in the dark limestones are consistent with persistent recurring dysoxic/anoxic conditions, and the light-gray bioturbated limestones represent relatively well-oxygenated episodes. Planktonic foraminifera (Rotalipora cushmani) and Inoceramu labiatus indicate a time interval from the latest Cenomanian through the earliest Turonian, thus this long interval of severe oxygen deficiency is coeval with Oceanic Anoxic Event 2 (OAE-2). [Duque-Botero and Maurrasse. 2005. Jour. Iberian Geology (31), 85-98; 2008. Cret. Res., 29, 957-964; Kremer. 2006. Acta Palaeontologica Polonica (51, 1), 143-154

Baltileuctra gen. nov., a new genus of Leuctridae (Insecta: Plecoptera) in Baltic amber.

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Chen, Zhi-Teng

2018-04-10

A new genus and species of the stonefly family Leuctridae, Baltileuctra foraminis gen. et sp. nov., is described and illustrated based on a well-preserved male specimen from the Eocene Baltic amber. The new genus possesses typical characters of Leuctridae but has diagnostic characters of the thoracic sclerites and terminalia. The relationship between the new genus and other leuctrids is briefly discussed.

Southern Dobrogea coastal potable water sources and Upper Quaternary Black Sea level changes

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Caraivan, Glicherie; Stefanescu, Diana

2013-04-01

Southern Dobrogea is a typical geologic platform unit, placed in the south-eastern part of Romania, with a Pre-Cambrian crystalline basement and a Paleozoic - Quaternary sedimentary cover. It is bordered to the north by the Capidava - Ovidiu fault and by the Black Sea to the east. A regional WNW - ESE and NNE - SSW fault system divides the Southern Dobrogea structure in several tectonic blocks. Four drinking water sources have been identified: surface water, phreatic water, medium depth Sarmatian aquifer, and deep Upper Jurassic - Lower Cretaceous aquifer. Surface water sources are represented by several springs emerged from the base of the loess cliff, and a few small rivers, barred by coastal beaches. The phreatic aquifer develops at the base of the loess deposits, on the impervious red clay, overlapping the Sarmatian limestones. The medium depth aquifer is located in the altered and karstified Sarmatian limestones, and discharges into the Black Sea. The Sarmatian aquifer is unconfined where covered by silty loess deposits, and locally confined, where capped by clayey loess deposits. The aquifer is supplied from the Pre-Balkan Plateau. The Deep Upper Jurassic - Lower Cretaceous aquifer, located in the limestone and dolomite deposits, is generally confined and affected by the regional WNW - ESE and NNE - SSW fault system. In the south-eastern Dobrogea, the deep aquifer complex is separated from the Sarmatian aquifer by a Senonian aquitard (chalk and marls). The natural boundary of the Upper Jurassic - Lower Cretaceous aquifer is the Capidava - Ovidiu Fault. The piezometric heads show that the Upper Jurassic - Lower Cretaceous aquifer is supplied from the Bulgarian territory, where the Upper Jurassic deposits crop out. The aquifer discharges into the Black Sea to the east and into Lake Siutghiol to the northeast. The cyclic Upper Quaternary climate changes induced drastic remodeling of the Black Sea level and the corresponding shorelines. During the Last Glacial

Remarkable preservation of terpenoids and record of volatile signalling in plant-animal interactions from Miocene amber.

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Dutta, Suryendu; Mehrotra, Rakesh C; Paul, Swagata; Tiwari, R P; Bhattacharya, Sharmila; Srivastava, Gaurav; Ralte, V Z; Zoramthara, C

2017-09-08

Plants produce and release a large array of volatile organic compounds that play many ecological functions. These volatile plant metabolites serve as pollinator attractants, herbivore and pathogen repellents and protect plants from abiotic stresses. To date, the geological evolution of these organic compounds remains unknown. The preservation potential of these metabolites in the fossil record is very poor due to their low boiling points. Here we report a series of volatile sesquiterpenoids, including δ-elemene, α-copaene, β-elemene, β-caryophyllene, α-humulene, germacrene D, δ-cadiene and spathunenol, from early Miocene (~17 million year) amber from eastern India. The survival of these unaltered bioterpenoids can be attributed to the existence of extraordinary taphonomic conditions conducive to the preservation of volatile biomolecules through deep time. Furthermore, the occurrence of these volatiles in the early Miocene amber suggests that the plants from this period had evolved metabolic pathways to synthesize these organic molecules to play an active role in forest ecology, especially in plant-animal interactions.

Preliminary magnetostratigraphy and environmental magnetism of the Lower Cretaceous from the Italian Dolomites

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Savian, J. F.; Jovane, L.; Florindo, F.; Lukeneder, A.

2011-12-01

The Lower Cretaceous (~146 to 100 Ma) represents an enigmatic time interval for paleoclimatic, paleogeography and paleomagnetic evolution of the Earth's history. The climatic changes include global oceanic anoxic events (OAEs), biotic changes, global excursions of carbon and strontium isotopes, rises in eustatic sea level and paleotemperature. Paleoceanography was marked by a rapid rate of ocean spreading in the Atlantic. The opening of the Atlantic Ocean was wide enough to allow significant circulation of masses of waters across the equator. This period is furthermore important for the oceanographic events occurring at the base of the Aptian (Selli Level). This period also present one of the most intriguing geomagnetic events: the long normal Cretaceous superchron, lasted for almost 40 million years. We study here the lower Cretaceous deposits of the Puez section in the Dolomites (northern Italy) which represents a continuous section during this period. The samples collected represent marine sedimentary materials of the Biancone and Puez formations. The Puez section consists essentially of green-grey to red limestones and calcareous marls. We present preliminary results of integrated magnetostratigraphic analysis, including a detailed lithostratigraphy and environmental magnetism. We recognize magnetic behavior that are relative to normal polarity (the normal Cretaceous superchron), with a short reverse interval that might represent the M-1r event. We also recognize a series of normal and reverse polarities (below the normal Cretaceous superchron) which can be referred to the magnetozones M1/M5. The environmental magnetic data consists of magnetic susceptibility (χ), natural remanent magnetization (NRM), anhysteretic remanent magnetization (ARM), isothermal remanent magnetization (IRM) at 900 mT and backfield isothermal remanent magnetization (BIRM) at 100 mT and 300 mT. Derived parameters, such as S-ratio (S300=BIRM300/IRM900) and hard isothermal remanent

Nonexplosive and explosive magma/wet-sediment interaction during emplacement of Eocene intrusions into Cretaceous to Eocene strata, Trans-Pecos igneous province, West Texas

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Befus, K.S.; Hanson, R.E.; Miggins, D.P.; Breyer, J.A.; Busbey, A.B.

2009-01-01

Eocene intrusion of alkaline basaltic to trachyandesitic magmas into unlithified, Upper Cretaceous (Maastrichtian) to Eocene fluvial strata in part of the Trans-Pecos igneous province in West Texas produced an array of features recording both nonexplosive and explosive magma/wet-sediment interaction. Intrusive complexes with 40Ar/39Ar dates of ~ 47-46??Ma consist of coherent basalt, peperite, and disrupted sediment. Two of the complexes cutting Cretaceous strata contain masses of conglomerate derived from Eocene fluvial deposits that, at the onset of intrusive activity, would have been > 400-500??m above the present level of exposure. These intrusive complexes are inferred to be remnants of diatremes that fed maar volcanoes during an early stage of magmatism in this part of the Trans-Pecos province. Disrupted Cretaceous strata along diatreme margins record collapse of conduit walls during and after subsurface phreatomagmatic explosions. Eocene conglomerate slumped downward from higher levels during vent excavation. Coherent to pillowed basaltic intrusions emplaced at the close of explosive activity formed peperite within the conglomerate, within disrupted Cretaceous strata in the conduit walls, and within inferred remnants of the phreatomagmatic slurry that filled the vents during explosive volcanism. A younger series of intrusions with 40Ar/39Ar dates of ~ 42??Ma underwent nonexplosive interaction with Upper Cretaceous to Paleocene mud and sand. Dikes and sills show fluidal, billowed, quenched margins against the host strata, recording development of surface instabilities between magma and groundwater-rich sediment. Accentuation of billowed margins resulted in propagation of intrusive pillows into the adjacent sediment. More intense disruption and mingling of quenched magma with sediment locally produced fluidal and blocky peperite, but sufficient volumes of pore fluid were not heated rapidly enough to generate phreatomagmatic explosions. This work suggests that

Linking Late Cretaceous to Eocene Tectonostratigraphy of the San Jacinto Fold Belt of NW Colombia With Caribbean Plateau Collision and Flat Subduction

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Mora, J. Alejandro; Oncken, Onno; Le Breton, Eline; Ibánez-Mejia, Mauricio; Faccenna, Claudio; Veloza, Gabriel; Vélez, Vickye; de Freitas, Mario; Mesa, Andrés.

2017-11-01

Collision with and subduction of an oceanic plateau is a rare and transient process that usually leaves an indirect imprint only. Through a tectonostratigraphic analysis of pre-Oligocene sequences in the San Jacinto fold belt of northern Colombia, we show the Late Cretaceous to Eocene tectonic evolution of northwestern South America upon collision and ongoing subduction with the Caribbean Plate. We linked the deposition of four fore-arc basin sequences to specific collision/subduction stages and related their bounding unconformities to major tectonic episodes. The Upper Cretaceous Cansona sequence was deposited in a marine fore-arc setting in which the Caribbean Plate was being subducted beneath northwestern South America, producing contemporaneous magmatism in the present-day Lower Magdalena Valley basin. Coeval strike-slip faulting by the Romeral wrench fault system accommodated right-lateral displacement due to oblique convergence. In latest Cretaceous times, the Caribbean Plateau collided with South America marking a change to more terrestrially influenced marine environments characteristic of the upper Paleocene to lower Eocene San Cayetano sequence, also deposited in a fore-arc setting with an active volcanic arc. A lower to middle Eocene angular unconformity at the top of the San Cayetano sequence, the termination of the activity of the Romeral Fault System, and the cessation of arc magmatism are interpreted to indicate the onset of low-angle subduction of the thick and buoyant Caribbean Plateau beneath South America, which occurred between 56 and 43 Ma. Flat subduction of the plateau has continued to the present and would be the main cause of amagmatic post-Eocene deposition.

Improving care for patients whose recovery is uncertain. The AMBER care bundle: design and implementation.

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Carey, Irene; Shouls, Susanna; Bristowe, Katherine; Morris, Michelle; Briant, Linda; Robinson, Carole; Caulkin, Ruth; Griffiths, Mathew; Clark, Kieron; Koffman, Jonathan; Hopper, Adrian

2015-12-01

Despite preferences to the contrary, 53% of deaths in England occur in hospital. Difficulties in managing clinical uncertainty can result in delayed recognition that a person may be approaching the end of life, and a failure to address his/her preferences. Planning and shared decision-making for hospital patients need to improve where an underlying condition responds poorly to acute medical treatment and there is a risk of dying in the next 1-2 months. This paper suggests an approach to improve this care. A care bundle (the AMBER care bundle) was designed by a multiprofessional development team, which included service users, utilising the model for improvement following an initial scoping exercise. The care bundle includes two identification questions, four subsequent time restricted actions and systematic daily follow-up. This paper describes the development and implementation of a care bundle. From August 2011 to July 2012, 638 patients received care supported by the AMBER care bundle. In total 42.8% died in hospital and a further 14.5% were readmitted as emergencies within 30 days of discharge. Clinical outcome measures are in development. It has been possible to develop a care bundle addressing a complex area of care which can be a lever for cultural change. The implementation of the AMBER care bundle has the potential to improve care of clinically uncertain hospital patients who may be approaching the end of life by supporting their recognition and prompting discussion of their preferences. Outcomes associated with its use are currently being formally evaluated. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Stratigraphy and structural setting of Upper Cretaceous Frontier Formation, western Centennial Mountains, southwestern Montana and southeastern Idaho

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Dyman, T.S.; Tysdal, R.G.; Perry, W.J.; Nichols, D.J.; Obradovich, J.D.

2008-01-01

Stratigraphic, sedimentologic, and palynologic data were used to correlate the Frontier Formation of the western Centennial Mountains with time-equivalent rocks in the Lima Peaks area and other nearby areas in southwestern Montana. The stratigraphic interval studied is in the middle and upper parts (but not uppermost) of the formation based on a comparison of sandstone petrography, palynologic age data, and our interpretation of the structure using a seismic line along the frontal zone of the Centennial Mountains and the adjacent Centennial Valley. The Frontier Formation is comprised of sandstone, siltstone, mudstone, limestone, and silty shale in fluvial and coastal depositional settings. A distinctive characteristic of these strata in the western Centennial Mountains is the absence of conglomerate and conglomeratic sandstone beds. Absence of conglomerate beds may be due to lateral facies changes associated with fluvial systems, a distal fining of grain size, and the absence of both uppermost and lower Frontier rocks in the study area. Palynostratigraphic data indicate a Coniacian age for the Frontier Formation in the western Centennial Mountains. These data are supported by a geochronologic age from the middle part of the Frontier at Lima Peaks indicating a possible late Coniacian-early Santonian age (86.25 ?? 0.38 Ma) for the middle Frontier there. The Frontier Formation in the western Centennial Mountains is comparable in age and thickness to part of the Frontier at Lima Peaks. These rocks represent one of the thickest known sequences of Frontier strata in the Rocky Mountain region. Deposition was from about 95 to 86 Ma (middle Cenomanian to at least early Santonian), during which time, shoreface sandstone of the Telegraph Creek Formation and marine shale of the Cody Shale were deposited to the east in the area now occupied by the Madison Range in southwestern Montana. Frontier strata in the western Centennial Mountains are structurally isolated from other

Two cloned β thalassemia genes are associated with amber mutations at codon 39

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Pergolizzi, Robert; Spritz, Richard A.; Spence, Sally; Goossens, Michel; Kan, Yuet Wai; Bank, Arthur

1981-01-01

Two β globin genes from patients with the β+ thalassemia phenotype have been cloned and sequenced. A single nucleotide change from CAG to TAG (an amber mutation) at codon 39 is the only difference from normal in both genes analyzed. The results are consistent with the assumption that both patients are doubly heterozygous for β+ and β° thalassemia, and that we have isolated and analyzed the β° thalassemia gene. Images PMID:6278453

Cretaceous origin of dogwoods: an anatomically preserved Cornus (Cornaceae fruit from the Campanian of Vancouver Island

Directory of Open Access Journals (Sweden)

Brian A. Atkinson

2016-12-01

Full Text Available Background Cornaceae consists of 58 species, all within the genus Cornus. The Cenozoic record of Cornus is extensive and well documented. Molecular divergence-time studies suggest that crown-group Cornus may have originated by the Late Cretaceous. However, there has been no formal report of Cornus from Cretaceous deposits. Here, we characterize a permineralized fossil fruit assignable to Cornus subg. Cornus from the Upper Cretaceous (Campanian Shelter Point locality of Vancouver Island, British Columbia, Canada. Methods Serial sections of the specimen were made using the cellulose acetate peel technique. Peels were mounted onto microscope slides and studied by light microscopy. Results The fossil fruit consists of a tri-locular woody endocarp with dorsal germination valves. The locules are sub-triangular to ellipsoidal in transverse section and are separated by thin septa. Endocarp tissue consists of elongated and isodiametric sclereids and secretory cavities. Internal vascular tissue was not observed, but is interpreted to have been located along the outer periphery of the septa for some length, common in many cornalean taxa. There is one seed in each locule, one of which was found to have endosperm and a dicotyledonous embryo. Discussion Woody endocarps with germination valves, without central vascular bundles, and with one seed per locule are characteristic of several families within the order Cornales. The interpreted vascular pattern and presence of secretory cavities indicates that the fossil fruit is assignable to Cornus subg. Cornus. Comparative analysis suggests that the fossil is most similar to Cornus piggae, a species described from the Paleocene of North Dakota. This fossil is the first evidence of crown-group Cornaceae from the Cretaceous and sheds light on both the plesiomorphic fruit characters and the timing of the initial diversification of the family and basal asterid lineage, Cornales.

An age-calibrated record of upper Campanian – Maastrichtian climate change in the Boreal Realm

DEFF Research Database (Denmark)

Thibault, Nicolas Rudolph; Schovsbo, Niels; Harlou, Rikke

nannofossil chalk is in agreement with planktic biotic events of the latest Cretaceous and matches well with climatic trends of intermediate- and deep-waters from other oceanic basins recorded through benthic foraminiferal d18O (Barrera and Savin, 1999). However, most planktic foraminiferal d18O data do......The latest Cretaceous climate of the Boreal Realm was recorded through high-resolution bulk carbon- and oxygen-stable isotopes and a nannofossil temperature index (NTI) on the Stevns-1 core (Denmark) which recovered 456 m of upper Campanian to basal Danian chalk with ~100% recovery and an excellent...... temperatures (SSTs) in the Boreal Realm. Three warming events punctuate the overall cooling trend of the latest Cretaceous: (1) the late Campanian climatic optimum (73.9–71.6 Ma) is characterized by maximum SSTs of 20°C, (2) the mid-Maastrichtian warming (69.7–68 Ma) is characterized by stable SSTs around 17°C...

Chemical characteristics of Upper Cretaceous (Turonian) jet of the Gosau Group of Gams/Hieflau (Styria, Austria)

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Bechtel, A.; Gratzer, R.; Sachsenhofer, R.F. [Institut fuer Geowissenschaften, Prospektion und Angewandte Sedimentologie, Montanuniversitaet Leoben, Peter-Tunner-Str. 5, A-8700 Leoben (Austria)

2001-03-01

Jet and coaly sediments within the Upper Cretaceous (Gosau) Schoenleiten Formation were collected from two outcrops near Gams/Hieflau (Styria, Austria). For comparison, additional jet and coal samples from different Gosau localities were included in the study. The identification of jet as bituminous driftwood (collotelinite) has been provided by microscopical examination of organic matter [Kollmann, H.A. and Sachsenhofer, R.F., Mitt. Ref. Geol. und Palaeont. Landesmuseum Joanneum SH 2 (1998) 223]. Rock-Eval analyses revealed enhanced HI and lower T{sub max} values of jet compared with the coals and coaly shales. The results reflect the higher contents of bituminous organic matter compared to vitrain-rich coals of similar maturity. In comparison with the coals and coaly shales, high amounts of liberated hydrocarbons (mg HC/g C{sub org}) are in contrast to generally lower yields of soluble organic matter during extraction with dichloromethane, indicating that portions of the hydrocarbons are liberated from lipids loosely bound to kerogen during pyrolysis. Further differences in n-alkane distribution patterns, odd over even predominance, pristane/phytane, and pristane/n-C{sub 17} ratios exist between jet, coals and coaly shales. The microbial origin of short-chain n-alkanes presumably resulted from the degradation of the predominant odd-numbered long-chain n-alkanes within the jet. The occurrence of biological markers (sesqui and diterpenoids) within the sediments (coaly shales), coals and jet samples indicates the origin of terrestrial organic matter from conifers. Biomarker composition of jet samples indicates enhanced aromatisation of sesqui and diterpenoids. These results correspond to enhanced aromatisation of steranes, as reflected by generally higher relative contents of triaromatic steroids in the jet. Because of comparable maturation (0.5-0.6% R{sub r}) of the coals, coaly shales and the jet samples, confirmed by the isomerisation of {alpha}{beta} C{sub 31

Australian provenance for Upper Permian to Cretaceous rocks forming accretionary complexes on the New Zealand sector of the Gondwana land margin

International Nuclear Information System (INIS)

Pickard, A.L.; Barley, M.E.

2000-01-01

U-Pb (SHRIMP) detrital zircon age patterns are reported for 12 samples of Permian to Cretaceous turbiditic quartzo-feldspathic sandstone from the Torlesse and Waipapa suspect terranes of New Zealand. Their major Permian to Triassic, and minor Early Palaeozoic and Mesoproterozoic, age components indicate that most sediment was probably derived from the Carboniferous to Triassic New England Orogen in northeastern Australia. Rapid deposition of voluminous Torlesse/Waipapa turbidite fans during the Late Permian to Late Triassic appears to have been directly linked to uplift and exhumation of the magmatically active orogen during the 265-230 Ma Hunter-Bowen event. This period of cordilleran-type orogeny allowed transport of large volumes of quartzo-feldspathic sediment across the convergent Gondwana land margin. Post-Triassic depocentres also received (recycled?) sediment from the relict orogen as well as from Jurassic and Cretaceous volcanic provinces now offshore from southern Queensland and northern New South Wales. The detailed provenance-age fingerprints provided by the detrital zircon data are also consistent with progressive southward derivation of sediment: from northeastern Queensland during the Permian, southeastern Queensland during the Triassic, and northeastern New South Wales - Lord Howe Rise - Norfolk Ridge during the Jurassic to Cretaceous. Although the dextral sense of displacement is consistent with the tectonic regime during this period, detailed characterisation of source terranes at this scale is hindered by the scarcity of published zircon age data for igneous and sedimentary rocks in Queensland and northern New South Wales. Mesoproterozoic and Neoproterozoic age components cannot be adequately matched with likely source terranes in the Australian-Antarctic Precambrian craton, and it is possible they originated in the Proterozoic cores of the Cathaysia and Yangtze Blocks of southeast China. Copyright (1999) Geological Society of Australia

Description of Pintomyia (Pifanomyia falcaorum sp. n. (Diptera: Psychodidae: Phlebotominae, a Fossil Sand Fly from Dominican Amber

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Reginaldo Peçanha Brazil

2002-06-01

Full Text Available A new species of sand fly, Pintomyia (Pifanomyia falcaorum is described from an amber originated from the northern mountain range of Dominican Republic. The male sand fly specimen is well preserved and most features used in Phlebotominae taxonomy are seen with remarkable clarity.

A new species of Cretalamna sensu stricto (Lamniformes, Otodontidae) from the Late Cretaceous (Santonian-Campanian) of Alabama, USA

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Ehret, Dana J.

2018-01-01

Decades of collecting from exposures of the Upper Cretaceous Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk in Alabama, USA has produced large numbers of isolated Cretalamna (sensu stricto) teeth. Many of these teeth had formerly been assigned to the extinct Late Cretaceous shark Cretalamna appendiculata (Agassiz, 1843), a taxon that is now considered largely restricted to the Turonian of Europe. Recent studies have shed light on the diversity of Late Cretaceous Cretalamna (s.s.) taxa, and here we recognize a new species from Alabama, Cretalamna bryanti. The teeth of C. bryanti sp. nov. appear aligned with the members of the Cretalamna borealis species group, but can be distinguished from these other species by a combination of the following: anterior teeth with a more pronounced and triangular lingual root protuberance, broader triangular cusp, and a taller root relative to the height of the crown; anteriorly situated lateroposterior teeth have a distally inclined or hooked main cusp and more than one pair of lateral cusplets; and lateroposterior teeth have a strong distally hooked main cusp and a root that is largely symmetrical in basal view. At present, C. bryanti sp. nov. is stratigraphically confined to the Santonian/Campanian Dicarinella asymetrica Sigal, 1952 and Globotruncanita elevata Brotzen, 1934 Planktonic Foraminiferal Zones within the Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk, and teeth have been collected from only four counties in central and western Alabama. The recognition of C. bryanti sp. nov. in Alabama adds to our knowledge on the diversity and distribution of Late Cretaceous otodontids in the region. PMID:29333348

A new species of Cretalamna sensu stricto (Lamniformes, Otodontidae from the Late Cretaceous (Santonian-Campanian of Alabama, USA

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Jun A. Ebersole

2018-01-01

Full Text Available Decades of collecting from exposures of the Upper Cretaceous Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk in Alabama, USA has produced large numbers of isolated Cretalamna (sensu stricto teeth. Many of these teeth had formerly been assigned to the extinct Late Cretaceous shark Cretalamna appendiculata (Agassiz, 1843, a taxon that is now considered largely restricted to the Turonian of Europe. Recent studies have shed light on the diversity of Late Cretaceous Cretalamna (s.s. taxa, and here we recognize a new species from Alabama, Cretalamna bryanti. The teeth of C. bryanti sp. nov. appear aligned with the members of the Cretalamna borealis species group, but can be distinguished from these other species by a combination of the following: anterior teeth with a more pronounced and triangular lingual root protuberance, broader triangular cusp, and a taller root relative to the height of the crown; anteriorly situated lateroposterior teeth have a distally inclined or hooked main cusp and more than one pair of lateral cusplets; and lateroposterior teeth have a strong distally hooked main cusp and a root that is largely symmetrical in basal view. At present, C. bryanti sp. nov. is stratigraphically confined to the Santonian/Campanian Dicarinella asymetrica Sigal, 1952 and Globotruncanita elevata Brotzen, 1934 Planktonic Foraminiferal Zones within the Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk, and teeth have been collected from only four counties in central and western Alabama. The recognition of C. bryanti sp. nov. in Alabama adds to our knowledge on the diversity and distribution of Late Cretaceous otodontids in the region.

A Re-Evaluation of the Chasmosaurine Ceratopsid Genus Chasmosaurus (Dinosauria: Ornithischia) from the Upper Cretaceous (Campanian) Dinosaur Park Formation of Western Canada.

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Campbell, James A; Ryan, Michael J; Holmes, Robert B; Schröder-Adams, Claudia J

2016-01-01

The chasmosaurine ceratopsid Chasmosaurus is known from the Upper Cretaceous (Campanian) Dinosaur Park Formation of southern Alberta and Saskatchewan. Two valid species, Chasmosaurus belli and C. russelli, have been diagnosed by differences in cranial ornamentation. Their validity has been supported, in part, by the reported stratigraphic segregation of chasmosaurines in the Dinosaur Park Formation, with C. belli and C. russelli occurring in discrete, successive zones within the formation. An analysis of every potentially taxonomically informative chasmosaurine specimen from the Dinosaur Park Formation indicates that C. belli and C. russelli have indistinguishable ontogenetic histories and overlapping stratigraphic intervals. Neither taxon exhibits autapomorphies, nor a unique set of apomorphies, but they can be separated and diagnosed by a single phylogenetically informative character-the embayment angle formed by the posterior parietal bars relative to the parietal midline. Although relatively deeply embayed specimens (C. russelli) generally have relatively longer postorbital horncores than specimens with more shallow embayments (C. belli), neither this horncore character nor epiparietal morphology can be used to consistently distinguish every specimen of C. belli from C. russelli. Kosmoceratops is purportedly represented in the Dinosaur Park Formation by a specimen previously referred to Chasmosaurus. The reassignment of this specimen to Kosmoceratops is unsupported here, as it is based on features that are either influenced by taphonomy or within the realm of individual variation for Chasmosaurus. Therefore, we conclude that Kosmoceratops is not present in the Dinosaur Park Formation, but is instead restricted to southern Laramidia, as originally posited.

Novel insect leaf-mining after the end-Cretaceous extinction and the demise of cretaceous leaf miners, Great Plains, USA.

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Michael P Donovan

Full Text Available Plant and associated insect-damage diversity in the western U.S.A. decreased significantly at the Cretaceous-Paleogene (K-Pg boundary and remained low until the late Paleocene. However, the Mexican Hat locality (ca. 65 Ma in southeastern Montana, with a typical, low-diversity flora, uniquely exhibits high damage diversity on nearly all its host plants, when compared to all known local and regional early Paleocene sites. The same plant species show minimal damage elsewhere during the early Paleocene. We asked whether the high insect damage diversity at Mexican Hat was more likely related to the survival of Cretaceous insects from refugia or to an influx of novel Paleocene taxa. We compared damage on 1073 leaf fossils from Mexican Hat to over 9000 terminal Cretaceous leaf fossils from the Hell Creek Formation of nearby southwestern North Dakota and to over 9000 Paleocene leaf fossils from the Fort Union Formation in North Dakota, Montana, and Wyoming. We described the entire insect-feeding ichnofauna at Mexican Hat and focused our analysis on leaf mines because they are typically host-specialized and preserve a number of diagnostic morphological characters. Nine mine damage types attributable to three of the four orders of leaf-mining insects are found at Mexican Hat, six of them so far unique to the site. We found no evidence linking any of the diverse Hell Creek mines with those found at Mexican Hat, nor for the survival of any Cretaceous leaf miners over the K-Pg boundary regionally, even on well-sampled, surviving plant families. Overall, our results strongly relate the high damage diversity on the depauperate Mexican Hat flora to an influx of novel insect herbivores during the early Paleocene, possibly caused by a transient warming event and range expansion, and indicate drastic extinction rather than survivorship of Cretaceous insect taxa from refugia.

Novel insect leaf-mining after the end-Cretaceous extinction and the demise of cretaceous leaf miners, Great Plains, USA.

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Donovan, Michael P; Wilf, Peter; Labandeira, Conrad C; Johnson, Kirk R; Peppe, Daniel J

2014-01-01

Plant and associated insect-damage diversity in the western U.S.A. decreased significantly at the Cretaceous-Paleogene (K-Pg) boundary and remained low until the late Paleocene. However, the Mexican Hat locality (ca. 65 Ma) in southeastern Montana, with a typical, low-diversity flora, uniquely exhibits high damage diversity on nearly all its host plants, when compared to all known local and regional early Paleocene sites. The same plant species show minimal damage elsewhere during the early Paleocene. We asked whether the high insect damage diversity at Mexican Hat was more likely related to the survival of Cretaceous insects from refugia or to an influx of novel Paleocene taxa. We compared damage on 1073 leaf fossils from Mexican Hat to over 9000 terminal Cretaceous leaf fossils from the Hell Creek Formation of nearby southwestern North Dakota and to over 9000 Paleocene leaf fossils from the Fort Union Formation in North Dakota, Montana, and Wyoming. We described the entire insect-feeding ichnofauna at Mexican Hat and focused our analysis on leaf mines because they are typically host-specialized and preserve a number of diagnostic morphological characters. Nine mine damage types attributable to three of the four orders of leaf-mining insects are found at Mexican Hat, six of them so far unique to the site. We found no evidence linking any of the diverse Hell Creek mines with those found at Mexican Hat, nor for the survival of any Cretaceous leaf miners over the K-Pg boundary regionally, even on well-sampled, surviving plant families. Overall, our results strongly relate the high damage diversity on the depauperate Mexican Hat flora to an influx of novel insect herbivores during the early Paleocene, possibly caused by a transient warming event and range expansion, and indicate drastic extinction rather than survivorship of Cretaceous insect taxa from refugia.

Tectonics and Volcanism During the Cretaceous Normal Superchron Seafloor in the Western Pacific Ocean

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O'Brien, E.

2017-12-01

We have conducted an integration study on the origin and evolution of the tectonics and volcanism of seafloor in the Western Pacific Ocean that took place during the Cretaceous Normal Superchron (CNS) where sparse data has so far precluded detailed investigation. We have compiled the latest satellite-based gravity, gravity gradient, and magnetic grids (EMAG2 v.3) for this region. These crustal-scale high-resolution grids suggest that the CNS seafloor contains fossilized lithospheric morphology possibly attributed to the interaction between Cretaceous supervolcanism activity and Mid-Cretaceous Pacific mid ocean ridge systems that have continuously expanded the Pacific Plate. We recognize previously identified fossilized microplates west of the Magellan Rise, short-lived abandoned propagating rifts and fracture zones, all of which show significant rotation of seafloor fabric. In addition to these large scale observations, we have also compiled marine geological information from previously drilled cores and new data from a Kongsberg Topas PS18 Parametric Sub-Bottom Profiler collected on a transect from Honolulu, Hawaii to Apra, Guam acquired during research cruise SKQ2014S2. In particular, the narrow beam and high bandwidth signal of the Topas PS18 sub-bottom profiler provides sonar data of the seabed with a resolution and depth penetration that is unprecedented compared with previously available surveys in the region. A preliminary assessment of this high resolution Topas data allows us to better characterize sub-seafloor sediment properties and identify features, including the Upper Transparent Layer with identifiable pelagic clay and porcelanite-chert reflectors as well as tectonic features such as the westernmost tip of the Waghenaer Fracture Zone.

Cretacic tectonics in Uruguay

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Gomez Rifas, C.

2012-01-01

This work is about Cretacic tectonics in Uruguay, this formation is characterized by high level cortex because the basament is cratonized since Middle Devonian. There were formed two main grabens such as Santa Lucia and Mirim-Pelotas which are filled with basalt and sediments.

Geochemical characteristics of natural gas in the hydrocarbon accumulation history, and its difference among gas reservoirs in the Upper Triassic formation of Sichuan Basin, China

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Peng Wang

2016-08-01

Full Text Available The analysis of hydrocarbon generation, trap formation, inclusion homogenization temperature, authigenic illite dating, and ESR dating were used to understand the history of hydrocarbon accumulation and its difference among gas reservoirs in the Upper Triassic formation of Sichuan Basin. The results show the hydrocarbon accumulation mainly occurred during the Jurassic and Cretaceous periods; they could also be classified into three stages: (1 early hydrocarbon generation accumulation stage, (2 mass hydrocarbon generation accumulation stage before the Himalayan Epoch, (3 and parts of hydrocarbon adjustment and re-accumulation during Himalayan Epoch. The second stage is more important than the other two. The Hydrocarbon accumulation histories are obviously dissimilar in different regions. In western Sichuan Basin, the gas accumulation began at the deposition period of member 5 of Xujiahe Formation, and mass accumulation occurred during the early Middle Jurassic up to the end of the Late Cretaceous. In central Sichuan Basin, the accumulation began at the early Late Jurassic, and the mass accumulation occurred from the middle Early Cretaceous till the end of the Late Cretaceous. In southern Sichuan Basin, the accumulation began at the middle Late Jurassic, and the mass accumulation occurred from the middle of the Late Cretaceous to the end of the Later Cretaceous. The accumulation history of the western Sichuan Basin is the earliest, and the southern Sichuan Basin is the latest. This paper will help to understand the accumulation process, accumulation mechanism, and gas reservoir distribution of the Triassic gas reservoirs in the Sichuan Basin better. Meanwhile, it is found that the authigenic illite in the Upper Triassic formation of Sichuan Basin origin of deep-burial and its dating is a record of the later accumulation. This suggests that the illite dating needs to fully consider illite origin; otherwise the dating results may not accurately

Faunal turnover of marine tetrapods during the Jurassic-Cretaceous transition.

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Benson, Roger B J; Druckenmiller, Patrick S

2014-02-01

Marine and terrestrial animals show a mosaic of lineage extinctions and diversifications during the Jurassic-Cretaceous transition. However, despite its potential importance in shaping animal evolution, few palaeontological studies have focussed on this interval and the possible climate and biotic drivers of its faunal turnover. In consequence evolutionary patterns in most groups are poorly understood. We use a new, large morphological dataset to examine patterns of lineage diversity and disparity (variety of form) in the marine tetrapod clade Plesiosauria, and compare these patterns with those of other organisms. Although seven plesiosaurian lineages have been hypothesised as crossing the Jurassic-Cretaceous boundary, our most parsimonious topology suggests the number was only three. The robust recovery of a novel group including most Cretaceous plesiosauroids (Xenopsaria, new clade) is instrumental in this result. Substantial plesiosaurian turnover occurred during the Jurassic-Cretaceous boundary interval, including the loss of substantial pliosaurid, and cryptoclidid diversity and disparity, followed by the radiation of Xenopsaria during the Early Cretaceous. Possible physical drivers of this turnover include climatic fluctuations that influenced oceanic productivity and diversity: Late Jurassic climates were characterised by widespread global monsoonal conditions and increased nutrient flux into the opening Atlantic-Tethys, resulting in eutrophication and a highly productive, but taxonomically depauperate, plankton. Latest Jurassic and Early Cretaceous climates were more arid, resulting in oligotrophic ocean conditions and high taxonomic diversity of radiolarians, calcareous nannoplankton and possibly ammonoids. However, the observation of discordant extinction patterns in other marine tetrapod groups such as ichthyosaurs and marine crocodylomorphs suggests that clade-specific factors may have been more important than overarching extrinsic drivers of faunal

Fire-adapted Gondwanan Angiosperm floras evolved in the Cretaceous

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Lamont Byron B

2012-11-01

Full Text Available Abstract Background Fires have been widespread over the last 250 million years, peaking 60−125 million years ago (Ma, and might therefore have played a key role in the evolution of Angiosperms. Yet it is commonly believed that fireprone communities existed only after the global climate became more arid and seasonal 15 Ma. Recent molecular-based studies point to much earlier origins of fireprone Angiosperm floras in Australia and South Africa (to 60 Ma, Paleocene but even these were constrained by the ages of the clades examined. Results Using a molecular-dated phylogeny for the great Gondwanan family Proteaceae, with a 113-million-year evolutionary history, we show that the ancestors of many of its characteristic sclerophyll genera, such as Protea, Conospermum, Leucadendron, Petrophile, Adenanthos and Leucospermum (all subfamily Proteoideae, occurred in fireprone habitats from 88 Ma (83−94, 95% HPD, Mid-Upper Cretaceous. This coincided with the highest atmospheric oxygen (combustibility levels experienced over the past 150 million years. Migration from non-fireprone (essentially rainforest-climate-type environments was accompanied by the evolution of highly speciose clades with a range of seed storage traits and fire-cued seed release or germination mechanisms that was diagnostic for each clade by 71 Ma, though the ant-dispersed lineage (as a soil seed-storage subclade was delayed until 45 Ma. Conclusions Focusing on the widespread 113-million-year-old family Proteaceae, fireproneness among Gondwanan Angiosperm floras can now be traced back almost 90 million years into the fiery Cretaceous. The associated evolution of on-plant (serotiny and soil seed storage, and later ant dispersal, affirms them as ancient adaptations to fire among flowering plants.

Late Cretaceous vicariance in Gondwanan amphibians.

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Ines Van Bocxlaer

Full Text Available Overseas dispersals are often invoked when Southern Hemisphere terrestrial and freshwater organism phylogenies do not fit the sequence or timing of Gondwana fragmentation. We used dispersal-vicariance analyses and molecular timetrees to show that two species-rich frog groups, Microhylidae and Natatanura, display congruent patterns of spatial and temporal diversification among Gondwanan plates in the Late Cretaceous, long after the presumed major tectonic break-up events. Because amphibians are notoriously salt-intolerant, these analogies are best explained by simultaneous vicariance, rather than by oceanic dispersal. Hence our results imply Late Cretaceous connections between most adjacent Gondwanan landmasses, an essential concept for biogeographic and palaeomap reconstructions.

Wildfires and animal extinctions at the Cretaceous/Tertiary boundary

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Adair, Robert K.

2010-06-01

Persuasive models of the ejection of material at high velocities from the Chicxulub asteroid impact marking the Cretaceous/Tertiary boundary have led to the conclusion that upon return, that material, heated in passage through the upper atmosphere, generated a high level of infrared energy density over the Earth's surface. That radiant energy has been considered to be a direct source of universal wildfires, which were presumed to be a major cause of plant and animal species extinctions. The extinction of many animal species, especially the dinosaurs, has also been attributed to the immediate lethal effects of the radiation. I find that the absorption of the radiation by the atmosphere, by cloud formations, and by ejecta drifting in the lower atmosphere reduced the radiation at the surface to a level that cannot be expected to have generated universal fires. Although the reduced radiation will have likely caused severe injuries to many animals, such insults alone seem unlikely to have generated the overall species extinctions that have been deduced.

Basin analysis in the Southern Tethyan margin: Facies sequences, stratal pattern and subsidence history highlight extension-to-inversion processes in the Cretaceous Panormide carbonate platform (NW Sicily)

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Basilone, Luca; Sulli, Attilio

2018-01-01

In the Mediterranean, the South-Tethys paleomargin experienced polyphased tectonic episodes and paleoenvironmental perturbations during Mesozoic time. The Cretaceous shallow-water carbonate successions of the Panormide platform, outcropping in the northern edge of the Palermo Mountains (NW Sicily), were studied by integrating facies and stratal pattern with backstripping analysis to recognize the tectonics vs. carbonate sedimentation interaction. The features of the Requienid limestone, including geometric configuration, facies sequence, lithological changes and significance of the top-unconformity, highlight that at the end of the Lower Cretaceous the carbonate platform was tectonically dismembered in various rotating fault-blocks. The variable trends of the subsidence curves testify to different responses, both uplift and downthrow, of various platform-blocks impacted by extensional tectonics. Physical stratigraphic and facies analysis of the Rudistid limestone highlight that during the Upper Cretaceous the previously carbonate platform faulted-blocks were subjected to vertical movements in the direction opposite to the displacement produced by the extensional tectonics, indicating a positive tectonic inversion. Comparisons with other sectors of the Southern Tethyan and Adria paleomargins indicate that during the Cretaceous these areas underwent the same extensional and compressional stages occurring in the Panormide carbonate platform, suggesting a regional scale significance, in time and kinematics, for these tectonic events.

High-precision U-Pb geochronologic constraints on the Late Cretaceous terrestrial cyclostratigraphy and geomagnetic polarity from the Songliao Basin, Northeast China

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Wang, Tiantian; Ramezani, Jahandar; Wang, Chengshan; Wu, Huaichun; He, Huaiyu; Bowring, Samuel A.

2016-07-01

The Cretaceous continental sedimentary records are essential to our understanding of how the terrestrial geologic and ecologic systems responded to past climate fluctuations under greenhouse conditions and our ability to forecast climate change in the future. The Songliao Basin of Northeast China preserves a near-complete, predominantly lacustrine, Cretaceous succession, with sedimentary cyclicity that has been tied to Milankocitch forcing of the climate. Over 900 meters of drill-core recovered from the Upper Cretaceous (Turonian to Campanian) of the Songliao Basin has provided a unique opportunity for detailed analyses of its depositional and paleoenvironmental records through integrated and high-resolution cyclostratigraphic, magnetostratigraphic and geochronologic investigations. Here we report high-precision U-Pb zircon dates (CA-ID-TIMS method) from four interbedded bentonites from the drill-core that offer substantial improvements in accuracy, and a ten-fold enhancement in precision, compared to the previous U-Pb SIMS geochronology, and allow a critical evaluation of the Songliao astrochronological time scale. The results indicate appreciable deviations of the astrochronologic model from the absolute radioisotope geochronology, which more likely reflect cyclostratigraphic tuning inaccuracies and omitted cycles due to depositional hiatuses, rather than suspected limitations of astronomical models applied to distant geologic time. Age interpolation based on our new high-resolution geochronologic framework and the calibrated cyclostratigraphy places the end of the Cretaceous Normal Superchon (C34n-C33r chron boundary) in the Songliao Basin at 83.07 ± 0.15 Ma. This date also serves as a new and improved estimate for the global Santonian-Campanian stage boundary.

Identification of an impact structure in the Upper Cretaceous of the Santos Basin in 3D seismic reflection data; Identificacao de uma estrutura de impacto no Cretaceo Superior da Bacia de Santos em sismica de reflexao 3D

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Correia, Gustavo Alberto [PETROBRAS, Santos, SP (Brazil). Exploracao e Producao. Interpretacao e Avaliacao das Bacias da Costa Sul Polo Sul]. E-mail: gustavoac@petrobras.com.br; Menezes, Jorge Rui Correa de; Bueno, Gilmar Vital

2005-05-01

This work presents the unpublished Praia Grande impact structure, located in the Santos basin, approximately 200 km southeast from the coastline of Sao Paulo State, Brazil. The identification of this structure is based on the interpretation of three-dimensional seismic data, acquired and processed in 2004 for petroleum exploration in a PETROBRAS concession block in the Santos Basin. The main morphological elements imposed on Upper Cretaceous rocks are a structural high in the center of the crater, an adjacent ring syncline, and, externally, several concentric circular listric normal faults. The structure is apparently well preserved from erosion, measures around 20 km in diameter, is buried by 4 km of rocks and occurred in the Santonian (85,8-83,5 Ma). (author)

Rates of morphological evolution are heterogeneous in Early Cretaceous birds

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Lloyd, Graeme T.

2016-01-01

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

Eonandeva gen. nov., a new distinctive genus from Eocene Baltic amber (Diptera: Chironomidae).

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Zakrzewska, Marta; Giłka, Wojciech

2015-11-20

A new fossil genus, Eonandeva gen. nov., with two new species: E. helva sp. nov. (type for the genus) and E. latistyla sp. nov., is described from Eocene Baltic amber (~45-40 Ma). Adult males of both new species show the wing venation pattern, shape and chaetotaxy typical for the tribe Tanytarsini. The characters defined as prior apomorphies for the new genus--the gonostylus with a subapical flattened lobe and the stout, strongly elongated superior volsella--separate Eonandeva from the closely related extant genus Nandeva Wiedenbrug, Reiss et Fittkau, 1998.

Evidence for subduction-related magmatism during the Cretaceous and Cenozoic in Myanmar

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Sevastjanova, Inga; Sagi, David Adam; Webb, Peter; Masterton, Sheona; Hill, Catherine; Davies, Clare

2017-04-01

Myanmar's complex geological history, numerous controversies around its tectonic evolution and the presence of prospective hydrocarbon basins make it a key area of interest for geologists. Understanding whether a passive or an active margin existed in the region during the Cenozoic is particularly important for the production of accurate basin models; active Cenozoic subduction would imply that hydrocarbon basins in the forearc experienced extension due to slab rollback. The geology of Myanmar was influenced by the regional tectonics associated with the Cretaceous and Cenozoic closure of the Neotethys Ocean. During this time, India travelled rapidly from Gondwana to Asia at speeds up to 20 cm/yr. To accommodate the north-eastward motion of India, the Neotethys Ocean was consumed at the subduction zone along the southern margin of Eurasia. Based on our Global Plate Model, this subduction zone can reasonably be expected to extend for the entire width of the Neotethys Ocean as far as Myanmar and Southeast Asia at their eastern extent. Moreover, a) Cretaceous volcanism onshore Myanmar, b) the middle Cenozoic arc-related extension in the Present Day eastern Andaman Sea and c) the late Cenozoic uplift of the Indo-Burman Ranges are all contemporaneous with the subduction ages predicted by the global plate motions. However, because of the geological complexity of the area, additional evidence would augment interpretations that are based on structural data. In an attempt to reduce the uncertainty in the existing interpretations, we have compiled published zircon geochronological data from detrital and igneous rocks in the region. We have used published zircon U-Pb ages and, where available, published Hf isotope data and CL images (core/rim) in order to distinguish 'juvenile' mantle-derived zircons from those of reworked crustal origin. The compilation shows that Upper Cretaceous and Cenozoic zircons, which are interpreted to have a volcanic provenance, are common across the

Effect of some parameters in the response of the Perspex 3042, Lot L amber dosemeters

International Nuclear Information System (INIS)

Prieto M, E.F.; Barrera G, G.

2004-01-01

The answer of the dosimetric systems is affected by several factors, for what should know as these factors they influence in each one of the different dosimetric systems and by this way to minimize its effect in the value of the absorbed dose and to obtain exact dose values. One of the dosimetric systems more used in the high dose dosimetry like routine dosemeter for the control of the irradiation process are the Perspex dosemeters, for their speed in the obtaining the information, their easy manipulation and the precision that they present. To this dosemeters group they belong the same as the Red and Clear the Amber, which are adequate for the measurement of the radiation dose in the range of high doses. The objective of the present work is to obtain the calibration curves of the dosemeters Amber Perspex 3042, Lot L under our work conditions, like they are the irradiation temperatures and of storage and to know the influence of the rate dose in the value of the absorbed dose for different measurement wavelengths, as well as, the relationship among the one post-irradiation time and the specific absorbance value induced in function of the absorbed dose. (Author)

An unusual new species of Hallodapomimus Herczek, 2000 from the Eocene Baltic amber (Hemiptera, Heteroptera, Miridae, Phylinae

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Aleksander Herczek

2015-03-01

Full Text Available Hallodapomimus antennatus sp. n. (Hemiptera: Heteroptera, Miridae, Phylinae, Hallodapini is described from a macropterous female found in Eocene Baltic amber. The new species can be recognized readily from the other species of the genus, mainly due to its unusual second antennal segment. A key for the identification of all known fossil Hallodapini is presented.

Females of the genus Podmosta (Plecoptera: Nemouridae): comparison of terminalia and a new female record in Baltic Amber.

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Chen, Zhi-Teng

2018-04-10

Based on a specimen preserved in Baltic amber from Lithuania, a new fossil female of the nemourid genus Podmosta Ricker, 1952 is described, illustrated and compared to other described species of the genus. The new female specimen is distinguished from other Podmosta females by the "rabbit-shaped" sclerite on sternum 8.

Diagenesis of arc-derived sandstones of Cretaceous formations in the Queen Charlotte Islands, British Columbia, Canada(MEMORIAL VOLUME TO THE LATE PROFESSOR TERUHIKO SAMESHIMA)

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Yagishita, Koji

1994-01-01

Diagenesis of sediments derived from a magmatic arc provenance may greatly differ from that of sediments derived from an intracratonic- or foreland-type provenance. Sediments from the magmatic arc are compositionally immature and rich in volcanic and sedimentary rock fragments. Sandstone samples of mid- to Upper Cretaceous formations in the Queen Charlotte Islands, British Columbia, Canada, contain either large amounts of pseudomatrix or authigenic cements. An inverse relationship between the...

A basal thunnosaurian from Iraq reveals disparate phylogenetic origins for Cretaceous ichthyosaurs

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Fischer, Valentin; Appleby, Robert M.; Naish, Darren; Liston, Jeff; Riding, James B.; Brindley, Stephen; Godefroit, Pascal

2013-01-01

Cretaceous ichthyosaurs have typically been considered a small, homogeneous assemblage sharing a common Late Jurassic ancestor. Their low diversity and disparity have been interpreted as indicative of a decline leading to their Cenomanian extinction. We describe the first post-Triassic ichthyosaur from the Middle East, Malawania anachronus gen. et sp. nov. from the Early Cretaceous of Iraq, and re-evaluate the evolutionary history of parvipelvian ichthyosaurs via phylogenetic and cladogenesis rate analyses. Malawania represents a basal grade in thunnosaurian evolution that arose during a major Late Triassic radiation event and was previously thought to have gone extinct during the Early Jurassic. Its pectoral morphology appears surprisingly archaic, retaining a forefin architecture similar to that of its Early Jurassic relatives. After the initial latest Triassic radiation of early thunnosaurians, two subsequent large radiations produced lineages with Cretaceous representatives, but the radiation events themselves are pre-Cretaceous. Cretaceous ichthyosaurs therefore include distantly related lineages, with contrasting evolutionary histories, and appear more diverse and disparate than previously supposed. PMID:23676653

A MODEL OF THE INNOVATIVE AMBER CLUSTER AS A CENTRE OF COOPERATION OF AUTHORITIES - BUSINESS - SCIENCE

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Gleb B. Trifonov

2015-01-01

Full Text Available A mechanism of forming an innovative amber cluster was developed, including structural interconnections of cluster partners,a package of basic innovative technologies, which will createa new value chain, new vacancies, provide contributions to theregional budget.A method of analytical estimation was suggested to assess cluster synergism of partners: authorities, business, science/education, culture, which reflects potential possibilities of thecluster model of region development.

Abrasiveness and hardness of rocks of Cretaceous deposits of Chechen-Ingushetiya. Ob abrazivnosti i tverdosti gornykh porod melovykh otlozhenii Checheno-Ingushetii

Energy Technology Data Exchange (ETDEWEB)

Trofimenko, Yu.P.

1981-01-01

Presented are results of studies of the abrasiveness and hardness of core material taken from Upper Cretaceous deposits in the process of drilling deep boreholes in the areas of Chechen-Ingushetiya. Based on the studies it is established that the abrasiveness of rock is mainly influenced by the coarseness of the mineral grains in the rock, their mineralogical composition, and the composition of the cement. Given is a system of clasification of the investigated core material with respect to abrasiveness and hardness.

The mid-Cretaceous super plume, carbon dioxide, and global warming

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Caldeira, Ken; Rampino, Michael R.

1991-01-01

Carbon-dioxide releases associated with a mid-Cretaceous super plume and the emplacement of the Ontong-Java Plateau have been suggested as a principal cause of the mid-Cretaceous global warming. A carbonate-silicate cycle model is developed to quantify the possible climatic effects of these CO2 releases, utilizing four different formulations for the rate of silicate-rock weathering as a function of atmospheric CO2. CO2 emissions resulting from super-plume tectonics could have produced atmospheric CO2 levels from 3.7 to 14.7 times the modern preindustrial value of 285 ppm. Based on the temperature sensitivity to CO2 increases used in the weathering-rate formulations, this would cause a global warming of from 2.8 to 7.7 C over today's glogal mean temperature. Altered continental positions and higher sea level may have been contributed about 4.8 C to mid-Cretaceous warming. Thus, the combined effects of paleogeographic changes and super-plume related CO2 emissions could be in the range of 7.6 to 12.5 C, within the 6 to 14 C range previously estimated for mid-Cretaceous warming. CO2 releases from oceanic plateaus alone are unlikely to have been directly responsible for more than 20 percent of the mid-Cretaceous increase in atmospheric CO2.

Molecular fossils in Cretaceous condensate from western India

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Bhattacharya, Sharmila; Dutta, Suryendu; Dutta, Ratul

2014-06-01

The present study reports the biomarker distribution of condensate belonging to the early Cretaceous time frame using gas chromatography-mass spectrometry (GC-MS). The early Cretaceous palaeoenvironment was inscribed into these molecular fossils which reflected the source and conditions of deposition of the condensate. The saturate fraction of the condensate is characterized by normal alkanes ranging from n-C9 to n-C29 (CPI-1.13), cycloalkanes and C14 and C15 sesquiterpanes. The aromatic fraction comprises of naphthalene, phenanthrene, their methylated derivatives and cyclohexylbenzenes. Isohexylalkylnaphthalenes, a product of rearrangement process of terpenoids, is detected in the condensate. Several aromatic sesquiterpenoids and diterpenoids have been recorded. Dihydro- ar-curcumene, cadalene and ionene form the assemblage of sesquiterpenoids which are indicative of higher plant input. Aromatic diterpenoid fraction comprises of simonellite and retene. These compounds are also indicative of higher plants, particularly conifer source which had been a predominant flora during the Cretaceous time.

A new azhdarchid pterosaur from the Late Cretaceous of the Transylvanian Basin, Romania: implications for azhdarchid diversity and distribution.

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Mátyás Vremir

Full Text Available We describe a new taxon of medium-sized (wing span ca. 3 m azhdarchid pterosaur from the Upper Cretaceous Transylvanian Basin (Sebeş Formation of Romania. This specimen is the most complete European azhdarchid yet reported, comprising a partially articulated series of vertebrae and associated forelimb bones. The new taxon is most similar to the Central Asian Azhdarcho lancicollis Nessov but possesses a suite of autapomorphies in its vertebrae that include the relative proportions of cervicals three and four and the presence of elongated prezygapophyseal pedicles. The new taxon is interesting in that it lived contemporaneously with gigantic forms, comparable in size to the famous Romanian Hatzegopteryx thambema. The presence of two distinct azhdarchid size classes in a continental depositional environment further strengthens suggestions that these pterosaurs were strongly linked to terrestrial floodplain and wooded environments. To support this discussion, we outline the geological context and taphonomy of our new specimen and place it in context with other known records for this widespread and important Late Cretaceous pterosaurian lineage.

Reappraisal of Europe’s most complete Early Cretaceous plesiosaurian: Brancasaurus brancai Wegner, 1914 from the “Wealden facies” of Germany

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Sven Sachs

2016-12-01

Full Text Available The holotype of Brancasaurus brancai is one of the most historically famous and anatomically complete Early Cretaceous plesiosaurian fossils. It derived from the Gerdemann & Co. brickworks clay pit near Gronau (Westfalen in North Rhine-Westphalia, northwestern Germany. Stratigraphically this locality formed part of the classic European “Wealden facies,” but is now more formally attributed to the upper-most strata of the Bückeberg Group (upper Berriasian. Since its initial description in 1914, the type skeleton of B. brancai has suffered damage both during, and after WWII. Sadly, these mishaps have resulted in the loss of substantial information, in particular many structures of the cranium and limb girdles, which are today only evidenced from published text and/or illustrations. This non-confirmable data has, however, proven crucial for determining the relationships of B. brancai within Plesiosauria: either as an early long-necked elasmosaurid, or a member of the controversial Early Cretaceous leptocleidid radiation. To evaluate these competing hypotheses and compile an updated osteological compendium, we undertook a comprehensive examination of the holotype as it is now preserved, and also assessed other Bückeberg Group plesiosaurian fossils to establish a morphological hypodigm. Phylogenetic simulations using the most species-rich datasets of Early Cretaceous plesiosaurians incorporating revised scores for B. brancai, together with a second recently named Bückeberg Group plesiosaurian Gronausaurus wegneri (Hampe, 2013, demonstrated that referral of these taxa to Leptocleididae was not unanimous, and that the topological stability of this clade is tenuous. In addition, the trait combinations manifested by B. brancai and G. wegneri were virtually identical. We therefore conclude that these monotypic individuals are ontogenetic morphs and G. wegneri is a junior synonym of B. brancai. Finally, anomalies detected in the diagnostic features

STRATIGRAPHY, SEDIMENTOLOGY AND SYNDEPOSITIONAL TECTONICS OF THE JURASSIC-CRETACEOUS SUCCESSION AT THE TRANSITION BETWEEN PROVENÇAL AND DAUPHINOIS DOMAINS (MARITIME ALPS, NW ITALY

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LUCA BARALE

2017-08-01

Full Text Available The Provençal and Dauphinois Mesozoic successions cropping out at the southeastern margin of the Argentera Massif (Maritime Alps, NW Italy were deposited at the transition between the Provençal platform and the Dauphinois basin, marked in the study area by a partly preserved Mesozoic palaeoescarpment. These successions show important lateral variations occurring over relatively short distances, probably related to syndepositional tectonics. Different stratigraphic intervals of the pelagic-hemipelagic Dauphinois succession contain resedimented deposits, made up of both intra- and extrabasinal material, which provide a twofold evidence of syndepositional tectonics indicating both tectonically-triggered gravitational processes and a tectonically-driven evolution of the source areas. Two stages of syndepositional tectonics have been recognized: the first in the earliest Cretaceous, which is related to the deposition of carbonate breccias in the Dauphinois succession and to hydrothermal dolomitization of the Middle Triassic-Jurassic Provençal carbonates, and the second in the Late Cretaceous, which triggered the deposition of different detrital lithozones in the Upper Cretaceous Puriac Limestone. The cited evidence indicates that syndepositional tectonics continued to influence the evolution of the Alpine Tethys European passive margin long after the Late Triassic-Early Jurassic syn-rift stage, which caused the differentiation between the Dauphinois basin and the Provençal platform.

Vascular plants from the Devonian to Lower Cretaceous in southern Africa

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J. M. Anderson

1983-11-01

Full Text Available The succession of pre-angiospermous megafloras in southern Africa from the Devonian to Lower Cretaceous is outlined. Interrelationships between continental drift, global climatic trends, and floral and faunal evolution are emphasized. Data are given on numbers of assemblages sampled; on species diversity; and on relative abundance of each genus per productive ‘formation’. A total of 79 genera and about 250 species are recognized in the 150 assemblages from the 11 horizons considered. Floras are unknown from the Carboniferous and are as yet undescribed from the Jurassic. Aside from these gaps, a good idea of the floral development is obtained. Diversity lows of around 5 to 10 species per ‘formation’ are witnessed in the Devonian, whereas a peak of 112 species is encountered in the Upper Triassic Molteno Formation. Diversity remains around 20 to 30 species for all other ‘formations’.

Highly specialized mammalian skulls from the Late Cretaceous of South America.

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Rougier, Guillermo W; Apesteguía, Sebastián; Gaetano, Leandro C

2011-11-02

Dryolestoids are an extinct mammalian group belonging to the lineage leading to modern marsupials and placentals. Dryolestoids are known by teeth and jaws from the Jurassic period of North America and Europe, but they thrived in South America up to the end of the Mesozoic era and survived to the beginnings of the Cenozoic. Isolated teeth and jaws from the latest Cretaceous of South America provide mounting evidence that, at least in western Gondwana, dryolestoids developed into strongly endemic groups by the Late Cretaceous. However, the lack of pre-Late Cretaceous dryolestoid remains made study of their origin and early diversification intractable. Here we describe the first mammalian remains from the early Late Cretaceous of South America, including two partial skulls and jaws of a derived dryolestoid showing dental and cranial features unknown among any other group of Mesozoic mammals, such as single-rooted molars preceded by double-rooted premolars, combined with a very long muzzle, exceedingly long canines and evidence of highly specialized masticatory musculature. On one hand, the new mammal shares derived features of dryolestoids with forms from the Jurassic of Laurasia, whereas on the other hand, it is very specialized and highlights the endemic, diverse dryolestoid fauna from the Cretaceous of South America. Our specimens include only the second mammalian skull known for the Cretaceous of Gondwana, bridging a previous 60-million-year gap in the fossil record, and document the whole cranial morphology of a dryolestoid, revealing an unsuspected morphological and ecological diversity for non-tribosphenic mammals.

Late Cretaceous seasonal ocean variability from the Arctic.

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Davies, Andrew; Kemp, Alan E S; Pike, Jennifer

2009-07-09

The modern Arctic Ocean is regarded as a barometer of global change and amplifier of global warming and therefore records of past Arctic change are critical for palaeoclimate reconstruction. Little is known of the state of the Arctic Ocean in the greenhouse period of the Late Cretaceous epoch (65-99 million years ago), yet records from such times may yield important clues to Arctic Ocean behaviour in near-future warmer climates. Here we present a seasonally resolved Cretaceous sedimentary record from the Alpha ridge of the Arctic Ocean. This palaeo-sediment trap provides new insight into the workings of the Cretaceous marine biological carbon pump. Seasonal primary production was dominated by diatom algae but was not related to upwelling as was previously hypothesized. Rather, production occurred within a stratified water column, involving specially adapted species in blooms resembling those of the modern North Pacific subtropical gyre, or those indicated for the Mediterranean sapropels. With increased CO(2) levels and warming currently driving increased stratification in the global ocean, this style of production that is adapted to stratification may become more widespread. Our evidence for seasonal diatom production and flux testify to an ice-free summer, but thin accumulations of terrigenous sediment within the diatom ooze are consistent with the presence of intermittent sea ice in the winter, supporting a wide body of evidence for low temperatures in the Late Cretaceous Arctic Ocean, rather than recent suggestions of a 15 degrees C mean annual temperature at this time.

The mid-Cretaceous North Atlantic nutrient trap: black shales and OAEs

NARCIS (Netherlands)

Trabucho Alexandre, J.; Tuenter, E.; Henstra, G.A.; Zwan, C.J. van der; Wal, R.S.W. van de; Dijkstra, H.A.; Boer, P.L. de

2010-01-01

Organic-rich sediments are the salient marine sedimentation product in the mid-Cretaceous of the ocean basins formed in the Mesozoic. Oceanic anoxic events (OAEs) are discrete and particularly organic-rich intervals within these mid-Cretaceous organic-rich sequences and are defined by pronounced

Palynological and iridium anomalies at Cretaceous-Tertiary boundary, south-central Saskatchewan

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Nichols, D.J.; Jarzen, D.M.; Orth, C.J.; Oliver, P.Q.

1986-01-01

The Cretaceous-Tertiary boundary in south-central Saskatchewan is marked by coincident anomalies in abundance of iridium and fern spores at the extinction level of a suite of Cretaceous pollen taxa. Evidence of disruption of the terrestrial flora includes the fern-spore abundance anomaly and local extinction of as much as 30 percent of angiosperm species. The reorganized earliest Tertiary flora is made up largely of surviving species that assumed new roles of dominance. Persistence of climatically sensitive taxa across the boundary indicates that if paleoclimate was altered by the terminal Cretaceous event, it returned quickly to the pre-event condition.

Coalbed methane potential of the Upper Cretaceous Mesaverde and Meeteetse formations, Wind River Reservation, Wyoming

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Johnson, R.C.; Clark, A.C.; Barker, C.E.; Crysdale, B.L.; Higley, D.K.; Szmajter, R.J.; Finn, T.M.

1993-01-01

The environments of deposition of the uppermost part of the Cody Shale and the Mesaverde and Meeteetse Formations of Late Cretaceous age were studied on outcrop in the Shotgun Butte area in the north-central part of the Wind River Reservation. A shoreface sandstone occurs in the lower part of the Mesaverde Formation at all localities studied, and is directly overlain by a coaly interval. Repetitive coarsening-upward cycles of mudstone, siltstone, and sandstone occur in the 200 ft interval of the upper part of the Cody Shale below the shoreface sandstone. These Cody sandstones are typically hummocky cross stratified with symmetrical ripples near the top, indicating that they are largely storm surge deposits that were later reworked. Channel-form sandstones from 10 to 20 ft thick, with abundant locally derived clayey clasts, occur in a 75 ft thick interval below the shoreface at one locality. These unusual sandstones are largely confined to a narrow area of the outcrop and grade laterally into more typical storm surge deposits. They may be unusually large storm surge channels created when high-energy flow conditions were localized to a limited area of the shelf.The Mesaverde Formation above the shoreface sandstone is divided into a middle member and the Teapot Sandstone Member. The lower part of the middle member is everywhere coaly. Erosional-based sandstones in this coaly interval are highly variable in thickness and architecture. Thin, single channel sandstone bodies were deposited by moderate to high sinuosity streams, and thick, multistory channel sandstone bodies were deposited by rapidly switching fluvial channel systems that remained relatively stationary for extended periods of time. The architecture of the fluvial channel sandstones in the overlying noncoaly interval appears to be highly variable as well, with complex multistory sandstones occurring at different stratigraphic levels at different localities. This distribution may be explained by long term

Cretaceous to Recent Asymetrical Subsidence of South American and West African Conjugate Margins

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Kenning, J.; Mann, P.

2017-12-01

Two divergent interpretations have been proposed for South American rifted-passive margins: the "mirror hypothesis" proposes that the rifted margins form symmetrically from pure shear of the lithosphere while upper-plate-lower plate models propose that the rifted margins form asymmetrically by simple shear. Models based on seismic reflection and refraction imaging and comparison of conjugate, rifted margins generally invoke a hybrid stretching process involving elements of both end member processes along with the effects of mantle plumes active during the rift and passive margin phases. We use subsidence histories of 14, 1-7 km-deep exploration wells located on South American and West African conjugate pairs now separated by the South Atlantic Ocean, applying long-term subsidence to reveal the symmetry or asymmetry of the underlying, conjugate, rift processes. Conjugate pairs characterize the rifted margin over a distance of 3500 km and include: Colorado-South Orange, Punta Del Este-North Orange, South Pelotas-Lüderitz and the North Pelotas-Walvis Basins. Of the four conjugate pairs, more rapid subsidence on the South American plate is consistently observed with greater initial rift and syn-rift subsidence rates of >60m/Ma (compared to 100 m/Ma are observed offshore South Africa between approximately 120-80 Ma, compatible with onset of the post-rift thermal sag phase. During this period the majority of burial is completed and rates remain low at Argentina/Uruguay displays more gradual subsidence throughout the Cretaceous, consistently averaging a moderate 15-30m/Ma. By the end of this stage there is a subsequent increase to 25-60 m/Ma within the last 20 Ma, interpreted to reflect lithospheric loading due to increased sedimentation rates during the Cenozoic. This increase in subsidence rate is not seen in the African conjugate section where the majority of sediments bypassed the highly aggraded Cretaceous shelf. Initially greater on the Brazilian margin compared to

Kilop Cretaceous Hardground (Kale, Gümüshane, NE Turkey):description and origin

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Eren, Muhsin; Tasli, Kemal

2002-06-01

A hardground surface is well exposed in the Kilop area of Kale (Gümüshane, NE Turkey) which forms part of the Eastern Pontides. Here, the hardground is underlain by shallow water Lower Cretaceous limestones, and overlain by Upper Cretaceous red limestones/marls which contains a planktonic microfauna including Globotruncanidae. In the field, the recognition of the hardground is based on the presence of extensive burrows (especially vertical burrows), the encrusting rudistid bivalve Requienia, neptunian-dykes with infills of pelagic sediments and synsedimentary faults. Skolithos and Thalassinoides-type burrows are present. Some burrow walls show iron hydroxide-staining. The extensive burrowing occurred prior to lithification. On the other hand, the neptunian-dykes and synsedimentary faults, which cut the hard ground, occurred after the lithification. These features indicate the progressive hardening of the substrate. The burrowed limestone consists of an intrabioclastic peloidal grainstone which was deposited in an intertidal to shallow, subtidal, moderate to relatively high energy environment. The peloidal limestone shows little or no evidence of submarine cementation, characterized by only scarce relics of isopachous cement rims of bladed calcite spar. The grainstone cement is composed predominantly of blocky calcite and overgrowth calcite cements on the echinoid-fragments. The origin of this cement is controversial. Biostratigraphic analysis of the limestones demonstrates that there is a marked stratigraphic gap (hiatus), spanning the Aptian to the Santonian, in the Cretaceous of the Kilop area. The formation of the Kilop Hardground is related to the break-up and subsidence of the Eastern Pontides carbonate platform during the formation of the Black Sea backarc basin. Hardground development was initiated in a shallow marine environment of slow sedimentation and with moderate to high energy indicating slow subsidence. Later, the hardground subsided abruptly, as

Potential of Sm3+ doped LiSrVO4 nanophosphor to fill amber gap in LEDs

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Biswas, P.; Kumar, Vinay; Sharma, Vishal; Bedyal, A. K.; Padha, Naresh; Swart, H. C.

2018-04-01

The LiSrVO4:Sm3+ phosphor powders were synthesized by the combustion method by varying the concentration of the Sm3+ ions from 0.25 mol% to 2.5 mol%. The powder X-ray diffraction (XRD) studies confirmed that the phosphors were crystallized as monoclinic structure belonging to space group P2/m and the transmission electron microscopy (TEM) revealed nanosized grains of the powders. The Fourier transform infrared studies (FTIR) established the formation of non-hygroscopic vanadate powders. The photoluminescence (PL) and diffused reflectance studies (DRS) were also carried out and discussed. Under 401 nm excitation, the optimized phosphor exhibited the characteristic 568, 600, 646 and 704 nm emissions of Sm3+ which corresponded to the orange-red (amber) color with (0.59, 0.41) Commission Internationale de' Eclairage (CIE) chromaticity coordinates. Concentration quenching of phosphor intensity on account of non-radiative energy transfer was ascribed to dipole-dipole interaction between activators. DRS study reveals that the host of the phosphor is a wide bandgap material which accommodates the dopant successfully. The present results signify that the LiSrVO4:Sm3+ phosphor can suitably be excited by the GaN family of UV-LEDs chips for efficient amber LEDs applications.

Tyrant dinosaur evolution tracks the rise and fall of Late Cretaceous oceans.

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Loewen, Mark A; Irmis, Randall B; Sertich, Joseph J W; Currie, Philip J; Sampson, Scott D

2013-01-01

The Late Cretaceous (∼95-66 million years ago) western North American landmass of Laramidia displayed heightened non-marine vertebrate diversity and intracontinental regionalism relative to other latest Cretaceous Laurasian ecosystems. Processes generating these patterns during this interval remain poorly understood despite their presumed role in the diversification of many clades. Tyrannosauridae, a clade of large-bodied theropod dinosaurs restricted to the Late Cretaceous of Laramidia and Asia, represents an ideal group for investigating Laramidian patterns of evolution. We use new tyrannosaurid discoveries from Utah--including a new taxon which represents the geologically oldest member of the clade--to investigate the evolution and biogeography of Tyrannosauridae. These data suggest a Laramidian origin for Tyrannosauridae, and implicate sea-level related controls in the isolation, diversification, and dispersal of this and many other Late Cretaceous vertebrate clades.

Two flat-backed polydesmidan millipedes from the Miocene Chiapas-amber Lagerstätte, Mexico.

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Francisco Riquelme

Full Text Available Two species of fossil polydesmidan millipedes (Diplopoda: Polydesmida embedded in amber are described from Miocene strata near Simojovel, in the Chiapas Highlands, Mexico. Maatidesmus paachtun gen. et sp. nov., placed into Chelodesmidae Cook, 1895, and Anbarrhacus adamantis gen. et sp. nov., assigned in the family Platyrhacidae Pocock, 1895. Morphological data from fossil specimens have been recovered using 3D X-ray micro-computed tomography and regular to infrared-reflected microscopy. Both fossil species are recognizable as new primarily but not exclusively, by collum margin modification and remarkable paranotal and metatergite dorsal sculpture.

Two Flat-Backed Polydesmidan Millipedes from the Miocene Chiapas-Amber Lagerstätte, Mexico

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Riquelme, Francisco; Hernández-Patricio, Miguel; Martínez-Dávalos, Arnulfo; Rodríguez-Villafuerte, Mercedes; Montejo-Cruz, Maira; Alvarado-Ortega, Jesús; Ruvalcaba-Sil, José L.; Zúñiga-Mijangos, Luis

2014-01-01

Two species of fossil polydesmidan millipedes (Diplopoda: Polydesmida) embedded in amber are described from Miocene strata near Simojovel, in the Chiapas Highlands, Mexico. Maatidesmus paachtun gen. et sp. nov., placed into Chelodesmidae Cook, 1895, and Anbarrhacus adamantis gen. et sp. nov., assigned in the family Platyrhacidae Pocock, 1895. Morphological data from fossil specimens have been recovered using 3D X-ray micro-computed tomography and regular to infrared-reflected microscopy. Both fossil species are recognizable as new primarily but not exclusively, by collum margin modification and remarkable paranotal and metatergite dorsal sculpture. PMID:25162220

Late Cretaceous restructuring of terrestrial communities facilitated the end-Cretaceous mass extinction in North America.

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Mitchell, Jonathan S; Roopnarine, Peter D; Angielczyk, Kenneth D

2012-11-13

The sudden environmental catastrophe in the wake of the end-Cretaceous asteroid impact had drastic effects that rippled through animal communities. To explore how these effects may have been exacerbated by prior ecological changes, we used a food-web model to simulate the effects of primary productivity disruptions, such as those predicted to result from an asteroid impact, on ten Campanian and seven Maastrichtian terrestrial localities in North America. Our analysis documents that a shift in trophic structure between Campanian and Maastrichtian communities in North America led Maastrichtian communities to experience more secondary extinction at lower levels of primary production shutdown and possess a lower collapse threshold than Campanian communities. Of particular note is the fact that changes in dinosaur richness had a negative impact on the robustness of Maastrichtian ecosystems against environmental perturbations. Therefore, earlier ecological restructuring may have exacerbated the impact and severity of the end-Cretaceous extinction, at least in North America.

La coupe d'Ouled Haddou (Rif externe oriental) : un affleurement continu de la transition Crétacé Paléogène au Maroc, révélé par les Foraminifères planctoniquesThe Ouled Haddou section (oriental external Rif): a continuous outcrop of the Cretaceous Palaeogene transition in Morocco, revealed by planktonic Foraminifera

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Toufiq, Abdelkabir; Bellier, Jean-Pierre; Boutakiout, Mohamed; Feinberg, Hugues

2002-10-01

In the Ouled Haddou section, deposits of the Uppermost Maastrichtian correspond to the Abathomphalus mayaroensis Biozone. The index species is regularly present until the Cretaceous-Palaeogene boundary, which is marked by a mass extinction affecting 41 species (large and complex). Some Cretaceous small species persist in the Lowermost Danian. The first levels of the Danian are assigned to the Guembelitria cretacea Biozone, in which the species index persist without being affected, and the first species of the Tertiary appear. The upper part of the Lower Danian corresponds to the succession of Parvularugoglobigerina eugubina, Parasubbotina pseudobulloides, and Subbotina triloculinoides Biozones. From the P. eugubina Biozone, associations of Danian vary to undergo a complete renewal in the upper zones. The Ouled Haddou section, described for the first time, presents, according to planktonic Foraminifera, a complete record of the Cretaceous-Palaeogene transition. To cite this article: A. Toufiq et al., C. R. Geoscience 334 (2002) 995-1001.

New species of Compsocidae (Insecta, Psocodea) from Cretaceous Burmese amber

Czech Academy of Sciences Publication Activity Database

Sroka, Pavel; Nel, A.

2017-01-01

Roč. 4320, č. 3 (2017), s. 597-600 ISSN 1175-5326 Institutional support: RVO:60077344 Keywords : Psocoptera * Troctomorpha * Burmacompsocus Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 0.972, year: 2016 https://biotaxa.org/Zootaxa/article/view/zootaxa.4320.3.12

Description of a new species, Pintomyia dissimilis nov. sp., a phlebotomine fossil from Dominican Republic amber (Diptera: Psychodidae: Phlebotominae

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Sanguinette Cristiani

2009-05-01

Full Text Available Abstract Background Phlebotomine sandflies are the vectors of etiological agents of leishmaniases in several areas of the world. In the Neotropical Region, the biodiversity of these insects is more than other regions, probably due the long evolutionary period of this group. Miocene amber from Dominican Republic, currently, has a record of 14 extinct species of Phlebotomine sandflies. Results This paper describes a new fossil species of phlebotomine sandfly from amber found in Dominican Republic. This new species is based on morphological characters of a male such as 5° palpomere longer than 3° + 4°, three well-developed spines in the gonostyle, lateral lobe longer than gonocoxite and permit inclusion of the new species in the genus Pintomyia, series serrana. The paramere, with a curvature in the ventral margin, of the middle of the structure, separates the new species from the others fossils or extant species. Conclusion The new species described in the present study named Pintomyia dissimilis nov. sp. is well differenciated from all known species in this genus.

Lutzomyia adiketis sp. n. (Diptera: Phlebotomidae, a vector of Paleoleishmania neotropicum sp. n. (Kinetoplastida: Trypanosomatidae in Dominican amber

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Poinar George

2008-07-01

Full Text Available Abstract Background Amber fossils can be used to trace the history of disease-vector associations because microorganisms are preserved "in situ" inside the alimentary tract and body cavity of blood-sucking insects. Results Lutzomyia adiketis sp. n. (Phlebotomidae: Diptera is described from Dominican amber as a vector of Paleoleishmania neotropicum sp. n. (Kinetoplastida: Trypanosomatidae. The fossil sand fly differs from all previously described extinct and extant members of the genus by the following combination of characters: Sc forked with the branches meeting the costa and radius veins; wing L/W value of 4.1; a δ value of 18; a ratio β/α value of 0.86, and the shape and size of the spatulate rods on the ninth sternite. The trypanosomatid is characterized by the structure of its promastigotes, amastigotes and paramastigotes and its transmission by an extinct species of sand fly. Conclusion Morphological characters show that the fossil sand fly is a new extinct species and that it is host to a digenetic species of trypanosomatid. This study provides the first fossil evidence that Neotropical sand flies were vectors of trypanosomatids in the mid-Tertiary (20–30 mya.

An aegialodontid upper molar and the evolution of mammal dentition.

Science.gov (United States)

Lopatin, Alexey V; Averianov, Alexander O

2006-08-25

The most obvious key synapomorphy of the therian mammals is the tribosphenic pattern of their molars. Tribosphenic teeth are capable of both shearing and grinding, which substantially increase effectiveness of food processing and, in turn, permit evolution of a wide range of dietary specializations. Functional tribospheny developed repeatedly during mammalian evolution but was successful only in the Boreosphenida. The earliest stage in the development of boreosphenidan tribospheny has remained poorly understood, being documented only by lower molars of aegialodontids. Here, we report a known upper molar of an aegialodontid mammal, Kielantherium, from the Early Cretaceous of Mongolia.

From nappe stacking to exhumation: Cretaceous tectonics in the Apuseni Mountains (Romania)

Science.gov (United States)

Reiser, Martin Kaspar; Schuster, Ralf; Spikings, Richard; Tropper, Peter; Fügenschuh, Bernhard

2017-03-01

New Ar-Ar muscovite and Rb-Sr biotite age data in combination with structural analyses from the Apuseni Mountains provide new constraints on the timing and kinematics of deformation during the Cretaceous. Time-temperature paths from the structurally highest basement nappe of the Apuseni Mountains in combination with sedimentary data indicate exhumation and a position close to the surface after the Late Jurassic emplacement of the South Apuseni Ophiolites. Early Cretaceous Ar-Ar muscovite ages from structurally lower parts in the Biharia Nappe System (Dacia Mega-Unit) show cooling from medium-grade conditions. NE-SW-trending stretching lineation and associated kinematic indicators of this deformation phase (D1) are overprinted by top-NW-directed thrusting during D2. An Albian to Turonian age (110-90 Ma) is proposed for the main deformation (D2) that formed the present-day geometry of the nappe stack and led to a pervasive retrograde greenschist-facies overprint. Thermochronological and structural data from the Bihor Unit (Tisza Mega-Unit) allowed to establish E-directed differential exhumation during Early-Late Cretaceous times (D3.1). Brittle detachment faulting (D3.2) and the deposition of syn-extensional sediments indicate general uplift and partial surface exposure during the Late Cretaceous. Brittle conditions persist during the latest Cretaceous compressional overprint (D4).

A New Oviraptorid Dinosaur (Dinosauria: Oviraptorosauria) from the Late Cretaceous of Southern China and Its Paleobiogeographical Implications.

Science.gov (United States)

Lü, Junchang; Pu, Hanyong; Kobayashi, Yoshitsugu; Xu, Li; Chang, Huali; Shang, Yuhua; Liu, Di; Lee, Yuong-Nam; Kundrát, Martin; Shen, Caizhi

2015-07-02

The Ganzhou area of Jiangxi Province, southern China is becoming one of the most productive oviraptorosaurian localities in the world. A new oviraptorid dinosaur was unearthed from the uppermost Upper Cretaceous Nanxiong Formation of Ganzhou area. It is characterized by an anterodorsally sloping occiput and quadrate (a feature shared with Citipati), a circular supratemporal fenestra that is much smaller than the lower temporal fenestra, and a dentary in which the dorsal margin above the external mandibular fenestra is strongly concave ventrally. The position of the anteroventral corner of the external naris in relation to the posterodorsal corner of the antorbital fenestra provides new insight into the craniofacial evolution of oviraptorosaurid dinosaurs. A phylogenetic analysis recovers the new taxon as closely related to the Mongolian Citipati. Six oviraptorid dinosaurs from the Nanxiong Formation (Ganzhou and Nanxiong) are distributed within three clades of the family. Each of the three clades from the Nanxiong Formation has close relatives in Inner Mongolia and Mongolia, and in both places each clade may have had a specific diet or occupied a different ecological niche. Oviraptorid dinosaurs were geographically widespread across Asia in the latest Cretaceous and were an important component of terrestrial ecosystems during this time.

Cretaceous rocks of the Western Interior basin

International Nuclear Information System (INIS)

Molenaar, C.M.; Rice, D.D.

1988-01-01

The Cretaceous rocks of the conterminous United States are discussed in this chapter. Depositional facies and lithology are reviewed along with economic resources. The economic resources include coal, hydrocarbons, and uranium

Preliminary data on dinosaurs habitat during the Upper Maastrichtian, Hateg Basin, Romania

International Nuclear Information System (INIS)

Grigorescu, D.; Klarik, L.; Bojar, A.-V.

2002-01-01

The Hateg basin is located in the south-western part of the Transylvanian Depression and it is filled with sediments that overly the crystalline rocks of the Getic nappe. The basin show multiple stage of Mesozoic evolution. The Latest Cretaceous (Middle and Upper Maastrichtian) with continuous transition to Paleocene is represented by two continental lithostratigraphic units: the Densus-Ciula and the Sinpetru Formations. The Upper Maastrichtian of Densus-Ciula Formation at Tustea Quarry is represented by a pebbly alluvium with massive, matrix supported conglomerates, cross bedded sandstones and mudstones, the last one containing calcretes and dinosaur remains, including eggs and hatchlings of the hadrosaurid Telmatosaurus transsylvanicus. In order to constrain the paleoenvironment in which dinosaurs lived, calcretes and dinosaur eggshells were analyzed for carbon and oxygen isotopic composition

Preliminary data on dinosaurs habitat during the Upper Maastrichtian, Hateg Basin, Romania

Energy Technology Data Exchange (ETDEWEB)

Grigorescu, D; Klarik, L [University of Bucharest, Faculty of Geology and Geophysics (Romania); Bojar, A -V [Department of Geology and Paleontology, Graz (Austria)

2002-10-01

The Hateg basin is located in the south-western part of the Transylvanian Depression and it is filled with sediments that overly the crystalline rocks of the Getic nappe. The basin show multiple stage of Mesozoic evolution. The Latest Cretaceous (Middle and Upper Maastrichtian) with continuous transition to Paleocene is represented by two continental lithostratigraphic units: the Densus-Ciula and the Sinpetru Formations. The Upper Maastrichtian of Densus-Ciula Formation at Tustea Quarry is represented by a pebbly alluvium with massive, matrix supported conglomerates, cross bedded sandstones and mudstones, the last one containing calcretes and dinosaur remains, including eggs and hatchlings of the hadrosaurid Telmatosaurus transsylvanicus. In order to constrain the paleoenvironment in which dinosaurs lived, calcretes and dinosaur eggshells were analyzed for carbon and oxygen isotopic composition.

Small theropod teeth from the Late Cretaceous of the San Juan Basin, northwestern New Mexico and their implications for understanding latest Cretaceous dinosaur evolution.

Science.gov (United States)

Williamson, Thomas E; Brusatte, Stephen L

2014-01-01

Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary evidence for understanding the diversity and evolution of small-bodied theropod dinosaurs during the Late Cretaceous, but few such specimens have been well documented from outside of the northern Rockies, making it difficult to assess Late Cretaceous dinosaur diversity and biogeographic patterns. We describe small theropod teeth from the San Juan Basin of northwestern New Mexico. These specimens were collected from strata spanning Santonian - Maastrichtian. We grouped isolated theropod teeth into several morphotypes, which we assigned to higher-level theropod clades based on possession of phylogenetic synapomorphies. We then used principal components analysis and discriminant function analyses to gauge whether the San Juan Basin teeth overlap with, or are quantitatively distinct from, similar tooth morphotypes from other geographic areas. The San Juan Basin contains a diverse record of small theropods. Late Campanian assemblages differ from approximately coeval assemblages of the northern Rockies in being less diverse with only rare representatives of troodontids and a Dromaeosaurus-like taxon. We also provide evidence that erect and recurved morphs of a Richardoestesia-like taxon represent a single heterodont species. A late Maastrichtian assemblage is dominated by a distinct troodontid. The differences between northern and southern faunas based on isolated theropod teeth provide evidence for provinciality in the late Campanian and the late Maastrichtian of North America. However, there is no indication that major components of small-bodied theropod diversity were lost

Shallow magnetic inclinations in the Cretaceous Valle Group, Baja California: remagnetization, compaction, or terrane translation?

Science.gov (United States)

Smith, Douglas P.; Busby, Cathy J.

1993-10-01

Paleomagnetic data from Albian to Turonian sedimentary rocks on Cedros Island, Mexico (28.2° N, 115.2° W) support the interpretation that Cretaceous rocks of western Baja California have moved farther northward than the 3° of latitude assignable to Neogene oblique rifting in the Gulf of California. Averaged Cretaceous paleomagnetic results from Cedros Island support 20 ± 10° of northward displacement and 14 ± 7° of clockwise rotation with respect to cratonic North America. Positive field stability tests from the Vizcaino terrane substantiate a mid-Cretaceous age for the high-temperature characteristic remanent magnetization in mid-Cretaceous strata. Therefore coincidence of characteristic magnetization directions and the expected Quaternary axial dipole direction is not due to post mid-Cretaceous remagnetization. A slump test performed on internally coherent, intrabasinal slump blocks within a paleontologically dated olistostrome demonstrates a mid-Cretaceous age of magnetization in the Valle Group. The in situ high-temperature natural remanent magnetization directions markedly diverge from the expected Quaternary axial dipole, indicating that the characteristic, high-temperature magnetization was acquired prior to intrabasinal slumping. Early acquisition of the characteristic magnetization is also supported by a regional attitude test involving three localities in coherent mid-Cretaceous Valle Group strata. Paleomagnetic inclinations in mudstone are not different from those in sandstone, indicating that burial compaction did not bias the results toward shallow inclinations in the Vizcaino terrane.

Carbon and oxygen stable isotopes of selected Cenomanian and Turonian rudists from Egypt and Czech Republic, and a note on changes in rudist diversity

Czech Academy of Sciences Publication Activity Database

El-Shazly, S.; Košťák, M.; Abdel-Gawad, G.; Kloučková, B.; Saber, G. S.; Salama, Y. F.; Mazuch, M.; Žák, Karel

2011-01-01

Roč. 86, č. 2 (2011), s. 209-226 ISSN 1214-1119 Institutional research plan: CEZ:AV0Z30130516 Keywords : rudists * Upper Cretaceous * Cenomanian * Turonian * paleoecology * C and O stable isotopes * Upper Cretaceous (Egypt) * Upper Cretaceous (Czech Republic) Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.099, year: 2011

An early cretaceous phase of accelerated erosion on the south-western margin of Africa: evidence from apatite fission track analysis and the offshore sedimentary record

International Nuclear Information System (INIS)

Brown, R.W.; Gleadow, A.J.W.; Rust, D.J.; Summerfield, M.A.; De Wit, M.C.J.

1990-01-01

Apatite fission track ages and confined track length distributions have been determined for rock samples from the south-western continental margin of Africa. The apatite ages fall into two groups, one having early Cretaceous ages and mean confined track lengths of ∼ 14 μm with very few short tracks, and the other having older ages with confined track length distributions containing a significant proportion of strongly annealed tracks (<10 μm). In any particular area the older apatite ages only occur above a critical threshold elevation, forming a regional pattern in the data and indicating cooling of the upper few kilometres of the crust during the early cretaceous. This episode of cooling is shown to have been the consequence of an accelerated phase of erosion associated with the early stages of rifting and break-up of Gondwana, and correlates with sedimentation patterns derived from borehole data for the adjacent offshore basin. (author)

An early cretaceous phase of accelerated erosion on the south-western margin of Africa: evidence from apatite fission track analysis and the offshore sedimentary record

Energy Technology Data Exchange (ETDEWEB)

Brown, R.W.; Gleadow, A.J.W. (La Trobe Univ., Bundoora (Australia)); Rust, D.J.; Summerfield, M.A. (Edinburgh Univ. (UK)); De Wit, M.C.J. (De Beers Consolidated Mines Ltd., Kimberley (South Africa))

1990-01-01

Apatite fission track ages and confined track length distributions have been determined for rock samples from the south-western continental margin of Africa. The apatite ages fall into two groups, one having early Cretaceous ages and mean confined track lengths of {approx} 14 {mu}m with very few short tracks, and the other having older ages with confined track length distributions containing a significant proportion of strongly annealed tracks (<10 {mu}m). In any particular area the older apatite ages only occur above a critical threshold elevation, forming a regional pattern in the data and indicating cooling of the upper few kilometres of the crust during the early cretaceous. This episode of cooling is shown to have been the consequence of an accelerated phase of erosion associated with the early stages of rifting and break-up of Gondwana, and correlates with sedimentation patterns derived from borehole data for the adjacent offshore basin. (author).

Parasites in the fossil record: a Cretaceous fauna with isopod-infested decapod crustaceans, infestation patterns through time, and a new ichnotaxon.

Directory of Open Access Journals (Sweden)

Adiël A Klompmaker

Full Text Available Parasites are common in modern ecosystems and are also known from the fossil record. One of the best preserved and easily recognisable examples of parasitism in the fossil record concerns isopod-induced swellings in the branchial chamber of marine decapod crustaceans. However, very limited quantitative data on the variability of infestation percentages at the species, genus, and family levels are available. Here we provide this type of data for a mid-Cretaceous (upper Lower Cretaceous, upper Albian reef setting at Koskobilo, northern Spain, on the basis of 874 specimens of anomurans and brachyurans. Thirty-seven specimens (4.2%, arranged in ten species, are infested. Anomurans are more heavily infested than brachyurans, variability can be high within genera, and a relationship may exist between the number of specimens and infestation percentage per taxon, possibly suggesting host-specificity. We have also investigated quantitative patterns of infestation through geological time based on 88 infested species (25 anomurans, 55 brachyurans, seven lobsters, and one shrimp, to show that the highest number of infested species can be found in the Late Jurassic, also when corrected for the unequal duration of epochs. The same Late Jurassic peak is observed for the percentage of infested decapod species per epoch. This acme is caused entirely by infested anomurans and brachyurans. Biases (taphonomic and otherwise and causes of variability with regard to the Koskobilo assemblage and infestation patterns through time are discussed. Finally, a new ichnogenus and -species, Kanthyloma crusta, are erected to accommodate such swellings or embedment structures (bioclaustrations.

Diverse dinosaur-dominated ichnofaunas from the Potomac Group (Lower Cretaceous) Maryland

Science.gov (United States)

Stanford, Ray; Lockley, Martin G.; Weems, Robert E.

2007-01-01

Until recently fossil footprints were virtually unknown from the Cretaceous of the eastern United States. The discovery of about 300 footprints in iron-rich siliciclastic facies of the Patuxent Formation (Potomac Group) of Aptian age is undoubtedly one of the most significant Early Cretaceous track discoveries since the Paluxy track discoveries in Texas in the 1930s. The Patuxent tracks include theropod, sauropod, ankylosaur and ornithopod dinosaur footprints, pterosaur tracks, and miscellaneous mammal and other vertebrate ichnites that collectively suggest a diversity of about 14 morphotypes. This is about twice the previous maximum estimate for any known Early Cretaceous vertebrate ichnofauna. Among the more distinctive forms are excellent examples of hypsilophodontid tracks and a surprisingly large mammal footprint. A remarkable feature of the Patuxent track assemblage is the high proportion of small tracks indicative of hatchlings, independently verified by the discovery of a hatchling-sized dinosaur. Such evidence suggests the proximity of nest sites. The preservation of such small tracks is very rare in the Cretaceous track record, and indeed throughout most of the Mesozoic.This unusual preservation not only provides us with a window into a diverse Early Cretaceous ecosystem, but it also suggests the potential of such facies to provide ichnological bonanzas. A remarkable feature of the assemblage is that it consists largely of reworked nodules and clasts that may have previously been reworked within the Patuxent Formation. Such unusual contexts of preservation should provide intriguing research opportunities for sedimentologists interested in the diagenesis and taphonomy of a unique track-bearing facies.

At least 10% shorter C–H bonds in cryogenic protein crystal structures than in current AMBER forcefields

Energy Technology Data Exchange (ETDEWEB)

Pang, Yuan-Ping, E-mail: pang@mayo.edu

2015-03-06

High resolution protein crystal structures resolved with X-ray diffraction data at cryogenic temperature are commonly used as experimental data to refine forcefields and evaluate protein folding simulations. However, it has been unclear hitherto whether the C–H bond lengths in cryogenic protein structures are significantly different from those defined in forcefields to affect protein folding simulations. This article reports the finding that the C–H bonds in high resolution cryogenic protein structures are 10–14% shorter than those defined in current AMBER forcefields, according to 3709 C–H bonds in the cryogenic protein structures with resolutions of 0.62–0.79 Å. Also, 20 all-atom, isothermal–isobaric, 0.5-μs molecular dynamics simulations showed that chignolin folded from a fully-extended backbone formation to the native β-hairpin conformation in the simulations using AMBER forcefield FF12SB at 300 K with an aggregated native state population including standard error of 10 ± 4%. However, the aggregated native state population with standard error reduced to 3 ± 2% in the same simulations except that C–H bonds were shortened by 10–14%. Furthermore, the aggregated native state populations with standard errors increased to 35 ± 3% and 26 ± 3% when using FF12MC, which is based on AMBER forcefield FF99, with and without the shortened C–H bonds, respectively. These results show that the 10–14% bond length differences can significantly affect protein folding simulations and suggest that re-parameterization of C–H bonds according to the cryogenic structures could improve the ability of a forcefield to fold proteins in molecular dynamics simulations. - Highlights: • Cryogenic crystal structures are commonly used in computational studies of proteins. • C–H bonds in the cryogenic structures are shorter than those defined in forcefields. • A survey of 3709 C–H bonds shows that the cryogenic bonds are 10–14% shorter. • The

Explosive Radiation of Malpighiales Supports a Mid-Cretaceous Origin of Modern Tropical Rain Forests

OpenAIRE

Wurdack, Kenneth J.; Jaramillo, Carlos A.; Davis, Charles; Webb, Campbell O.; Donoghue, Michael J.

2005-01-01

Fossil data have been interpreted as indicating that Late Cretaceous tropical forests were open and dry adapted and that modern closed-canopy rain forest did not originate until after the Cretaceous-Tertiary (K/T) boundary. However, some mid-Cretaceous leaf floras have been interpreted as rain forest. Molecular divergence-time estimates within the clade Malpighiales, which constitute a large percentage of species in the shaded, shrub, and small tree layer in tropical rain forests worldwide, p...

The fossil history of pseudoscorpions (Arachnida: Pseudoscorpiones

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D. Harms

2017-08-01

Full Text Available Pseudoscorpions, given their resemblance to scorpions, have attracted human attention since the time of Aristotle, although they are much smaller and lack the sting and elongated tail. These arachnids have a long evolutionary history but their origins and phylogenetic affinities are still being debated. Here, we summarise their fossil record based on a comprehensive review of the literature and data contained in other sources. Pseudoscorpions are one of the oldest colonisers of the land, with fossils known since the Middle Devonian (ca. 390 Ma. The only arachnid orders with an older fossil record are scorpions, harvestmen and acariform mites, plus two extinct groups. Pseudoscorpions do not fossilise easily, and records from the Mesozoic and Cenozoic consist almost exclusively of amber inclusions. Most Mesozoic fossils come from Archingeay and Burmese ambers (Late Cretaceous and those from the Cenozoic are primarily from Eocene Baltic amber, although additional fossils from, for example, Miocene Dominican and Mexican ambers, are known. Overall, 16 of the 26 families of living pseudoscorpions have been documented from fossils and 49 currently valid species are recognised in the literature. Pseudoscorpions represent a case of morphological stasis and even the Devonian fossils look rather modern. Indeed, most amber fossils are comparable to Recent groups despite a major gap in the fossil record of almost 250 Myr. Baltic amber inclusions indicate palaeofauna inhabiting much warmer climates than today and point to climatic shifts in central Europe since the Eocene. They also indicate that some groups (e.g. Feaellidae and Pseudogarypidae had much wider Eocene distributions. Their present-day occurrence is relictual and highlights past extinction events. Faunas from younger tropical amber deposits (e.g. Dominican and Mexican amber are comparable to Recent ones. Generally, there is a strong bias in the amber record towards groups that live under tree

Paleomagnetism of the Cretaceous Galula Formation and implications for vertebrate evolution

Science.gov (United States)

Widlansky, Sarah J.; Clyde, William C.; O'Connor, Patrick M.; Roberts, Eric M.; Stevens, Nancy J.

2018-03-01

This study uses magnetostratigraphy to help constrain the age of the paleontologically important Galula Formation (Rukwa Rift Basin, southwestern Tanzania). The formation preserves a Cretaceous vertebrate fauna, including saurischian dinosaurs, a putative gondwanatherian mammal, and notosuchian crocodyliforms. With better dating, the Galula Formation and its fossils help fill a temporal gap in our understanding of vertebrate evolution in continental Africa, enabling better evaluation of competing paleobiogeographic hypotheses concerning faunal exchange throughout Gondwana during the Cretaceous. Paleomagnetic samples for this study were collected from the Namba (higher in section) and Mtuka (lower in section) members of the Galula Formation and underwent stepwise thermal demagnetization. All samples displayed a strong normal magnetic polarity overprint, and maximum unblocking temperatures at approximately 690 °C. Three short reversed intervals were identified in the Namba Member, whereas the Mtuka Member lacked any clear reversals. Given the relatively limited existing age constraints, one interpretation correlates the Namba Member to Chron C32. An alternative correlation assigns reversals in the Namba Member to recently proposed short reversals near the end of the Cretaceous Normal Superchron (Chron C34), a time that is traditionally interpreted as having stable normal polarity. The lack of reversals in the Mtuka Member supports deposition within Chron C34. These data suggest that the Namba Member is no older than Late Cretaceous (Cenomanian-Campanian), with the Mtuka Member less well constrained to the middle Cretaceous (Aptian-Cenomanian). The paleomagnetic results are supported by the application of fold and reversal tests for paleomagnetic stability, and paleomagnetic poles for the Namba (246.4°/77.9°, α95 5.9°) and Mtuka (217.1°/72.2°, α95 11.1°) members closely matching the apparent polar wander path for Africa during the Late Cretaceous. These

The Alberta moving beyond breast cancer (AMBER cohort study: a prospective study of physical activity and health-related fitness in breast cancer survivors

Directory of Open Access Journals (Sweden)

Courneya Kerry S

2012-11-01

Full Text Available Abstract Background Limited research has examined the association between physical activity, health-related fitness, and disease outcomes in breast cancer survivors. Here, we present the rationale and design of the Alberta Moving Beyond Breast Cancer (AMBER Study, a prospective cohort study designed specifically to examine the role of physical activity and health-related fitness in breast cancer survivorship from the time of diagnosis and for the balance of life. The AMBER Study will examine the role of physical activity and health-related fitness in facilitating treatment completion, alleviating treatment side effects, hastening recovery after treatments, improving long term quality of life, and reducing the risks of disease recurrence, other chronic diseases, and premature death. Methods/Design The AMBER Study will enroll 1500 newly diagnosed, incident, stage I-IIIc breast cancer survivors in Alberta, Canada over a 5 year period. Assessments will be made at baseline (within 90 days of surgery, 1 year, and 3 years consisting of objective and self-reported measurements of physical activity, health-related fitness, blood collection, lymphedema, patient-reported outcomes, and determinants of physical activity. A final assessment at 5 years will measure patient-reported data only. The cohort members will be followed for an additional 5 years for disease outcomes. Discussion The AMBER cohort will answer key questions related to physical activity and health-related fitness in breast cancer survivors including: (1 the independent and interactive associations of physical activity and health-related fitness with disease outcomes (e.g., recurrence, breast cancer-specific mortality, overall survival, treatment completion rates, symptoms and side effects (e.g., pain, lymphedema, fatigue, neuropathy, quality of life, and psychosocial functioning (e.g., anxiety, depression, self-esteem, happiness, (2 the determinants of physical activity and

Stability of diclofenac sodium oral suspensions packaged in amber polyvinyl chloride bottles.

Science.gov (United States)

Donnelly, Ronald F; Pascuet, Elena; Ma, Carmen; Vaillancourt, Régis

2010-01-01

Prescribing of diclofenac for children usually involves a dose different from commercially available strengths. This drug is available only as tablets, which can be divided only so many times before the dose obtained becomes inaccurate. In addition, children may have difficulty swallowing tablets. For these reasons, a compounding formula for a liquid dosage form is essential to ensure effective delivery of the drug to pediatric patients. To develop a compounding formula for diclofenac sodium and to determine the extended physical and chemical stability of this compound when stored in amber polyvinyl chloride (PVC) prescription bottles under refrigeration and at room temperature. A suspension of diclofenac sodium (10 mg/mL) was prepared from commercially available diclofenac sodium tablets, with Ora-Blend as the suspending and flavouring agent. The suspension was packaged in 60-mL amber PVC prescription bottles and stored at either room temperature (23°C) or under refrigeration (5°C). Samples were collected on days 0, 7, 14, 21, 27, 56, and 93. Chemical stability was determined using a validated stability-indicating high-performance liquid chromatography method. At each sampling time, the suspensions were checked for changes in appearance (i.e., colour, layering, caking, ease of resuspension), odour, and pH. The diclofenac sodium suspensions were very stable, retaining at least 99.5% of the original concentration for up to 93 days, regardless of storage temperature. There were no apparent changes in the physical appearance of the suspensions, nor were there any substantial changes in odour or pH. Suspensions of diclofenac sodium (10 mg/mL) were quantitatively stable but difficult to prepare because of the enteric coating of the tablets. Therefore, it is recommended that diclofenac powder be used for the preparation of suspensions. For pediatric use, palatability is a consideration, and a masking agent should be added before administration. An expiry date of up to

Long-term solute transport through thick Cretaceous shale in the Williston Basin Canada using naturally-occurring tracer profiles

International Nuclear Information System (INIS)

Hendry, M. Jim; Novakowski, Kent; Smith, Laura; Koehler, Geoff; Wassenaar, L.I.

2012-01-01

Document available in abstract form only. The hydrogeologic evolution of sedimentary basins is generally determined from hydraulic and chemical data collected from aquifers. Hydraulic and chemical data from aquitards, which constitute a much greater volume of basins than aquifers and provide important controls on water and solute transport in the basins, are generally not collected nor studied. In this study we characterized the paleo-groundwater flow and solute transport controls through a vertical section of Cretaceous sediments in the Williston Basin, Canada located near Esterhazy, Saskatchewan. It consists of 384 m of thick argillaceous sediment (aquitard) overlying 93 m of heterogeneous calcareous silt, shale and sandstone (Mannville Fm.; aquifer). Paleo-hydrologic conditions were determined by interpreting high-resolution depth profiles of natural tracers of water isotopes (δ 18 O and (δ 2 H) and Cl- measured on (1) continuous core samples through the aquitard, upper aquifer, and thin Quaternary sediments, (2) water samples collected from monitoring wells installed in the aquifer and the Quaternary sediments, and (3) water samples collected from mine shaft inflows to 900 m below ground. 1D numerical transport modeling reproduced the measured profiles and yielded valuable information on the large-scale and long-term transport behavior in both the Cretaceous aquitard and the Basin. In the modeling, the shapes of the tracer profiles was explained by diffusion with paleo-events identified from the modeling including the introduction of fresher water into the aquifer possibly from the onset of glaciation (activation of the lower boundary) about 1 Ma ago and the impact of the most recent deglaciation about 10 ka ago (activation of the upper boundary). These findings show that the hydrogeologic conditions in deep, extensive basins, such as the Williston Basin, cannot be assumed to be static over geologic time. (authors)

Marine reptiles from the Late Cretaceous of northern Patagonia

Science.gov (United States)

Gasparini, Z.; Casadio, S.; Fernández, M.; Salgado, L.

2001-04-01

During the Campanian-Maastrichtian, Patagonia was flooded by the Atlantic and reduced to an archipelago. Several localities of northern Patagonia have yielded marine reptiles. Analysis of several assemblages suggests that the diversity and abundance of pelagic marine reptiles in northern Patagonia was higher by the end of the Cretaceous than previously thought. Several plesiosaurids, including Aristonectes parvidens and the polycotylid Sulcusuchus, and the first remains of mosasaurinae have been found. The Cretaceous marine reptile record from South America is scanty. Nevertheless, materials described here suggest that Tethyan and Weddelian forms converged in northern Patagonia, as seen with invertebrates.

Thermal maturity and petroleum kitchen areas of Liassic Black Shales (Lower Jurassic) in the central Upper Rhine Graben, Germany

Science.gov (United States)

Böcker, Johannes; Littke, Ralf

2016-03-01

In the central Upper Rhine Graben (URG), several major oil fields have been sourced by Liassic Black Shales. In particular, the Posidonia Shale (Lias ɛ, Lower Toarcian) acts as excellent and most prominent source rock in the central URG. This study is the first comprehensive synthesis of Liassic maturity data in the URG area and SW Germany. The thermal maturity of the Liassic Black Shales has been analysed by vitrinite reflectance (VRr) measurements, which have been verified with T max and spore coloration index (SCI) data. In outcrops and shallow wells (oil window (ca. 0.50-0.60 % VRr). This maturity is found in Liassic outcrops and shallow wells in the entire URG area and surrounding Swabian Jura Mountains. Maximum temperatures of the Posidonia Shale before graben formation are in the order of 80-90 °C. These values were likely reached during Late Cretaceous times due to significant Upper Jurassic and minor Cretaceous deposition and influenced by higher heat flows of the beginning rift event at about 70 Ma. In this regard, the consistent regional maturity data (VRr, T max, SCI) of 0.5-0.6 % VRr for the Posidonia Shale close to surface suggest a major burial-controlled maturation before graben formation. These consistent maturity data for Liassic outcrops and shallow wells imply no significant oil generation and expulsion from the Posidonia Shale before formation of the URG. A detailed VRr map has been created using VRr values of 31 wells and outcrops with a structure map of the Posidonia Shale as reference map for a depth-dependent gridding operation. Highest maturity levels occur in the area of the Rastatt Trough (ca. 1.5 % VRr) and along the graben axis with partly very high VRr gradients (e.g. well Scheibenhardt 2). In these deep graben areas, the maximum temperatures which were reached during upper Oligocene to Miocene times greatly exceed those during the Cretaceous.

High-resolution sequence stratigraphic correlation of the braided river and vertical distribution characteristics of sand body-Take upper member of saihan formation of lower cretaceous in Bayanwula deposit, for instance

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Dai Mingjian; Peng Yunbiao; Yang Jianxin; Shen Kefeng

2014-01-01

In recent years, the high-resolution sequence stratigraphy of which reference surface is base level cycle get rapid development. Its biggest advantage is the ability to apply to the continental sedimentary basins controlled by multiple factors, especially applied to the thin layer contrast of the paleochannel sandstone type uranium reservoir. This paper, by using drill core and logging data, has made the high resolution sequence stratigraphy studies on braided river uranium reservoir of Upper Member of Saihan Formation of Lower Cretaceous (Kls2) in Bayanwula deposit and identified the base level cycle interface. The study interval is divided into one long-term cycle and seven mid-term base level cycle, and high-resolution time stratigraphic framework of the deposit is established. Depth analysis is taken for the relationship between the braided river sand body and base level cycles. And the position, distribution, and genesis in vertical of the braided river sand body are discussed in detail. Ore body is mainly hosted in edge of braided bar sand body, which formed in the low accommodation space, and braided channel and the braided bar interchange. So uranium enriched in the mid-term base level cycle MSC2-MSC5 in the study area. (authors)

Cretaceous biota of the Triângulo Mineiro region (Brazil: A review of recent finds

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Candeiro, C. R. A.

2007-06-01

Full Text Available The Bauru Group (Adamantina, Uberaba, and Marília Formations crop out in the Triângulo Mineiro region, Minas Gerais State, Brazil, and yield a rich continental biota. Invertebrate and vertebrate taxa from underlying and overlying strata, as well as biostratigraphical correlations with other fossil sites in Argentina, suggest an Upper Cretaceous age for this biota. The diversity of the fossil assemblage recorded in these formations is summarized here and includes: frogs, lizards, crocodiles, titanosaurs, abelisaurid and carcharodontosaurid dinosaurs. This fossil assemblage provides important clues to understand faunas from other southern landmasses, particularly those from the Cretaceous of the African continent.Los afloramientos del Grupo Bauru (formaciones Adamantina, Uberaba y Marília en la región del Triângulo Mineiro, Provincia de Minas Gerais, Brasil, posee un rico contenido de biota continental. Los taxa de invertebrados y vertebrados de estos estratos, así como las correlaciones biostratigráficas con otros yacimientos fósiles de Argentina, sugieren una edad del Cretácico Tardío. La diversidad de la asociación fósil registrada en las formaciones del Triângulo Mineiro se resume en el presente trabajo e incluye: sapos, lagartos, tortugas, cocodrilianos, titanosaurideos, dinosaurios abelisaurideos y carcharodontosaurideos. Esta asociación es importante para la comprensión de las faunas del sur de América y también de las del Cretácico de África.

A new genus and species of enantiornithine bird from the Early Cretaceous of Brazil

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Ismar de Souza Carvalho

Full Text Available The fossil record of birds in Gondwana is almost restricted to the Late Cretaceous. Herein we describe a new fossil from the Araripe Basin, Cratoavis cearensis nov. gen et sp., composed of an articulated skeleton with feathers attached to the wings and surrounding the body. The present discovery considerably extends the temporal record of the Enantiornithes birds at South America to the Early Cretaceous. For the first time, an almost complete and articulated skeleton of an Early Cretaceous bird from South America is documented.

Larger miliolids of the Late Cretaceous and Paleogene seen through space and time

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Vlasta Ćosović

2002-12-01

Full Text Available Spatial and temporal occurrences of the larger (complex miliolids are discussed to give more light on biostratigraphy and paleobiogeographic provinces distribution. Seven generaand 47 species from the Late Cretaceous to Oligocene inhabited shallow marine settings in the Indo-Pacific, Tethyan and Caribbean regions. Of all genera only four (Idalina, Periloculina, Pseudolacazina, Lacazina widespread throughout Tethys in theLate Cretaceous and Paleogene. Single occurrence of Lacazina was recorded further to east (Moluccas. By now the Late Cretaceous genus Adrahentina is known only from the Spain. The newcomer’s Eocene genera were Fabularia and Lacazinella. Fabularia reachedhigh diversity in species term in the Central and Western Tethys and occured as unique genus in Caribbean realm, too. Conversely, during the same period, Lacazinella spread over the southern border of Neo-Tethys reaching New Guinea.On the Adriatic – Dinaric Carbonate Platform, larger miliolids occurred from the Late Cretaceous to Cuisian, having the same biostratigraphically trends and distribution as contemporaneous larger miliolids from the Tethys.

Lamellaptychi from the Lower Cretaceous of south-east Spain (Murcia and Jaen provinces)

Czech Academy of Sciences Publication Activity Database

Vašíček, Zdeněk; Company, M.; Měchová, L.

2015-01-01

Roč. 276, č. 3 (2015), s. 335-351 ISSN 0077-7749 Institutional support: RVO:68145535 Keywords : Lower Cretaceous * aptychi * ammonite zonation * Betic Cordillera Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.719, year: 2015 http://cretaceous.ru/files/pub/temp3/vasicek_et_al_2015_lamellaptychi.pdf

Evidence of reworked Cretaceous fossils and their bearing on the existence of Tertiary dinosaurs

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Eaton, J.G. (Museum of Northern Arizona, Flagstaff (USA)); Kirkland, J.I. (Univ. of Nebraska, Lincoln (USA)); Doi, K. (Univ. of Colorado, Boulder (USA))

1989-06-01

The Paleocene Shotgun fauna of Wyoming includes marine sharks as well as mammals. It has been suggested that the sharks were introduced from the Cannonball Sea. It is more likely that these sharks were reworked from a Cretaceous rock sequence that included both marine and terrestrial deposits as there is a mixture of marine and freshwater taxa. These taxa have not been recorded elsewhere after the Cretaceous and are not known from the Cannonball Formation. Early Eocene localities at Raven Ridge, Utah, similarly contain teeth of Cretaceous marine and freshwater fish, dinosaurs, and Eocene mammals. The Cretaceous teeth are well preserved, variably abraded, and serve to cast doubts on criteria recently used to claim that dinosaur teeth recovered from the Paleocene of Montana are not reworked. Another Eocene locality in the San Juan Basin has produced an Eocene mammalian fauna with diverse Cretaceous marine sharks. Neither the nature of preservation nor the degree of abrasion could be used to distinguish reworked from contemporaneous material. The mixed environments represented by the fish taxa and recognition of the extensive pre-Tertiary extinction of both marine and freshwater fish were employed to recognize reworked specimens.

Petroleum systems of the Upper Magdalena Valley, Colombia

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Sarmiento, L.F.; Rangel, A. [Instituto Colombiano del Petroleo, Bucaramanga (Colombia). ECOPETROL

2004-03-01

In the Upper Magdalena Valley, Colombia, four petroleum systems were identified. Two petroleum systems are located in the Girardot sub-basin and the other two in the Neiva sub- basin. Limestones laterally changing to shales of the lower part of the Villeta Gp, deposited during Albian and Turonian marine flooding events, constitutes the main source rocks of the oil families. These rocks contain 1-4% TOC and type II kerogen. The littoral quartz arenites of the Caballos (Albian) and Monserrate (Maastrichtian) Fms. are the main reservoir rocks. Seal rocks are Cretaceous and Paleocene shales. Overburden includes the Cretaceous rocks and the Tertiary molasse deposited simultaneously with development of two opposite verging thrust systems during Cenozoic time. These deformation events were responsible for trap creation. Except for the Villarrica area, where the source rock reached maturity during the Paleocene, generation occurred during Miocene. Two oil families are identified, each in both sub-basins: One derived from a clay-rich source and the second from a carbonate-rich source rock lithofacies of the lower part of Villeta Gp. Geochemical source-rock to oil correlations are demonstrated for the three of the petroleum systems. Up-dip lateral migration distances are relatively short and faults served as vertical migration pathways. A huge amount of oil was probably degraded at surface, as a result of Miocene deformation and erosion. (author)

Characteristics of depositional environment and evolution of Upper Cretaceous Mishrif Formation, Halfaya Oil field, Iraq based on sedimentary microfacies analysis

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Zhong, Yuan; Zhou, Lu; Tan, Xiucheng; Guo, Rui; Zhao, Limin; Li, Fei; Jin, Zhimin; Chen, Yantao

2018-04-01

As one of the most important carbonate targets in the Middle East, Upper Cretaceous Mishrif Formation has been highlighted for a long time. Although consensus has been reached on the overall sedimentary background, disputes still exist in understanding the sedimentary environment changes among sub-regions due to relatively limited research, rare outcrop, and incomplete drilled core, which hinders the analysis on sedimentary environment and thus the horizontal and vertical correlation. In this study, taking the Halfaya Oil Field as an example, the sedimentary microfacies analysis method was introduced to comprehensively characterize the cored interval of Mishrif Formation, including Single Layers MC1-1 to MA2. A total of 11 sedimentary microfacies are identified through system identification of sedimentary microfacies and environmental analysis, with reference to the standard microfacies classification in the rimmed carbonate platform. Then three kinds of environments are identified through microfacies assemblage analysis, namely restricted platform, open platform, and platform margin. Systematic analyses indicate that the deposits are mainly developed in the open platform and platform margin. Meanwhile, rock-electricity interpretation model is established according to the electricity response to cored intervals, and is then employed to interpret the uncored intervals, which finally helps build the sedimentary evolution pattern through horizontal and vertical correlation. It is proposed that the Single Layers MC1-1 to MB2-3 were deposited in the open platform featured by low water level, including sub-environments of low-energy shoal within platform and inter-shoal sea; Single Layers MB2-2 to MB1-2B were deposited in the open platform and platform margin, including sub-environments of high-energy shoal on the platform margin, low-energy shoal within platform, inter-shoal sea, and open sea; and Single Layers MB1-2A to MA2 were again deposited in the open platform

Mineral composition and geochemistry of the Upper Cretaceous siliciclastics (Nubia Group), Aswan District, south Egypt: Implications for provenance and weathering

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Hassan, Abdallah M.

2017-11-01

The Upper-Cretaceous clastic succession (Nubia Group) in the area northeast of Aswan includes three rock units, from base upwards: Abu Aggag Formation (Turonian), Timsah Formation (Coniacian -Santonian) and Um Barmil Formation (Santonian - Campanian). Quartz and clay minerals are the predominant phases throughout the whole succession while feldspars are very rare. Kaolinite is overwhelming among the clay minerals, in addition to less important amounts of illite and illite/smectite. The ultrastable heavy minerals are the prevailing non- opaque phases and they significantly change in relative abundance upsection. SiO2, Al2O3 and Fe2O3 are the dominant chemical components. The statistical examination had revealed that the chemical constituents are loaded on three main geochemical trends; the siliceous, the argillaceous and the ferruginous. The enrichment factor shows that the geochemical behavior of the major and trace elements is uniform throughout the sandstones and mudstones of the Abu Aggag Formation. A significant geochemical contrast is documented between the sandstones and mudstones of both the Timsah and the Um Barmil formations. The provenance - critical elemental ratios Ti/Nb and Ti/Y are nearly constant throughout the sandstones and mudstones of the Abu Aggag Formation, and they fall within the range of granitic-granodioritic composition. The Timsah sandstones have Ti/Nb and Ti/Y ratios that are consistent with those of the Abu Aggag rocks, suggesting a similar provenance. These elemental ratios are extremely higher in the Timsah mudstones, reflecting a great influx of mafic material. The Um Barmil sandstones exhibit exceedingly dispersed values of Ti/Nb and Ti/Y, reflecting their derivation from large catchment's areas of different rock types with the eroded products being mixed in various relative proportions. The Ti/Nb and Ti/Y of the Um Barmil mudstones are closely akin to those of the Timsah mudstones suggesting analogous source. The chemical index of

A complete skull of an early cretaceous sauropod and the evolution of advanced titanosaurians.

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Hussam Zaher

Full Text Available Advanced titanosaurian sauropods, such as nemegtosaurids and saltasaurids, were diverse and one of the most important groups of herbivores in the terrestrial biotas of the Late Cretaceous. However, little is known about their rise and diversification prior to the Late Cretaceous. Furthermore, the evolution of their highly-modified skull anatomy has been largely hindered by the scarcity of well-preserved cranial remains. A new sauropod dinosaur from the Early Cretaceous of Brazil represents the earliest advanced titanosaurian known to date, demonstrating that the initial diversification of advanced titanosaurians was well under way at least 30 million years before their known radiation in the latest Cretaceous. The new taxon also preserves the most complete skull among titanosaurians, further revealing that their low and elongated diplodocid-like skull morphology appeared much earlier than previously thought.

A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas

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Cung, Thu'ọ'ng Chí; Geissman, John W.

2013-09-01

Available paleomagnetic data from rock formations of Cretaceous age from Vietnam, Indochina and South China are compiled and reviewed in the context of their tectonic importance in a common reference frame with respect to Eurasia's coeval paleopoles. Key factors that play an important role in determining the reliability of a paleomagnetic result for utilization in tectonic studies have been taken into consideration and include the absence of evidence of remagnetization, which is a feature common to many rocks in this region. Overall, the Cretaceous paleomagnetic data from the South China Block show that the present geographic position of the South China Block has been relatively stable with respect to Eurasia since the mid-Cretaceous and that the paleomagnetically detected motion of a coherent lithospheric block must be based on the representative data obtained from different specific localities across the block in order to separate more localized, smaller scale deformation from true lithosphere scale motion (translation and/or rotation) of a tectonic block. Cretaceous to early Tertiary paleomagnetic data from the Indochina-Shan Thai Block reveal complex patterns of intra-plate deformation in response to the India-Eurasia collision. Paleomagnetically detected motions from the margins of tectonic blocks are interpreted to mainly reflect displacement of upper crustal blocks due to folding and faulting processes. Rigid, lithosphere scale block rotation is not necessarily supported by the paleomagnetic data. The paleomagnetic results from areas east and south of the Red River fault system suggest that this major transcurrent fault system has had a complicated slip history through much of the Cenozoic and that it does not demarcate completely non-rotated and significantly rotated parts of the crust in this area. However, most paleomagnetic results from areas east and south of the Red River fault system at the latitude of Yunnan Province are consistent with a very modest

A new species of the neopterygian fish Enchodus from the Duwi Formation, Campanian, Late Cretaceous, Western Desert, central Egypt

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Waymon L. Holloway

2017-09-01

Full Text Available The neopterygian fish Enchodus was a widespread, speciose genus consisting of approximately 30 recognized species that were temporally distributed from the late Early Cretaceous through the Paleocene. Many Enchodus specimens are fragmentary cranial remains or isolated dental elements, as is the case for previously reported occurrences in Egypt. Here, we present the most complete specimen of Enchodus recovered from the Late Cretaceous of northeast Africa. The specimen was collected from the upper Campanian Duwi Formation, near the village of Tineida (Dakhla Oasis, Western Desert, Egypt. The new species, Enchodus tineidae sp. nov., consists of right and left dentaries, a partial ectopterygoid, and other cranial bones. The size of the specimen places it into the upper body-size range for the genus. The palatine tooth, an element often useful for diagnosing Enchodus to the species level, is not preserved, but a combination of other cranial characters supports the referral of this specimen to Enchodus. In particular, the dentary preserves three symphysial rostroventral prongs and two tooth rows, the lateral of which consists of small denticles, whereas the medial row comprises large, mediolaterally-compressed teeth. The rostral-most tooth exhibits the highest crown, whereas the rest of the teeth are of lower, variable crown heights. The eight robust, caudal-most medial-row teeth are distributed in a cluster pattern never before observed in Enchodus. Additionally, the dentary and preopercle are both without dermal ornamentation, and the mandibular sensory canal is closed. Phylogenetic analysis recovers this new species as the sister species to E. dirus from North America. Along with previously described materials from Israel, Jordan, Syria, Lebanon, Italy, Morocco, and Libya, this specimen represents a thirteenth species from the northwestern Tethyan geographic distribution of Enchodus.

Cu-Ag Besshi type volcanogenic massive sulfide mineralization in the Late Cretaceous volcano- sedimentary sequence: the case of Garmabe Paein deposit, southeast of Shahrood

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Majid Tashi

2017-07-01

Full Text Available Introduction Iran hosts numerous types of Volcanogenic massive sulfide (VMS deposits that occur within different tectonic assemblages and have formed at discrete time periods (Mousivand et al. 2008. The Sabzevar zone hosts several VMS deposits including the Nudeh Cu-Ag deposit (Maghfouri, 2012 and some deposits in the Kharturan area (Tashi et al., 2014, and the Kharturan area locates in the Sabzevar subzone of the Central East Iranian Microcontinent. The Sabzevar subzone mainly involves Mesozoic and Cenozoic rock unites. The Late Cretaceous ophiolite mellanges and volcano-sedimentary sequences have high extension in the Subzone. Based on Rossetti (Rossetti et al. 2010, the Cretaceous rock units were formed in a back-arc setting due to subduction of the Neo-Tethyan oceanic crust beneath the Iranian plate. The exposed rock units of the Kharturan area from bottom to top are dominated by Early Cretaceous, orbitolina-bearing massive limestone, dacitic-andesitic volcanics and related volcaniclastic rocks٫ chert and radiolarite and Late Cretaceous globotrunkana- bearing limestone, paleocene polygenic conglomerate consisting of the Cretaceous volcanics and limestone pebbles (equal to the Kerman conglomerate, and Pliocene weakly-cemented polygenic conglomerate horizon. The Garmabe Paein copper-silver deposit and the Asbkeshan deposit and a few occurrences, are located at 290 km southeast of Shahrood and they have occurred within the Upper Cretaceous volcano-sedimentary sequence in the Sabzevar subzone. The aim of this study is to discuss the genesis of the Garmabe Paein deposit based on geological, textural and structural, mineralogical and geochemical evidence. Materials and methods A field study and sampling was performed during the year 2013. During the field observations, 94 rock samples were collected from the study area, and 45 thin sections were prepared and studied using a polarizing microscope. Also, 5 samples for the XRD method, 21 samples for

New ophthalmosaurid ichthyosaurs from the European Lower Cretaceous demonstrate extensive ichthyosaur survival across the Jurassic-Cretaceous boundary.

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Valentin Fischer

Full Text Available BACKGROUND: Ichthyosauria is a diverse clade of marine amniotes that spanned most of the Mesozoic. Until recently, most authors interpreted the fossil record as showing that three major extinction events affected this group during its history: one during the latest Triassic, one at the Jurassic-Cretaceous boundary (JCB, and one (resulting in total extinction at the Cenomanian-Turonian boundary. The JCB was believed to eradicate most of the peculiar morphotypes found in the Late Jurassic, in favor of apparently less specialized forms in the Cretaceous. However, the record of ichthyosaurs from the Berriasian-Barremian interval is extremely limited, and the effects of the end-Jurassic extinction event on ichthyosaurs remains poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Based on new material from the Hauterivian of England and Germany and on abundant material from the Cambridge Greensand Formation, we name a new ophthalmosaurid, Acamptonectes densus gen. et sp. nov. This taxon shares numerous features with Ophthalmosaurus, a genus now restricted to the Callovian-Berriasian interval. Our phylogenetic analysis indicates that Ophthalmosauridae diverged early in its history into two markedly distinct clades, Ophthalmosaurinae and Platypterygiinae, both of which cross the JCB and persist to the late Albian at least. To evaluate the effect of the JCB extinction event on ichthyosaurs, we calculated cladogenesis, extinction, and survival rates for each stage of the Oxfordian-Barremian interval, under different scenarios. The extinction rate during the JCB never surpasses the background extinction rate for the Oxfordian-Barremian interval and the JCB records one of the highest survival rates of the interval. CONCLUSIONS/SIGNIFICANCE: There is currently no evidence that ichthyosaurs were affected by the JCB extinction event, in contrast to many other marine groups. Ophthalmosaurid ichthyosaurs remained diverse from their rapid radiation in the Middle

New Ophthalmosaurid Ichthyosaurs from the European Lower Cretaceous Demonstrate Extensive Ichthyosaur Survival across the Jurassic–Cretaceous Boundary

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Fischer, Valentin; Maisch, Michael W.; Naish, Darren; Kosma, Ralf; Liston, Jeff; Joger, Ulrich; Krüger, Fritz J.; Pérez, Judith Pardo; Tainsh, Jessica

2012-01-01

Background Ichthyosauria is a diverse clade of marine amniotes that spanned most of the Mesozoic. Until recently, most authors interpreted the fossil record as showing that three major extinction events affected this group during its history: one during the latest Triassic, one at the Jurassic–Cretaceous boundary (JCB), and one (resulting in total extinction) at the Cenomanian-Turonian boundary. The JCB was believed to eradicate most of the peculiar morphotypes found in the Late Jurassic, in favor of apparently less specialized forms in the Cretaceous. However, the record of ichthyosaurs from the Berriasian–Barremian interval is extremely limited, and the effects of the end-Jurassic extinction event on ichthyosaurs remains poorly understood. Methodology/Principal Findings Based on new material from the Hauterivian of England and Germany and on abundant material from the Cambridge Greensand Formation, we name a new ophthalmosaurid, Acamptonectes densus gen. et sp. nov. This taxon shares numerous features with Ophthalmosaurus, a genus now restricted to the Callovian–Berriasian interval. Our phylogenetic analysis indicates that Ophthalmosauridae diverged early in its history into two markedly distinct clades, Ophthalmosaurinae and Platypterygiinae, both of which cross the JCB and persist to the late Albian at least. To evaluate the effect of the JCB extinction event on ichthyosaurs, we calculated cladogenesis, extinction, and survival rates for each stage of the Oxfordian–Barremian interval, under different scenarios. The extinction rate during the JCB never surpasses the background extinction rate for the Oxfordian–Barremian interval and the JCB records one of the highest survival rates of the interval. Conclusions/Significance There is currently no evidence that ichthyosaurs were affected by the JCB extinction event, in contrast to many other marine groups. Ophthalmosaurid ichthyosaurs remained diverse from their rapid radiation in the Middle Jurassic to

Integrated geophysical and geological study and petroleum appraisal of Cretaceous plays in the Western Gulf of Gabes, Tunisia

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Dkhaili, Noomen; Bey, Saloua; El Abed, Mahmoud; Gasmi, Mohamed; Inoubli, Mohamed Hedi

2015-09-01

An integrated study of available seismic and calibrated wells has been conducted in order to ascertain the structural development and petroleum potential of the Cretaceous Formations of the Western Gulf of Gabes. This study has resulted in an understanding of the controls of deep seated Tethyan tectonic lineaments by analysis of the Cretaceous deposits distribution. Three main unconformities have been identified in this area, unconformity U1 between the Jurassic and Cretaceous series, unconformity U2 separating Early from Late Cretaceous and known as the Austrian unconformity and the major unconformity U3 separating Cretaceous from Tertiary series. The seismic analysis and interpretation have confirmed the existence of several features dominated by an NE-SW extensive tectonic regime evidenced by deep listric faults, asymmetric horst and graben and tilted blocks structures. Indeed, the structural mapping of these unconformities, displays the presence of dominant NW-SE fault system (N140 to N160) bounding a large number of moderate sized basins. A strong inversion event related to the unconformity U3 can be demonstrated by the mapping of the unconformities consequence of the succession of several tectonic manifestations during the Cretaceous and post-Cretaceous periods. These tectonic events have resulted in the development of structural and stratigraphic traps further to the porosity and permeability enhancement of Cretaceous reservoirs.

Rovno Amber Ant Assamblage: Bias toward Arboreal Strata or Sampling Effect?

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Perkovsky E. E.

2016-06-01

Full Text Available In 2015 B. Guenard with co-authors indicated that the Rovno amber ant assemblage, as described by G. Dlussky and A. Rasnitsyn (2009, showed modest support for a bias towards arboreal origin comparing the Baltic and Bitterfeld assemblages, although it is not clear whether this reflects a sampling error or a signal of real deviation. Since 2009, the Rovno ant collection has now grown more than twice in volume which makes possible to check if the above inference about the essentially arboreal character of the assemblage is real or due to a sampling error. The comparison provided suggests in favour of the latter reason for the bias revealed by B. Guenard and co-authors. The new and larger data on the Rovno assemblage show that the share of non-arboreal ants is now well comparable with those concerning the Baltic and Bitterfeld assemblages. This holds true for the both total assemblages and subassemblages of worker ants only.

High-resolution leaf-fossil record spanning the Cretaceous/Tertiary boundary

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Johnson, K.R.; Nichols, D.J.; Attrep, M.; Orth, C.J.

1989-01-01

THEORIES that explain the extinctions characterizing the Cretaceous/Tertiary (K/T) boundary1-3 need to be tested by analyses of thoroughly sampled biotas. Palynological studies are the primary means for stratigraphic placement of the terrestrial boundary and for estimates of plant extinction4-12, but have not been combined with quantitative analyses of fossil leaves (megaflora). Megafloral studies complement palynology by representing local floras with assemblages capable of high taxonomic resolution13, but have previously lacked the sample size and stratigraphic spacing needed to resolve latest Cretaceous floral history5,14-18. We have now combined megafloral data from a 100-m-thick composite K/T boundary section in North Dakota with detailed palynological analysis. Here the boundary is marked by a 30% palynofloral extinction coincident with iridium and shocked-mineral anomalies and lies ???2 m above the highest dinosaur remains. The megaflora undergoes a 79% turnover across the boundary, and smaller changes 17- and 25-m below it. This pattern is consistent with latest Cretaceous climatic warming preceding a bolide impact. ?? 1989 Nature Publishing Group.

First record of Elasmosaurid Plesiosaurs (Sauropterygia: Plesiosauria in upper levels of the Dorotea Formation, Late Cretaceous (Maastrichtian, Puerto Natales, Chilean Patagonia Primer Registro de Plesiosaurios Elasmosáuridos (Sauropterygia: Plesiosauria en estratos superiores de la Formación Dorotea, Cretácico Tardío (Maastrichtiano, Puerto Natales, Patagonia Chilena

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Rodrigo A Otero

2009-07-01

Full Text Available New remains of plesiosaurs (Diapsida; Sauropterygia found in a transported block correlated with upper levels of the Dorotea Formation, Late Cretaceous (Maastrichtian are describedherein. They were collected on the southern slopes of Sierra Dorotea located northeast of Puerto Natales (51 °41 '20,4"S, 72°26'07,4"W, Magallanes Región, Chile. This is the first disco very of the family Elasmosauridae in high latitudes of South America, complementing the previously known paleodistribution of this group in the eastern Pacific Ocean and the Antarctic during the latest Cretaceous.Se describen nuevos restos de plesiosaurios (Diapsida; Sauropterygia incluidos en un bloque rodado correlacionado con estratos superiores de la Formación Dorotea (Cretácico Tardío, Maastrichtiano, recolectados en la parte sur de la sierra homómma, ubicada al noreste de Puerto Natales (51°41'20,4"S, 72°26'07,4"W, Región de Magallanes, Chile. Se reconoce por primera vez la presencia de la familia Elasmosauridae en altas latitudes de Sudamérica, complementando así la paleodistribution previamente conocida de este grupo en el margen oriental del Océano Pacífico y de la Antartica durante la última parte del Cretácico Tardío.

Paleoenvironments of the Jurassic and Cretaceous Oceans: Selected Highlights

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Ogg, J. G.

2007-12-01

There are many themes contributing to the sedimentation history of the Mesozoic oceans. This overview briefly examines the roles of the carbonate compensation depth (CCD) and the associated levels of atmospheric carbon dioxide, of the evolution of marine calcareous microplankton, of major transgressive and regressive trends, and of super-plume eruptions. Initiation of Atlantic seafloor spreading in the Middle Jurassic coincided with an elevated carbonate compensation depth (CCD) in the Pacific-Tethys mega-ocean. Organic-rich sediments that would become the oil wealth of regions from Saudi Arabia to the North Sea were deposited during a continued rise in CCD during the Oxfordian-early Kimmeridgian, which suggests a possible increase in carbon dioxide release by oceanic volcanic activity. Deep-sea deposits in near-equatorial settings are dominated by siliceous shales or cherts, which reflect the productivity of siliceous microfossils in the tropical surface waters. The end-Jurassic explosion in productivity by calcareous microplankton contributed to the lowering of the CCD and onset of the chalk ("creta") deposits that characterize the Tithonian and lower Cretaceous in all ocean basins. During the mid-Cretaceous, the eruption of enormous Pacific igneous provinces (Ontong Java Plateau and coeval edifices) increased carbon dioxide levels. The resulting rise in CCD terminated chalk deposition in the deep sea. The excess carbon was progressively removed in widespread black-shale deposits in the Atlantic basins and other regions - another major episode of oil source rock. A major long-term transgression during middle and late Cretaceous was accompanied by extensive chalk deposition on continental shelves and seaways while the oceanic CCD remained elevated. Pacific guyots document major oscillations (sequences) of global sea level superimposed on this broad highstand. The Cretaceous closed with a progressive sea-level regression and lowering of the CCD that again enabled

The Skælskør structure in eastern Denmark – wrench-related anticline or primary Late Cretaceous sea-floor topography?

DEFF Research Database (Denmark)

Surlyk, Finn; Boldreel, Lars Ole; Lykke-Andersen, Holger

2010-01-01

seismic studies of the Chalk Group in Øresund and Kattegat have shown that similar highs actually represent topographic highs on the Late Cretaceous – Danian seafloor formed by strong contourparallel bottom currents. Reflection seismic data collected over the Skælskør structure in order to test...... the Ringkøbing Fyn High into the Danish Basin. The elevated position is maintained due to reduced subsidence as compared with the Danish Basin north of the high. The hypothesis of wrench tectonics as origin can be refuted. The seismic data show that the upper part of the Chalk Group is characterised by irregular...

Integrated foraminiferal biostratigraphy and chemostratigraphy of the querecual formation (Cretaceous), Eastern Venezuela

Science.gov (United States)

Crespo De Cabrera, S.; Sliter, W.V.; Jarvis, I.

1999-01-01

An integrated foraminiferal biostratigraphy and chemostratigraphy is presented for the Lower to Upper Cretaceous Querecual Formation exposed on Chimana Grande Island, Eastern Venezuela. The formation consists of >450 m alternating foraminiferal and organic-rich carbonates and laminated mudrocks, and is considered the main hydrocarbon source rock for the eastern Venezuela Basin. Biostratigraphic resolution within the Querecual Formation is poor, due to a paucity of keeled planktonic foraminifera and impoverished benthic faunas. Deposition occurred in a bathyal environment, with dysaerobic or anoxic bottom waters resulting from high rates of surface productivity associated with an upwelling environment. Biostratigraphic evidence indicates that the Querecual Formation ranges from the upper Albian Rotalipora ticinensis Zone to the Santonian Dicarinella asymetrica Zone. Iron and Al contents fall through the Albian-Cenomanian indicating a progressive decrease in the detrital supply, driven by rising eustatic sea level. A Ca profile demonstrates variations in carbonate production and dissolution. High total organic carbon (TOC) intervals occur in the upper Albian to mid-Cenomanian and Turonian, and high Ba/Al and Si/Al ratios characterize mid-Cenomanian and younger sediments. Variations in these elements primarily reflect changes in marine productivity, but are also affected by diagenetic processes. A stable carbon isotope curve established from analysis of organic matter (??13Corg) correlates well with published ??13C curves for carbonates from England and Italy. The Cenomanian/Turonian boundary cannot be identified using planktonic foraminifera, because key taxa are absent, but the base of the Turonian is clearly indicated by a sharp fall in ??13C immediately above a major positive excursion. The bottom of the Coniacian is placed below a ??13C minimum, towards the base of the Dicarinella concavata Zone. Combined with the foraminiferal data, the isotopic data enable much

The organic matter of the Potosi basin (Cordillera Oriental, Bolivia) during the Upper Cretaceous-Lower tertiary: stratigraphic and palaeogeographic data

Energy Technology Data Exchange (ETDEWEB)

Blanc-Valleron, M.M.; Rouchy, J.M. (Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France)); Schuler, M.; Rauscher, R. (Strasbourg-1 Univ., 67 (France)); Camoin, G. (Aix-Marseille-1 Univ., 13 - Marseille (France))

1994-12-01

Palynological and Rock-Eval pyrolysis studies of the Chaunaca and El Molino Fm (Santonian to Thanetian, Cordillera Oriental, Bolivia) indicate that some facies have economic significance as potential oil source rocks. The occurrence of Pediastrum and Azolla testify a lacustrine environment. In the Upper Molino, the environmental interpretation of an almost monospecific association of dinocysts is discussed. The presence of Apectodinium quinquelatum indicates that the age of the upper part of the Upper El Molino Fm is likely to be Upper Thanetian. (authors). 22 refs., 5 figs.

Using Stable Isotope Geochemistry to Determine Changing Paleohydrology and Diagenetic Alteration in the Late Cretaceous Kaiparowits Formation, UT USA

Science.gov (United States)

Yamamura, Daigo

The Western Interior Basin of the North America preserves one of the best sedimentary and paleontological records of the Cretaceous in the world. The Upper Cretaceous Kaiparowits Formation is a rapidly deposited fluvial sequence and preserves one of the most complete terrestrial fossil record of the North America. Such a unique deposit provides an opportunity to investigate the interaction between the physical environment and ecology. In an effort to decipher such interaction, stable isotope composition of cements in sedimentary rocks, concretions and vertebrate fossils were analyzed. Despite the difference in facies and sedimentary architecture, the isotope composition does not change significantly at 110 m from the base of the formation. Among the well-preserved cement samples, stable isotope composition indicates a significant hydrologic change within the informal Middle unit; a 6.37‰ depletion in delta13C and 3.30‰ enrichment in delta 18O occurs at 300 m above the base of the formation. The isotope values indicate that the sandstone cements below 300 m were precipitated in a mixing zone between marine and terrestrial groundwater, whereas the cements in upper units were precipitated in a terrestrial groundwater. Despite the difference in physical appearance (i.e. color and shape), the isotopic compositions of cements in concretions are similar to well-cemented sandstone bodies in similar stratigraphic positions. Isotope compositions of the host rock are similar to that of mudrock and weathered sandstone, suggesting the origin of cementing fluids for the sandstone and concretions were the same indicating that: 1) the concretions were formed in shallow groundwater and not related to the groundwater migration, or 2) all cements in upper Kaiparowits Formation are precipitated or altered during later stage groundwater migration. Average delta18Oc from each taxon show the same trend as the delta18Op stratigraphic change, suggesting delta18Oc is still useful as a

Evolution and classification of Elaphoglossum and Asplenium ferns on Cuba, and discovery of a Miocene Elaphoglossum in Dominican amber

OpenAIRE

Lóriga Piñero, Josmaily

2018-01-01

This dissertation deals with the systematics and evolution of Neotropical ferns of the genera Elaphoglossum and Asplenium, with particular focus on the species of Cuba and the West Indies. It also includes an analysis and description of an Elaphoglossum frond fragment preserved in Miocene Dominican amber. The worldwide genera Elaphoglossum with 600 species and Asplenium with 685 species are the most species-rich groups of leptosporangiate ferns. On Cuba, Elaphoglossum has 34 species and Asple...

The Late Cretaceous frog Gobiates from Central Asia: its evolutionary status and possible phylogenetic relationships

Czech Academy of Sciences Publication Activity Database

Roček, Zbyněk

2008-01-01

Roč. 29, č. 4 (2008), s. 577-591 ISSN 0195-6671 Institutional research plan: CEZ:AV0Z30130516 Keywords : Amphibia * Anura * Gobiatidae * Cretaceous * Cretaceous (Mongolia) Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.938, year: 2008

A new Early Cretaceous eutherian mammal from the Sasayama Group, Hyogo, Japan.

Science.gov (United States)

Kusuhashi, Nao; Tsutsumi, Yukiyasu; Saegusa, Haruo; Horie, Kenji; Ikeda, Tadahiro; Yokoyama, Kazumi; Shiraishi, Kazuyuki

2013-05-22

We here describe a new Early Cretaceous (early Albian) eutherian mammal, Sasayamamylos kawaii gen. et sp. nov., from the 'Lower Formation' of the Sasayama Group, Hyogo Prefecture, Japan. Sasayamamylos kawaii is characterized by a robust dentary, a distinct angle on the ventral margin of the dentary at the posterior end of the mandibular symphysis, a lower dental formula of 3-4 : 1 : 4 : 3, a robust lower canine, a non-molariform lower ultimate premolar, and a secondarily reduced entoconid on the molars. To date, S. kawaii is the earliest known eutherian mammal possessing only four premolars, which demonstrates that the reduction in the premolar count in eutherians started in the late Early Cretaceous. The occurrence of S. kawaii implies that the relatively rapid diversification of eutherians in the mid-Cretaceous had already started by the early Albian.

Receiver function and gravity constraints on crustal structure and vertical movements of the Upper Mississippi Embayment and Ozark Uplift

Science.gov (United States)

Liu, Lin; Gao, Stephen S.; Liu, Kelly H.; Mickus, Kevin

2017-06-01

The Upper Mississippi Embayment (UME), where the seismically active New Madrid Seismic Zone resides, experienced two phases of subsidence commencing in the Late Precambrian and Cretaceous, respectively. To provide new constraints on models proposed for the mechanisms responsible for the subsidence, we computed and stacked P-to-S receiver functions recorded by 49 USArray and other seismic stations located in the UME and the adjacent Ozark Uplift and modeled Bouguer gravity anomaly data. The inferred thickness, density, and Vp/Vs of the upper and lower crustal layers suggest that the UME is characterized by a mafic and high-density upper crustal layer of ˜30 km thickness, which is underlain by a higher-density lower crustal layer of up to ˜15 km. Those measurements, in the background of previously published geological observations on the subsidence and uplift history of the UME, are in agreement with the model that the Cretaceous subsidence, which was suggested to be preceded by an approximately 2 km uplift, was the consequence of the passage of a previously proposed thermal plume. The thermoelastic effects of the plume would have induced wide-spread intrusion of mafic mantle material into the weak UME crust fractured by Precambrian rifting and increased its density, resulting in renewed subsidence after the thermal source was removed. In contrast, the Ozark Uplift has crustal density, thickness, and Vp/Vs measurements that are comparable to those observed on cratonic areas, suggesting an overall normal crust without significant modification by the proposed plume, probably owing to the relatively strong and thick lithosphere.

Strontium isotope geochemistry of late cretaceous granodiorites, Jamaica and Haiti, Greater Antilles

International Nuclear Information System (INIS)

Jones, L.M.; Walker, R.L.; Kesler, S.E.; Lewis, J.F.

1979-01-01

Initial 87 Sr/ 86 Sr ratios have been determined for a representative suite of Upper Cretaceous granodiorites and associated rocks from the Above Rocks composite stock in central Jamaica and the Terre-Neuve pluton in northwestern Haiti. The average initial 87 Sr/ 86 Sr ratio for seven samples of the Terre-Neuve intrusion is 0.7036, with a range of 0.7026-0.7047. For two samples of the Above Rocks the initial ratios are 0.7033 and 0.7034. A third sample from this intrusive has an initial ratio of 0.7084, which is tentatively attributed to contamination. The initial 87 Sr/ 86 Sr ratios indicate that neither ancient sialic crust nor sediments carried down a Benioff zone can be the primary source of the granodioritic magma. K/Rb ratios for these rocks range from 178 to 247, which are much lower than the average values (>= 1000) for tholeiitic basalts. It is concluded that the magmas originated primarily by melting of downthrust oceanic crust or adjacent mantle material. (Auth.)

Dose rate influence in the response of the amber 3042 perspex Dosimeter, batch l

International Nuclear Information System (INIS)

Prieto Miranda, E. F.; Barrera Gonzalez, G.

2001-01-01

The answer of the dosimetry systems is affected by several factors , as the temperature, humidity, light, concentration of oxygen, dose rate, energy spectrum and one can also add the technological conditions of the irradiation process. It should be known as these factors influence in each one of the different dosimetry systems and this way to minimize their effect in the value of the absorbed dose and to obtain exact values . The objective of this paper is to know the influence of the dose rate in the value of the absorbed dose in the Amber 3042 Perspex dosimeters, Batch L, for different measurement wavelengths, as well as, the relation between the post-irradiation time and the induced specific absorbance value in function of the absorbed dose

Dinosaur trackways from the early Late Cretaceous of western Cameroon

Science.gov (United States)

Martin, Jeremy E.; Menkem, Elie Fosso; Djomeni, Adrien; Fowe, Paul Gustave; Ntamak-Nida, Marie-Joseph

2017-10-01

Dinosaur trackways have rarely been reported in Cretaceous strata across the African continent. To the exception of ichnological occurrences in Morocco, Tunisia, Niger and Cameroon, our knowledge on the composition of Cretaceous dinosaur faunas mostly relies on skeletal evidence. For the first time, we document several dinosaur trackways from the Cretaceous of the Mamfe Basin in western Cameroon. Small and medium-size tridactyl footprints as well as numerous large circular footprints are present on a single horizon showing mudcracks and ripple marks. The age of the locality is considered Cenomanian-Turonian and if confirmed, this ichnological assemblage could be younger than the dinosaur footprints reported from northern Cameroon, and coeval with or younger than skeletal remains reported from the Saharan region. These trackways were left in an adjacent subsiding basin along the southern shore of the Benue Trough during a time of high-sea stand when the Trans-Saharan Seaway was already disconnecting West Africa from the rest of the continent. We predict that other similar track sites may be occurring along the margin of the Benue Trough and may eventually permit to test hypotheses related to provincialism among African dinosaur faunas.

Coal depositional models in some tertiary and cretaceous coal fields in the US western interior

Energy Technology Data Exchange (ETDEWEB)

Flores, R M

1979-12-01

Detailed stratigraphic and sedimentological studies of the Tertiary Tongue River Member of the Fort Union Formation in the Powder River Basin, Wyoming, and the Cretaceous Blackhawk Formation and Star Point Sandstone in the Wasatch Plateau, Utah, indicate that the depositional environments of coal played a major role in controlling coal thickness, lateral continuity, potential minability, and type of floor and roof rocks. The potentially minable, thick coal beds of the Tongue River Member were primarily formed in long-lived floodbasin backswamps of upper alluvial plain environment. Avulsion of meandering fluvial channels contributed to the erratic lateral extent of coals in this environment. Laterally extensive coals formed in floodbasin backswamps of a lower alluvial plain environment; however, interruption by overbank and crevasse-splay sedimentation produced highly split and merging coal beds. Lacustrine sedimentation common to the lower alluvial plain, similar to the lake-covered lower alluvial valley of the Atchafalaya River Basin, is related to a high-constructive delta. In contrast to these alluvial coals are the deltaic coal deposits of the Blackhawk Formation. The formation consists of three coal populations: upper delta plain, lower delta plain, and back-barrier. Coals of the lower delta plain are thick and laterally extensive, in contrast to those of the upper delta plain and back-barrier, which contain abundant, very thin and laterally discontinuous carbonaceous shale partings. The reworking of the delta-front sediments of the Star Point Sandstone suggests that the Blackhawk-Star Point delta was a high-destructive system. 1 figure, 1 table.

Synthesis of bacteriophage-coded gene products during infection of Escherichia coli with amber mutants of T3 and T7 defective in gene 1

DEFF Research Database (Denmark)

Issinger, O G; Hausmann, R

1973-01-01

During nonpermissive infection by a T7 amber mutant in gene 1 (phage RNA polymerase-deficient), synthesis of the products of the phage genes 3 (endonuclease), 3, 5 (lysozyme), 5 (DNA polymerase), and 17 (serum blocking power) was shown to occur at about half the rate as during wild-type infection...

Geotechnical properties of La Arganosa Formation (Upper Cretaceous, Oviedo); Propiedades geotecnicas de la Formacion La Arganosa (Cretacico Superior, Oviedo)

Energy Technology Data Exchange (ETDEWEB)

Pando, L.; Gutierrez Claverol, M.; Flor-Blanco, G.

2011-07-01

It is performed the first geotechnical synthesis for La Arganosa Formation, the Cretaceous lithostratigraphic unit with very low geomechanical quality under the urban core of Oviedo; it also configures a major regional aquifer. In this study, geotechnical parameters of identification and condition, as well as physical and hydraulic ones, are compiled, statistically treated and interpreted. They were obtained from about 400 laboratory tests and more than 250 field tests around the city. The unit, of detrital origin, is bounded at the bottom and top by limestone lithologies, and is made up of soils and very soft rocks in alternating granular and cohesive layers. It discusses the main properties that define its geotechnical behavior: particle size distribution, plasticity, strength, compactness, consistency, compressibility, expansivity, collapsibility, permeability, and chemical aggressiveness of the materials and water. Furthermore, same numerical values are provided for reference forward guidance for future research to develop on this formation. (Author) 31 refs.

Electrical, spectral and optical performance of yellow-green and amber micro-pixelated InGaN light-emitting diodes

Science.gov (United States)

Gong, Z.; Liu, N. Y.; Tao, Y. B.; Massoubre, D.; Xie, E. Y.; Hu, X. D.; Chen, Z. Z.; Zhang, G. Y.; Pan, Y. B.; Hao, M. S.; Watson, I. M.; Gu, E.; Dawson, M. D.

2012-01-01

Micro-pixelated InGaN LED arrays operating at 560 and 600 nm, respectively, are demonstrated for what the authors believe to be the first time. Such devices offer applications in areas including bioinstrumentation, visible light communications and optoelectronic tweezers. The devices reported are based on new epitaxial structures, retaining conventional (0 0 0 1) orientation, but incorporating electron reservoir layers which enhance the efficiency of radiative combination in the active regions. A measured output optical power density up to 8 W cm-2 (4.4 W cm-2) has been achieved from a representative pixel of the yellow-green (amber) LED array, substantially higher than that from conventional broad-area reference LEDs fabricated from the same wafer material. Furthermore, these micro-LEDs can sustain a high current density, up to 4.5 kA cm-2, before thermal rollover. A significant blueshift of the emission wavelength with increasing injection current is observed, however. This blueshift saturates at 45 nm (50 nm) for the yellow-green (amber) LED array, and numerical simulations have been used to gain insight into the responsible mechanisms in this microstructured format of device. In the relatively low-current-density regime (screening of the piezoelectric field by the injected carriers and the band-filling effect, whereas in the high-current regime, it is mainly due to band-filling. Further development of the epitaxial wafer material is expected to improve the current-dependent spectral stability.

Dimensional oscillation. A fast variation of energy embedding gives good results with the AMBER potential energy function.

Science.gov (United States)

Snow, M E; Crippen, G M

1991-08-01

The structure of the AMBER potential energy surface of the cyclic tetrapeptide cyclotetrasarcosyl is analyzed as a function of the dimensionality of coordinate space. It is found that the number of local energy minima decreases as the dimensionality of the space increases until some limit at which point equipotential subspaces appear. The applicability of energy embedding methods to finding global energy minima in this type of energy-conformation space is explored. Dimensional oscillation, a computationally fast variant of energy embedding is introduced and found to sample conformation space widely and to do a good job of finding global and near-global energy minima.

Rhinochelys amaberti Moret (1935, a protostegid turtle from the Early Cretaceous of France

Directory of Open Access Journals (Sweden)

Isaure Scavezzoni

2018-04-01

Full Text Available Modern marine turtles (chelonioids are the remnants of an ancient radiation that roots in the Cretaceous. The oldest members of that radiation are first recorded from the Early Cretaceous and a series of species are known from the Albian-Cenomanian interval, many of which have been allocated to the widespread but poorly defined genus Rhinochelys, possibly concealing the diversity and the evolution of early marine turtles. In order to better understand the radiation of chelonioids, we redescribe the holotype and assess the taxonomy of Rhinochelys amaberti Moret (1935 (UJF-ID.11167 from the Late Albian (Stoliczkaia dispar Zone of the Vallon de la Fauge (Isère, France. We also make preliminary assessments of the phylogenetic relationships of Chelonioidea using two updated datasets that widely sample Cretaceous taxa, especially Rhinochelys. Rhinochelys amaberti is a valid taxon that is supported by eight autapomorphies; an emended diagnosisis proposed. Our phylogenetic analyses suggest that Rhinochelys could be polyphyletic, but constraining it as a monophyletic entity does not produce trees that are significantly less parsimonious. Moreover, support values and stratigraphic congruence indexes are fairly low for the recovered typologies, suggesting that missing data still strongly affect our understanding of the Cretaceous diversification of sea turtles.

Arctic black shale formation during Cretaceous Oceanic Anoxic Event 2

DEFF Research Database (Denmark)

Lenniger, Marc; Nøhr-Hansen, Henrik; Hills, Len V.

2014-01-01

The Late Cretaceous Oceanic Anoxic Event 2 (OAE2) represents a major perturbation of the global carbon cycle caused by the widespread deposition of organic-rich black shales. Although the paleoceanographic response and the spatial extent of bottom-water anoxia in low and mid-paleolatitudes are re......The Late Cretaceous Oceanic Anoxic Event 2 (OAE2) represents a major perturbation of the global carbon cycle caused by the widespread deposition of organic-rich black shales. Although the paleoceanographic response and the spatial extent of bottom-water anoxia in low and mid...... caused massive organic-carbon burial on the Arctic shelf in general, with important implications for hydrocarbon source-rock distribution in the Arctic region....

Image Analysis and Estimation of Porosity and Permeability of Arnager Greensand, Upper Cretaceous, Denmark

DEFF Research Database (Denmark)

Solymar, Mikael; Fabricius, Ida

1999-01-01

Arnager Greensand consists of unconsolidated, poorly sorted fine-grained, glauconitic quartz sand, often silty or clayey, with a few horizons of cemented coarse-grained sand. Samples from the upper part of the Arnager Greensand were used for this study to estimate permeability from microscopic...... images. Backscattered Scanning Electron Microscope images from polished thin-sections were acquired for image analysis with the software PIPPIN(R). Differences in grey levels owing to density differences allowed us to estimate porosity, clay and particle content. The images were simplified into two...

[Proceedings of the 5th Symposium on Mesozoic and Cenozoic Decapod Crustaceans, Krakow, Poland, 2013: A tribute to Pál Mihály Müller / R.H.B. Fraaije, M. Hyžný, J.W.M. Jagt, M. Krobicki & B.W.M. van Bakel (eds.)]: Pristinaspinidae, a new family of Cretaceous kiwaiform stem-lineage squat lobster (Anomura, Chirostyloidea)

NARCIS (Netherlands)

Ahyong, S.T.; Roterman, C.N.

2014-01-01

The chirostyloid squat lobster Pristinaspina gelasina from the Upper Cretaceous of Alaska is most closely related to members of the genus Kiwa (Kiwaidae) as indicated by the presence of supraocular spines, a medially carinate rostrum and similar carapace groove patterns. Evidence from morphology,

Source rock potential of middle cretaceous rocks in Southwestern Montana

Science.gov (United States)

Dyman, T.S.; Palacas, J.G.; Tysdal, R.G.; Perry, W.J.; Pawlewicz, M.J.

1996-01-01

The middle Cretaceous in southwestern Montana is composed of a marine and nonmarine succession of predominantly clastic rocks that were deposited along the western margin of the Western Interior Seaway. In places, middle Cretaceous rocks contain appreciable total organic carbon (TOC), such as 5.59% for the Mowry Shale and 8.11% for the Frontier Formation in the Madison Range. Most samples, however, exhibit less than 1.0% TOC. The genetic or hydrocarbon potential (S1+S2) of all the samples analyzed, except one, yield less than 1 mg HC/g rock, strongly indicating poor potential for generating commercial amounts of hydrocarbons. Out of 51 samples analyzed, only one (a Thermopolis Shale sample from the Snowcrest Range) showed a moderate petroleum potential of 3.1 mg HC/g rock. Most of the middle Cretaceous samples are thermally immature to marginally mature, with vitrinite reflectance ranging from about 0.4 to 0.6% Ro. Maturity is high in the Pioneer Mountains, where vitrinite reflectance averages 3.4% Ro, and at Big Sky Montana, where vitrinite reflectance averages 2.5% Ro. At both localities, high Ro values are due to local heat sources, such as the Pioneer batholith in the Pioneer Mountains.

New Mid-Cretaceous (Latest Albian) Dinosaurs from Winton, Queensland, Australia

Science.gov (United States)

Hocknull, Scott A.; White, Matt A.; Tischler, Travis R.; Cook, Alex G.; Calleja, Naomi D.; Sloan, Trish; Elliott, David A.

2009-01-01

Background Australia's dinosaurian fossil record is exceptionally poor compared to that of other similar-sized continents. Most taxa are known from fragmentary isolated remains with uncertain taxonomic and phylogenetic placement. A better understanding of the Australian dinosaurian record is crucial to understanding the global palaeobiogeography of dinosaurian groups, including groups previously considered to have had Gondwanan origins, such as the titanosaurs and carcharodontosaurids. Methodology/Principal Findings We describe three new dinosaurs from the late Early Cretaceous (latest Albian) Winton Formation of eastern Australia, including; Wintonotitan wattsi gen. et sp. nov., a basal titanosauriform; Diamantinasaurus matildae gen. et sp. nov., a derived lithostrotian titanosaur; and Australovenator wintonensis gen. et sp. nov., an allosauroid. We compare an isolated astragalus from the Early Cretaceous of southern Australia; formerly identified as Allosaurus sp., and conclude that it most-likely represents Australovenator sp. Conclusion/Significance The occurrence of Australovenator from the Aptian to latest Albian confirms the presence in Australia of allosauroids basal to the Carcharodontosauridae. These new taxa, along with the fragmentary remains of other taxa, indicate a diverse Early Cretaceous sauropod and theropod fauna in Australia, including plesiomorphic forms (e.g. Wintonotitan and Australovenator) and more derived forms (e.g. Diamantinasaurus). PMID:19584929

New Mid-Cretaceous (latest Albian dinosaurs fromWinton, Queensland, Australia.

Directory of Open Access Journals (Sweden)

Scott A Hocknull

Full Text Available BACKGROUND: Australia's dinosaurian fossil record is exceptionally poor compared to that of other similar-sized continents. Most taxa are known from fragmentary isolated remains with uncertain taxonomic and phylogenetic placement. A better understanding of the Australian dinosaurian record is crucial to understanding the global palaeobiogeography of dinosaurian groups, including groups previously considered to have had Gondwanan origins, such as the titanosaurs and carcharodontosaurids. METHODOLOGY/PRINCIPAL FINDINGS: We describe three new dinosaurs from the late Early Cretaceous (latest Albian Winton Formation of eastern Australia, including; Wintonotitan wattsi gen. et sp. nov., a basal titanosauriform; Diamantinasaurus matildae gen. et sp. nov., a derived lithostrotian titanosaur; and Australovenator wintonensis gen. et sp. nov., an allosauroid. We compare an isolated astragalus from the Early Cretaceous of southern Australia; formerly identified as Allosaurus sp., and conclude that it most-likely represents Australovenator sp. CONCLUSION/SIGNIFICANCE: The occurrence of Australovenator from the Aptian to latest Albian confirms the presence in Australia of allosauroids basal to the Carcharodontosauridae. These new taxa, along with the fragmentary remains of other taxa, indicate a diverse Early Cretaceous sauropod and theropod fauna in Australia, including plesiomorphic forms (e.g. Wintonotitan and Australovenator and more derived forms (e.g. Diamantinasaurus.

An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina

Science.gov (United States)

Apesteguía, Sebastián; Smith, Nathan D.; Juárez Valieri, Rubén; Makovicky, Peter J.

2016-01-01

Background Late Cretaceous terrestrial strata of the Neuquén Basin, northern Patagonia, Argentina have yielded a rich fauna of dinosaurs and other vertebrates. The diversity of saurischian dinosaurs is particularly high, especially in the late Cenomanian-early Turonian Huincul Formation, which has yielded specimens of rebacchisaurid and titanosaurian sauropods, and abelisaurid and carcharodontosaurid theropods. Continued sampling is adding to the known vertebrate diversity of this unit. Methodology/ Principal Findings A new, partially articulated mid-sized theropod was found in rocks from the Huincul Formation. It exhibits a unique combination of traits that distinguish it from other known theropods justifying erection of a new taxon, Gualicho shinyae gen. et sp. nov. Gualicho possesses a didactyl manus with the third digit reduced to a metacarpal splint reminiscent of tyrannosaurids, but both phylogenetic and multivariate analyses indicate that didactyly is convergent in these groups. Derived characters of the scapula, femur, and fibula supports the new theropod as the sister taxon of the nearly coeval African theropod Deltadromeus and as a neovenatorid carcharodontosaurian. A number of these features are independently present in ceratosaurs, and Gualicho exhibits an unusual mosaic of ceratosaurian and tetanuran synapomorphies distributed throughout the skeleton. Conclusions/ Significance Gualicho shinyae gen. et sp. nov. increases the known theropod diversity of the Huincul Formation and also represents the first likely neovenatorid from this unit. It is the most basal tetatanuran to exhibit common patterns of digit III reduction that evolved independently in a number of other tetanuran lineages. A close relationship with Deltadromaeus from the Kem Kem beds of Niger adds to the already considerable biogeographic similarity between the Huincul Formation and coeval rock units in North Africa. PMID:27410683

Cretaceous magmatism in North-Eastern India and Gondwanaland ...

Indian Academy of Sciences (India)

jsray

Cretaceous magmatism of NEI: Major Objectives. • Age and duration of Sylhet Traps and its connection to Kerguelene hotspot and Gondwanaland breakup? • Age of carbonatite magmatism associated with the traps? • Relationship of basaltic-carbonatite magmatism with. Aptian (~116 Ma) Mass Extinction event? • Nature of ...

ESR characterization of point defects in amber colored c-BN super abrasive powders

International Nuclear Information System (INIS)

Nistor, S.V.; Ghica, D.; Stefan, M.; Bouwen, A.; Goovaerts, E.

2004-01-01

Cubic boron nitride (c-BN) crystalline superabrasive powder (Borazon ** CBN 400), consisting of 200-300 microns sized amber colored crystallites prepared by HP/HT synthesis, has been examined from 2.1 K to 293 K by X-band ESR spectroscopy. The observed spectrum consists of a component line A1, visible in the whole temperature range, and two component lines A2 and A3, visible at high and low temperatures, respectively. The A1 and A3 lines originate from transitions inside S = 1/2 ground states of distinct paramagnetic species and A2 from transitions inside an excited state of another paramagnetic center. The intensity of the A1 and A3 lines changes differently during in situ low temperature illumination in the UV-VIS range. * Borazon is a registered trademark of Diamond Innovations, Inc. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Large-scale compensation of errors in pairwise-additive empirical force fields: comparison of AMBER intermolecular terms with rigorous DFT-SAPT calculations

Czech Academy of Sciences Publication Activity Database

Zgarbová, M.; Otyepka, M.; Šponer, Jiří; Hobza, P.; Jurečka, P.

2010-01-01

Roč. 12, č. 35 (2010), s. 10476-10493 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA203/09/1476 Grant - others:GA MŠk(CZ) LC512; GA MŠk(CZ) GD203/09/H046 Program:LC; GD Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : amber empirical potential * DFT-SAPT * compensation of errors Subject RIV: BO - Biophysics Impact factor: 3.454, year: 2010

Sedimentary basin analysis and petroleum potential of the Cretaceous and Tertiary strata in Korea.

Energy Technology Data Exchange (ETDEWEB)

Son, Jin-Dam; Kwak, Young-Hoon; Bong, Pil-Yoon [Korea Institute of Geology Mining and Materials, Taejon (KR)] (and others)

1999-12-01

Since 1992 sedimentary basin analysis to assess petroleum potential of the Cretaceous and Tertiary strata in the Korean onshore and continental shelf have been carried out. The Cretaceous non-marine strata mainly occupy the Gyeongsang Basin in southeastern part of the Korean Peninsula and small basins such as Haenam and Gyeokpo depressions in western coastal areas. The Tertiary strata are mostly distributed in Domi, Cheju, Socotra subbasins, and Okinawa Trough in the South Continental Shelf, and Kunsan and Heuksan basins in the West. The basin evolution and petroleum potential for each basins are characterized as follow. The Cretaceous Gyeongsang sediments were deposited in three subbasins including Milyang, Euisung and Yongyang subbasins. The black shales in Nakdong and Jinju formations are interpreted to contain abundant organic matter during the deposition, thermal maturity reaching up to the zone of dry gas formation. Because porosity and permeability are too low, the sandstones can act as a tight gas reservoir rather than conventional oil and gas reservoir. The latest Cretaceous strata of Haenam and Kyeokpo depressions in western coastal area are correlated into the Yuchon Volcanic Group of the Gyeongsang Basin. Petroleum potential of the Early Cretaceous basin in the West Continental Shelf could be relatively high in terms of sedimentary basin filled with thick lacustrine sediments. The Kunsan basin in the West Continental Shelf originated in the Early Cretaceous time expanded during the Paleocene time followed by regional erosion at the end of Paleocene on which Neogene sediment have been accumulated. The Paleocene-Eocene sublacustrine shales may play an major role as a source and cap rocks. South Continental Shelf Basin is subdivided by Cheju subbasin in the center, Socotra Subbasin to the west, Domi Subbasin to the northeast and Okinawa Trough to the East. The potential hydrocarbon traps associated with anticline, titled fault blocks, fault, unconformity

Stratigraphic position, origin and characteristics of manganese mineralization horizons in the Late Cretaceous volcano-sedimentary sequence, south-southwest of Sabzevar

Directory of Open Access Journals (Sweden)

Sajjad Maghfouri

2014-10-01

Full Text Available Introduction The Mn mineralization occurs in the northeastern segment of the Sabzevar zone (SZ, north of the Central Iranian Microcontinent (CIM. This Zone (SZ is located between the CIM fragmentation in the south and the Kopeh dagh sedimentary sequence in the north. The ore deposits of the northeastern segment of the Sabzevar zone can be divided into three groups, each with different metal association and spatial distribution and each related to a major geodynamic event. The first mineralization with associated Ordovician host rock is characterized by Taknar polymetallic (Fe-rich massive sulfide deposit. The Cretaceous mineralization consists of Cr deposits associated with serpentinized peridotites, Cyprus type VMS, Mn deposit in pillow lava, volcano-sedimentary hosted Besshi type VMS and Mn deposit. Paleogene mineralization in eastern segment of the Sabzevar zone began with porphyry deposits, Cu Red Bed mineralization occurs in the Paleogene sandy red marl. Materials and methods A field study and sampling was performed during the autumn of 2012. To assess the geochemical characteristics of 48 systematic samples (least fractured and altered of ore-bearing layers and host rocks were collected from the deposit for polished thin section examination. In order to correctly characterize their chemical compositions, 15 least-altered and fractured samples were chosen for major elements analysis. Results The Late Cretaceous volcano-sedimentary sequence in south-southwest of Sabzevar hosts numerous manganese mineralization. The sequence based on the stratigraphic position, age and composition of the rocks, can be divided into two lower and upper parts. The lower part or K2tv unit mainly formed from marine sediments interbedded with volcanic rocks. The sedimentary rocks of this part include silicified tuff, chert, shale and sandstone, and the volcanic rocks involve pyroclastic rocks of various composition, rhyolite, dacite and andesitic lava. The upper

A diplodocid sauropod survivor from the early cretaceous of South America.

Directory of Open Access Journals (Sweden)

Pablo A Gallina

Full Text Available Diplodocids are by far the most emblematic sauropod dinosaurs. They are part of Diplodocoidea, a vast clade whose other members are well-known from Jurassic and Cretaceous strata in Africa, Europe, North and South America. However, Diplodocids were never certainly recognized from the Cretaceous or in any other southern land mass besides Africa. Here we report a new sauropod, Leikupal laticauda gen. et sp. nov., from the early Lower Cretaceous (Bajada Colorada Formation of Neuquén Province, Patagonia, Argentina. This taxon differs from any other sauropod by the presence of anterior caudal transverse process extremely developed with lateroventral expansions reinforced by robust dorsal and ventral bars, very robust centroprezygapophyseal lamina in anterior caudal vertebra and paired pneumatic fossae on the postzygapophyses in anterior-most caudal vertebra. The phylogenetic analyses support its position not only within Diplodocidae but also as a member of Diplodocinae, clustering together with the African form Tornieria, pushing the origin of Diplodocoidea to the Middle Jurassic or even earlier. The new discovery represents the first record of a diplodocid for South America and the stratigraphically youngest record of this clade anywhere.

A new dinosaur ichnotaxon from the Lower Cretaceous Patuxent Formation of Maryland and Virginia

Science.gov (United States)

Stanford, Ray; Weems, Robert E.; Lockley, Martin G.

2004-01-01

In recent years, numerous dinosaur footprints have been discovered on bedding surfaces within the Lower Cretaceous Patuxent Formation of Maryland and Virginia. Among these, distinctive small tracks that display a combination of small manus with five digit impressions and a relatively much larger pes with four toe impressions evidently were made by animals belonging to the ornithischian family Hypsilophodontidae. These tracks differ from any ornithischian ichnotaxon previously described. We here name them Hypsiloichnus marylandicus and provide a description of their diagnostic characteristics. Although hypsilophodontid skeletal remains have not been found in the Patuxent, their skeletal remains are known from Lower Cretaceous strata of similar age in both western North America and Europe. Therefore, it is not surprising to find that an Early Cretaceous representative of this family also existed in eastern North America.

Oil geochemistry of the Putumayo basin

International Nuclear Information System (INIS)

Ramon, J.C

1996-01-01

Bio marker fingerprinting of 2O crude oils from Putumayo Basin, Colombia, shows a vertical segregation of oil families. The Lower Cretaceous reservoirs (Caballos and 'U' Villeta sands) contain oils that come from a mixture of marine and terrestrial organic matter, deposited in a marginal, 'oxic' marine setting. The Upper Cretaceous ('T' and N ' sands) and Tertiary reservoirs contain oils with marine algal input deposited in a reducing, carbonate-rich environment. Lithology, environmental conditions and organic matter type of source rocks as predicted from oil bio marker differences correspond to organic composition of two Cretaceous source rocks. Vertical heterogeneity in the oils, even those from single wells, suggests the presence of two isolated petroleum systems. Hydrocarbons from Lower Cretaceous source rocks charged Lower Cretaceous reservoirs whereas oils from Upper Cretaceous source rocks charged Upper Cretaceous and Tertiary reservoirs. Oil migration from mature source rocks into multiple reservoirs has been stratigraphically up dip along the regional sandstone units and vertical migration through faults has been limited. Bio marker maturity parameters indicate that all oils were generated from early thermal maturity oil window

Revisions to the original extent of the Devonian Shale-Middle and Upper Paleozoic Total Petroleum System

Science.gov (United States)

Enomoto, Catherine B.; Rouse, William A.; Trippi, Michael H.; Higley, Debra K.

2016-04-11

Technically recoverable undiscovered hydrocarbon resources in continuous accumulations are present in Upper Devonian and Lower Mississippian strata in the Appalachian Basin Petroleum Province. The province includes parts of New York, Pennsylvania, Ohio, Maryland, West Virginia, Virginia, Kentucky, Tennessee, Georgia, and Alabama. The Upper Devonian and Lower Mississippian strata are part of the previously defined Devonian Shale-Middle and Upper Paleozoic Total Petroleum System (TPS) that extends from New York to Tennessee. This publication presents a revision to the extent of the Devonian Shale-Middle and Upper Paleozoic TPS. The most significant modification to the maximum extent of the Devonian Shale-Middle and Upper Paleozoic TPS is to the south and southwest, adding areas in Tennessee, Georgia, Alabama, and Mississippi where Devonian strata, including potential petroleum source rocks, are present in the subsurface up to the outcrop. The Middle to Upper Devonian Chattanooga Shale extends from southeastern Kentucky to Alabama and eastern Mississippi. Production from Devonian shale has been established in the Appalachian fold and thrust belt of northeastern Alabama. Exploratory drilling has encountered Middle to Upper Devonian strata containing organic-rich shale in west-central Alabama. The areas added to the TPS are located in the Valley and Ridge, Interior Low Plateaus, and Appalachian Plateaus physiographic provinces, including the portion of the Appalachian fold and thrust belt buried beneath Cretaceous and younger sediments that were deposited on the U.S. Gulf Coastal Plain.

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

Internal quantum efficiency in yellow-amber light emitting AlGaN-InGaN-GaN heterostructures

Energy Technology Data Exchange (ETDEWEB)

Ngo, Thi Huong; Gil, Bernard; Valvin, Pierre [Laboratoire Charles Coulomb – UMR 5221, CNRS and University Montpellier, Case courier 074, 34095 Montpellier Cedex 5 (France); Damilano, Benjamin; Lekhal, Kaddour; De Mierry, Philippe [CRHEA-CNRS Centre de Recherche sur l' Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, rue Bernard Gregory, 06560 Valbonne (France)

2015-09-21

We determine the internal quantum efficiency of strain-balanced AlGaN-InGaN-GaN hetero-structures designed for yellow-amber light emission, by using a recent model based on the kinetics of the photoluminescence decay initiated by Iwata et al. [J. Appl. Phys. 117, 075701 (2015)]. Our results indicate that low temperature internal quantum efficiencies sit in the 50% range and we measure that adding an AlGaN layer increases the internal quantum efficiency from 50% up to 57% with respect to the GaN-InGaN case. More dramatic, it almost doubles from 2.5% up to 4.3% at room temperature.

Geochemical features of the Cretaceous alkaline volcanics in the area of Morado hill, Jachal town, San Juan, Argentina

International Nuclear Information System (INIS)

Perez, L.

2010-01-01

This paper is about the alkaline volcanic rocks that crop out at the Morado hill located in the southern end of the Mogna ranges, which are part of the Eastern border of the pre mountain in the San Juan province, Argentina.The petrography and geochemistry study of the alkaline volcanics has allowed to classify them as tephrite basanite or basanite nephelinite, with strong alkaline chemical affinity, showing a characteristic composition of within plate geochemistry environment. The radimetric analysis, K-Ar data, has shown an average 90 ∓ 8 m.y. age for this rocks, (Cingolani et al. 1984) pointing out the Upper Cretaceous (lower section) stratigraphical position for the suite. The discussion of the results makes conspicuous the relationships of these alkaline rocks with others of the central and northwestern regions of the country that allowed to establish an alkaline petrographic province

Palaeomagnetism of lower cretaceous tuffs from Yukon-Kuskokwim delta region, western Alaska

Science.gov (United States)

Globerman, B.R.; Coe, R.S.; Hoare, J.M.; Decker, J.

1983-01-01

During the past decade, the prescient arguments1-3 for the allochthoneity of large portions of southern Alaska have been corroborated by detailed geological and palaeomagnetic studies in south-central Alaska 4-9 the Alaska Peninsula10, Kodiak Island11,12 and the Prince William Sound area13 (Fig. 1). These investigations have demonstrated sizeable northward displacements for rocks of late Palaeozoic, Mesozoic, and early Tertiary age in those regions, with northward motion at times culminating in collision of the allochthonous terranes against the backstop of 'nuclear' Alaska14,15. A fundamental question is which parts of Alaska underwent significantly less latitudinal translation relative to the 'stable' North American continent, thereby serving as the 'accretionary nucleus' into which the displaced 'microplates'16 were eventually incorporated17,18? Here we present new palaeomagnetic results from tuffs and associated volcaniclastic rocks of early Cretaceous age from the Yukon-Kuskokwin delta region in western Alaska. These rocks were probably overprinted during the Cretaceous long normal polarity interval, although a remagnetization event as recent as Palaeocene cannot be ruled out. This overprint direction is not appreciably discordant from the expected late Cretaceous direction for cratonal North America. The implied absence of appreciable northward displacement for this region is consistent with the general late Mesozoic-early Tertiary tectonic pattern for Alaska, based on more definitive studies: little to no poleward displacement for central Alaska, though substantially more northward drift for the 'southern Alaska terranes' (comprising Alaska Peninsula, Kodiak Island, Prince William Sound area, and Matunuska Valley) since late Cretaceous to Palaeocene time. ?? 1983 Nature Publishing Group.

The end-Cretaceous in the southwestern Tethys (Elles, Tunisia)

DEFF Research Database (Denmark)

Thibault, Nicolas Rudolph; Galbrun, Bruno; Gardin, Silvia

2016-01-01

An integrated study of magnetic mass susceptibility (MS), bulk stable isotopes and calcareous nannofossil paleoecological changes is undertaken on the late Maastrichtian of the Elles section, Tunisia, spanning the last ca. 1 Myr of the Cretaceous. A cyclostratigraphic analysis reveals the presenc...

Explosive radiation of Malpighiales supports a mid-cretaceous origin of modern tropical rain forests.

Science.gov (United States)

Davis, Charles C; Webb, Campbell O; Wurdack, Kenneth J; Jaramillo, Carlos A; Donoghue, Michael J

2005-03-01

Fossil data have been interpreted as indicating that Late Cretaceous tropical forests were open and dry adapted and that modern closed-canopy rain forest did not originate until after the Cretaceous-Tertiary (K/T) boundary. However, some mid-Cretaceous leaf floras have been interpreted as rain forest. Molecular divergence-time estimates within the clade Malpighiales, which constitute a large percentage of species in the shaded, shrub, and small tree layer in tropical rain forests worldwide, provide new tests of these hypotheses. We estimate that all 28 major lineages (i.e., traditionally recognized families) within this clade originated in tropical rain forest well before the Tertiary, mostly during the Albian and Cenomanian (112-94 Ma). Their rapid rise in the mid-Cretaceous may have resulted from the origin of adaptations to survive and reproduce under a closed forest canopy. This pattern may also be paralleled by other similarly diverse lineages and supports fossil indications that closed-canopy tropical rain forests existed well before the K/T boundary. This case illustrates that dated phylogenies can provide an important new source of evidence bearing on the timing of major environmental changes, which may be especially useful when fossil evidence is limited or controversial.

Mass Wasting during the Cretaceous/Tertiary Transition in the North Atlantic: Relationship to the Chicxulub Impact?

Science.gov (United States)

Mateo, Paula; Keller, Gerta; Adatte, Thierry; Spangenberg, Jorge

2015-04-01

Deep-sea sections in the North Atlantic are claimed to contain the most complete sedimentary records and ultimate proof that the Chicxulub impact is Cretaceous-Tertiary boundary (KTB) in age and caused the mass extinction. A multi-disciplinary study of North Atlantic DSDP Sites 384, 386 and 398, based on high-resolution planktonic foraminiferal biostratigraphy, carbon and oxygen stable isotopes, clay and whole-rock mineralogy and granulometry, reveals the age, stratigraphic completeness and nature of sedimentary disturbances. Results show a major KTB hiatus at Site 384 with zones CF1, P0 and P1a missing, spanning at least ~540 ky, similar to other North Atlantic and Caribbean localities associated with tectonic activity and Gulf Stream erosion. At Sites 386 and 398, discrete intervals of disturbed sediments with mm-to-cm-thick spherule layers have previously been interpreted as KTB age impact-generated earthquakes destabilizing continental margins prior to settling of impact spherules. However, improved age control based on planktonic foraminifera indicates deposition in the early Danian zone P1a(2) (upper Parvularugoglobigerina eugubina zone) more than 100 ky after the KTB. At Site 386, two intervals of white chalk contain very small (winnowing via distal turbidites. At Site 398, convoluted red to tan sediments with early Danian and reworked Cretaceous species represent slumping of shallow water sediments as suggested by dominance of mica and low smectite compared to in situ deposition. We conclude that mass wasting was likely the result of earthquakes associated with increased tectonic activity in the Caribbean and the Iberian Peninsula during the early Danian well after the Chicxulub impact.

Exhumation History Of Brasilian Highlands After Late Cretaceous Alcaline Magmatism

Science.gov (United States)

Doranti Tiritan, Carolina; Hackspacher, Peter Christian; Carina Siqueira Ribeiro, Marli; Glasmacher, Ulrich Anton; Françoso de Godoy, Daniel

2017-04-01

The southeast Brazilian margin recorded a long history of tectonic and magmatic events after the Gondwana continent break up. The drifting of the South American Platform over a thermal anomaly generated a series of alkaline intrusions that are distributed from the interior to the coast from west to east. Several exhumation events are recorded on the region and we are providing insights on the landscape evolution of the region since Late Cretaceous, comparing low temperature thermochronology results from two alkaline intrusions regions. Poços de Caldas Alkaline Massif (PCAM), is lied in the interior, 300km from the coastline, covering over 800km2 intruding the Precambrian basement around 83Ma, nepheline syenites, phonolites and tinguaites intruded in a continuous and rapid sequence lasting between 1 to 2 Ma. São Sebastião Island (SSI) on the other hand is located at the coast, 200 km southeast of São Paulo. It is characterized by an intrusion in Precambrian/Brazilian orogen and intruded by Early Cretaceous sub-alkaline basic and acid dykes, as well as by Late Cretaceous alkaline stocks (syenites) and dykes (basanite to phonolite). Will be presenting the apatite fission track (AFT) and (U-Th)/He results that shows the main difference between the areas is that PCAM region register older history then the coastal area of SSI, where thermal history starts register cooling event after the South Atlantic rifting process, while in the PCAM area register a previous history, since Carboniferous. The results are giving support to studies that indicate the development of the relief in Brazil being strongly influenced by the local and regional tectonic movements and the lithological and structural settings. The landscape at the Late Cretaceous was witness of heating process between 90 and 60Ma due the intense uplift of South American Platform. The elevation of the isotherms is associated with the mantellic plumes and the crustal thickness that caused thermal anomalies due

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.

Extended Late-Cretaceous Magnetostratigraphy of the James Ross Basin Island, Antarctica

Science.gov (United States)

Chaffee, T. M.; Mitchell, R.; Slotznick, S. P.; Buz, J.; Biasi, J.; O'Rourke, J.; Sousa, F.; Flannery, D.; Fu, R. R.; Kirschvink, J. L.

2017-12-01

Sediments in the James Ross Island Basin (JRB) in the West Antarctic Peninsula contain one of the world's highest-resolution records of the late Cretaceous period, including the end-Cretaceous (K-Pg) mass extinction event. However, the geological record of this region has been poorly studied, limited in the past only to the relative dating of local fossils. Recent studies of this region have provided only low-resolution data, with gaps of greater than 0.5 million years between samples where no data was collected. A high-resolution magnetostratigraphic sampling and analysis is necessary in order to accurately determine the age of the JRB sediments and connect them to the global time record. During the 2016 field season in Antarctica, our team collected nearly 1,300 sample cores from JRB sediments using a diamond-tipped, gasoline powered coring drill. Drill sites were densely clustered across bedding in order to obtain a high-resolution record of magnetostratigraphy, permitting the recognition of distinct, high-resolution units of time (group of over 300 of these samples from the Brandy Bay area which constrain the end of the Cretaceous Superchron (C34N) and the C34N/C34R reversal and allow us to investigate the presence of geomagnetic excursions before the end of superchron. These samples span in age from the top of C34N to the mid-Maastrichtian. We also test the Late Cretaceous True Polar Wander (TPW) hypothesis. Current theories on the global extent of TPW are not substantiated by any data sets that confirm the presence and similarity of the effect across multiple continents. Evidence of a rapid TPW oscillation in Antarctica can be correlated with other samples from the North American continent currently under study to provide evidence for the theory of global, short-timescale TPW.

Provenance and geochronological insights into Late Cretaceous-Paleogene foreland basin development in the Subandean Zone and Oriente Basin of Ecuador

Science.gov (United States)

Gutierrez, E. G.; Horton, B. K.; Vallejo, C.

2017-12-01

The tectonic history of the Oriente foreland basin and adjacent Subandean Zone of Ecuador during contractional mountain building in the northern Andes can be revealed through integrated stratigraphic, geochronological, structural, and provenance analyses of clastic sediments deposited during orogenesis. We present new maximum depositional ages and a comprehensive provenance analysis for key stratigraphic units deposited in the western (proximal) Oriente Basin. Detrital zircon U-Pb ages were obtained from Upper Cretaceous and Cenozoic clastic formations from exposures in the Subandean Zone. The sampled stratigraphic intervals span critical timeframes during orogenesis in the Ecuadorian Andes. Cenozoic formations have poorly defined chronostratigraphic relationships and are therefore a primary target of this study. In addition, the newly acquired U-Pb age spectra allow clear identification of the various sediment source regions that fed the system during distinct depositional phases. Maximum depositional ages (MDA) were obtained for five samples from three formations: the Tena (MDA=69.6 Ma), Chalcana (MDA=29.3 Ma), and Arajuno (MDA= 17.1, 14.2, 12.8 Ma) Formations, placing them in the Maastrichtian, early Oligocene, and early-middle Miocene, respectively. Detrital zircon U-Pb ages identify clear signatures of at least four different sources: craton (1600-1300 Ma, 1250-900 Ma), Eastern Cordillera fold-thrust belt (600-450 Ma, 250-145 Ma), Western Cordillera magmatic arc (age spectra of the Upper Cretaceous-Paleogene type sections allow us to recognize variations in the contribution of each recognized source over time. We identify recycled material with two dominant peak ages (1250-900 Ma and 600-450 Ma), material derived from the adjacent uplifted orogen or recycled from foredeep sediments incorporated into the deforming wedge. Finally, an apparent unroofing event is inferred from a 250-145 Ma age peak in the Plio-Pleistocene Mesa-Mera Formation revealing the

Publisher Correction: Ticks parasitised feathered dinosaurs as revealed by Cretaceous amber assemblages.

Science.gov (United States)

Peñalver, Enrique; Arillo, Antonio; Delclòs, Xavier; Peris, David; Grimaldi, David A; Anderson, Scott R; Nascimbene, Paul C; Fuente, Ricardo Pérez-de la

2018-01-30

The originally published version of this Article was updated shortly after publication to add the word 'Ticks' to the title, following its inadvertent removal during the production process. This has now been corrected in both the PDF and HTML versions of the Article.

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

Patterns of larval development in Cretaceous pipid frogs

Czech Academy of Sciences Publication Activity Database

Roček, Zbyněk; van Dijk, E.

2006-01-01

Roč. 51, č. 1 (2006), s. 111-126 ISSN 0567-7920 R&D Projects: GA AV ČR IAA3013206 Institutional research plan: CEZ:AV0Z30130516 Keywords : Anura * Pipidae * Cretaceous Subject RIV: EG - Zoology Impact factor: 1.076, year: 2006 http://app.pan.pl/archive/published/app51/app51-111.pdf

Glendonites as a paleoenvironmental tool: Implications for early Cretaceous high latitudinal climates in Australia

Science.gov (United States)

De Lurio, Jennifer L.; Frakes, L. A.

1999-04-01

Glendonites, calcite pseudomorphs after the metastable mineral ikaite (CaCO 3 · 6H 2O), occur in the Late Aptian interval of the Bulldog Shale in the Eromanga Basin, Australia and in other Early Cretaceous basins at high paleolatitudes. Ikaite precipitation in the marine environment requires near-freezing temperatures (not higher than 4°C), high alkalinity, increased levels of orthophosphate, and high P CO2. The rapid and complete transformation of ikaite to calcite at temperatures between 5 and 8°C provides an upper limit on the oxygen isotopic composition of the pore waters: -2.6 ikaite precipitation. Data previously reported as 11 to 16°C (assuming δ w = 0.0‰SMOW) yield paleotemperatures ranging from -1 to 5°C, squarely in the range of ikaite stability. The low δ w indicates hyposaline conditions, most likely caused by mixing high latitude meteoric waters with seawater. The 18O depleted, low temperature waters suggest that the region was at least seasonally colder than previously accepted.

Evidence of cretaceous to recent West African intertropical vegetation from continental sediment spore-pollen analysis

Science.gov (United States)

Salard-Cheboldaeff, M.; Dejax, J.

The succession of spore-pollen assemblages during the Cretaceous and Tertiary, as defined in each of the basin from Senegal to Angola, gives the possibility to consider the intertropical African flora evolution for the past 120 M.a. During the Early Cretaceous, xeric-adapted gymnosperms and various ferns were predominant the flora which nevertheless comprises previously unknown early angiosperm pollen. During the Middle Cretaceous, gymnospers were gradually replaced by angiosperms; these became more and more abundant, along with the diversification of new genera and species. During the Paleocene, the radiation of the monocotyledons (mainly that of the palm-trees) as well as a greater diversification among the dicotyledons and ferms are noteworthy. Since gymnosperms had almost disappeared by the Eocene, the diversification of the dicotyledons went on until the neogene, when all extinct pollen types are already present. These important modifications of the vegetation reflect evolutionary trends as well as climatic changes during the Cretaceous: the climate, firstly hot, dry and perhaps arid, did probably induced salt deposition, and later became gradually more humid under oceanic influences which arose in connection with the Gondwana break-up.

Detailed facies analysis of the Upper Cretaceous Tununk Shale Member, Henry Mountains Region, Utah: Implications for mudstone depositional models in epicontinental seas

Science.gov (United States)

Li, Zhiyang; Schieber, Juergen

2018-02-01

Lower-Middle Turonian strata of the Tununk Shale Member of the greater Mancos Shale were deposited along the western margin of the Cretaceous Western Interior Seaway during the Greenhorn second-order sea level cycle. In order to examine depositional controls on facies development in this mudstone-rich succession, this study delineates temporal and spatial relationships in a process-sedimentologic-based approach. The 3-dimensional expression of mudstone facies associations and their stratal architecture is assessed through a fully integrative physical and biologic characterization as exposed in outcrops in south-central Utah. Sedimentologic characteristics from the millimeter- to kilometer-scale are documented in order to fully address the complex nature of sediment transport mechanisms observed in this shelf muddy environment. The resulting facies model developed from this characterization consists of a stack of four lithofacies packages including: 1) carbonate-bearing, silty and sandy mudstone (CSSM), 2) silt-bearing, calcareous mudstone (SCM), 3) carbonate-bearing, silty mudstone to muddy siltstone (CMS), and 4) non-calcareous, silty and sandy mudstone (SSM). Spatial and temporal variations in lithofacies type and sedimentary facies characteristics indicate that the depositional environments of the Tununk Shale shifted in response to the 2nd-order Greenhorn transgressive-regressive sea-level cycle. During this eustatic event, the Tununk shows a characteristic vertical shift from distal middle shelf to outer shelf (CSSM to SCM facies), then from outer shelf to inner shelf environment (SCM to CMS, and to SSM facies). Shifting depositional environments, as well as changes in dominant paleocurrent direction throughout this succession, indicate multiple source areas and transport mechanisms (i.e. longshore currents, offshore-directed underflows, storm reworking). This study provides a rare documentation of the Greenhorn cycle as exposed across the entire shelf setting

Evidence for global cooling in the Late Cretaceous

Science.gov (United States)

Linnert, Christian; Robinson, Stuart A.; Lees, Jackie A.; Bown, Paul R.; Pérez-Rodríguez, Irene; Petrizzo, Maria Rose; Falzoni, Francesca; Littler, Kate; Arz, José Antonio; Russell, Ernest E.

2014-01-01

The Late Cretaceous ‘greenhouse’ world witnessed a transition from one of the warmest climates of the past 140 million years to cooler conditions, yet still without significant continental ice. Low-latitude sea surface temperature (SST) records are a vital piece of evidence required to unravel the cause of Late Cretaceous cooling, but high-quality data remain illusive. Here, using an organic geochemical palaeothermometer (TEX86), we present a record of SSTs for the Campanian–Maastrichtian interval (~83–66 Ma) from hemipelagic sediments deposited on the western North Atlantic shelf. Our record reveals that the North Atlantic at 35 °N was relatively warm in the earliest Campanian, with maximum SSTs of ~35 °C, but experienced significant cooling (~7 °C) after this to <~28 °C during the Maastrichtian. The overall stratigraphic trend is remarkably similar to records of high-latitude SSTs and bottom-water temperatures, suggesting that the cooling pattern was global rather than regional and, therefore, driven predominantly by declining atmospheric pCO2 levels. PMID:24937202

Late Cretaceous neosuchian crocodiles from the Sultanate of Oman

NARCIS (Netherlands)

Buscalioni, Angela D.; Schulp, Anne S.; Jagt, John W M; Hanna, Samir S.; Hartman, Axel Frans

Two apparently new crocodilian taxa from the Late Cretaceous (Late Campanian-Maastrichtian) Al-Khod Conglomerate of the Sultanate of Oman are described. The fragmentary state of preservation precludes formal naming, yet enables comparisons to be made with other taxa. One is a short-snouted

Evolution of Lower Brachyceran Flies (Diptera and Their Adaptive Radiation with Angiosperms

Directory of Open Access Journals (Sweden)

Bo Wang

2017-04-01

Full Text Available The Diptera (true flies is one of the most species-abundant orders of Insecta, and it is also among the most important flower-visiting insects. Dipteran fossils are abundant in the Mesozoic, especially in the Late Jurassic and Early Cretaceous. Here, we review the fossil record and early evolution of some Mesozoic lower brachyceran flies together with new records in Burmese amber, including Tabanidae, Nemestrinidae, Bombyliidae, Eremochaetidae, and Zhangsolvidae. The fossil records reveal that some flower-visiting groups had diversified during the mid-Cretaceous, consistent with the rise of angiosperms to widespread floristic dominance. These brachyceran groups played an important role in the origin of co-evolutionary relationships with basal angiosperms. Moreover, the rise of angiosperms not only improved the diversity of flower-visiting flies, but also advanced the turnover and evolution of other specialized flies.

Early Cretaceous paleomagnetic results from Marie Byrd Land, West Antarctica: Implications for the Weddellia collage of crustal blocks

Science.gov (United States)

Divenere, Vic; Kent, Dennis V.; Dalziel, Ian W. D.

1995-05-01

A new approximately 117 Ma paleomagnetic pole has been defined from the study of volcanic and plutonic rocks from the eastern portion Marie Byrd Land (MBL). The new pole (185.6 deg E/56.8 deg S, A(sub 95) = 8.7 deg) implies that the eastern portion of MBL was an integral part of Weddellia, which included the ancestral Antarctic Peninsula, Thurston Island, and Ellsworth-Whitmore Mountains blocks of West Antarctica. This pole is generally similar to a approximately 125 Ma pole from Thurston Island. Both poles call for major clockwise rotation and poleward motion of eastern MBL and Thurston Island between the Early Cretaceous (125-117 Ma) and the mid-Cretaceous (110-100 Ma). We propose that in the Early Cretaceous, eastern MBL and the Eastern Province of New Zealand were part of a continuous active Pacific margin of Gondwana, connecting with the Antarctic Peninsula, and distinct from western MBL, the Western Province of New Zealand, and North Victoria Land. These western terranes are thought to have accreted to Gondwana in the Devonian. Eastern MBL and the Eastern Province of New Zealand amalgamated with western MBL and the Western Province of New Zealand by the mid-Cretaceous. Major Early Cretaceous motions of the Weddellia blocks postdate the estimated initiation of seafloor spreading in the Weddell Sea and therefore may be the result of plate reorganization during the Cretaceous Quiet Zone.

ENSO-Type Signals Recorded in the Late Cretaceous Laminated Sediments of Songliao Basin, Northeast China

Science.gov (United States)

Yu, E.; Wang, C.; Hinnov, L. A.; Wu, H.

2014-12-01

The quasi-periodic, ca. 2-7 year El Niño Southern Oscillation (ENSO) phenomenon globally influences the inter-annual variability of temperature and precipitation. Global warming may increase the frequency of extreme ENSO events. Although the Cretaceous plate tectonic configuration was different from today, the sedimentary record suggests that ENSO-type oscillations had existed at the time of Cretaceous greenhouse conditions. Cored Cretaceous lacustrine sediments from the Songliao Basin in Northeast China (SK-1 cores from the International Continental Drilling Program) potentially offer a partially varved record of Cretaceous paleoclimate. Fourteen polished thin sections from the depth interval 1096.12-1096.53 m with an age of 84.4 Ma were analyzed by optical and scanning electron microscopy (SEM). ImageJ software was applied to extract gray scale curves from optical images at pixel resolution. We tracked minimum values of the gray scale curves to estimate the thickness of each lamina. Five sedimentary structures were recognized: flaser bedding, wavy bedding, lenticular bedding, horizontal bedding, and massive layers. The mean layer thicknesses with different sedimentary structures range from 116 to 162mm, very close to the mean sedimentation rate estimated for this sampled interval, 135mm/year, indicating that the layers bounded by pure clay lamina with the minimum gray values are varves. SEM images indicate that a varve is composed, in succession, of one lamina rich in coarse silt, one lamina rich in fine silt, one clay-rich lamina with some silt, and one clay-rich lamina. This suggests that a Cretaceous year featured four distinct depositional seasons, two of which were rainy and the others were lacking precipitation. Spectral analysis of extended intervals of the tuned gray scale curve indicates the presence of inter-annual periodicities of 2.2-2.7 yr, 3.5-6.1 year, and 10.1-14.5 year consistent with those of modern ENSO cycles and solar cycles, as well as

The mid-cretaceous water bearer: Isotope mass balance quantification of the Albian hydrologic cycle

Science.gov (United States)

Ufnar, David F.; Gonzalez, Luis A.; Ludvigson, Greg A.; Brenner, Richard L.; Witzke, B.J.

2002-01-01

A latitudinal gradient in meteoric ??18O compositions compiled from paleosol sphaerosiderites throughout the Cretaceous Western Interior Basin (KWIB) (34-75??N paleolatitude) exhibits a steeper, more depleted trend than modern (predicted) values (3.0??? [34??N latitude] to 9.7??? [75??N] lighter). Furthermore, the sphaerosiderite meteoric ??18O latitudinal gradient is significantly steeper and more depleted (5.8??? [34??N] to 13.8??? [75??N] lighter) than a predicted gradient for the warm mid-Cretaceous using modern empirical temperature-??18O precipitation relationships. We have suggested that the steeper and more depleted (relative to the modern theoretical gradient) meteoric sphaerosiderite ??18O latitudinal gradient resulted from increased air mass rainout effects in coastal areas of the KWIB during the mid-Cretaceous. The sphaerosiderite isotopic data have been used to constrain a mass balance model of the hydrologic cycle in the northern hemisphere and to quantify precipitation rates of the equable 'greenhouse' Albian Stage in the KWIB. The mass balance model tracks the evolving isotopic composition of an air mass and its precipitation, and is driven by latitudinal temperature gradients. Our simulations indicate that significant increases in Albian precipitation (34-52%) and evaporation fluxes (76-96%) are required to reproduce the difference between modern and Albian meteoric siderite ??18O latitudinal gradients. Calculations of precipitation rates from model outputs suggest mid-high latitude precipitation rates greatly exceeded modern rates (156-220% greater in mid latitudes [2600-3300 mm/yr], 99% greater at high latitudes [550 mm/yr]). The calculated precipitation rates are significantly different from the precipitation rates predicted by some recent general circulation models (GCMs) for the warm Cretaceous, particularly in the mid to high latitudes. Our mass balance model by no means replaces GCMs. However, it is a simple and effective means of obtaining

Petrogenesis and origin of the Upper Jurassic-Lower Cretaceous magmatism in Central High Atlas (Morocco): Major, trace element and isotopic (Sr-Nd) constraints

Science.gov (United States)

Essaifi, Abderrahim; Zayane, Rachid

2018-01-01

During an uplift phase, which lasted ca. 40 Ma, from the Late Jurassic (165 Ma) to the Early Cretaceous (125 Ma), transitional to moderately alkaline magmatic series were emplaced in the Central High Atlas. The corresponding magmatic products include basaltic lava flows erupted within wide synclines and intrusive complexes composed of layered mafic intrusions and monzonitic to syenitic dykes emplaced along narrow anticlinal ridges. The igneous rock sequence within the intrusive complexes is composed of troctolites, olivine-gabbros, oxide-gabbros, monzonites and syenites. The chemical compositions of the various intrusive rocks can be accounted for by crystal accumulation, fractional crystallization and post-magmatic remobilization. The evolution from the troctolites to the syenites was mainly controlled by a fractional crystallization process marked by early fractionation of olivine, plagioclase and clinopyroxene, followed by separation of biotite, amphibole, apatite, and Ti-magnetite. Hydrothermal activity associated with emplacement of the intrusions within the Jurassic limestones modified the elemental and the Sr isotopic composition of the hydrothermally altered rocks In particular the monzonitic to syenitic dykes underwent an alkali metasomatism marked by depletion in K and Rb and enrichment in Na and Sr. As a result, their Sr isotopic composition was shifted towards higher initial Sr isotopic ratios (0.7067-0.7075) with respect to the associated gabbros (0.7036-0.7046). On the contrary, the Nd isotopic compositions were preserved from isotope exchange with the limestones and vary in a similar range to those of the gabbros (+1.6 < εNdi < +4.1). The isotopic and the trace element ratios of the uncontaminated samples were used to constrain the source characteristics of this magmatism. The Sr-Nd isotopic data and the incompatible element ratios (e.g. La/Nb, Zr/Nb, Th/U, Ce/Pb) are consistent with generation from an enriched upper mantle similar to an ocean

Gateways and Water Mass Mixing in the Late Cretaceous North Atlantic

Science.gov (United States)

Asgharian Rostami, M.; Martin, E. E.; MacLeod, K. G.; Poulsen, C. J.; Vande Guchte, A.; Haynes, S.

2017-12-01

Regions of intermediate/deep water formation and water-mass mixing in the North Atlantic are poorly defined for the Late Cretaceous, a time of gateway evolution and cooler conditions following the Mid Cretaceous greenhouse. Improved proxy data combined with modeling efforts are required to effectively evaluate the relationship between CO2, paleogeography, and circulation during this cooler interval. We analyzed and compiled latest Cretaceous (79 - 66 Ma) ɛNd and δ13C records from seven bathyal (paleodepths 0.2 - 2 km) and eight abyssal (paleodepths > 2 km) sites in the North Atlantic. Data suggest local downwelling of Northern Component Water (NCW; ɛNd -9.5 and δ13C 1.7 ‰) is the primary source of intermediate/deep water masses in the basin. As this water flows southward and ages, δ13C values decrease and ɛNd values increase; however, additional chemical changes at several sites require mixing with contributions from several additional water masses. Lower ɛNd ( -10) and higher δ13C ( 1.9 ‰) values in the deep NW part of the basin indicate proximal contributions from a region draining old continental crust, potentially representing deep convection following opening of the Labrador Sea. In the deep NE Iberian Basin, higher ɛNd ( -7) and lower δ13C ( 0.8 ‰) during the Campanian suggest mixing with a Tethyan source (ɛNd -7 and δ13C 0.1 ‰) whose importance decreased with restriction of that gateway in the Maastrichtian. Data from bathyal sites suggest additional mixing. In the SE Cape Verde region, observed ɛNd variations from -10 in the Campanian to -13 and -12 in the early and late Maastrichtian, respectively, may record variations in output rates of Tethyan and/or NCW sources and Demerara Bottom Water (ɛNd -16), a proposed warm saline intermediate water mass formed in shallow, equatorial seas. Pacific inflow through the Caribbean gateway impacts intermediate sites at Blake Nose (ɛNd values -8), particularly the shallowest site during the late

Press/Pulse: Explaining selective terrestrial extinctions at the Cretaceous/Palaeogene boundary

Science.gov (United States)

Arens, Nan Crystal

2010-05-01

Single-cause mass extinction scenarios require extreme conditions to generate sufficiently strong kill mechanisms. Such dire effects are commonly at odds with the taxonomic selectivity that characterizes most extinction events. In response, some researchers have proposed that the interaction of a variety of factors typify episodes of elevated extinction. Previous work (Arens & West 2008 Paleobiology 34:456-471) has shown that a combination of press and pulse disturbances increases the probability of elevated extinction. The press/pulse contrast is borrowed from community ecology, where researchers have long recognized that the ecological response to long-term stress differs from that of an instantaneous catastrophe. Scaled to the macroevolutionary level, press disturbances alter community composition by placing multigenerational stress on populations. Press disturbances do not necessarily cause mortality, but reduce population size by a variety of mechanisms such as curtailed reproduction. Pulse disturbances are sudden catastrophic events that cause extensive mortality. Either press or pulse disturbances of sufficient magnitude can cause extinction, however elevated extinction occurs more commonly during the coincidence of lower-magnitude press and pulse events. The Cretaceous/Palaeogene (K/P) extinction is one of the best examples of a press/pulse extinction. Deccan Trap volcanism, which straddled the K/P boundary, altered atmospheric composition and climate. This episodic volcanism likely contributed to the climate instability observed in terrestrial ecosystems and exerted press stress. Pulse disturbance was produced by bolide impact, which punctuated the end of the Cretaceous. The press/pulse mechanism also more effectively explains selectivity in terrestrial vertebrate and plant extinctions at the K/P boundary than do single-mechanisms scenarios. For example, why do environmentally sensitive vertebrates such as amphibians experience no extinction? And why do

Extended Stability of Epinephrine Hydrochloride Injection in Polyvinyl Chloride Bags Stored in Amber Ultraviolet Light-Blocking Bags.

Science.gov (United States)

Van Matre, Edward T; Ho, Kang C; Lyda, Clark; Fullmer, Beth A; Oldland, Alan R; Kiser, Tyree H

2017-09-01

Objective: The objective of this study was to evaluate the stability of epinephrine hydrochloride in 0.9% sodium chloride in polyvinyl chloride bags for up to 60 days. Methods: Dilutions of epinephrine hydrochloride to concentrations of 16 and 64 µg/mL were performed under aseptic conditions. The bags were then placed into ultraviolet light-blocking bags and stored at room temperature (23°C-25°C) or under refrigeration (3°C-5°C). Three samples of each preparation and storage environment were analyzed on days 0, 30, 45, and 60. Physical stability was performed by visual examination. The pH was assessed at baseline and upon final degradation evaluation. Sterility of the samples was not assessed. Chemical stability of epinephrine hydrochloride was evaluated using high-performance liquid chromatography. To determine the stability-indicating nature of the assay, degradation 12 months following preparation was evaluated. Samples were considered stable if there was less than 10% degradation of the initial concentration. Results: Epinephrine hydrochloride diluted to 16 and 64 µg/mL with 0.9% sodium chloride injection and stored in amber ultraviolet light-blocking bags was physically stable throughout the study. No precipitation was observed. At days 30 and 45, all bags had less than 10% degradation. At day 60, all refrigerated bags had less than 10% degradation. Overall, the mean concentration of all measurements demonstrated less than 10% degradation at 60 days at room temperature and under refrigeration. Conclusion: Epinephrine hydrochloride diluted to 16 and 64 µg/mL with 0.9% sodium chloride injection in polyvinyl chloride bags stored in amber ultraviolet light-blocking bags was stable up to 45 days at room temperature and up to 60 days under refrigeration.

Low ecological disparity in Early Cretaceous birds

Science.gov (United States)

Mitchell, Jonathan S.; Makovicky, Peter J.

2014-01-01

Ecological divergence is thought to be coupled with evolutionary radiations, yet the strength of this coupling is unclear. When birds diversified ecologically has received much less attention than their hotly debated crown divergence time. Here, we quantify how accurately skeletal morphology can predict ecology in living and extinct birds, and show that the earliest known assemblage of birds (= pygostylians) from the Jehol Biota (≈ 125 Ma) was substantially impoverished ecologically. The Jehol avifauna has few representatives of highly preservable ecomorphs (e.g. aquatic forms) and a notable lack of ecomorphological overlap with the pterosaur assemblage (e.g. no large or aerially foraging pygostylians). Comparisons of the Jehol functional diversity with modern and subfossil avian assemblages show that taphonomic bias alone cannot explain the ecomorphological impoverishment. However, evolutionary simulations suggest that the constrained ecological diversity of the Early Cretaceous pygostylians is consistent with what is expected from a relatively young radiation. Regardless of the proximate biological explanation, the anomalously low functional diversity of the Jehol birds is evidence both for ecological vacancies in Cretaceous ecosystems, which were subsequently filled by the radiation of crown Aves, and for discordance between taxonomic richness and ecological diversity in the best-known Mesozoic ecosystem. PMID:24870044

Sedimentary environments and hydrocarbon potential of cretaceous rocks of indus basin, Pakistan

International Nuclear Information System (INIS)

Sheikh, S.A.; Naseem, S.

1999-01-01

Cretaceous rocks of Indus Basin of Pakistan are dominated by clastics with subordinate limestone towards the top. These rocks represent shelf facies and were deposited in deltaic to reducing marine conditions at variable depths. Indications of a silled basin with restricted circulation are also present. Cretaceous fine clastics/carbonates have good source and reservoir qualities. Variable geothermal gradients in different parts of basin have placed these rocks at different maturity levels; i.e. from oil to condensate and to gas. The potential of these rocks has been proved by several oil and gas discoveries particularly in the Central and Southern provinces of Indus Basin. (author)

An estimation of Central Iberian Peninsula atmospheric δ13C and water δD in the Upper Cretaceous using pyrolysis compound specific isotopic analysis (Py-CSIA) of a fossil conifer.

Science.gov (United States)

González-Pérez, José A.; Jiménez-Morillo, Nicasio T.; De la Rosa, José M.; Almendros, Gonzalo; González-Vila, Francisco J.

2015-04-01

Frenelopsis is a frequently found genus of the Cretaceous floras adapted to dry, saline and in general to environmental conditions marked by severe water stress [1]. Stable isotope analysis of fossil organic materials can be used to infer palaeoenvironmental variables helpful to reconstruct plant paleohabitats [2]. In this study stable isotope analysis of organic fossil remains (FR) and humic fractions (FA, HA and humin) of Frenelopsis oligiostomata are studied in bulk (C, H, O, N IRMS) and in specific compounds released by pyrolysis (C, H, Py-CSIA). Well preserved F. oligiostomata fossils were handpicked from a limestone included in compacted marls from Upper Cretaceous (Senonian c. 72 Mya) in Guadalix de la Sierra (Madrid, Spain) [3]. The fossils were decarbonated with 6M HCl. Humic substances were extracted from finely ground fossil remains (FR) by successive treatments with 0.1M Na4P2O7 + NaOH [4]. The extract was acidified resulting into insoluble HA and soluble FA fractions. The HA and FA were purified as in [5] and [6] respectively. Bulk stable isotopic analysis (δ13C, δD, δ18O, δ15N IRMS) was done in an elemental micro-analyser coupled to a continuous flow Delta V Advantage isotope ratio mass spectrometer (IRMS). Pyrolysis compound specific isotopic analysis Py-CSIA (δ13C, δD): was done by coupling a double-shot pyrolyzer to a chromatograph connected to an IRMS. Structural features of specific peaks were inferred by comparing/matching mass spectra from conventional Py-GC/MS (data not shown) with Py-GC/IRMS chromatograms obtained using the same chromatographic conditions. Bulk C isotopic signature found for FR (-20.5±0.02 ‰) was in accordance with previous studies [2, 7-9]. This heavy isotopic δ13C signature indicates a depleted stomatal conductance and paleoenvironmental growth conditions of water and salt stress. This is in line with the morphological and depositional characteristics [3] confirming that F. oligostomata was adapted to highly xeric

A sequence of events across the Cretaceous-Tertiary boundary

NARCIS (Netherlands)

Smit, J.; Romein, A.J.T.

1985-01-01

The lithological and biological sequence of events across the Cretaceous-Tertiary (K/T), as developed in thick and complete landbased sections and termed the standard K/T event sequence, is also found in many DSDP cores from all over the globe. Microtektite-like spherules have been found in

Carbonate deposition and salt diapirism during the Cretaceous in the Persian Gulf, offshore Iran

OpenAIRE

U. P. Baaske; M. Mutti; F. Baioni; R. Buonaguro; G. Bertozzi; M. A. Naini; C. M. Krawczyk; P. Kukla; R. Littke; H. Stollhofen; D. Schwarzer;  

2004-01-01

The Cretaceous deposits in the Persian Gulf area are part of one of the largest hydrocarbon systems in the world. The stratigraphic evolution of the northern part of the Gulf is, however, poorly constrained. Seismic data from offshore Iran reveal that the shallow water deposition is marked by topographic features like the NNE-SSW trending Qatar-Fars-Arch and salt-related structures (diapirs and salt walls) of smaller scale. These structures were active during the Cretaceous. To examine the ef...

Timing of Late Cretaceous Gulf Coast volcanism and chronostratigraphic constraints on deposition of the Ripley Formation from a newly recognized bentonite bed, Pontotoc County, Mississippi

Science.gov (United States)

Vitale, E. J.; Gifford, J.; Platt, B. F.

2017-12-01

The Upper Cretaceous Ripley Formation is present throughout the Mississippi (MS) Embayment and contains local bentonite lenses related to regional volcanism. The Pontotoc bentonite is such a lens located near the town of Pontotoc, MS, that was strip-mined and has not been accessible since reclamation of the land. Recent investigations in Pontotoc County south of the Pontotoc bentonite site resulted in the discovery of a previously unknown bentonite bed. Litho- and biostratigraphy indicate that the bentonite is younger than known volcanism from MS. The purposes of the present investigation are 1) to test whether the new bentonite bed is correlative to the Pontotoc bentonite & 2) to recover volcanogenic zircons for U-Pb dating to better constrain timing of volcanism and chronostratigraphy of the Ripley Fm. Outcrops in an active sand pit in the field area expose 2.5 m of fine sand, and an upper gradational contact with an overlying 2.5 m of sandy clay, containing the bentonite bed. Two trenches were excavated through the outcrop, and in each trench a stratigraphic section was measured and bulk samples collected for zircons. Sampling began in the lower bounding sand and continued upsection in 1 m intervals, corresponding to the gradational contact with the bentonite, and 2 locations within the bentonite. The Ripley Fm. consists of 73 m of fossiliferous clay, sand, and calcareous sand beds. Recent stratigraphic revisions of the lateral facies in MS recognize a lower transitional clay facies, a limestone, marl, and calcareous sand facies, a sandy upper Ripley facies, and the formally named Chiwapa Sandstone Member. Ammonite biostratigraphy places the contact between the Chiwapa and the overlying Owl Creek/Prairie Bluff at 68.5 Ma. Unlike the mined area north of Pontotoc where the bentonite is within the Chiwapa, the bed here is directly above the Chiwapa section and its upper contact represents the Ripley Fm. / Owl Creek Fm. contact. Where the bentonite is present, it

Astronomical calibration of the Maastrichtian (Late Cretaceous)

DEFF Research Database (Denmark)

Husson, Dorothée; Galbrun, Bruno; Laskar, Jacques

2011-01-01

/Pg boundary, considering the uncertainty of the long-term variation of the 405 ka eccentricity cycle. The first proposal provides a Cretaceous/Paleogene boundary age of 65.59 ± 0.07 Ma and the second an age of 66 ± 0.07 Ma, which is coherent with the most recent radio-isotopic datings. Magnetochron boundaries...... and the Campanian/Maastrichtian boundary are dated relative to these numerical ages of the K/Pg boundary....

Chapter 2. Assessment of undiscovered conventional oil and gas resources--Upper Jurassic-Lower Cretaceous Cotton Valley group, Jurassic Smackover interior salt basins total petroleum system, in the East Texas basin and Louisiana-Mississippi salt basins provinces.

Science.gov (United States)

Dyman, T.S.; Condon, S.M.

2006-01-01

The Jurassic Smackover Interior Salt Basins Total Petroleum System is defined for this assessment to include (1) Upper Jurassic Smackover Formation carbonates and calcareous shales and (2) Upper Jurassic and Lower Cretaceous Cotton Valley Group organic-rich shales. The Jurassic Smackover Interior Salt Basins Total Petroleum System includes four conventional Cotton Valley assessment units: Cotton Valley Blanket Sandstone Gas (AU 50490201), Cotton Valley Massive Sandstone Gas (AU 50490202), Cotton Valley Updip Oil and Gas (AU 50490203), and Cotton Valley Hypothetical Updip Oil (AU 50490204). Together, these four assessment units are estimated to contain a mean undiscovered conventional resource of 29.81 million barrels of oil, 605.03 billion cubic feet of gas, and 19.00 million barrels of natural gas liquids. The Cotton Valley Group represents the first major influx of clastic sediment into the ancestral Gulf of Mexico. Major depocenters were located in south-central Mississippi, along the Louisiana-Mississippi border, and in northeast Texas. Reservoir properties and production characteristics were used to identify two Cotton Valley Group sandstone trends across northern Louisiana and east Texas: a high-permeability blanket-sandstone trend and a downdip, low-permeability massive-sandstone trend. Pressure gradients throughout most of both trends are normal, which is characteristic of conventional rather than continuous basin-center gas accumulations. Indications that accumulations in this trend are conventional rather than continuous include (1) gas-water contacts in at least seven fields across the blanket-sandstone trend, (2) relatively high reservoir permeabilities, and (3) high gas-production rates without fracture stimulation. Permeability is sufficiently low in the massive-sandstone trend that gas-water transition zones are vertically extensive and gas-water contacts are poorly defined. The interpreted presence of gas-water contacts within the Cotton Valley

Chemical Remagnetization of Jurassic Carbonates and a Primary Paleolatitude of Lower Cretaceous Volcaniclastic Rocks of the Tibetan Himalaya

Science.gov (United States)

Huang, W.; Van Hinsbergen, D. J. J.; Dekkers, M. J.; Garzanti, E.; Dupont Nivet, G.; Lippert, P. C.; Li, X.; Maffione, M.; Langereis, C. G.; Hu, X.; Guo, Z.; Kapp, P. A.

2014-12-01

Paleolatitudes for the Tibetan Himalaya Zone based on paleomagnetic inclinations provide kinematic constraints of the passive northern Indian margin and the extent of 'Greater India' before the India-Asia collision. Here, we present a paleomagnetic investigation of the Jurassic (carbonates) to Lower Cretaceous (volcaniclastic rocks) Wölong section of the Tibetan Himalaya in the Everest region. The carbonates yield positive fold tests, suggesting that the remanent magnetizations have a pre-folding origin. However, detailed paleomagnetic analyses, rock magnetic tests, end-member modeling of acquisition curves of isothermal remanent magnetization, and petrographic studies reveal that the magnetic carrier of the Jurassic carbonates is authigenic magnetite, whereas the dominant magnetic carrier of the Lower Cretaceous volcaniclastic rocks is detrital magnetite. We conclude that the Jurassic carbonates were remagnetized, whereas the Lower Cretaceous volcaniclastics retain a primary remanence. We hypothesize that remagnetization of the Jurassic carbonates was probably caused by the oxidation of early diagenetic pyrite to magnetite within the time interval at ~86-84 Ma during the latest Cretaceous Normal Superchron and earliest deposition of Cretaceous oceanic red beds in the Tibetan Himalaya. The remagnetization of the limestones prevents determining the size of 'Greater India' during Jurassic time. Instead, a paleolatitude of the Tibetan Himalaya of 23.8±2.1° S at ~86-84 Ma is suggested. This value is lower than the expected paleolatitude of India from apparent polar wander path (APWP). The volcaniclastic rocks with the primary remanence, however, yielded a Lower Cretaceous paleolatitude of Tibetan Himalaya of 55.5±3° S, fitting well with the APWP of India.

Late Cretaceous origin of the rice tribe provides evidence for early diversification in Poaceae.

Science.gov (United States)

Prasad, V; Strömberg, C A E; Leaché, A D; Samant, B; Patnaik, R; Tang, L; Mohabey, D M; Ge, S; Sahni, A

2011-09-20

Rice and its relatives are a focal point in agricultural and evolutionary science, but a paucity of fossils has obscured their deep-time history. Previously described cuticles with silica bodies (phytoliths) from the Late Cretaceous period (67-65 Ma) of India indicate that, by the latest Cretaceous, the grass family (Poaceae) consisted of members of the modern subclades PACMAD (Panicoideae-Aristidoideae-Chloridoideae-Micrairoideae-Arundinoideae-Danthonioideae) and BEP (Bambusoideae-Ehrhartoideae-Pooideae), including a taxon with proposed affinities to Ehrhartoideae. Here we describe additional fossils and show that, based on phylogenetic analyses that combine molecular genetic data and epidermal and phytolith features across Poaceae, these can be assigned to the rice tribe, Oryzeae, of grass subfamily Ehrhartoideae. The new Oryzeae fossils suggest substantial diversification within Ehrhartoideae by the Late Cretaceous, pushing back the time of origin of Poaceae as a whole. These results, therefore, necessitate a re-evaluation of current models for grass evolution and palaeobiogeography.

Soil development on loess overlying Cretaceous sediments and Devonian limestones

Czech Academy of Sciences Publication Activity Database

Žigová, Anna; Šťastný, Martin

2015-01-01

Roč. 12, č. 3 (2015), s. 267-278 ISSN 1214-9705 Institutional support: RVO:67985831 Keywords : loess * Cretaceous and Devonian rocks * mineral composition * soil development * Luvic Chernozem * Albic Luvisol Subject RIV: DF - Soil Science Impact factor: 0.561, year: 2015

Biostratigraphy and carbon isotope stratigraphy of uppermost Cretaceous-lower Cenozoic Muzzle Group in middle Clarence valley, New Zealand

International Nuclear Information System (INIS)

Hollis, C.J.; Field, B.D.; Jones, C.M.; Strong, C.P.; Wilson, G.J.; Dickens, G.R.

2005-01-01

Muzzle Group strata exposed along southeast-flowing tributaries of the Clarence River valley, Marlborough, record hemipelagic-pelagic sedimentation across a high latitude (c. 55 degrees S), terrigenous sediment-starved, continental margin from latest Cretaceous to middle Eocene times. Studies of dinoflagellates, foraminifera, calcareous nannofossils, and radiolarians have been integrated with bulk carbonate δ 13 C profiles to establish the chronostratigraphy for two stratigraphic sections along Bluff and Muzzle Streams, middle Clarence valley. The two sections comprise similar successions. Uppermost Cretaceous (upper Haumurian) micritic limestone of Mead Hill Formation is overlain unconformably by Teredo Limestone, a c. 0.25 m thick bed of highly glauconitic, calcareous sandstone. This unit, the basal member of Amuri Limestone, is overlain conformably by c. 15 m thick Lower Limestone, micritic limestone that is glauconitic at base and progressively more marl-rich in its upper part. Lower Limestone grades up into Lower Marl, a poorly exposed, 40-70 m thick unit of alternating marl and micritic limestone beds. Biostratigraphy indicates that the base of Amuri Limestone is younger at Bluff Stream (earliest Eocene, early Waipawan) than at Muzzle Stream (late Paleocene, late Teurian). In the condensed (12 m) upper Paleocene-lower Eocene Amuri Limestone sequence at Muzzle Stream, a trend in δ 13 C from high (≥2.4 permille) to low (≤1 permille) values is consistent with global records across three major climate or carbon cycle perturbations: the late Paleocene carbon isotope maximum (PCIM, 59-56 Ma), the initial Eocene thermal maximum (IETM, 55.5 Ma), and the early Eocene climatic optimum (EECO, 53-50 Ma). Probably only the upper PCIM is preserved in the 4 m thick siliceous limestone interval overlying Teredo Limestone. The IETM is well-defined by a 1 permille negative δ 13 C excursion at the base of a 0.8 m thick marl-rich unit (Dee Marl), 5 m above the base of

Paleomagnetism of Cretaceous Oceanic Red Beds (CORBs) from Gyangze, northern Tethys Himalaya: Evidence for Intra-oceanic Subduction System and Southern Paleolatitute Limit for the Lhasa Block

Science.gov (United States)

Tan, Xiaodong

2016-04-01

In the northern Tethys Himalaya, sporadically distributed Cretaceous oceanic red beds (CORBs, the Chuangde Formation) have been described. The sequence was interpreted to be firstly deposited in the outer continental shelf and upper slope, and later slumped into deep basin. Based on this model, and paleomagnetic data of shallow water deposits from the southern Tethys Himalaya, the CORBs were derived from the northern tip of the passive margin of the greater India. If so, the CORBs would provide more accurate record of the northern extent of the greater India, which is an important parameter for estimating the initial time of India-Asia continental collision and the amount of crustal shortening. The well studied and most accessible section is located in the Chuangde village, about 40km east from the Gyangze city. The formation is about 25m thick, ranging from 84 to 75Ma in age according to fossil records of planktonic foraminiferal species. The lower and upper parts are 2 and 5 meter thick marlstones, respectively, and the middle section is dominated by shale with a few layers of centimeter scale marlstones. Fifty cores were collected from the marlstones of the section, and for the purpose of fold test, 30 more cores were collected from the upper part of the formation from a second section located in the Pulong village, ~3km to the northeast of the Chuangde village. All samples were subject to stepwise thermal demagnetization. About 60% of the samples yielded interpretable demagnetization results. The bottom of the upper part of the formation show reversed high temperature component, and the rest of the upper part and the lower part show normal polarity. The Chuangde section data failed reversal test, because the normal polarity direction is likely not fully resolved from overprint component. However, the well resolved reversal direction from the Chuangde village and the normal direction from Pulong pass both reversal and fold tests. The mean paleomagnetic data

Terpenoid composition and botanical affinity of Cretaceous resins from India and Myanmar

Energy Technology Data Exchange (ETDEWEB)

Dutta, Suryendu; Mallick, Monalisa [Department of Earth Sciences, Indian Institute of Technology-Bombay (India); Kumar, Kishor [Wadia Institute of Himalayan Geology, Uttarakhand (India); Mann, Ulrich [Forschungzentrum Juelich (Germany). Institut fuer Chemie und Dynamik der Geosphaere; Greenwood, Paul F. [John De Laeter Mass Spectrometry and WA Biogeochemistry Centres (M090), University of Western Australia, Crawley (Australia)

2011-01-01

Fossil resins from the Cretaceous sediments of Meghalaya, India and Kachin, Myanmar (Burma) were analysed using Curie point pyrolysis-gas chromatography-mass spectrometry and thermochemolysis gas chromatography-mass spectrometry to help elucidate their botanical source. The major pyrolysis products and methyl-esterified thermochemolysis products of both the resins were abietane and labdane type diterpenoids with minor amount of sesquiterpenoids. The thermochemolysis products also included methyl-16,17-dinor callitrisate, methyl-16,17-dinor dehydroabietate and methyl-8-pimaren-18-oate - the latter two from just the Myanmarese resin. The exclusive presence of both labdane and abietane diterpenoids and the lack of phenolic terpenoids may suggest that the studied Cretaceous resins were derived from Pinaceae (pine family) conifers. (author)

Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs.

Science.gov (United States)

Hassler, A; Martin, J E; Amiot, R; Tacail, T; Godet, F Arnaud; Allain, R; Balter, V

2018-04-11

Large predators are overabundant in mid-Cretaceous continental dinosaur assemblages of North Africa. Such unbalanced ecosystem structure involves, among predatory dinosaurs, typical abelisaurid or carcharodontosaurid theropods co-occurring with long-snouted spinosaurids of debated ecology. Here, we report calcium (Ca) isotope values from tooth enamel (expressed as δ 44/42 Ca) to investigate resource partitioning in mid-Cretaceous assemblages from Niger (Gadoufaoua) and Morocco (Kem Kem Beds). In both assemblages, spinosaurids display a distinct isotopic signature, the most negative in our dataset. This distinct taxonomic clustering in Ca isotope values observed between spinosaurids and other predators provides unambiguous evidence for niche partitioning at the top of the trophic chains: spinosaurids foraged on aquatic environments while abelisaurid and carcharodontosaurid theropods relied almost exclusively on terrestrial resources. © 2018 The Author(s).

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

Time scales of critical events around the Cretaceous-Paleogene boundary

NARCIS (Netherlands)

Renne, P.R.; Deino, A.L.; Hilgen, F.J.; Kuiper, K.F.; Mark, D.F.; Mitchell III, W.S.; Morgan, L.; Mundil, R.; Smit, J.

2013-01-01

Mass extinctions manifest in Earth's geologic record were turning points in biotic evolution. We present 40Ar/39Ar data that establish synchrony between the Cretaceous-Paleogene boundary and associated mass extinctions with the Chicxulub bolide impact to within 32,000 years. Perturbation of the

Intermolecular Force Field Parameters Optimization for Computer Simulations of CH4 in ZIF-8

Directory of Open Access Journals (Sweden)

Phannika Kanthima

2016-01-01

Full Text Available The differential evolution (DE algorithm is applied for obtaining the optimized intermolecular interaction parameters between CH4 and 2-methylimidazolate ([C4N2H5]− using quantum binding energies of CH4-[C4N2H5]− complexes. The initial parameters and their upper/lower bounds are obtained from the general AMBER force field. The DE optimized and the AMBER parameters are then used in the molecular dynamics (MD simulations of CH4 molecules in the frameworks of ZIF-8. The results show that the DE parameters are better for representing the quantum interaction energies than the AMBER parameters. The dynamical and structural behaviors obtained from MD simulations with both sets of parameters are also of notable differences.

Extraterrestrial cause for the Cretaceous-Tertiary extinction

International Nuclear Information System (INIS)

Alvarez, L.W.; Alvarez, W.; Asaro, F.; Michel, H.V.

1980-01-01

Platinum metals are depleted in the earth's crust relative to their cosmic abundance; concentrations of these elements in deep-sea sediments may thus indicate influxes of extraterrestrial material. Deep-sea limestones exposed in Italy, Denmark, and New Zealand show iridium increases of about 30, 160, and 20 times, respectively, above the background level at precisely the time of the Cretaceous-Tertiary extinctions, 65 million years ago. Reasons are given to indicate that this iridium is of extraterrestrial origin, but did not come from a nearby supernova. A hypothesis is suggested which accounts for the extinctions and the iridium observations. Impact of a large earth-crossing asteroid would inject about 60 times the object's mass into the atmosphere as pulverized rock; a fraction of this dust would stay in the stratosphere for several years and be distributed worldwide. The resulting darkness would suppress photosynthesis, and the expected biological consequences match quite closely the extinctions observed in the paleontological record. One prediction of this hypothesis has been verified: the chemical composition of the boundary clay, which is thought to come from the stratospheric dust, is markedly different from that of clay mixed with the Cretaceous and Tertiary limestones, which are chemically similar to each other. Four different independent estimates of the diameter of the asteroid give values that lie in the range 10 +- 4 kilometers

Integrated stratigraphy of the Jurassic-Cretaceous sequences of the Kurovice Quarry, Outer Western Carpathians: correlations and tectonic implications

Czech Academy of Sciences Publication Activity Database

Pruner, Petr; Schnabl, Petr; Čížková, Kristýna; Elbra, Tiiu; Kdýr, Šimon; Svobodová, Andrea; Reháková, D.

2017-01-01

Roč. 120 (2017), s. 216-216 ISSN 1017-8880. [International Symposium on the Cretaceous /10./. 21.08.2017-26.08.2017, Vienna] R&D Projects: GA ČR(CZ) GA16-09979S Institutional support: RVO:67985831 Keywords : stratigraphy * Jurassic-Cretaceous sequences * Western Carpathians Subject RIV: DB - Geology ; Mineralogy

Causes and consequences of short-term sea-level changes in the Cretaceous green- and "hothouse": Topics and context of IGCP Project 609

Science.gov (United States)

Sames, Benjamin; Wagreich, Michael

2015-04-01

In contrast to the well-understood process of glacial eustasy, controlled mainly by waxing and waning of continental ice sheets, significant short-term, i.e. 10s kyr to a few myr (3rd to 4th order cycles) sea-level changes during the Cretaceous major greenhouse episode remain enigmatic. Such cyclic changes are often explained by the presence of ephemeral ice sheets even during the hottest greenhouse phases ("hothouse periods"), such as the mid-Cretaceous. Though Cretaceous global eustasy involves processes like brief glacial episodes (glacio-eustasy) for which evidence was given - at least for the Early Cretaceous and the late Late Cretaceous - other mechanisms have to be taken into consideration for the "hothouse periods" during which continental ice shields are highly improbable, like the storage and release of groundwater (termed "limno-eustasy" or "aquifer-eustasy"), the possible effect and magnitude of which might have been highly underestimated. Investigation of the timing, the causes, and the consequences of significant short-term (i.e. mainly kyr to 100s of kyr) sea-level changes during the last major greenhouse episode of Earth history, the Cretaceous, is the ultimate goal of the UNESCO IGCP (International Geoscience Programme) project number 609 "Climate-environmental deteriorations during greenhouse phases: Causes and consequences of short-term Cretaceous sea-level changes" (2013-2017; http://www.univie.ac.at/igcp609/). This also comprises the global versus regional correlation and extent of the sequences, their cyclicities, as well as the processes and triggering mechanisms for these, and marine to non-marine correlations. Recent refinements of the geological time scale have made major advances for the Cretaceous to yield a resolution comparable to that of younger Earth history. It is now for the first time possible to correlate and date short-term Cretaceous sea-level records with a resolution appropriate for their detailed analysis. Recognized

Dental Disparity and Ecological Stability in Bird-like Dinosaurs prior to the End-Cretaceous Mass Extinction.

Science.gov (United States)

Larson, Derek W; Brown, Caleb M; Evans, David C

2016-05-23

The causes, rate, and selectivity of the end-Cretaceous mass extinction continue to be highly debated [1-5]. Extinction patterns in small, feathered maniraptoran dinosaurs (including birds) are important for understanding extant biodiversity and present an enigma considering the survival of crown group birds (Neornithes) and the extinction of their close kin across the end-Cretaceous boundary [6]. Because of the patchy Cretaceous fossil record of small maniraptorans [7-12], this important transition has not been closely examined in this group. Here, we test the hypothesis that morphological disparity in bird-like dinosaurs was decreasing leading up to the end-Cretaceous mass extinction, as has been hypothesized in some dinosaurs [13, 14]. To test this, we examined tooth morphology, an ecological indicator in fossil reptiles [15-19], from over 3,100 maniraptoran teeth from four groups (Troodontidae, Dromaeosauridae, Richardoestesia, and cf. Aves) across the last 18 million years of the Cretaceous. We demonstrate that tooth disparity, a proxy for variation in feeding ecology, shows no significant decline leading up to the extinction event within any of the groups. Tooth morphospace occupation also remains static over this time interval except for increased size during the early Maastrichtian. Our data provide strong support that extinction within this group occurred suddenly after a prolonged period of ecological stability. To explain this sudden extinction of toothed maniraptorans and the survival of Neornithes, we propose that diet may have been an extinction filter and suggest that granivory associated with an edentulous beak was a key ecological trait in the survival of some lineages. Copyright © 2016 Elsevier Ltd. All rights reserved.

Noble metals in cretaceous/tertiary sediments from El Kef

International Nuclear Information System (INIS)

Kuslys, M.; Kraehenbuehl, U.

1983-01-01

Sediments from El Kef, Tunisia, were analysed by RNAA for Au, Ir and Os. All three elements show a 10-20 fold enrichment at the Cretaceous/Tertiary boundary. This enrichment must be the result of the addition of material with a high concentration of noble metals. It is plausible that this exotic material has an extra-terrestrial origin. (orig.)

Noble metals in Cretaceous/Tertiary sediments from El Kef

International Nuclear Information System (INIS)

Kuslys, M.; Kraehenbuehl, U.

1983-01-01

Sediments from El Kef, Tunisia, were analysed by RNAA for Au, Ir and Os. All three elements show a 10-20 fold enrichment at the Cretaceous/Tertiary boundary. This enrichment must be the result of the addition of material with a high concentration of noble metals. It is plausible that this exotic material has an extraterrestrial origin. (orig.)

Calibrating Late Cretaceous Terrestrial Cyclostratigraphy with High-precision U-Pb Zircon Geochronology: Qingshankou Formation of the Songliao Basin, China

Science.gov (United States)

Wang, T.; Ramezani, J.; Wang, C.

2015-12-01

A continuous succession of Late Cretaceous lacustrine strata has been recovered from the SK-I south (SK-Is) and SKI north (SK-In) boreholes in the long-lived Cretaceous Songliao Basin in Northeast China. Establishing a high-resolution chronostratigraphic framework is a prerequisite for integrating the Songliao record with the global marine Cretaceous. We present high-precision U-Pb zircon geochronology by the chemical abrasion isotope dilution thermal-ionization mass spectrometry method from multiple bentonite core samples from the Late Cretaceous Qingshankou Formation in order to assess the astrochronological model for the Songliao Basin cyclostratigraphy. Our results from the SK-Is core present major improvements in precision and accuracy over the previously published geochronology and allow a cycle-level calibration of the cyclostratigraphy. The resulting choronostratigraphy suggest a good first-order agreement between the radioisotope geochronology and the established astrochronological time scale over the corresponding interval. The dated bentonite beds near the 1780 m depth straddle a prominent oil shale layer of the Qingshankou Formation, which records a basin-wide lake anoxic event (LAE1), providing a direct age constraint for the LAE1. The latter appears to coincide in time with the Late Cretaceous (Turonian) global sea level change event Tu4 presently constrained at 91.8 Ma.

Sedimentary Provenance Constraints on the Middle Jurassic to Late Cretaceous Paleogeography of the Sichuan Basin, SW China

Science.gov (United States)

Li, Y.; He, D.; Li, D.; Lu, R.

2017-12-01

Sedimentary provenance of the Middle Jurassic to Late Cretaceous sediments in the Sichuan Basin is constrained by sandstone petrology and detrital zircon U-Pb geochronology, which provides critical insights into mid-late Mesozoic paleogeographic evolution of the Sichuan Basin. Petrographic analyses of 22 sandstone samples indicate moderate to high mature sediments and are primarily derived from cratonic or recycled sources. U-Pb age data for the Middle Jurassic to Late Cretaceous detrital zircons generally show populations at 130-200, 200-330, 400-490, 680-890, 1730-1960, and 2360-2600 Ma, with up-section variations. The Middle Jurassic sediments contain a relatively high density of 1.85 and 2.5 Ga zircons and a low density of the 800 Ma zircons, which are consistent with derivation mainly from the Songpan-Ganzi terrane and the South Qinling belt, and secondarily from the Western Jiangnan Orogen. The Late Jurassic and Early Cretaceous sedimentation with a scattered age distribution shared common multiple-source to sink systems that were predominantly draining towards the south and southeast, but increasingly drained southward, and were later disrupted by a synchronous northeastward drainage capture. Late Cretaceous sediments have a distinct reduction in Block.

The Difference Between the Potentiometric Surfaces of the Upper Patapsco Aquifer in Southern Maryland, September 1990 and September 2007

Science.gov (United States)

Curtin, Stephen E.; Andreasen, David C.; Staley, Andrew W.

2009-01-01

This report presents a map showing the change in the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland for September 1990 and September 2007. The map, based on water-level measurements in 33 wells, shows that during the 17-year period, the change in the potentiometric surface ranged from zero at the edge of the outcrop area in northern Anne Arundel County to a decline of 28 feet at Crofton Meadows, 38 feet at Arnold, 36 feet at Waldorf, 35 feet at the Chalk Point power plant, and 40 feet at Lexington Park.

Mid-Cretaceous aeolian desert systems in the Yunlong area of the Lanping Basin, China: Implications for palaeoatmosphere dynamics and paleoclimatic change in East Asia

Science.gov (United States)

Li, Gaojie; Wu, Chihua; Rodríguez-López, Juan Pedro; Yi, Haisheng; Xia, Guoqing; Wagreich, Michael

2018-02-01

The mid-Cretaceous constitutes a period of worldwide atmospheric and oceanic change associated with slower thermohaline circulation and ocean anoxic events, possible polar glaciations and by a changing climate pattern becoming controlled by a zonal planetary wind system and an equatorial humid belt. During the mid-Cretaceous, the subtropical high-pressure arid climate belt of the planetary wind system controlled the palaeolatitude distribution of humid belts in Asia as well as the spatial distribution of rain belts over the massive continental blocks at mid-low latitudes in the southern and northern hemispheres. Additionally, the orographic effect of the Andean-type active continental margin in East Asia hindered the transportation of ocean moisture to inland regions. With rising temperatures and palaeoatmospheric conditions dominated by high pressure systems, desert climate environments expanded at the inland areas of East Asia including those accumulated in the mid-Cretaceous of the Simao Basin, the Sichuan Basin, and the Thailand's Khorat Basin, and leading the Late Cretaceous erg systems in the Xinjiang Basin and Jianghan Basin. This manuscript presents evidences that allow to reinterpret previously considered water-laid sediments to be accumulated as windblown deposits forming part of extensive erg (sandy desert) systems. Using a multidisciplinary approach including petrological, sedimentological and architectural observations, the mid-Cretaceous (Albian-Turonian) Nanxin Formation from the Yunlong region of Lanping Basin, formerly considered to aqueous deposits is here interpreted as representing aeolian deposits, showing local aeolian-fluvial interaction deposits. The palaeowind directions obtained from the analysis of aeolian dune cross-beddings indicates that inland deserts were compatible with a high-pressure cell (HPC) existing in the mid-low latitudes of East Asia during the mid-Cretaceous. Compared with the Early Cretaceous, the mid-Cretaceous had

Comparative analysis of the calcretization process in the Marilia formations (Bauru group - Brasil) and Mercedes ( Paysandu group - Uruguay), Upper Cretaceous of the Parana basin; Analisis comparativo de los procesos de calcretizacion en las Formaciones Marilia (Grupo Bauru-Brasil) y Mercedes (Grupo Paysandu-Uruguay), Cretacico Superior de la cuenca de Parana

Energy Technology Data Exchange (ETDEWEB)

Veroslavsky, G; Etchebehere, M; Sad, A; Fulfaro, J

1998-07-01

Pedogenic and non-pedogenic calcrete facies are very common feature of Marilia (Brazil) and Mercedes (Uruguay) formations in the Parana Basin. The non-pedogenic ones constitute massive limestone facies that have been recently interpreted as groundwater calcretes. These limestones are exploited in both countries to supply raw materials to Portland cement and soil conditioner in origin and age of calcretization phenomena. In Uruguay, the calcretization process seens to be band formation. Field relationships and fossil assemblage point to a Paleocene (or later) age for the calcretization. In Brazilian territory, the groundwater calcretes aresupposed to be of Upper Cretaceous age due to the presence of dinosaurs scattered through the Bauru Group, including siliciclastic beds below and above the calcretes. The authors assume that calcretization processes are similar in both countries (host rocks, intensity, size, textures, geometries and economic potential). The main difference is in age of the calcretization. (author)

A critical transition in leaf evolution facilitated the Cretaceous angiosperm revolution

NARCIS (Netherlands)

Boer, H.J. de; Eppinga, M.B.; Wassen, M.J.; Dekker, S.C.

2012-01-01

The revolutionary rise of broad-leaved (flowering) angiosperm plant species during the Cretaceous initiated a global ecological transformation towards modern biodiversity. Still, the mechanisms involved in this angiosperm radiation remain enigmatic. Here we show that the period of rapid

The role of E-W basement faults in the Mesozoic geodynamic ...

Indian Academy of Sciences (India)

8

Zones 1 and 2. However, the Upper Cretaceous units are thicker westward. The thickness of. Cenozoic series decreases from west to east. This configuration highlights an Upper. Cretaceous tectonic activity of the segments of NW–SE fault that affects the series near the western periclinal termination of the Sehib anticline ...

Late cretaceous aquatic plant world in Patagonia, Argentina.

Directory of Open Access Journals (Sweden)

N Rubén Cúneo

Full Text Available In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla and a monocot (Araceae. Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae. Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form and the eudicot angiosperm Nelumbo (Nelumbonaceae are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae, ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America.

Late Cretaceous Aquatic Plant World in Patagonia, Argentina

Science.gov (United States)

Cúneo, N. Rubén; Gandolfo, María A.; Zamaloa, María C.; Hermsen, Elizabeth

2014-01-01

In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla) and a monocot (Araceae). Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae). Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form) and the eudicot angiosperm Nelumbo (Nelumbonaceae) are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae), ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America. PMID:25148081

Thyasirid bivalves from Cretaceous and Paleogene cold seeps

Directory of Open Access Journals (Sweden)

Krzysztof Hryniewicz

2017-11-01

Full Text Available We present a systematic study of thyasirid bivalves from Cretaceous to Oligocene seep carbonates worldwide. Eleven species of thyasirid bivalves are identified belonging to three genera: Conchocele, Maorithyas, and Thyasira. Two species are new: Maorithyas humptulipsensis sp. nov. from middle Eocene seep carbonates in the Humptulips Formation, Washington State, USA, and Conchocele kiritachiensis sp. nov. from the late Eocene seep deposit at Kiritachi, Hokkaido, Japan. Two new combinations are provided: Conchocele townsendi (White, 1890 from Maastrichtian strata of the James Ross Basin, Antarctica, and Maorithyas folgeri (Wagner and Schilling, 1923 from Oligocene rocks from California, USA. Three species are left in open nomenclature. We show that thyasirids have Mesozoic origins and appear at seeps before appearing in “normal” marine environments. These data are interpreted as a record of seep origination of thyasirids, and their subsequent dispersal to non-seep environments. We discuss the age of origination of thyasirids in the context of the origin of the modern deep sea fauna and conclude that thyasirids could have deep sea origins. This hypothesis is supported by the observed lack of influence of the Cretaceous and Paleogene Oceanic Anoxic Events on the main evolutionary lineages of the thyasirids, as seen in several other members of the deep sea fauna.

Evolution of anuran assemblages in the Late Cretaceous of Utah, USA

Czech Academy of Sciences Publication Activity Database

Roček, Zbyněk; Eaton, J. G.; Gardner, J.; Přikryl, Tomáš

2010-01-01

Roč. 90, č. 4 (2010), s. 341-393 ISSN 1867-1594 R&D Projects: GA MŠk ME08066 Institutional research plan: CEZ:AV0Z30130516 Keywords : Anura * evolution * Late Cretaceous * fossil frogs * stratigraphy * Utah Subject RIV: EG - Zoology

Further along the Road Less Traveled: AMBER ff15ipq, an Original Protein Force Field Built on a Self-Consistent Physical Model

Science.gov (United States)

2016-01-01

We present the AMBER ff15ipq force field for proteins, the second-generation force field developed using the Implicitly Polarized Q (IPolQ) scheme for deriving implicitly polarized atomic charges in the presence of explicit solvent. The ff15ipq force field is a complete rederivation including more than 300 unique atomic charges, 900 unique torsion terms, 60 new angle parameters, and new atomic radii for polar hydrogens. The atomic charges were derived in the context of the SPC/Eb water model, which yields more-accurate rotational diffusion of proteins and enables direct calculation of nuclear magnetic resonance (NMR) relaxation parameters from molecular dynamics simulations. The atomic radii improve the accuracy of modeling salt bridge interactions relative to contemporary fixed-charge force fields, rectifying a limitation of ff14ipq that resulted from its use of pair-specific Lennard-Jones radii. In addition, ff15ipq reproduces penta-alanine J-coupling constants exceptionally well, gives reasonable agreement with NMR relaxation rates, and maintains the expected conformational propensities of structured proteins/peptides, as well as disordered peptides—all on the microsecond (μs) time scale, which is a critical regime for drug design applications. These encouraging results demonstrate the power and robustness of our automated methods for deriving new force fields. All parameters described here and the mdgx program used to fit them are included in the AmberTools16 distribution. PMID:27399642

Early cretaceous zircon SHRIMP U-Pb age of the trachyte and its significances of the Gan-Hang belt

International Nuclear Information System (INIS)

Liu Feiyu; Wu Jianhua; Liu Shuai

2009-01-01

The Shixi basin was located at Gan-Hang tectonic volcanic uranium deposit of rock-magma belt which belong to a part of the Mesozoic volcanic rocks in the northeastern of China. The appearance of the trachyte in Shixi basin have the majoy elements characteristic of the shoshonite series volcanic rocks. To determine the geological age of trachyte have very important significance on the geodynamics research and the study on the cause of uranium mineralization. The zircons of the trachyte have clear ring and high Th/U ratio which belong to the typical magmatic zircons. The zircon SHRIMP U-Pb dating resules show that 14points' age range is very smaller is 132-144 Ma and the weighted average age is (137.00±0.94)Ma which represents the diagenetic age of volcanic rocks. Accronding to the latest International Stratigraphic Chart the boundary of Jurassic and Cretaceous is (145.4±4.0)Ma. So the trachyte of Shixi Group belong to early Cretaceous. The large-scale acidic volcanic activity occurred in the Early Cretaceous in Southeastern China, and the Volcanic uranium deposit of Gan-Hang tectonic belt relate to Alkali metasomatism Uranium mineralization also occurred in the Early Cretaceous (120-130 Ma). The determined of trachyte in Shixi Group in the Early Cretaceous show that the acidic volcanic activity have connection with magma activity and the early Uranium mineralization consistent with the Alkali magma activity. (authors)

Evaluating amber force fields using computed NMR chemical shifts.

Science.gov (United States)

Koes, David R; Vries, John K

2017-10-01

NMR chemical shifts can be computed from molecular dynamics (MD) simulations using a template matching approach and a library of conformers containing chemical shifts generated from ab initio quantum calculations. This approach has potential utility for evaluating the force fields that underlie these simulations. Imperfections in force fields generate flawed atomic coordinates. Chemical shifts obtained from flawed coordinates have errors that can be traced back to these imperfections. We use this approach to evaluate a series of AMBER force fields that have been refined over the course of two decades (ff94, ff96, ff99SB, ff14SB, ff14ipq, and ff15ipq). For each force field a series of MD simulations are carried out for eight model proteins. The calculated chemical shifts for the 1 H, 15 N, and 13 C a atoms are compared with experimental values. Initial evaluations are based on root mean squared (RMS) errors at the protein level. These results are further refined based on secondary structure and the types of atoms involved in nonbonded interactions. The best chemical shift for identifying force field differences is the shift associated with peptide protons. Examination of the model proteins on a residue by residue basis reveals that force field performance is highly dependent on residue position. Examination of the time course of nonbonded interactions at these sites provides explanations for chemical shift differences at the atomic coordinate level. Results show that the newer ff14ipq and ff15ipq force fields developed with the implicitly polarized charge method perform better than the older force fields. © 2017 Wiley Periodicals, Inc.

Late Cretaceous extension and exhumation of the Stong Complex and Taku Schist, NE Peninsular Malaysia

Science.gov (United States)

François, Thomas; Afiq Md, Muhammad; Matenco, Liviu; Willingshofer, Ernst; Fatt Ng, Tham; Iskandar Taib, N.; Kamal Shuib, Mustaffa

2017-04-01

Dismembering large continental areas by post-orogenic extension requires favourable geodynamic conditions and frequently occurs along pre-existing suture zones or nappe contacts as exemplified by the Stong Complex and Taku Schist of northern Peninsular Malaysia. For this particular case we have employed a field and microstructural kinematic study combined with low temperature thermo-chronology to analyse the tectonic and exhumation history. The results show that the late Palaeozoic - Triassic Indosinian orogeny created successive phases of burial related metamorphism, shearing and contractional deformation. This orogenic structure was then dismembered during a Cretaceous thermal event that culminated in the formation of a large scale late Santonian - early Maastrichtian extensional detachment, genetically associated with crustal melting, the emplacement of syn-kinematic plutons and widespread migmatisation. The emplacement of these magmatic rocks led to an array of simultaneously formed structures that document deformation conditions over a wide temperature range, represented by amphibolite-facies mylonites and more brittle structures, such as cataclastic zones and normal faults that formed during exhumation in the footwall of the detachment. The formation of this detachment and a first phase of Late Cretaceous cooling was followed by renewed Eocene - Oligocene exhumation evidenced from our apatite fission track ages. We infer that an initial Cretaceous thermal anomaly was responsible for the formation of an extensional gneiss dome associated with simple shear and normal fault rotation. These Cretaceous processes played a critical role in the establishment of the presently observed crustal structure of Peninsular Malaysia.

Trace element patterns at a non-marine cretaceous-tertiary boundary

Science.gov (United States)

Gilmore, J.S.; Knight, J.D.; Orth, C.J.; Pillmore, C.L.; Tschudy, R.H.

1984-01-01

At the fossil-pollen-defined Cretaceous-Tertiary boundary in the Raton Basin of New Mexico and Colorado, an iridium abundance anomaly and excess scandium, titanium, and chromium are associated with a thin ash or dust fallout bed (now kaolinitic clay) that was preserved in freshwater coal swamps. ?? 1984 Nature Publishing Group.

Origin of Cretaceous phosphorites from the onshore of Tamil Nadu ...

Indian Academy of Sciences (India)

Cretaceous phosphorites occur as light brown to yellow- ish brown or white nodules in Karai Shale of the Uttatur Group in the onshore Cauvery basin. Nodules exhibit phosphatic nucleus encrusted by a chalky shell of carbonate. The nucleus of the nodules consists of light and dark coloured laminae, phosphate ...

A New Megaraptoran Dinosaur (Dinosauria, Theropoda, Megaraptoridae) from the Late Cretaceous of Patagonia

Science.gov (United States)

2016-01-01

A skeleton discovered in the Upper Cretaceous Sierra Barrosa Formation (Turonian-Coniacian) of Neuquén Province, Argentina represents a new species of theropod dinosaur related to the long snouted, highly pneumatized Megaraptoridae. The holotype specimen of Murusraptor barrosaensis n.gen et n.sp. (MCF-PVPH-411) includes much of the skull, axial skeleton, pelvis and tibia. Murusraptor is unique in having several diagnostic features that include anterodorsal process of lacrimal longer than height of preorbital process, and a thick, shelf-like thickening on the lateral surface of surangular ventral to the groove between the anterior surangular foramen and the insert for the uppermost intramandibular process of the dentary. Other characteristic features of Murusraptor barrosaensis n.gen. et n. sp.include a large mandibular fenestra, distal ends of caudal neural spines laterally thickened into lateral knob-like processes, short ischia distally flattened and slightly expanded dorsoventrally. Murusraptor belongs to a Patagonian radiation of megaraptorids together with Aerosteon, Megaraptor and Orkoraptor. In spite being immature, it is a larger but more gracile animal than existing specimens of Megaraptor, and is comparable in size with Aerosteon and Orkoraptor. The controversial phylogeny of the Megaraptoridae as members of the Allosauroidea or a clade of Coelurosauria is considered analyzing two alternative data sets. PMID:27439002

A New Megaraptoran Dinosaur (Dinosauria, Theropoda, Megaraptoridae from the Late Cretaceous of Patagonia.

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Rodolfo A Coria

Full Text Available A skeleton discovered in the Upper Cretaceous Sierra Barrosa Formation (Turonian-Coniacian of Neuquén Province, Argentina represents a new species of theropod dinosaur related to the long snouted, highly pneumatized Megaraptoridae. The holotype specimen of Murusraptor barrosaensis n.gen et n.sp. (MCF-PVPH-411 includes much of the skull, axial skeleton, pelvis and tibia. Murusraptor is unique in having several diagnostic features that include anterodorsal process of lacrimal longer than height of preorbital process, and a thick, shelf-like thickening on the lateral surface of surangular ventral to the groove between the anterior surangular foramen and the insert for the uppermost intramandibular process of the dentary. Other characteristic features of Murusraptor barrosaensis n.gen. et n. sp.include a large mandibular fenestra, distal ends of caudal neural spines laterally thickened into lateral knob-like processes, short ischia distally flattened and slightly expanded dorsoventrally. Murusraptor belongs to a Patagonian radiation of megaraptorids together with Aerosteon, Megaraptor and Orkoraptor. In spite being immature, it is a larger but more gracile animal than existing specimens of Megaraptor, and is comparable in size with Aerosteon and Orkoraptor. The controversial phylogeny of the Megaraptoridae as members of the Allosauroidea or a clade of Coelurosauria is considered analyzing two alternative data sets.

Evidence of Egg Diversity in Squamate Evolution from Cretaceous Anguimorph Embryos

Czech Academy of Sciences Publication Activity Database

Fernandez, V.; Buffetaut, E.; Suteethorn, V.; Rage, J. C.; Tafforeau, P.; Kundrát, Martin

2015-01-01

Roč. 10, č. 7 (2015), e0128610 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GAP302/12/1207 Institutional support: RVO:67985823 Keywords : squamates * egg * fossils * cretaceous Subject RIV: EA - Cell Biology Impact factor: 3.057, year: 2015

Investigating the stratigraphy and palaeoenvironments for a suite of newly discovered mid-Cretaceous vertebrate fossil-localities in the Winton Formation, Queensland, Australia

Science.gov (United States)

Tucker, Ryan T.; Roberts, Eric M.; Darlington, Vikie; Salisbury, Steven W.

2017-08-01

The Winton Formation of central Queensland is recognized as a quintessential source of mid-Cretaceous terrestrial faunas and floras in Australia. However, sedimentological investigations linking fossil assemblages and palaeoenvironments across this unit remain limited. The intent of this study was to interpret depositional environments and improve stratigraphic correlations between multiple fossil localities within the preserved Winton Formation in the Eromanga Basin, including Isisford, Lark Quarry, and Bladensburg National Park. Twenty-three facies and six repeated facies associations were documented, indicating a mosaic of marginal marine to inland alluvial depositional environments. These developed synchronously with the final regression of the Eromanga Seaway from central Australia during the late Albian-early Turonian. Investigations of regional- and local-scale structural features and outcrop, core and well analysis were combined with detrital zircon provenance signatures to help correlate stratigraphy and vertebrate faunas across the basin. Significant palaeoenvironmental differences exist between the lower and upper portions of the preserved Winton Formation, warranting informal subdivisions; a lower tidally influenced fluvial-deltaic member and an upper inland alluvial member. This work further demonstrates that the Isisford fauna is part of the lower member of the preserved Winton Formation; whereas, fossil localities around Winton, including Lark Quarry and Bladensburg National Park, are part of the upper member of the Winton Formation. These results permit a more meaningful framework for both regional and global comparisons of the Winton flora and fauna.

Stratigraphy of Guichon Formation (lower cretaceous) in litoral basin, Uruguay

International Nuclear Information System (INIS)

Goso, C.; Perea, D.; Perinotto, J.

1999-01-01

This report is about the stratigraphic al analysis of the Guichon Formation (lower cretaceous, litoral basin in Uruguay). The facies association is represented by conglomerates mainly fine sandstones and mud stones wi ch is interpreted as an alluvial system. A regional palaeogeography and a new geochronological alternative are established for this formation. (author).

The last dinosaurs of Brazil: The Bauru Group and its implications for the end-Cretaceous mass extinction

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STEPHEN L. BRUSATTE

Full Text Available ABSTRACT The non-avian dinosaurs died out at the end of the Cretaceous, ~66 million years ago, after an asteroid impact. The prevailing hypothesis is that the effects of the impact suddenly killed the dinosaurs, but the poor fossil record of latest Cretaceous (Campanian-Maastrichtian dinosaurs from outside Laurasia (and even more particularly, North America makes it difficult to test specific extinction scenarios. Over the past few decades, a wealth of new discoveries from the Bauru Group of Brazil has revealed a unique window into the evolution of terminal Cretaceous dinosaurs from the southern continents. We review this record and demonstrate that there was a diversity of dinosaurs, of varying body sizes, diets, and ecological roles, that survived to the very end of the Cretaceous (Maastrichtian: 72-66 million years ago in Brazil, including a core fauna of titanosaurian sauropods and abelisaurid and carcharodontosaurid theropods, along with a variety of small-to-mid-sized theropods. We argue that this pattern best fits the hypothesis that southern dinosaurs, like their northern counterparts, were still diversifying and occupying prominent roles in their ecosystems before the asteroid suddenly caused their extinction. However, this hypothesis remains to be tested with more refined paleontological and geochronological data, and we give suggestions for future work.

The last dinosaurs of Brazil: The Bauru Group and its implications for the end-Cretaceous mass extinction.

Science.gov (United States)

Brusatte, Stephen L; Candeiro, Carlos R A; Simbras, Felipe M

2017-01-01

The non-avian dinosaurs died out at the end of the Cretaceous, ~66 million years ago, after an asteroid impact. The prevailing hypothesis is that the effects of the impact suddenly killed the dinosaurs, but the poor fossil record of latest Cretaceous (Campanian-Maastrichtian) dinosaurs from outside Laurasia (and even more particularly, North America) makes it difficult to test specific extinction scenarios. Over the past few decades, a wealth of new discoveries from the Bauru Group of Brazil has revealed a unique window into the evolution of terminal Cretaceous dinosaurs from the southern continents. We review this record and demonstrate that there was a diversity of dinosaurs, of varying body sizes, diets, and ecological roles, that survived to the very end of the Cretaceous (Maastrichtian: 72-66 million years ago) in Brazil, including a core fauna of titanosaurian sauropods and abelisaurid and carcharodontosaurid theropods, along with a variety of small-to-mid-sized theropods. We argue that this pattern best fits the hypothesis that southern dinosaurs, like their northern counterparts, were still diversifying and occupying prominent roles in their ecosystems before the asteroid suddenly caused their extinction. However, this hypothesis remains to be tested with more refined paleontological and geochronological data, and we give suggestions for future work.

A New Sail-Backed Styracosternan (Dinosauria: Ornithopoda) from the Early Cretaceous of Morella, Spain.

Science.gov (United States)

Gasulla, José Miguel; Escaso, Fernando; Narváez, Iván; Ortega, Francisco; Sanz, José Luis

2015-01-01

A new styracosternan ornithopod genus and species is here described based on a partial postcranial skeleton and an associated dentary tooth of a single specimen from the Arcillas de Morella Formation (Early Cretaceous, late Barremian) at the Morella locality, (Castellón, Spain). Morelladon beltrani gen. et sp. nov. is diagnosed by eight autapomorphic features. The set of autapomorphies includes: very elongated and vertical neural spines of the dorsal vertebrae, midline keel on ventral surface of the second to fourth sacral vertebrae restricted to the anterior half of the centrum, a posterodorsally inclined medial ridge on the postacetabular process of the ilium that meets its dorsal margin and distal end of the straight ischial shaft laterally expanded, among others. Phylogenetic analyses reveal that the new Iberian form is more closely related to its synchronic and sympatric contemporary European taxa Iguanodon bernissartensis and Mantellisaurus atherfieldensis, known from Western Europe, than to other Early Cretaceous Iberian styracosternans (Delapparentia turolensis and Proa valdearinnoensis). The recognition of Morelladon beltrani gen. et sp. nov. indicates that the Iberian Peninsula was home to a highly diverse medium to large bodied styracosternan assemblage during the Early Cretaceous.

Possible markers of the Jurassic/Cretaceous boundary in the Mediterranean Tethys: A review and state of art

Directory of Open Access Journals (Sweden)

Jozef Michalík

2011-10-01

Full Text Available During the last decades, several integrated studies of Tethyan Jurassic/Cretaceous boundary sections from different countries were published with the objective to indicate problems for the selection of biological, chemical or physical markers suitable for identification of the Jurassic/Cretaceous boundary – the only system boundary within the Phanerozoic still not fixed by GSSP. Drawing the boundary between the Jurassic and Cretaceous systems is a matter of global scale discussions. The problem of proposing possible J/K boundary stratotypes results from lack of a global index fossils, global sea level drop, paleogeographic changes causing development of isolated facies areas, as well as from the effect of Late Cimmerian Orogeny. This contribution summarizes and comments data on J/K boundary interval obtained from several important Tethyan sections and shows still existing problems and discrepancies in its determination.

Hadrosauroid dinosaurs from the Late Cretaceous of the Sultanate of Oman

NARCIS (Netherlands)

Buffetaut, Eric; Hartman, Axel Frans; Al-Kindi, Mohammed; Schulp, Anne S.

2015-01-01

Fragmentary post-cranial remains (femora, tibia, vertebrae) of ornithischian dinosaurs from the Late Cretaceous of the Sultanate of Oman are described and referred to hadrosauroids. The specimens come from the Al-Khod Conglomerate, of latest Campanian to Maastrichtian age, in the north-eastern part

A Late Cretaceous theropod caudal vertebra from the Sultanate of Oman

NARCIS (Netherlands)

Schulp, Anne S.; Hanna, Samir S.; Hartman, Axel Frans; Jagt, John W M

2000-01-01

A caudal vertebra collected from conglomerates of the Al-Khod Formation (Late Cretaceous) in the Al-Khod area, Sultanate of Oman, is assigned to a medium-sized theropod dinosaur. The Al-Khod discovery represents one of the very few dinosaur records from the Middle East.

Cretaceous sedimentology of the Barmer Basin, Rajasthan, India

OpenAIRE

Beaumont, Hazel

2017-01-01

The Barmer Basin, western India, is a well-known and prospected petroleum system. However, the Lower Cretaceous Ghaggar-Hakra Formation has not been recognised as basin fill and not documented prior to this study. The formation outcrops in rotational fault blocks at the Sarnoo Hills and surrounding areas, on the eastern Barmer Basin margin. The thesis here describes and analyses the nature and evolution of the formation at both outcrop and within the subsurface, producing facies and depositio...

Evaluating controls on fluvial sand-body clustering in the Ferris Formation (Cretaceous/Paleogene, Wyoming, USA)

Science.gov (United States)

Hajek, E. A.; Heller, P.

2009-12-01

A primary goal of sedimentary geologists is to interpret past tectonic, climatic, and eustatic conditions from the stratigraphic record. Stratigraphic changes in alluvial-basin fills are routinely interpreted as the result of past tectonic movements or changes in climate or sea level. Recent physical and numerical models have shown that sedimentary systems can exhibit self-organization on basin-filling time scales, suggesting that structured stratigraphic patterns can form spontaneously rather than as the result of changing boundary conditions. The Ferris Formation (Upper Cretaceous/Paleogene, Hanna Basin, Wyoming) exhibits stratigraphic organization where clusters of closely-spaced channel deposits are separated from other clusters by intervals dominated by overbank material. In order to evaluate the role of basinal controls on deposition and ascertain the potential for self-organization in this ancient deposit, the spatial patterns of key channel properties (including sand-body dimensions, paleoflow depth, maximum clast size, paleocurrent direction, and sediment provenance) are analyzed. Overall the study area lacks strong trends sand-body properties through the stratigraphic succession and in cluster groups. Consequently there is no indication that the stratigraphic pattern observed in the Ferris Formation was driven by systematic changes in climate or tectonics.

Ecological impact of the end-Cretaceous extinction on lamniform sharks.

Directory of Open Access Journals (Sweden)

Rachel A Belben

Full Text Available Lamniform sharks are apex marine predators undergoing dramatic local and regional decline worldwide, with consequences for marine ecosystems that are difficult to predict. Through their long history, lamniform sharks have faced widespread extinction, and understanding those 'natural experiments' may help constrain predictions, placing the current crisis in evolutionary context. Here we show, using novel morphometric analyses of fossil shark teeth, that the end-Cretaceous extinction of many sharks had major ecological consequences. Post-extinction ecosystems supported lower diversity and disparity of lamniforms, and were dominated by significantly smaller sharks with slimmer, smoother and less robust teeth. Tooth shape is intimately associated with ecology, feeding and prey type, and by integrating data from extant sharks we show that latest Cretaceous sharks occupied similar niches to modern lamniforms, implying similar ecosystem structure and function. By comparison, species in the depauperate post-extinction community occupied niches most similar to those of juvenile sand tigers (Carcharias taurus. Our data show that quantitative tooth morphometrics can distinguish lamniform sharks due to dietary differences, providing critical insights into ecological consequences of past extinction episodes.

Ecological impact of the end-Cretaceous extinction on lamniform sharks.

Science.gov (United States)

Belben, Rachel A; Underwood, Charlie J; Johanson, Zerina; Twitchett, Richard J

2017-01-01

Lamniform sharks are apex marine predators undergoing dramatic local and regional decline worldwide, with consequences for marine ecosystems that are difficult to predict. Through their long history, lamniform sharks have faced widespread extinction, and understanding those 'natural experiments' may help constrain predictions, placing the current crisis in evolutionary context. Here we show, using novel morphometric analyses of fossil shark teeth, that the end-Cretaceous extinction of many sharks had major ecological consequences. Post-extinction ecosystems supported lower diversity and disparity of lamniforms, and were dominated by significantly smaller sharks with slimmer, smoother and less robust teeth. Tooth shape is intimately associated with ecology, feeding and prey type, and by integrating data from extant sharks we show that latest Cretaceous sharks occupied similar niches to modern lamniforms, implying similar ecosystem structure and function. By comparison, species in the depauperate post-extinction community occupied niches most similar to those of juvenile sand tigers (Carcharias taurus). Our data show that quantitative tooth morphometrics can distinguish lamniform sharks due to dietary differences, providing critical insights into ecological consequences of past extinction episodes.

Mountain building triggered late cretaceous North American megaherbivore dinosaur radiation.

Directory of Open Access Journals (Sweden)

Terry A Gates

Full Text Available Prior studies of Mesozoic biodiversity document a diversity peak for dinosaur species in the Campanian stage of the Late Cretaceous, yet have failed to provide explicit causal mechanisms. We provide evidence that a marked increase in North American dinosaur biodiversity can be attributed to dynamic orogenic episodes within the Western Interior Basin (WIB. Detailed fossil occurrences document an association between the shift from Sevier-style, latitudinally arrayed basins to smaller Laramide-style, longitudinally arrayed basins and a well substantiated decreased geographic range/increased taxonomic diversity of megaherbivorous dinosaur species. Dispersal-vicariance analysis demonstrates that the nearly identical biogeographic histories of the megaherbivorous dinosaur clades Ceratopsidae and Hadrosauridae are attributable to rapid diversification events within restricted basins and that isolation events are contemporaneous with known tectonic activity in the region. SymmeTREE analysis indicates that megaherbivorous dinosaur clades exhibited significant variation in diversification rates throughout the Late Cretaceous. Phylogenetic divergence estimates of fossil clades offer a new lower boundary on Laramide surficial deformation that precedes estimates based on sedimentological data alone.

Mountain building triggered late cretaceous North American megaherbivore dinosaur radiation.

Science.gov (United States)

Gates, Terry A; Prieto-Márquez, Albert; Zanno, Lindsay E

2012-01-01

Prior studies of Mesozoic biodiversity document a diversity peak for dinosaur species in the Campanian stage of the Late Cretaceous, yet have failed to provide explicit causal mechanisms. We provide evidence that a marked increase in North American dinosaur biodiversity can be attributed to dynamic orogenic episodes within the Western Interior Basin (WIB). Detailed fossil occurrences document an association between the shift from Sevier-style, latitudinally arrayed basins to smaller Laramide-style, longitudinally arrayed basins and a well substantiated decreased geographic range/increased taxonomic diversity of megaherbivorous dinosaur species. Dispersal-vicariance analysis demonstrates that the nearly identical biogeographic histories of the megaherbivorous dinosaur clades Ceratopsidae and Hadrosauridae are attributable to rapid diversification events within restricted basins and that isolation events are contemporaneous with known tectonic activity in the region. SymmeTREE analysis indicates that megaherbivorous dinosaur clades exhibited significant variation in diversification rates throughout the Late Cretaceous. Phylogenetic divergence estimates of fossil clades offer a new lower boundary on Laramide surficial deformation that precedes estimates based on sedimentological data alone.

Late Cretaceous Sub-Marine Fan System in Batain Mélange Zone, the Fayah Formation in Northeastern Oman

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Iftikhar Ahmed Abbasi

2014-06-01

Full Text Available The Batain coast along the northeastern margin of Oman between Ra’s Al-Hadd and Ra’s Jibsch, is comprised of Permian to Late Cretaceous complex stratigraphy in a tectonically deformed area recording Permian rifting to late Cretaceous Tethys closure events. These rocks are thrust over Mesozoic and older autochthonous sedimentary cover in the form of a major nappe structure known as the Batain Nappe. The uppermost part of the Batain nappe is comprised of isolated outcrops of early Maastrichtian siliciclastic Fayah Formation dominated by gravity flow deposits. The Fayah Formation in the Jabal Fayah area is over four hundred meters thick and comprised of five distinct facies associations; namely, i coarsening-up sandstone, ii conglomerate, iii debris- flow, iv turbidite, and v inter-bedded sandstone and shale lithofacies. These lithofacies associations are repeated many times in the section. The sandstone lithofacies association exhibits a coarsening-upward trend making sequences tens of meters thick in various parts of the formation. Waterscape structures are common along with occasional sandstone dykes and convolute bedding, reflecting fluidized conditions of deposition. The conglomerate lithofacies association is comprised of a series of interbedded coarsening-upward pebble to gravel size conglomerates containing chert, limestone, granite and volcanic clasts ranging a few mm to cm in diameter. Occasionally these are interbedded with sandstone lithofacies. The conglomerate lithofacies was deposited by a high-energy channelized flow in a sub-aqueous setting. The debris-flow lithofacies association is a matrix supported chaotic mixture of clay and boulders of granite, limestone and volcanic rocks, some of which are meter-sized in diameter, and possibly derived from the nearby basement rocks such as the Jabal Ja’alan basement rocks. It constitutes the most dominant part of the formation. These sediments were deposited along a slope setting

Latest Cretaceous climatic and environmental change in the South Atlantic region

NARCIS (Netherlands)

Woelders, L.; Vellekoop, J.; Kroon, D.; Smit, J.; Casadío, S.; Prámparo, M. B.; Dinarès-Turell, J.; Peterse, F.; Sluijs, A.; Lenaerts, J.T.M.; Speijer, R. P.

Latest Maastrichtian climate change caused by Deccan volcanism has been invoked as a cause of mass extinction at the Cretaceous-Paleogene (K-Pg) boundary (~66.0 Ma). Yet late Maastrichtian climate and ecological changes are poorly documented, in particular on the Southern Hemisphere. Here we present

Latest Cretaceous climatic and environmental change in the South Atlantic region

NARCIS (Netherlands)

Woelders, L.; Vellekoop, J.; Kroon, D.; Smit, J.; Casadío, S.; Prámparo, M. B.; Dinarès-Turell, J.; Peterse, F.; Sluijs, A.; Lenaerts, J. T.M.; Speijer, R. P.

2017-01-01

Latest Maastrichtian climate change caused by Deccan volcanism has been invoked as a cause of mass extinction at the Cretaceous-Paleogene (K-Pg) boundary (~66.0 Ma). Yet late Maastrichtian climate and ecological changes are poorly documented, in particular on the Southern Hemisphere. Here we present

Using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to explore geochemical taphonomy of vertebrate fossils in the upper cretaceous two medicine and Judith River formations of Montana

Science.gov (United States)

Rogers, R.R.; Fricke, H.C.; Addona, V.; Canavan, R.R.; Dwyer, C.N.; Harwood, C.L.; Koenig, A.E.; Murray, R.; Thole, J.T.; Williams, J.

2010-01-01

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to determine rare earth element (REE) content of 76 fossil bones collected from the Upper Cretaceous (Campanian) Two Medicine (TMF) and Judith River (JRF) Formations of Montana. REE content is distinctive at the formation scale, with TMF samples exhibiting generally higher overall REE content and greater variability in REE enrichment than JRF samples. Moreover, JRF bones exhibit relative enrichment in heavy REE, whereas TMF bones span heavy and light enrichment fields in roughly equal proportions. TMF bones are also characterized by more negative Ce anomalies and greater U enrichment than JRF bones, which is consistent with more oxidizing diagenetic conditions in the TMF. Bonebeds in both formations show general consistency in REE content, with no indication of spatial or temporal mixing within sites. Previous studies, however, suggest that the bonebeds in question are attritional assemblages that accumulated over considerable time spans. The absence of geochemical evidence for mixing is consistent with diagenesis transpiring in settings that remained chemically and hydrologically stable during recrystallization. Lithology-related patterns in REE content were also compared, and TMF bones recovered from fluvial sandstones show relative enrichment in heavy REE when compared with bones recovered from fine-grained floodplain deposits. In contrast, JRF bones, regardless of lithologic context (sandstone versus mudstone), exhibit similar patterns of REE uptake. This result is consistent with previous reconstructions that suggest that channel-hosted microfossil bonebeds of the JRF developed via the reworking of preexisting concentrations embedded in the interfluve. Geochemical data further indicate that reworked elements were potentially delivered to channels in a recrystallized condition, which is consistent with rapid adsorption of REE postmortem. Copyright ?? 2010, SEPM (Society for

Earth history. U-Pb geochronology of the Deccan Traps and relation to the end-Cretaceous mass extinction.

Science.gov (United States)

Schoene, Blair; Samperton, Kyle M; Eddy, Michael P; Keller, Gerta; Adatte, Thierry; Bowring, Samuel A; Khadri, Syed F R; Gertsch, Brian

2015-01-09

The Chicxulub asteroid impact (Mexico) and the eruption of the massive Deccan volcanic province (India) are two proposed causes of the end-Cretaceous mass extinction, which includes the demise of nonavian dinosaurs. Despite widespread acceptance of the impact hypothesis, the lack of a high-resolution eruption timeline for the Deccan basalts has prevented full assessment of their relationship to the mass extinction. Here we apply uranium-lead (U-Pb) zircon geochronology to Deccan rocks and show that the main phase of eruptions initiated ~250,000 years before the Cretaceous-Paleogene boundary and that >1.1 million cubic kilometers of basalt erupted in ~750,000 years. Our results are consistent with the hypothesis that the Deccan Traps contributed to the latest Cretaceous environmental change and biologic turnover that culminated in the marine and terrestrial mass extinctions. Copyright © 2015, American Association for the Advancement of Science.

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.)

AN APPROACH TO PROVENANCE, TECTONIC AND REDOX CONDITIONS OF JURASSIC-CRETACEOUS AKKUYU FORMATION, CENTRAL TAURIDS, TURKEY

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Ali SARI

2012-06-01

Full Text Available - Late Jurassic-Early Cretaceous Akkuyu formation was deposited in a marine carbonate platform in Central Tarurids. The organic material of the unit is composed of Type III kerogen which is woody material transported from the land. Late Jurassic- Early Cretaceous is an important period which great anoxic events in deep sea bottom occurred due to the primary organic productivity in global sea surface. Use of several trace elements values (Ni, V, U, Cr, Co, Th revealed that Late Jurassic-Early Cretaceous Akkuyu formation shows oxic, disoxic and anoxic paleoredox conditions. In this period the primary productivity was considerably high. Examination of specimen derived from Akkuyu formation revealed that there exists a very good positive relationship between the major oxides of Al2O3, SiO2, Fe2O3, TiO2, and K2O. These combinations of major oxides indicate a detrital origin of source rock. Chemical weathering evaluations of Central Taurids in the Jurassic-Cretaceous period indicated moderate and strong weathering of source rock. K2O/Na2O versus SiO2; SiO2/Al2O3 versus K2O/Na2O; Al2O3/ SiO2 versus Fe2O3 + MgO ve TiO2 versus Fe2O3 + MgO diagrams indicated that Akkuyu formation was deposited along active and/or passive continental margin and derived from basalt and basalt+granite mixed rocks.

Spectroscopic Studies on Organic Matter from Triassic Reptile Bones, Upper Silesia, Poland

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Surmik, Dawid; Boczarowski, Andrzej; Balin, Katarzyna; Dulski, Mateusz; Szade, Jacek; Kremer, Barbara; Pawlicki, Roman

2016-01-01

Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles) bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk) strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS) of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment. PMID:26977600

Spectroscopic Studies on Organic Matter from Triassic Reptile Bones, Upper Silesia, Poland.

Directory of Open Access Journals (Sweden)

Dawid Surmik

Full Text Available Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment.

Strain-compensated (Ga,In)N/(Al,Ga)N/GaN multiple quantum wells for improved yellow/amber light emission

Energy Technology Data Exchange (ETDEWEB)

Lekhal, K.; Damilano, B., E-mail: bd@crhea.cnrs.fr; De Mierry, P.; Vennéguès, P. [CRHEA-CNRS, Centre de Recherche sur l' Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, Valbonne 06560 (France); Ngo, H. T.; Rosales, D.; Gil, B. [Laboratoire Charles Coulomb, CNRS-INP-UMR 5221, Université Montpellier 2, F-34095 Montpellier (France); Hussain, S. [CRHEA-CNRS, Centre de Recherche sur l' Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, Valbonne 06560 (France); Université de Nice Sophia Antipolis, Parc Valrose, 28 av. Valrose, 06108 Nice cedex 2 (France)

2015-04-06

Yellow/amber (570–600 nm) emitting In{sub x}Ga{sub 1−x}N/Al{sub y}Ga{sub 1−y}N/GaN multiple quantum wells (QWs) have been grown by metal organic chemical vapor deposition on GaN-on- sapphire templates. When the (Al,Ga)N thickness of the barrier increases, the room temperature photoluminescence is red-shifted while its yield increases. This is attributed to an increase of the QW internal electric field and an improvement of the material quality due to the compensation of the compressive strain of the In{sub x}Ga{sub 1−x}N QWs by the Al{sub y}Ga{sub 1−y}N layers, respectively.

Early Cretaceous climate change (Hauterivian - Early Aptian): Learning from the past to prevent modern reefs decline

Science.gov (United States)

Godet, Alexis; Bodin, Stéphane; Adatte, Thierry; Föllmi, Karl B.

2010-05-01

Kieselkalk Formation (Fm), is dated as Hauterivian; it consists of a quartz-bearing crinoidal limestone with bryozoans (Föllmi et al., 2007). The Lidernen Member (Mb; glauconitic and phosphatic interval) splits the Kieselkalk Fm into a lower and an upper part. Following on top of the Kieselkalk Fm, the Altmann Mb represents a second phase of slow-down or even cessation in the platform ecosystem activity, when the PAR values are the highest in basinal sections. This suggests that high trophic levels control the disappearance of healthy carbonate ecosystems; this hypothesis is testified by the rise of Urgonian-type carbonates during time of low nutrient input in the Late Barremian (Schrattenkalk Fm from the Gerhardtia sartousiana ammonozone upward). Interestingly, the same evolutionary pattern is recovered in the western Swiss Jura, where heterozoan association characterizes the Pierre Jaune de Neuchâtel (Hauterivian), whereas the Urgonien Blanc (Late Barremian - earliest Aptian), corresponds to photozoan carbonates deposited under oligotrophic conditions, as is suggested by the presence of rudists and corals. References Bodin et al., 2006. "The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates." Palaeogeography, Palaeoclimatology, Palaeoecology 235: 245-264. Bryant et al., 1998. Reefs at Risk: A Map-Based Indicator of Potential Threats to the World's Coral Reefs. Washington D.C. Föllmi et al., 2007. "Unlocking paleo-environmental interaction from Early Cretceous shelf sediments in the Helvetic Alps: stratigraphy is the key!" Swiss Journal of Geosciences 100: 349-369. Godet et al., 2008. "Platform-induced clay-mineral fractionation along a northern Tethyan basin-platform transect: implications for the interpretation of Early Cretaceous climate change (Late Hauterivian-Early Aptian)." Cretaceous Research 29: 830-847.

New tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies evolution of giant body sizes and advanced senses in tyrant dinosaurs.

Science.gov (United States)

Brusatte, Stephen L; Averianov, Alexander; Sues, Hans-Dieter; Muir, Amy; Butler, Ian B

2016-03-29

Tyrannosaurids--the familiar group of carnivorous dinosaurs including Tyrannosaurus and Albertosaurus--were the apex predators in continental ecosystems in Asia and North America during the latest Cretaceous (ca. 80-66 million years ago). Their colossal sizes and keen senses are considered key to their evolutionary and ecological success, but little is known about how these features developed as tyrannosaurids evolved from smaller basal tyrannosauroids that first appeared in the fossil record in the Middle Jurassic (ca. 170 million years ago). This is largely because of a frustrating 20+ million-year gap in the mid-Cretaceous fossil record, when tyrannosauroids transitioned from small-bodied hunters to gigantic apex predators but from which no diagnostic specimens are known. We describe the first distinct tyrannosauroid species from this gap, based on a highly derived braincase and a variety of other skeletal elements from the Turonian (ca. 90-92 million years ago) of Uzbekistan. This taxon is phylogenetically intermediate between the oldest basal tyrannosauroids and the latest Cretaceous forms. It had yet to develop the giant size and extensive cranial pneumaticity of T. rex and kin but does possess the highly derived brain and inner ear characteristic of the latest Cretaceous species. Tyrannosauroids apparently developed huge size rapidly during the latest Cretaceous, and their success in the top predator role may have been enabled by their brain and keen senses that first evolved at smaller body size.

New tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies evolution of giant body sizes and advanced senses in tyrant dinosaurs

Science.gov (United States)

Brusatte, Stephen L.; Averianov, Alexander; Sues, Hans-Dieter; Muir, Amy; Butler, Ian B.

2016-03-01

Tyrannosaurids-the familiar group of carnivorous dinosaurs including Tyrannosaurus and Albertosaurus-were the apex predators in continental ecosystems in Asia and North America during the latest Cretaceous (ca. 80-66 million years ago). Their colossal sizes and keen senses are considered key to their evolutionary and ecological success, but little is known about how these features developed as tyrannosaurids evolved from smaller basal tyrannosauroids that first appeared in the fossil record in the Middle Jurassic (ca. 170 million years ago). This is largely because of a frustrating 20+ million-year gap in the mid-Cretaceous fossil record, when tyrannosauroids transitioned from small-bodied hunters to gigantic apex predators but from which no diagnostic specimens are known. We describe the first distinct tyrannosauroid species from this gap, based on a highly derived braincase and a variety of other skeletal elements from the Turonian (ca. 90-92 million years ago) of Uzbekistan. This taxon is phylogenetically intermediate between the oldest basal tyrannosauroids and the latest Cretaceous forms. It had yet to develop the giant size and extensive cranial pneumaticity of T. rex and kin but does possess the highly derived brain and inner ear characteristic of the latest Cretaceous species. Tyrannosauroids apparently developed huge size rapidly during the latest Cretaceous, and their success in the top predator role may have been enabled by their brain and keen senses that first evolved at smaller body size.

Palynology of uppermost Jurassic and lowermost Cretaceous strata in the Eastern Netherlands

NARCIS (Netherlands)

Burger, D.

1965-01-01

The present investigation is a systematical treatment of the sporomorphs from strata at the Jurassic-Cretaceous boundary in the eastern Netherlands Twente area, and an attempt to apply palynology to detailed stratigraphical study, by making use of quantitative pollen analyses. The rock samples used

Traces of a large crocodylian from the Lower Cretaceous Sousa Formation, Brazil

DEFF Research Database (Denmark)

Campos, Herbert B.N.; da Silva, Rafael C.; Milàn, Jesper

2010-01-01

Body imprints and tracks attributed to large crocodylians from the Lower Cretaceous Sousa Formation of Brazil are described and interpreted as having been produced in a subaqueous environment. In addition to the crocodylian tracks, the assemblage also comprises isolated tracks from medium-sized t...

Similarities and differences in the ilia of Late Cretaceous anurans and urodeles

Czech Academy of Sciences Publication Activity Database

Roček, Zbyněk; Gardner, J. D.; Eaton, J. G.; Přikryl, Tomáš

2012-01-01

Roč. 183, č. 6 (2012), s. 529-535 ISSN 0037-9409 R&D Projects: GA MŠk ME08066 Institutional support: RVO:67985831 Keywords : Anura * Cretaceous * Ilium * North America * Postcranial skeleton * Urodela Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.182, year: 2012

Cretaceous origin and repeated tertiary diversification of the redefined butterflies.

Science.gov (United States)

Heikkilä, Maria; Kaila, Lauri; Mutanen, Marko; Peña, Carlos; Wahlberg, Niklas

2012-03-22

Although the taxonomy of the ca 18 000 species of butterflies and skippers is well known, the family-level relationships are still debated. Here, we present, to our knowledge, the most comprehensive phylogenetic analysis of the superfamilies Papilionoidea, Hesperioidea and Hedyloidea to date based on morphological and molecular data. We reconstructed their phylogenetic relationships using parsimony and Bayesian approaches. We estimated times and rates of diversification along lineages in order to reconstruct their evolutionary history. Our results suggest that the butterflies, as traditionally understood, are paraphyletic, with Papilionidae being the sister-group to Hesperioidea, Hedyloidea and all other butterflies. Hence, the families in the current three superfamilies should be placed in a single superfamily Papilionoidea. In addition, we find that Hedylidae is sister to Hesperiidae, and this novel relationship is supported by two morphological characters. The families diverged in the Early Cretaceous but diversified after the Cretaceous-Palaeogene event. The diversification of butterflies is characterized by a slow speciation rate in the lineage leading to Baronia brevicornis, a period of stasis by the skippers after divergence and a burst of diversification in the lineages leading to Nymphalidae, Riodinidae and Lycaenidae.

Seryl-tRNA Synthetases from Methanogenic Archaea: Suppression of Bacterial Amber Mutation and Heterologous Toxicity

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Drasko Boko

2010-01-01

Full Text Available Methanogenic archaea possess unusual seryl-tRNA synthetases (SerRS, evolutionarily distinct from the SerRSs found in other archaea, eucaryotes and bacteria. Our recent X-ray structural analysis of Methanosarcina barkeri SerRS revealed an idiosyncratic N-terminal domain and catalytic zinc ion in the active site. To shed further light on substrate discrimination by methanogenic-type SerRS, we set up to explore in vivo the interaction of methanogenic-type SerRSs with their cognate tRNAs in Escherichia coli or Saccharomyces cerevisiae. The expression of various methanogenic-type SerRSs was toxic for E. coli, resulting in the synthesis of erroneous proteins, as revealed by β-galactosidase stability assay. Although SerRSs from methanogenic archaea recognize tRNAsSer from all three domains of life in vitro, the toxicity presumably precluded the complementation of endogenous SerRS function in both, E. coli and S. cerevisiae. However, despite the observed toxicity, coexpression of methanogenic-type SerRS with its cognate tRNA suppressed bacterial amber mutation.

Post Cretaceous cooling trend documented in the gastropods (Turritella Sp.) from the Cenozoic startigraphic successions of India

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Banerjee, Y.; Ghosh, P.; Halder, K.; Malarkodi, N.; Pathak, P.

2017-12-01

The aftermath of the Himalyan orogeny and subsequent cooling is documented in the deep sea sedimentary record from the Oceanic realm (1). Here we attempt to reconstruct the temperature pattern based on marine gastropods i.e. Turritella sp. which became abundant during the post Cretaceous period and have successfully been used for the reconstruction of climate by measuring the stable isotopic composition (2,3,4). Well preserved specimens of Cretaceous Turritella from the Rajamundry Infratrappean beds and those from the Miocene, Holocene succession of Kutch, western India were analysed along with specimen from the modern time scale (also from Kutch). The Cretaceous, early to mid Miocene, early Holocene and modern shells recorded δ13C variability from 0.36 to 4.94‰, -1.83 to -4.83‰, -3.26 to 0.40‰, -1.47 to -4.70‰ respectively suggesting drop in the productivity during mid Miocene and subsequent period of rapid growth. The Variability in terms of δ18O ranges from -2.28 to -4.99‰, -2.66 to -7.06‰, -2.86 to 0.96‰, -1.05 to -3.23‰ for the Cretaceous, early to mid Miocene, early Holocene and modern shells respectively. Corbula sp. collected from the same strata with that of the early to mid Holocene Turritella showed a similar δ13C and δ18O values denoting similar environmental condition during deposition. Absence of any significant correlation between δ13C vs δ18O support equilibrium precipitation of shell growth bands. We used Epstein oxygen isotope thermometry to derive temperature from the oxygen isotope of carbonate and adopted water isotopic composition (1‰ for the Cretaceous and -0.7‰ for the Miocene) from the literature. Our observation captured an overall cooling trend from the Cretaceous to the Holocene time period (especially in between mid Miocene to Holocene) and a subsequent warming trend in modern time. Validation with other thermometry method will be displayed at the time of presentation. References: [1] Zachos et al., 2001

High geomagnetic intensity during the mid-Cretaceous from Thellier analyses of single plagioclase crystals.

Science.gov (United States)

Tarduno, J A; Cottrell, R D; Smirnov, A V

2001-03-02

Recent numerical simulations have yielded the most efficient geodynamo, having the largest dipole intensity when reversal frequency is low. Reliable paleointensity data are limited but heretofore have suggested that reversal frequency and paleointensity are decoupled. We report data from 56 Thellier-Thellier experiments on plagioclase crystals separated from basalts of the Rajmahal Traps (113 to 116 million years old) of India that formed during the Cretaceous Normal Polarity Superchron. These data suggest a time-averaged paleomagnetic dipole moment of 12.5 +/- 1.4 x 10(22) amperes per square meter, three times greater than mean Cenozoic and Early Cretaceous-Late Jurassic dipole moments when geomagnetic reversals were frequent. This result supports a correlation between intervals of low reversal frequency and high geomagnetic field strength.

Geochemical evolution of Cenozoic-Cretaceous magmatism and its relation to tectonic setting, southwestern Idaho, U.S.A

International Nuclear Information System (INIS)

Norman, M.D.; Leeman, W.P.

1989-01-01

Magmatism in the western United States spanned a change in tectonic setting from Mesozoic and early Tertiary plate convergence to middle and late Tertiary crustal extension. This paper presents new major element, trace element, and isotopic (Sr, Nd, Pb) data on a diverse suite of Cretaceous to Neogene igneous rocks from the Owyhee area of southwestern Idaho to evaluate possible relationships between the evolving tectonic regime and temporal changes in igneous activity. The oldest studied rocks are Cretaceous granitic intrusives that probably formed by large-scale mixing of Precambrian crust with subduction-related magmas. Silicic Eocene tuffs are also rich in crustal components, but have isotopic compositions unlike the Cretaceous intrusives. These data require at least two crustal sources that may correspond to domains of significantly different age (Archean vs. Proterozoic). The oldest mafic lavas in the study area are Oligocene andesites and basalts compositionally similar to subduction-related magmas derived from asthenospheric mantle and erupted through thick continental crust. Direct crustal involvement during oligocene time was limited to minor interaction with the mafic magmas. Miocene activity produced bimodal basalt-rhyolite suites and minor volumes of hybrid lavas. Compositions of Miocene basalts demonstrate the decline of subduction-related processes, and increased involvement of subcontinental lithospheric mantle as a magma source. Crustally-derived Miocene rhyolites have isotopic compositions similar to those of the Cretaceous granitic rocks but trace element abundances more typical of within-plate magmas. (orig./WB)

Extension of the AMBER molecular dynamics software to Intel's Many Integrated Core (MIC) architecture

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Needham, Perri J.; Bhuiyan, Ashraf; Walker, Ross C.

2016-04-01

We present an implementation of explicit solvent particle mesh Ewald (PME) classical molecular dynamics (MD) within the PMEMD molecular dynamics engine, that forms part of the AMBER v14 MD software package, that makes use of Intel Xeon Phi coprocessors by offloading portions of the PME direct summation and neighbor list build to the coprocessor. We refer to this implementation as pmemd MIC offload and in this paper present the technical details of the algorithm, including basic models for MPI and OpenMP configuration, and analyze the resultant performance. The algorithm provides the best performance improvement for large systems (>400,000 atoms), achieving a ∼35% performance improvement for satellite tobacco mosaic virus (1,067,095 atoms) when 2 Intel E5-2697 v2 processors (2 ×12 cores, 30M cache, 2.7 GHz) are coupled to an Intel Xeon Phi coprocessor (Model 7120P-1.238/1.333 GHz, 61 cores). The implementation utilizes a two-fold decomposition strategy: spatial decomposition using an MPI library and thread-based decomposition using OpenMP. We also present compiler optimization settings that improve the performance on Intel Xeon processors, while retaining simulation accuracy.

Geology of hole drill thermal infra basaltic (Guarani Aquifer System) in Salto Uruguay

International Nuclear Information System (INIS)

Goso, C.; Muzio, R.; Marmisolle, J.; De Souza, S.

2004-01-01

This paper deals with the lithological description of a thermal infrabasaltic (Guarani Aquifer System) hole drill cutting in Dayman (Kanarek Hotel), Salto department (Uruguay). This hole drill shows 152 meters of Buena Vista Formation (Upper Permian- Lower Triassic), 188 meters of Tacuarembo Formation (Upper Jurassic-Lower Cretaceous) and 940meters of Arapey Formation (Lower Cretaceous). Petrographical studies of six basaltic levels were done [es

A large Cretaceous theropod from Patagonia, Argentina, and the evolution of carcharodontosaurids

Science.gov (United States)

Novas, Fernando E.; Valais, Silvina; Vickers-Rich, Pat; Rich, Tom

2005-05-01

The Cretaceous Carcharodontosauridae is the latest clade of carnosaurs, including the largest predatory dinosaurs yet recorded. Albeit spectacular for their size, the skeletal anatomy of these theropods remains poorly-known, and their diversity was until recently restricted to two Cenomanian species: the highly derived Giganotosaurus carolinii, from southern South America, and the incompletely known Carcharodontosaurus saharicus, from northern Africa. Here we describe an older and basal member of the group, Tyrannotitan chubutensis gen. et sp. nov., from Aptian strata of Patagonia, Argentina. The new taxon gives new insights into the systematics and evolution of carcharodontosaurids and offers a better understanding of the evolution of Southern theropod faunas. We suggest that carcharodontosaurids radiated in Gondwana sharing with spinosaurids the role of top-predators until their extinction in Cenomanian Turonian times. During this interval, the diplodocoid sauropods and giant titanosaurians went extinct (probably as part of a global-scale crisis), and the smaller abelisaurid theropods took dominance, reigning until the end of the Cretaceous. Electronic Supplementary Material is available.

Depositional environments and oil potential of Jurassic/Cretaceous source rocks within the Seychelles microcontinent

Energy Technology Data Exchange (ETDEWEB)

Plummer, P.S.; Joseph, P.R.; Samson, P.J. [Seychelles National Oil Co., Mahe (Seychelles)

1998-12-31

The Seychelles microcontinent became isolated between the Somali, Mascarene and Arabian basins of the Indian Ocean as a result of the Mesozoic fragmentation of Gondwana. Major rifting events occurred during the Triassic-Middle Jurassic and Late Cretaceous (Cenomanian-Santonian and Maastrichtian) during which shaly source rock facies accumulated in principally marginal marine/deltaic environments. Between these times, post-rift passive margin deposition within restricted to open marine environments produced shaly source rocks during late Middle Jurasic-Early Cretaceous, Campanian-Maastrichtian and Paleocene times. Recent geochemical analysis of cuttings from the Seagull Shoals-1 well has identified an oil-prone liptinitic (Type II) coaly shale within early Middle Jurassic abandoned deltaic deposits. This coaly source rock is regionally developed, having also been identified in the Majunja and Morondava basins of Madagascar. Oil-prone Type II organic matter has also been identified in the Owen Bank A-1 well within restricted marine shales of late Middle Jurassic age. These shales are part of a thick post-rift source rock sequence that extends into the Early Cretaceous and is in part correlative with the proven Late Jurassic Uarandab Shale of Somalia. Analysis of Campanian marine shales from Reith Bank-1 well identified significant dilution of total organic carbon content in composite, compared to picked, well cuttings samples. This finding supports a published inference that these post-rift shales have source rock potential. (author)

Cretaceous plutonic rocks in the Donner Lake-Cisco Grove area, northern Sierra Nevada, California

Science.gov (United States)

Kulow, Matthew J.; Hanson, Richard E.; Girty, Gary H.; Girty, Melissa S.; Harwood, David S.

1998-01-01

The northernmost occurrences of extensive, glaciated exposures of the Sierra Nevada batholith occur in the Donner Lake-Cisco Grove area of the northern Sierra Nevada. The plutonic rocks in this area, which are termed here the Castle Valley plutonic assemblage, crop out over an area of 225 km2 and for the most part are shown as a single undifferentiated mass on previously published geological maps. In the present work, the plutonic assemblage is divided into eight separate intrusive units or lithodemes, two of which each consist of two separate plutons. Compositions are dominantly granodiorite and tonalite, but diorite and granite form small plutons in places. Spectacular examples of comb layering and orbicular texture occur in the diorites. U-Pb zircon ages have been obtained for all but one of the main units and range from ~120 to 114 Ma, indicating that the entire assemblage was emplaced in a narrow time frame in the Early Cretaceous. This is consistent with abundant field evidence that many of the individual phases were intruded penecontemporaneously. The timing of emplacement correlates with onset of major Cretaceous plutonism in the main part of the Sierra Nevada batholith farther south. The emplacement ages also are similar to isotopic ages for gold-quartz mineralization in the Sierran foothills west of the study area, suggesting a direct genetic relationship between the voluminous Early Cretaceous plutonism and hydrothermal gold mineralization.

Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous

Digital Repository Service at National Institute of Oceanography (India)

Rao, D.G.; Krishna, K.S.; Sar, D.

on three latitudinal profiles) in the Bay of Bengal. The trend of the fracture zones, the locations of the magnetic chron 34, and the Cretaceous Magnetic Quiet Zone suggest that Greater India separated from Antarctica after a period of transform motion...

Results of the study of a new Groznensky Field with fissured reservoir rocks

Energy Technology Data Exchange (ETDEWEB)

Lebedinets, N P; Merkulov, A V; Pristanskii, G T; Postash, M F

1970-06-01

Geological information on the Eldarovsky field, situated in the central part of Tersky anticlinal zone and discovered in 1964, is given. Commercial quantities of oil were discovered in the foraminifera (thickness 40 to 70 m) and Upper Cretaceous (305 to 330 m thickness) deposits, consisting of fissured limestones and marls. Both the foraminifera and Upper Cretaceous deposits are divided into various zones which are hydrodynamically connected with each other and constitute a single pool. No hydrodynamical connection was observed between the Eldarovsky pools and surrounding oil fields. The secondary porosity of the Upper Cretaceous and forammifera deposits is 0.49% and 0.2%, respectively, and is responsible for most of the oil reserves. The analysis of the pressure buildup curves shows that the field has an elastic water drive.

How many upper Eocene microspherule layers: More than we thought

Science.gov (United States)

Hazel, Joseph E.

1988-01-01

The scientific controversy over the origin of upper Eocene tektites, microtektites and other microspherules cannot be logically resolved until it is determined just how many events are involved. The microspherule-bearing beds in marine sediments have been dated using standard biozonal techniques. Although a powerful stratigraphic tool, zonal biostratigraph has its limitations. One is that if an event, such as a microspherule occurrence, is observed to occur in a zone at one locality and then a similar event observed in the same zone at another locality, it still may be unwarranted to conclude that these events exactly correlate. To be in a zone a sample only need be between the fossil events that define the zone boundaries. It is often very difficult to accurately determine where within a zone one might be. Further, the zone defining events do not everywhere occur at the same points in time. That is, the ranges of the defining taxa are not always filled. Thus, the length of time represented by a zone (but not, of course, its chronozone) can vary from place to place. These problems can be offset by use of chronostratigraphic modelling techniques such as Graphic Correlation. This technique was used to build a Cretaceous and Cenozoic model containing fossil, magnetopolarity, and other events. The scale of the model can be demonstrated to be linear with time. This model was used to determine the chronostratigraphic position of upper Eocene microspherule layers.

Geomagnetic Reversals of the Late Jurassic and Early Cretaceous Captured in a North China Core

Science.gov (United States)

Kuhn, T.; Fu, R. R.; Kent, D. V.; Olsen, P. E.

2016-12-01

The Tuchengzi formation in North China nominally spans nearly 20 million years of the Late Jurassic and Early Cretaceous, an interval during which age calibration of the Geomagnetic Polarity Time Scale (GPTS) based on seafloor magnetic anomalies is poorly known. The overlying Yixian formation is of special paleontological interest due to an abundance of spectacularly preserved macrofossils of feathered non-avian dinosaurs, birds, mammals, and insects. Scarce fossils in the Tuchengzi, sparse accurate radiometric dates on both the Tuchengzi and overlying Yixian formation, and scant previous paleomagnetic studies on these formations motivated our application of magnetostratigraphy as a geochronological tool. We constructed a geomagnetic reversal sequence from the upper 142m of a 200m core extracted in Liaoning Province at Huangbanjigou spanning the lower Yixian Formation and the unconformably underlying Tuchengzi Formation. Thermal demagnetization up to 680°C in steps of 25-50°C revealed predominantly normal overprints consistent with the modern day field with unblocking temperatures between 125°C and as high as 550°C, as well as normal and reverse characteristic components with unblocking temperatures between 500°C and 680°C. Going up from the base of the core, there is a reverse polarity magnetozone >6m thick, followed by a 5m normal magnetozone, a 10m reverse magnetozone, a 25m normal magnetozone, and a 6m reverse magnetozone truncated by the Yixian-Tuchengzi unconformity. Above the unconformity, all 81m of core were normal. These results indicate that a meaningful polarity stratigraphy can be recovered from the Tuchengzi and Yixian formations that will be invaluable for correlations across the Tuchengzi and potentially the Yixian formations, which span thousands of square kilometers and vary in thickness by many hundreds of meters. The results also demonstrate that, in combination with accurate and precise radiometric dates, the Tuchengzi Formation has the

A Triassic to Cretaceous Sundaland-Pacific subduction margin in West Sarawak, Borneo

Science.gov (United States)

Breitfeld, H. Tim; Hall, Robert; Galin, Thomson; Forster, Margaret A.; BouDagher-Fadel, Marcelle K.

2017-01-01

Metamorphic rocks in West Sarawak are poorly exposed and studied. They were previously assumed to be pre-Carboniferous basement but had never been dated. New 40Ar/39Ar ages from white mica in quartz-mica schists reveal metamorphism between c. 216 to 220 Ma. The metamorphic rocks are associated with Triassic acid and basic igneous rocks, which indicate widespread magmatism. New U-Pb dating of zircons from the Jagoi Granodiorite indicates Triassic magmatism at c. 208 Ma and c. 240 Ma. U-Pb dating of zircons from volcaniclastic sediments of the Sadong and Kuching Formations confirms contemporaneous volcanism. The magmatic activity is interpreted to represent a Triassic subduction margin in westernmost West Sarawak with sediments deposited in a forearc basin derived from the magmatic arc at the Sundaland-Pacific margin. West Sarawak and NW Kalimantan are underlain by continental crust that was already part of Sundaland or accreted to Sundaland in the Triassic. One metabasite sample, also previously assumed to be pre-Carboniferous basement, yielded Early Cretaceous 40Ar/39Ar ages. They are interpreted to indicate resumption of subduction which led to deposition of volcaniclastic sediments and widespread magmatism. U-Pb ages from detrital zircons in the Cretaceous Pedawan Formation are similar to those from the Schwaner granites of NW Kalimantan, and the Pedawan Formation is interpreted as part of a Cretaceous forearc basin containing material eroded from a magmatic arc that extended from Vietnam to west Borneo. The youngest U-Pb ages from zircons in a tuff layer from the uppermost part of the Pedawan Formation indicate that volcanic activity continued until c. 86 to 88 Ma when subduction terminated.

Micropaleontology and palaeoclimate during the early Cretaceous in the Lishu depression, Songliao basin, Northeast China

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Wei Yan

2017-01-01

Full Text Available Diverse and abundant microfossils, such as palynomorphs, algae and Ostracoda, were collected from lower Cretaceous strata of Lishu depression, located in southeastern Songliao basin, and were identified and classified in order to provide relevant, detailed records for paleoclimate research. The early Cretaceous vegetation and climate of southeastern Songliao basin have been inferred from the analysis of palynomorph genera, algae and Ostracoda of the LS1 and SW110 wells. The lower Cretaceous strata include, in ascending stratigraphic order, the Shahezi, Yingcheng and Denglouku formations. Palynological assemblages for each formation, based on biostratigraphic and statistical analyses, provide an assessment of their longitudinal variations. During deposition of the Shahezi Formation, the climate was mid-subtropical. Vegetation consisted of coniferous forest and herbage. During deposition of the Yingcheng Formation, the climate was south Asian tropical. Vegetation consisted mainly of coniferous forest and herbal shrub. In addition, fresh and saline non-marine water dominated the lacustrine setting during deposition of these formations. Deposition of the Denglouku Formation, however, occurred under a hot and dry tropical climate. The vegetation was mostly coniferous forest and lake waters became saline. Palaeoclimate variation is correlated by the lake level change and the development of sedimentary facies. Palaeoclimate contribute to the formation of hydrocarbon source rocks and reservoir.

Progress in Late Cretaceous planktonic foraminiferal stable isotope paleoecology and implications for paleoceanographic reconstructions

Science.gov (United States)

Petrizzo, Maria Rose; Falzoni, Francesca; Huber, Brian T.; MacLeod, Kenneth G.

2015-04-01

Paleoecological preferences proposed for Cretaceous planktonic foraminiferal taxa have traditionally been based on morphological analogies with depth-stratified modern species, on biofacies comparison in continental margin and deepwater settings, and limited oxygen and carbon stable isotope data. These studies concluded that large-sized, keeled and heavily calcified planktonic foraminifera generally lived at deeper levels in the surface waters than small-sized, thinner-walled non-keeled species. Stable isotope data have been used to infer information on paleotemperature, paleoceanography and paleoproductivity of ancient oceans and constrain biological paleo-activities (i.e. photosymbiosis and respiration) of fossil species. These studies have suggested that the depth-distribution model based on analogy with modern taxa might not be fully applicable for Cretaceous species, and found particularly 13C-enriched values in some Maastrichtian multiserial taxa that have been related to the activity of photosymbionts. We have collected about 1500 δ18O and δ13C species-specific analyses on glassy preserved planktonic foraminifera from Tanzania (Tanzania Drilling Project TDP sites 23, 28 and 32) and well-preserved planktonic foraminifera from other mid-low latitude localities (Shatsky Rise, northwestern Pacific Ocean, ODP Leg 198 Hole 1210B; Exmouth Plateau, eastern Indian Ocean, ODP Leg 122, Hole 762C; Eratosthenes Seamount, eastern Mediterranean, ODP Leg 160, Hole 967E; Blake Nose, central Atlantic Ocean, ODP Leg 171B, holes 1050C and 1052E) to investigate Late Cretaceous species paleoecological preferences, life strategies and depth distribution in the surface water column. Our results indicates that several large-sized (> 500 μm) double-keeled species belonging to the genera Dicarinella, Marginotruncana and Contusotruncana, generally interpreted as deep to thermocline dwellers, instead occupied shallow/warm layers of the water column, whilst not all biserial species

A vertebrate assemblage of Las Curtiembres Formation (Upper Cretaceous of northwestern Argentina Una asociación de vertebrados de la Formación Las Curtiembres (Cretácico Superior del Noroeste de la Argentina

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Agustín Scanferla

2011-12-01

Full Text Available We describe an association of fossil vertebrates from the Morales Member of the Las Curtiembres Formation (Campanian near Puente Morales, Salta Province, NW Argentina. The fossils include teleostean fishes, pipid frogs, pleurodiran turtles, mesoeucrocodylians, non-avian theropod dinosaurs, and enantiornithine birds. The vertebrate record is dominated by freshwater taxa. With the exception of pipid frogs, all taxa here described constitute new records for this sedimentary unit. Among them, the turtles are reported for the first time in the Cretaceous of northwestern Argentina (Salta Group. Additionally, the recently published small enantiornithine Intiornis inexpectatus enlarges the diversity of cretaceous birds from South America. Despite the fragmentary nature of the specimens, the information provided by this Late Cretaceous assemblage sheds new light on the composition of the continental vertebrate fauna in a paleontologically poorly known region of South America.Aquí describimos una asociación de fósiles de vertebrados proveniente del Miembro Morales de la Formación Las Curtiembres (Campaniano exhumada en la localidad de Puente Morales, provincia de Salta, Argentina. Esta asociación se encuentra conformada por peces teleósteos, anuros pipidos, tortugas pleurodiras, mesoeucrocodilidos, dinosaurios terópodos no avianos y aves Enantiornithes. Este registro de vertebrados se encuentra dominado por taxa de agua dulce. Con la excepción de los anuros pipidos, todos los demás taxa aquí descriptos constituyen nuevos registros para esta unidad sedimentaria. Entre ellos, el registro de tortugas resulta ser el primero para el Grupo Salta. Adicionalmente, el Enantiornithes Intiornis inexpectatus amplía la diversidad de aves cretácicas de América del Sur. Más allá de la naturaleza fragmentaria de algunos de los especímenes, la información proporcionada por esta asociación del Cretácico Superior aporta novedosa información acerca de la

Definition, age, and correlation of the Clarence Series stages in New Zealand (late Early to early Late Cretaceous)

International Nuclear Information System (INIS)

Crampton, J.S.; Tulloch, A.J.; Wilson, G.J.; Ramezani, J.; Speden, I.G.

2004-01-01

The New Zealand local Clarence Series spans the Lower/Upper Cretaceous boundary and includes three stages, in ascending order, the Urutawan, Motuan, and Ngaterian. All three were defined originally from a type section at Motu Falls, Raukumara Peninsula. To address problems with their original definitions and to improve correlations between the New Zealand time-scale and Global Chronostratigraphic Scale, four key sections have been re-studied: the Motu Falls and adjacent Te Waka sections, and the Coverham and Seymour sections in the Clarence valley, Marlborough. The sections contain locally abundant macrofossils and have been sampled at a reconnaissance level for dinoflagellates. In addition, a middle Motuan tuff bed in the Motu Falls section has yielded a zircon U-Pb age of 101.6 ± 0.2 Ma, and an upper Ngaterian basalt flow in the Seymour section has yielded a plagioclase Ar/Ar age of 96.1 ± 0.6 Ma. The older of these dates allows, for the first time, direct age correlation of Clarence Series stages that are based on marine strata in eastern New Zealand, with non-marine rocks in the west. Thus, the Stitts Tuff, at the base of the Pororari Group in the western South Island, is shown to be middle Motuan. Based on the new data, we emend the definitions of the Clarence Series stages. The base of the Urutawan is defined using the lowest occurrence of the inoceramid bivalve Mytiloides ipuanus in the Motu Falls section. The base of the Motuan is defined using the lowest occurrence of the bivalve Aucellina euglypha in the same section. The base of the Ngaterian is defined using the lowest occurrence of the inoceramid 'I.' tawhanus in the Te Waka section. In all three cases, the placements of the lowest occurrence datums are subject to uncertainties that can only be resolved by further biostratigraphic and/or taxonomic study. Based on biostratigraphic data and the new radiometric dates, the following international correlations are proposed: Urutawan Stage = lower

First complete sauropod dinosaur skull from the Cretaceous of the Americas and the evolution of sauropod dentition.

Science.gov (United States)

Chure, Daniel; Britt, Brooks B; Whitlock, John A; Wilson, Jeffrey A

2010-04-01

Sauropod dinosaur bones are common in Mesozoic terrestrial sediments, but sauropod skulls are exceedingly rare--cranial materials are known for less than one third of sauropod genera and even fewer are known from complete skulls. Here we describe the first complete sauropod skull from the Cretaceous of the Americas, Abydosaurus mcintoshi, n. gen., n. sp., known from 104.46 +/- 0.95 Ma (megannum) sediments from Dinosaur National Monument, USA. Abydosaurus shares close ancestry with Brachiosaurus, which appeared in the fossil record ca. 45 million years earlier and had substantially broader teeth. A survey of tooth shape in sauropodomorphs demonstrates that sauropods evolved broad crowns during the Early Jurassic but did not evolve narrow crowns until the Late Jurassic, when they occupied their greatest range of crown breadths. During the Cretaceous, brachiosaurids and other lineages independently underwent a marked diminution in tooth breadth, and before the latest Cretaceous broad-crowned sauropods were extinct on all continental landmasses. Differential survival and diversification of narrow-crowned sauropods in the Late Cretaceous appears to be a directed trend that was not correlated with changes in plant diversity or abundance, but may signal a shift towards elevated tooth replacement rates and high-wear dentition. Sauropods lacked many of the complex herbivorous adaptations present within contemporaneous ornithischian herbivores, such as beaks, cheeks, kinesis, and heterodonty. The spartan design of sauropod skulls may be related to their remarkably small size--sauropod skulls account for only 1/200th of total body volume compared to 1/30th body volume in ornithopod dinosaurs.

Late Cretaceous extension and exhumation of the Stong and Taku magmatic and metamorphic complexes, NE Peninsular Malaysia

Science.gov (United States)

François, T.; Md Ali, M. A.; Matenco, L.; Willingshofer, E.; Ng, T. F.; Taib, N. I.; Shuib, M. K.

2017-08-01

Fragmentation of large continental areas by post-orogenic extension requires favourable geodynamic conditions and frequently occurs along pre-existing suture zones or nappe contacts, as exemplified by the Stong and Taku magmatic and metamorphic complexes of northern Peninsular Malaysia. For this case, we have employed a field and microstructural kinematic study combined with low temperature thermo-chronology to analyse the tectonic and exhumation history. The results show that the Late Palaeozoic - Triassic Indosinian orogeny created successive phases of burial related metamorphism, shearing and contractional deformation. This orogenic structure was subsequently dismembered during a Cretaceous thermal event that culminated in the formation of a large scale Late Santonian - Early Maastrichtian extensional detachment, genetically associated with crustal melting, the emplacement of syn-kinematic plutons and widespread migmatisation. The emplacement of these magmatic rocks led to an array of simultaneously formed structures that document deformation conditions over a wide temperature range, represented by amphibolite- and greenschist- facies mylonites and as well as brittle structures, such as cataclastic zones and normal faults that formed during exhumation in the footwall of the detachment. The formation of this detachment and a first phase of Late Cretaceous cooling was followed by renewed Eocene - Oligocene exhumation, as evidenced from our fission track ages. We infer that an initial Cretaceous thermal anomaly was responsible for the formation of an extensional gneiss dome associated with simple shear and rotation of normal faults. These Cretaceous processes played a critical role in the establishment of the presently observed crustal structure of Peninsular Malaysia.

A Cretaceous origin for fire adaptations in the Cape flora.

Science.gov (United States)

He, Tianhua; Lamont, Byron B; Manning, John

2016-10-05

Fire has had a profound effect on the evolution of worldwide biotas. The Cape Floristic Region is one of the world's most species-rich regions, yet it is highly prone to recurrent fires and fire-adapted species contribute strongly to the overall flora. It is hypothesized that the current fire regimes in the Cape could be as old as 6-8 million years (My), while indirect evidence indicates that the onset of fire could have reached 18 million years ago (Ma). Here, we trace the origin of fire-dependent traits in two monocot families that are significant elements in the fire-prone Cape flora. Our analysis shows that fire-stimulated flowering originated in the Cape Haemodoraceae 81 Ma, while fire-stimulated germination arose in the African Restionaceae at least 70 Ma, implying that wildfires have been a significant force in the evolution of the Cape flora at least 60 My earlier than previous estimates. Our results provide strong evidence for the presence of fire adaptations in the Cape from the Cretaceous, leading to the extraordinary persistence of a fire-adapted flora in this biodiversity hotspot, and giving support to the hypothesis that Cretaceous fire was a global phenomenon that shaped the evolution of terrestrial floras.

Middle Jurassic - Early Cretaceous rifting of the Danish Central Graben

Energy Technology Data Exchange (ETDEWEB)

Moeller, J.J.; Rasmussen, E.S.

1998-12-01

During the Jurassic-early Cretaceous, the Danish Central Graben developed as a N-S to NNW-SSE trending Graben bounded by the Ringkoebing-Fyn High towards the east and the Mid North Sea High towards the west. The Graben consists of a system of half-Grabens and evolved by fault-controlled subsidence; three main rift pulses have been recognized. The first pulse ranged from the Callovian to the early Oxfordian, the second pulse was initiated in the latest Late Kimmeridgian and Early Volgian, and the third and final pulse occurred within the Valanginian in the Early Cretaceous. The first pulse was characterized by subsidence along N-S trending faults. During the second pulse, in early Volgian times, subsidence was concentrated along new NNW-SSE trending faults and the main depocentre shifted westward, being most marked within the Tail End Graben, the Arne-Elin Graben, and the Feda Graben. This tectonic event was accompanied by the accumulation of a relatively thick sediment load resulting in the development of salt diapers, especially within the Salt Dome Province. The third tectonic pulse was essentially a reactivation of the NNW-SSE trending structures. This tectonic pulse also shows clear evidence of combined fault-controlled subsidence and salt movements. (EG) 12 figs.; 45 refs.

Potentiometric surface of the Upper Patapsco aquifer in southern Maryland, September 2009

Science.gov (United States)

Curtin, Stephen E.; Andreasen, David C.; Staley, Andrew W.

2010-01-01

This report presents a map showing the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland during September 2009. The map is based on water-level measurements in 65 wells. The highest measured water level was 118 feet above sea level near the northern boundary and outcrop area of the aquifer in northern Anne Arundel County. From this area, the potentiometric surface declined to the south toward a well field in the Annapolis-Arnold area, and from all directions toward three additional cones of depression. These cones are located in the Waldorf-La Plata area, Chalk Point, and the Leonardtown-Lexington Park area. The lowest measured groundwater levels were 26 feet below sea level at Annapolis, 108 feet below sea level south of Waldorf, 60 feet below sea level at Chalk Point, and 83 feet below sea level at Leonardtown. The map also shows well yield in gallons per day for 2008 at wells or well fields.

15N/14N variations in Cretaceous Atlantic sedimentary sequences: implication for past changes in marine nitrogen biogeochemistry

Science.gov (United States)

Rau, G.H.; Arthur, M.A.; Dean, W.E.

1987-01-01

At two locations in the Atlantic Ocean (DSDP Sites 367 and 530) early to middle Cretaceous organic-carbon-rich beds ("black shales") were found to have significantly lower ??15N values (lower 15N/14N ratios) than adjacent organic-carbon-poor beds (white limestones or green claystones). While these lithologies are of marine origin, the black strata in particular have ??15N values that are significantly lower than those previously found in the marine sediment record and most contemporary marine nitrogen pools. In contrast, black, organic-carbon-rich beds at a third site (DSDP Site 603) contain predominantly terrestrial organic matter and have C- and N-isotopic compositions similar to organic matter of modern terrestrial origin. The recurring 15N depletion in the marine-derived Cretaceous sequences prove that the nitrogen they contain is the end result of an episodic and atypical biogeochemistry. Existing isotopic and other data indicate that the low 15N relative abundance is the consequence of pelagic rather than post-depositional processes. Reduced ocean circulation, increased denitrification, and, hence, reduced euphotic zone nitrate availability may have led to Cretaceous phytoplankton assemblages that were periodically dominated by N2-fixing blue-green algae, a possible source of this sediment 15N-depletion. Lack of parallel isotopic shifts in Cretaceous terrestrially-derived nitrogen (Site 603) argues that the above change in nitrogen cycling during this period did not extend beyond the marine environment. ?? 1987.

Intense acidic volcanism at the Cretaceous-Tertiary boundary

International Nuclear Information System (INIS)

Javoy, M.; Courtillot, V.

1989-01-01

A 87 Sr/ 86 Sr spike in seawater strontium with amplitude 2 x 10 -4 and duration of order 2 Ma is superimposed on longer-term variations at the Cretaceous-Tertiary boundary. The anomaly has been attributed to increased continental runoff due either to meteorite impact-related acid rain or sea-level regression. We speculate here that the spike could have resulted from intense, explosive acid volcanism preceding the development of the Deccan traps. A good model, both in tectonic position and geochemical characteristics, for these as yet elusive acidic products is provided by granites in the Seychelles Islands and particularly Mahe. (orig.)

Nagylengyel: an interesting reservoir. [Yugoslovia

Energy Technology Data Exchange (ETDEWEB)

Dedinszky, J

1971-04-01

The Nagylengyel oil field, discovered in 1951, has oil-producing formations mostly in the Upper-Triassic dolomites, in the Norian-Ractian transition formations, in the Upper-Cretaceous limestones and shales, and in the Miocene. The formation of the reservoir space occurred in many stages. A porous, cavernous fractured reservoir is developed in the Norian principal dolomite. A cavernous fractured reservoir exists in the Cretaceous limestone and in the Cretaceous shale and porous fractured reservoir is developed in the Miocene. The derivation of the model of the reservoir, and the conservative evaluation of the volume of the reservoir made it possible to use secondary recovery.

Hadrosauroid Dinosaurs from the Late Cretaceous of the Sultanate of Oman.

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Eric Buffetaut

Full Text Available Fragmentary post-cranial remains (femora, tibia, vertebrae of ornithischian dinosaurs from the Late Cretaceous of the Sultanate of Oman are described and referred to hadrosauroids. The specimens come from the Al-Khod Conglomerate, of latest Campanian to Maastrichtian age, in the north-eastern part of the country. Although the fragmentary condition of the fossils precludes a precise identification, various characters, including the shape of the fourth trochanter of the femur and the morphology of its distal end, support an attribution to hadrosauroids. With the possible exception of a possible phalanx from Angola, this group of ornithopod dinosaurs, which apparently originated in Laurasia, was hitherto unreported from the Afro-Arabian plate. From a paleobiogeographical point of view, the presence of hadrosauroids in Oman in all likelihood is a result of trans-Tethys dispersal from Asia or Europe, probably by way of islands in the Tethys shown on all recent paleogeographical maps of that area. Whether hadrosauroids were widespread on the Afro-Arabian landmass in the latest Cretaceous, or where restricted to the « Oman island » shown on some paleogeographical maps, remains to be determined.

Hadrosauroid Dinosaurs from the Late Cretaceous of the Sultanate of Oman.

Science.gov (United States)

Buffetaut, Eric; Hartman, Axel-Frans; Al-Kindi, Mohammed; Schulp, Anne S

2015-01-01

Fragmentary post-cranial remains (femora, tibia, vertebrae) of ornithischian dinosaurs from the Late Cretaceous of the Sultanate of Oman are described and referred to hadrosauroids. The specimens come from the Al-Khod Conglomerate, of latest Campanian to Maastrichtian age, in the north-eastern part of the country. Although the fragmentary condition of the fossils precludes a precise identification, various characters, including the shape of the fourth trochanter of the femur and the morphology of its distal end, support an attribution to hadrosauroids. With the possible exception of a possible phalanx from Angola, this group of ornithopod dinosaurs, which apparently originated in Laurasia, was hitherto unreported from the Afro-Arabian plate. From a paleobiogeographical point of view, the presence of hadrosauroids in Oman in all likelihood is a result of trans-Tethys dispersal from Asia or Europe, probably by way of islands in the Tethys shown on all recent paleogeographical maps of that area. Whether hadrosauroids were widespread on the Afro-Arabian landmass in the latest Cretaceous, or where restricted to the « Oman island » shown on some paleogeographical maps, remains to be determined.

Hints of the Early Jehol Biota: Important Dinosaur Footprint Assemblages from the Jurassic-Cretaceous Boundary Tuchengzi Formation in Beijing, China

Science.gov (United States)

Xing, Lida; Zhang, Jianping; Lockley, Martin G.; McCrea, Richard T.; Klein, Hendrik; Alcalá, Luis; Buckley, Lisa G.; Burns, Michael E.; Kümmell, Susanna B.; He, Qing

2015-01-01

New reports of dinosaur tracksites in the Tuchengzi Formation in the newly established Yanqing Global Geopark, Beijing, China, support previous inferences that the track assemblages from this formation are saurischian-dominated. More specifically, the assemblages appear theropod-dominated, with the majority of well-preserved tracks conforming to the Grallator type (sensus lato), thus representing relatively small trackmakers. Such ichnofaunas supplement the skeletal record from this unit that lacks theropods thus far, proving a larger diversity of dinosaur faunas in that region. Sauropods are represented by medium to large sized and narrow and wide-gauge groups, respectively. The latter correspond with earlier discoveries of titanosauriform skeletons in the same unit. Previous records of ornithischian tracks cannot be positively confirmed. Purported occurrences are re-evaluated here, the trackways and imprints, except of a single possible specimen, re-assigned to theropods. Palecologically the Tuchengzi ichnofauna is characteristic of semi-arid fluvio-lacustrine inland basins with Upper Jurassic-Lower Cretaceous deposits in northern China that all show assemblages with abundant theropod and sauropod tracks and minor components of ornithopod, pterosaur and bird tracks. PMID:25901363

The asteroid genus Haccourtaster (Echinodermata, Goniasteridae) in the Bohemian Cretaceous Basin, Czech Republic

Czech Academy of Sciences Publication Activity Database

Žítt, Jiří

2005-01-01

Roč. 26, č. 2 (2005), s. 225-237 ISSN 0195-6671 R&D Projects: GA ČR(CZ) GA206/01/1580 Institutional research plan: CEZ:AV0Z30130516 Keywords : Cretaceous * Asteroidea * New species Subject RIV: EG - Zoology Impact factor: 0.981, year: 2005

National uranium resource evaluation: Sheridan Quadrangle, Wyoming and Montana

International Nuclear Information System (INIS)

Damp, J.N.; Jennings, M.D.

1982-04-01

The Sheridan Quadrangle of north-central Wyoming was evaluated for uranium favorability according to specific criteria of the National Uranium Resource Evaluation program. Procedures consisted of geologic and radiometric surveys; rock, water, and sediment sampling; studying well logs; and reviewing the literature. Five favorable environments were identified. These include portions of Eocene Wasatch and Upper Cretaceous Lance sandstones of the Powder River Basin and Lower Cretaceous Pryor sandstones of the Bighorn Basin. Unfavorable environments include all Precambrian, Cambrian, Ordovician, Permian, Triassic, and Middle Jurassic rocks; the Cretaceous Thermopolis, Mowry, Cody, Meeteetse, and Bearpaw Formations; the Upper Jurassic Sundance and Morrison, the Cretaceous Frontier, Meseverde, Lance, and the Paleocene Fort Union and Eocene Willwood Formations of the Bighorn Basin; the Wasatch Formation of the Powder River Basin, excluding two favorable areas and all Oligocene and Miocene rocks. Remaining rocks are unevaluated

National uranium resource evaluation: Sheridan Quadrangle, Wyoming and Montana

Energy Technology Data Exchange (ETDEWEB)

Damp, J N; Jennings, M D

1982-04-01

The Sheridan Quadrangle of north-central Wyoming was evaluated for uranium favorability according to specific criteria of the National Uranium Resource Evaluation program. Procedures consisted of geologic and radiometric surveys; rock, water, and sediment sampling; studying well logs; and reviewing the literature. Five favorable environments were identified. These include portions of Eocene Wasatch and Upper Cretaceous Lance sandstones of the Powder River Basin and Lower Cretaceous Pryor sandstones of the Bighorn Basin. Unfavorable environments include all Precambrian, Cambrian, Ordovician, Permian, Triassic, and Middle Jurassic rocks; the Cretaceous Thermopolis, Mowry, Cody, Meeteetse, and Bearpaw Formations; the Upper Jurassic Sundance and Morrison, the Cretaceous Frontier, Meseverde, Lance, and the Paleocene Fort Union and Eocene Willwood Formations of the Bighorn Basin; the Wasatch Formation of the Powder River Basin, excluding two favorable areas and all Oligocene and Miocene rocks. Remaining rocks are unevaluated.

Terrestrial catastrophe caused by cometary impact at the end of Cretaceous

Science.gov (United States)

Hsü, Kenneth J.

1980-05-01

Evidence is presented indicating that the extinction, at the end of the Cretaceous, of large terrestrial animals was caused by atmospheric heating during a cometary impact and that the extinction of calcareous marine plankton was a consequence of poisoning by cyanide released by the fallen comet and of a catastrophic rise in calcite-compensation depth in the oceans after the detoxification of the cyanide.

Lower Cretaceous smarl turbidites of the Argo Abyssal Plain, Indian Ocean

Science.gov (United States)

Dumoulin, Julie A.; Stewart, Sondra K.; Kennett, Diana; Mazzullo, Elsa K.

1992-01-01

Sediments recovered during Ocean Drilling Program (ODP) Leg 123 from the Argo Abyssal Plain (AAP) consist largely of turbidites derived from the adjacent Australian continental margin. The oldest abundant turbidites are Valanginian-Aptian in age and have a mixed (smarl) composition; they contain subequal amounts of calcareous and siliceous biogenic components, as well as clay and lesser quartz. Most are thin-bedded, fine sand to mud-sized, and best described by Stow and Piper's model (1984) for fine-grained biogenic turbidites. Thicker (to 3 m), coarser-grained (medium-to-coarse sand-sized) turbidites fit Bouma's model (1962) for sandy turbidites; these generally are base-cut-out (BCDE, BDE) sequences, with B-division parallel lamination as the dominant structure. Parallel laminae most commonly concentrate quartz and/or calcispheres vs. lithic clasts or clay, but distinctive millimeter to centimeter-thick, radiolarian-rich laminae occur in both fine and coarse-grained Valanginian-Hauterivian turbidites.AAP turbidites were derived from relatively deep parts of the continental margin (outer shelf, slope, or rise) that lay below the photic zone, but above the calcite compensation depth (CCD). Biogenic components are largely pelagic (calcispheres, foraminifers, radiolarians, nannofossils); lesser benthic foraminifers are characteristic of deep-water (abyssal to bathyal) environments. Abundant nonbiogenic components are mostly clay and clay clasts; smectite is the dominant clay species, and indicates a volcanogenic provenance, most likely the Triassic-Jurassic volcanic suite exposed along the northern Exmouth Plateau.Lower Cretaceous smarl turbidites were generated during eustatic lowstands and may have reached the abyssal plain via Swan Canyon, a submarine canyon thought to have formed during the Late Jurassic. In contrast to younger AAP turbidites, however, Lower Cretaceous turbidites are relatively fine-grained and do not contain notably older reworked fossils. Early

Paleolatitudes of the Tibetan Himalaya from primary and secondary magnetizations of Jurassic to Lower Cretaceous sedimentary rocks

Science.gov (United States)

Huang, Wentao; van Hinsbergen, Douwe J. J.; Dekkers, Mark J.; Garzanti, Eduardo; Dupont-Nivet, Guillaume; Lippert, Peter C.; Li, Xiaochun; Maffione, Marco; Langereis, Cor G.; Hu, Xiumian; Guo, Zhaojie; Kapp, Paul

2015-01-01

The Tibetan Himalaya represents the northernmost continental unit of the Indian plate that collided with Asia in the Cenozoic. Paleomagnetic studies on the Tibetan Himalaya can help constrain the dimension and paleogeography of "Greater India," the Indian plate lithosphere that subducted and underthrusted below Asia after initial collision. Here we present a paleomagnetic investigation of a Jurassic (limestones) and Lower Cretaceous (volcaniclastic sandstones) section of the Tibetan Himalaya. The limestones yielded positive fold test, showing a prefolding origin of the isolated remanent magnetizations. Detailed paleomagnetic analyses, rock magnetic tests, end-member modeling of acquisition curves of isothermal remanent magnetization, and petrographic investigation reveal that the magnetic carrier of the Jurassic limestones is authigenic magnetite, whereas the dominant magnetic carrier of the Lower Cretaceous volcaniclastic sandstones is detrital magnetite. Our observations lead us to conclude that the Jurassic limestones record a prefolding remagnetization, whereas the Lower Cretaceous volcaniclastic sandstones retain a primary remanence. The volcaniclastic sandstones yield an Early Cretaceous paleolatitude of 55.5°S [52.5°S, 58.6°S] for the Tibetan Himalaya, suggesting it was part of the Indian continent at that time. The size of "Greater India" during Jurassic time cannot be estimated from these limestones. Instead, a paleolatitude of the Tibetan Himalaya of 23.8°S [21.8°S, 26.1°S] during the remagnetization process is suggested. It is likely that the remagnetization, caused by the oxidation of early diagenetic pyrite to magnetite, was induced during 103-83 or 77-67 Ma. The inferred paleolatitudes at these two time intervals imply very different tectonic consequences for the Tibetan Himalaya.

Effect of some parameters in the response of the Perspex 3042, Lot L amber dosemeters; Efectos de algunos parametros en la respuesta de los dosimetros ambar Perspex 3042, Lote L

Energy Technology Data Exchange (ETDEWEB)

Prieto M, E.F.; Barrera G, G. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN). Calle 30, No. 502, esq. 5ta. Avenida, Playa, Ciudad de La Habana (Cuba)]. e-mail: efprieto@ceaden.edu.cu

2004-07-01

The answer of the dosimetric systems is affected by several factors, for what should know as these factors they influence in each one of the different dosimetric systems and by this way to minimize its effect in the value of the absorbed dose and to obtain exact dose values. One of the dosimetric systems more used in the high dose dosimetry like routine dosemeter for the control of the irradiation process are the Perspex dosemeters, for their speed in the obtaining the information, their easy manipulation and the precision that they present. To this dosemeters group they belong the same as the Red and Clear the Amber, which are adequate for the measurement of the radiation dose in the range of high doses. The objective of the present work is to obtain the calibration curves of the dosemeters Amber Perspex 3042, Lot L under our work conditions, like they are the irradiation temperatures and of storage and to know the influence of the rate dose in the value of the absorbed dose for different measurement wavelengths, as well as, the relationship among the one post-irradiation time and the specific absorbance value induced in function of the absorbed dose. (Author)

Tectonostratigraphic reconstruction Cretaceous volcano-sedimentary in the northwestern Andes: from extensional tectonics to arc accretion.

Science.gov (United States)

Zapata, S.; Patino, A. M.; Cardona, A.; Mejia, D.; Leon, S.; Jaramillo, J. S.; Valencia, V.; Parra, M.; Hincapie, S.

2014-12-01

Active continental margins characterized by continuous convergence experienced overimposed tectonic configurations that allowed the formation of volcanic arcs, back arc basins, transtensional divergent tectonics or the accretion of exotic volcanic terranes. Such record, particularly the extensional phases, can be partially destroyed and obscure by multiple deformational events, the accretion of exotic terranes and strike slip fragmentation along the margin. The tectonic evolution of the northern Andes during the Mesozoic is the result of post Pangea extension followed by the installation of a long-lived Jurassic volcanic arc (209 - 136 ma) that apparently stops between 136 Ma and 110 Ma. The Quebradagrande Complex has been define as a single Lower Cretaceous volcano-sedimentary unit exposed in the western flank of the Central Cordillera of the Colombian Andes that growth after the Late Jurassic to Early Cretaceous magmatic hiatus. The origin of this unit have been related either to an oceanic volcanic arc or a marginal basin environment. The existence of such contrasting models reflect the regional perspective followed in published studies and the paucity of detail analysis of the volcano-sedimentary sequences.We integrate multiple approaches including structural mapping, stratigraphy, geochemistry, U-Pb provenance and geochronology to improve the understanding of this unit and track the earlier phases of accumulation that are mask on the overimposed tectonic history. Our preliminary results suggest the existence of different volcano-sedimentary units that accumulated between 100 Ma and 82 Ma.The older Lower Cretaceous sequences was deposited over Triassic metamorphic continental crust and include a upward basin deepening record characterized by thick fan delta conglomerates, followed by distal turbidites and a syn-sedimentary volcanic record at 100 ma. The other sequence include a 85 - 82 Ma fringing arc that was also formed close to the continental margin or

Proximal Cretaceous-Tertiary boundary impact deposits in the Caribbean

Science.gov (United States)

Hildebrand, Alan R.; Boynton, Willam V.

1990-01-01

Trace element, isotopic, and mineralogic studies indicate that the proposed impact at the Cretaceous-Tertiary boundary occurred in an ocean basin, although a minor component of continental material is required. The size and abundance of shocked minerals and the restricted geographic occurrence of the ejecta layer and impact-wave deposits suggest an impact between the Americas. Coarse boundary sediments at sites 151 and 153 in the Colombian Basin and 5- to 450-meter-thick boundary sediments in Cuba may be deposits of a giant wave produced by a nearby oceanic impact.

The difference between the potentiometric surfaces of the Upper Patapsco aquifer in southern Maryland, September 1990 and September 2009

Science.gov (United States)

Curtin, Stephen E.; Andreasen, David C.; Staley, Andrew W.

2010-01-01

This report presents a map showing the change in the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland between September 1990 and September 2009. The map, based on water level differences obtained from 33 wells, shows that during the 19-year period, the change in the potentiometric surface ranged from zero at the edge of the outcrop area in northern Anne Arundel County to a decline of 20 feet at Broad Creek, 16 feet near Arnold, 32 feet at Waldorf, 37 feet at the Chalk Point power plant, and 43 feet at Lexington Park. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Latest Cretaceous climatic and environmental change in the South Atlantic region

Science.gov (United States)

Woelders, L.; Vellekoop, J.; Kroon, D.; Smit, J.; Casadío, S.; Prámparo, M. B.; Dinarès-Turell, J.; Peterse, F.; Sluijs, A.; Lenaerts, J. T. M.; Speijer, R. P.

2017-05-01

Latest Maastrichtian climate change caused by Deccan volcanism has been invoked as a cause of mass extinction at the Cretaceous-Paleogene (K-Pg) boundary ( 66.0 Ma). Yet late Maastrichtian climate and ecological changes are poorly documented, in particular on the Southern Hemisphere. Here we present upper Maastrichtian-lower Danian climate and biotic records from the Bajada del Jagüel (BJ) shelf site (Neuquén Basin, Argentina), employing the TEX86 paleothermometer, marine palynology (dinoflagellate cysts), and micropaleontology (foraminifera). These records are correlated to the astronomically tuned Ocean Drilling Program Site 1262 (Walvis Ridge). Collectively, we use these records to assess climatic and ecological effects of Deccan volcanism in the Southern Atlantic region. Both the TEX86-based sea surface temperature (SST) record at BJ and the bulk carbonate δ18O-based SST record of Site 1262 show a latest Maastrichtian warming of 2.5-4°C, at 450 to 150 kyr before the K-Pg boundary, coinciding with the a large Deccan outpouring phase. Benthic foraminiferal and dinocyst assemblage changes indicate that this warming resulted in enhanced runoff and stratification of the water column, likely resulting from more humid climate conditions in the Neuquén Basin. These climate conditions could have been caused by an expanding and strengthening thermal low over the South American continent. Biotic changes in response to late Maastrichtian environmental changes are rather limited, when compared to the major turnovers observed at many K-Pg boundary sites worldwide. This suggests that environmental perturbations during the latest Maastrichtian warming event were less severe than those following the K-Pg boundary impact.

Spatiotemporal evolution of magmatic pulses and regional metamorphism during a Cretaceous flare-up event: Constraints from the Ryoke belt (Mikawa area, central Japan)

Science.gov (United States)

Takatsuka, Kota; Kawakami, Tetsuo; Skrzypek, Etienne; Sakata, Shuhei; Obayashi, Hideyuki; Hirata, Takafumi

2018-05-01

The spatiotemporal relationship between granitoid intrusions and low-pressure/temperature type regional metamorphism in the Ryoke belt (Mikawa area) is investigated to understand the tectono-thermal evolution of the upper- to middle-crust during a Cretaceous flare-up event at the Eurasian active continental margin. Three plutono-metamorphic stages are recognized; (1) 99-84 Ma: intrusion of granitoids (99-95 Ma pulse) into the upper crust and high-T regional metamorphism reaching sillimanite-grade (97.0 ± 4.4 Ma to 88.5 ± 2.5 Ma) in the middle crust, (2) 81-75 Ma: intrusion of gneissose granitoids (81-75 Ma Ma pulse) into the middle crust at 19-24 km depth, and (3) 75-69 Ma: voluminous intrusions of massive to weakly-foliated granitoids (75-69 Ma pulse) at 9-13 km depth and formation of contact metamorphic aureoles. Cooling of the highest-grade metamorphic zone below the wet solidus of granitic rocks is estimated at 88.5 ± 2.5 Ma. At ca. 75 Ma, the upper-middle crustal section underwent northward tilting, resulting in the exhumation of regional metamorphic zones to 9-13 km depth. Although the highest-grade metamorphic rocks and the 99-95 Ma pulse granitoids preserve similar U-Pb zircon ages, the absence of spatial association suggests that the regional metamorphic zones were mainly produced by a transient thermal anomaly in the mantle and thermal conduction through the crust, supplemented by localized advection due to granitoid intrusions. The successive emplacement of granitoids into shallow, deep and shallow levels of the crust was probably controlled by the combination of change in thermal structure of the crust and tectonics during granitoid intrusions.

The clasts of Cretaceous marls in the conglomerates of the Konradsheim Formation (Pöchlau quarry, Gresten Klippen Zone, Austria)

Science.gov (United States)

Ślączka, Andrzej; Gasiñski, M. Adam; Bąk, Marta; Wessely, Godfrid

2009-04-01

Investigations were carried out on foraminiferids and radiolaria from redeposited clasts within the conglomerates of the Konradsheim Formation (Gresten Klippen Zone) in the area of the Pöchlau hill, east of Maria Neustift. These shales and marls are of Middle to Late Jurassic and Early Cretaceous age. In the latter clasts, foraminiferal assemblages with Tritaxia ex gr. gaultina as well as radiolaria species Angulobracchia portmanni Baumgartner, Dictyomitra communis (Squinabol), Hiscocapsa asseni (Tan), Pseudodictyomitra lodogaensis Pessagno, Pseudoeucyrtis hanni (Tan), Rhopalosyringium fossile (Squinabol) were found. In one block from the uppermost part of the sequence there is an assemblage with Caudammina (H) gigantea, Rotalipora appenninica and Globotruncana bulloides. However, the brecciated character of this block and occurrence near a fault suggest that it was probably wedged into the conglomerates of the Konradsheim Formation during tectonic movements. In pelitic siliceous limestones below the Konradsheim Limestone radiolarian assemblages of Middle Callovian to Early Tithonian age were found. They enable correlation with the Scheibbsbach Formation. In a marly sequence, above the conglomeratic limestone, the foraminiferal assemblages contain taxa from mid-Cretaceous up to Paleocene. The present biostratigraphic investigation confirmed the previous stratigraphic assignments and imply clearly that the sedimentation of deposits similar to the Konradsheim Formation also occurred at the end of the Early Cretaceous and deposition of conglomeratic limestones within the Gresten Klippen Zone, and especially within the Konradsheim Formation, was repeated several times during the Late Jurassic and Early Cretaceous.

Genetic stratigraphy of Coniacian deltaic deposits of the northwestern part of the Bohemian Cretaceous Basin

Czech Academy of Sciences Publication Activity Database

Nádaskay, R.; Uličný, David

2014-01-01

Roč. 165, č. 4 (2014), s. 547-575 ISSN 1860-1804 Institutional support: RVO:67985530 Keywords : genetic stratigraphy * well log * Bohemian Cretaceous Basin Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.569, year: 2014

Continental weathering as a driver of Late Cretaceous cooling: new insights from clay mineralogy of Campanian sediments from the southern Tethyan margin to the Boreal realm

Science.gov (United States)

Chenot, Elise; Deconinck, Jean-François; Pucéat, Emmanuelle; Pellenard, Pierre; Guiraud, Michel; Jaubert, Maxime; Jarvis, Ian; Thibault, Nicolas; Cocquerez, Théophile; Bruneau, Ludovic; Razmjooei, Mohammad J.; Boussaha, Myriam; Richard, James; Sizun, Jean-Pierre; Stemmerik, Lars

2018-03-01

New clay mineralogical analyses have been performed on Campanian sediments from the Tethyan and Boreal realms along a palaeolatitudinal transect from 45° to 20°N (Danish Basin, North Sea, Paris Basin, Mons Basin, Aquitaine Basin, Umbria-Marche Basin and Tunisian Atlas). Significant terrigenous inputs are evidenced by increasing proportions of detrital clay minerals such as illite, kaolinite and chlorite at various levels in the mid- to upper Campanian, while smectitic minerals predominate and represented the background of the Late Cretaceous clay sedimentation. Our new results highlight a distinct latitudinal distribution of clay minerals, with the occurrence of kaolinite in southern sections and an almost total absence of this mineral in northern areas. This latitudinal trend points to an at least partial climatic control on clay mineral sedimentation, with a humid zone developed between 20° and 35°N. The association and co-evolution of illite, chlorite and kaolinite in most sections suggest a reworking of these minerals from basement rocks weathered by hydrolysis, which we link to the formation of relief around the Tethys due to compression associated with incipient Tethyan closure. Diachronism in the occurrence of detrital minerals between sections, with detrital input starting earlier during the Santonian in the south than in the north, highlights the northward progression of the deformation related to the anticlockwise rotation of Africa. Increasing continental weathering and erosion, evidenced by our clay mineralogical data through the Campanian, may have resulted in enhanced CO2 consumption by silicate weathering, thereby contributing to Late Cretaceous climatic cooling.

Evaluating thermodynamic integration performance of the new amber molecular dynamics package and assess potential halogen bonds of enoyl-ACP reductase (FabI) benzimidazole inhibitors.

Science.gov (United States)

Su, Pin-Chih; Johnson, Michael E

2016-04-05

Thermodynamic integration (TI) can provide accurate binding free energy insights in a lead optimization program, but its high computational expense has limited its usage. In the effort of developing an efficient and accurate TI protocol for FabI inhibitors lead optimization program, we carefully compared TI with different Amber molecular dynamics (MD) engines (sander and pmemd), MD simulation lengths, the number of intermediate states and transformation steps, and the Lennard-Jones and Coulomb Softcore potentials parameters in the one-step TI, using eleven benzimidazole inhibitors in complex with Francisella tularensis enoyl acyl reductase (FtFabI). To our knowledge, this is the first study to extensively test the new AMBER MD engine, pmemd, on TI and compare the parameters of the Softcore potentials in the one-step TI in a protein-ligand binding system. The best performing model, the one-step pmemd TI, using 6 intermediate states and 1 ns MD simulations, provides better agreement with experimental results (RMSD = 0.52 kcal/mol) than the best performing implicit solvent method, QM/MM-GBSA from our previous study (RMSD = 3.00 kcal/mol), while maintaining similar efficiency. Briefly, we show the optimized TI protocol to be highly accurate and affordable for the FtFabI system. This approach can be implemented in a larger scale benzimidazole scaffold lead optimization against FtFabI. Lastly, the TI results here also provide structure-activity relationship insights, and suggest the parahalogen in benzimidazole compounds might form a weak halogen bond with FabI, which is a well-known halogen bond favoring enzyme. © 2015 Wiley Periodicals, Inc.

Evidence for Cretaceous-Paleogene boundary bolide "impact winter" conditions from New Jersey, USA

NARCIS (Netherlands)

Vellekoop, J.; Esmeray-Senlet, S.; Miller, K.G.; Browning, J.V.; Sluijs, A.|info:eu-repo/dai/nl/311474748; van de Schootbrugge, B.|info:eu-repo/dai/nl/376758562; Sinninghe Damsté, J.S.|info:eu-repo/dai/nl/07401370X; Brinkhuis, H.|info:eu-repo/dai/nl/095046097

2016-01-01

Abrupt and short-lived “impact winter” conditions have commonly been implicated as the main mechanism leading to the mass extinction at the Cretaceous-Paleogene (K-Pg) boundary (ca. 66 Ma), marking the end of the reign of the non-avian dinosaurs. However, so far only limited evidence has been

The contribution of the young Cretaceous Caribbean Oceanic Plateau to the genesis of late Cretaceous arc magmatism in the Cordillera Occidental of Ecuador

Science.gov (United States)

Allibon, J.; Monjoie, P.; Lapierre, H.; Jaillard, E.; Bussy, F.; Bosch, D.; Senebier, F.

2008-12-01

The eastern part of the Cordillera Occidental of Ecuador comprises thick buoyant oceanic plateaus associated with island-arc tholeiites and subduction-related calc-alkaline series, accreted to the Ecuadorian Continental Margin from Late Cretaceous to Eocene times. One of these plateau sequences, the Guaranda Oceanic Plateau is considered as remnant of the Caribbean-Colombian Oceanic Province (CCOP) accreted to the Ecuadorian Margin in the Maastrichtien. Samples studied in this paper were taken from four cross-sections through two arc-sequences in the northern part of the Cordillera Occidental of Ecuador, dated as (Río Cala) or ascribed to (Macuchi) the Late Cretaceous and one arc-like sequence in the Chogòn-Colonche Cordillera (Las Orquídeas). These three island-arcs can clearly be identified and rest conformably on the CCOP. In all four localities, basalts with abundant large clinopyroxene phenocrysts can be found, mimicking a picritic or ankaramitic facies. This mineralogical particularity, although not uncommon in island arc lavas, hints at a contribution of the CCOP in the genesis of these island arc rocks. The complete petrological and geochemical study of these rocks reveals that some have a primitive island-arc nature (MgO values range from 6 to 11 wt.%). Studied samples display marked Nb, Ta and Ti negative anomalies relative to the adjacent elements in the spidergrams characteristic of subduction-related magmatism. These rocks are LREE-enriched and their clinopyroxenes show a tholeiitic affinity (FeO T-TiO 2 enrichment and CaO depletion from core to rim within a single crystal). The four sampled cross-sections through the island-arc sequences display homogeneous initial Nd, and Pb isotope ratios that suggest a unique mantellic source for these rocks resulting from the mixing of three components: an East-Pacific MORB end-member, an enriched pelagic sediment component, and a HIMU component carried by the CCOP. Indeed, the ankaramite and Mg

National uranium resource evaluation: Lemmon quadrangle, South Dakota and North Dakota

International Nuclear Information System (INIS)

Sewell, J.M.; Pickering, L.A.

1982-06-01

The Lemmon Quadrangle was evaluated to identify and delineate geologic environments favorable for the occurrence of uranium deposits using criteria developed for the National Uranium Resource Evaluation program. Surface studies included investigation of uranium occurrences, general surface reconnaissance, and detailed rock sampling in selected areas. In addition, followup studies were conducted on carborne spectrometric, aerial radiometric, and hydrogeochemical and stream-sediment surveys. Subsurface investigations included examination of geophysical well logs and ground-water geochemical data. These investigations indicate environments favorable for sandstone-type uranium deposits in the Upper Cretaceous strata and lignite-type deposits in the Paleocene strata. Environments unfavorable for uranium deposits include Tertiary sandstones and Jurassic and Cretaceous strata, exclusive of the Upper Cretaceous sandstones

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)