نتایج جستجو برای: lower triassic

تعداد نتایج: 695069  

2018
J. Roberts C. H. Vane

The measurement of isotope ratios in sedimentary rocks deposited over geological time can provide key insights to past environmental change over important intervals in the past. However, it is important to be aware that secondary alteration can overprint the original isotopic records. We demonstrate this principle using high-resolution carbon, sulfur, and oxygen isotope measurements in organic ...

2002
THEO ANDREW ALASTAIR H. F ROBERTSON

The Beyşehir–Hoyran–Hadim Nappes crop out over 700 km from NW to SE. Above a regionally autochthonous Tauride carbonate platform the Beyşehir–Hoyran Nappes begin with a thrust sheet (c. 400 m) of mainly redeposited carbonates, quartzose sandstones and mudstones of Mid–Late Triassic age, interpreted as a proximal slope–base-of-slope succession. Above is a thrust sheet (c. 1 km) of Middle–Upper T...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Kimberly V Lau Kate Maher Demir Altiner Brian M Kelley Lee R Kump Daniel J Lehrmann Juan Carlos Silva-Tamayo Karrie L Weaver Meiyi Yu Jonathan L Payne

Delayed Earth system recovery following the end-Permian mass extinction is often attributed to severe ocean anoxia. However, the extent and duration of Early Triassic anoxia remains poorly constrained. Here we use paired records of uranium concentrations ([U]) and (238)U/(235)U isotopic compositions (δ(238)U) of Upper Permian-Upper Triassic marine limestones from China and Turkey to quantify va...

2014
Roland B. Sookias Corwin Sullivan Jun Liu Richard J. Butler

The South African species Euparkeria capensis is of great importance for understanding the early radiation of archosauromorphs (including archosaurs) following the Permo-Triassic mass extinction, as most phylogenetic analyses place it as the sister taxon to crown group Archosauria within the clade Archosauriformes. Although a number of species from Lower-Middle Triassic deposits worldwide have ...

2014
David J. Gower P. John Hancox Jennifer Botha-Brink Andrey G. Sennikov Richard J. Butler

A new species of the erythrosuchid archosauriform reptile Garjainia Ochev, 1958 is described on the basis of disarticulated but abundant and well-preserved cranial and postcranial material from the late Early Triassic (late Olenekian) Subzone A of the Cynognathus Assemblage Zone of the Burgersdorp Formation (Beaufort Group) of the Karoo Basin of South Africa. The new species, G. madiba, differs...

2006
JONATHAN L. PAYNE DANIEL J. LEHRMANN SHANNON CHRISTENSEN JIAYONG WEI ANDREW H. KNOLL

The Great Bank of Guizhou (GBG) is an isolated Late Permian to Late Triassic carbonate platform in the Nanpanjiang Basin of Guizhou Province, southwest China. A faulted syncline exposes a cross section of the platform margin, including a well-preserved Anisian (earliest Middle Triassic) reef complex approximately 1 km wide and 800 meters thick. Geochronologic constraints from associated basin-m...

Journal: :Proceedings. Biological sciences 2011
Shi-xue Hu Qi-yue Zhang Zhong-Qiang Chen Chang-yong Zhou Tao Lü Tao Xie Wen Wen Jin-yuan Huang Michael J Benton

The timing and nature of biotic recovery from the devastating end-Permian mass extinction (252 Ma) are much debated. New studies in South China suggest that complex marine ecosystems did not become re-established until the middle-late Anisian (Middle Triassic), much later than had been proposed by some. The recently discovered exceptionally preserved Luoping biota from the Anisian Stage of the ...

1994
S. J. Fowell P. E. Olsen

Evidence from sedimentation rates and stratigraphic ranges of palynomorph species indicate that van Veen is incorrect in inferring a condensed section at the Triassic/Jurassic (TR / J ) boundary in the Newark Supergroup. Van Veen bases his argument entirely on the ranges of palynomorph species in western Europe, but correlation of the European sections is equivocal, and the range data employed ...

2010
Nicole Klein

BACKGROUND Sauropterygia is an abundant and successful group of Triassic marine reptiles. Phylogenetic relationships of Triassic Sauropterygia have always been unstable and recently questioned. Although specimens occur in high numbers, the main problems are rareness of diagnostic material from the Germanic Basin and uniformity of postcranial morphology of eosauropterygians. In the current paper...

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