نتایج جستجو برای: upper permian

تعداد نتایج: 207735  

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Qara Aqaj titanium potential is one of the two major known titanium resources in Iran. The main host rocks of the ore body are ultramafics including wehrlite and lherzolite with minor clinopyroxenite. Qara Aqaj intrusion is composed mainly of ultramafic-mafic rocks, layered gabbro, diorite, microdiorite and some monzonite and alkali syenite. This intrusion has intruded the basement complex (amp...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Juan Carlos Cisneros Fernando Abdala Saniye Atayman-Güven Bruce S Rubidge A M Celâl Şengörc Cesar L Schultz

The medial Permian (~270-260 Ma: Guadalupian) was a time of important tetrapod faunal changes, in particular reflecting a turnover from pelycosaurian- to therapsid-grade synapsids. Until now, most knowledge on tetrapod distribution during the medial Permian has come from fossils found in the South African Karoo and the Russian Platform, whereas other areas of Pangaea are still poorly known. We ...

Journal: :journal of tethys 0

the permian deposits in the stratigraphic section of sangsar (located in the eastern alborz), are the best expose in the semnan area. this sequence consists of the doroud (asselian-sakmarian), ruteh (artinskian-murgabian) and nessen (early djulfian) formations. the dorud formation in the studied section with 56 m thickness consists of conglomerate, sandstone and quartzite, which is disconformit...

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 ...

2008
Thomas Algeo Yanan Shen Tonggang Zhang Harry Rowe T. K. T. Nguyen

[1] A marine Permian-Triassic boundary (PTB) section at Nhi Tao, Vietnam, contains a series of at least 9 pyritic horizons characterized by concurrent decreases in pyrite S(dSpy) and carbonate C-isotopic compositions (dCcarb). The first and largest of the events that precipitated these pyritic horizons was coincident with the Late Permian mass extinction, while subsequent events were generally ...

2005
KENNETH D. ANGIELCZYK PETER D. ROOPNARINE STEVE C. WANG

The end-Permian mass extinction is well-known as the most severe mass extinction of the Phanerozoic. Terrestrial communities appear to have been strongly affected by the event, but the cause of the extinction remains enigmatic. Here we explore whether primary producer disruption (e.g., extinction of terrestrial plants) could have led to a collapse of end-Permian terrestrial ecosystems, using mo...

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