نتایج جستجو برای: upper triassic diversification

تعداد نتایج: 228621  

2006
Lawrence H. Tanner

Paleosols are prominent features of the Upper Triassic Chinle Group. The oldest (Carnian-age) formations of the Chinle Group (Zuni Mountains and Shinarump Formations) contain kaolinitic paleosols that display gley features but generally lack calcretes. Paleosols of the (Upper Carnian) Blue Mesa Member of the Petrifi ed Forest Formation are mostly mature Alfi sols that have distinctive horizonat...

Journal: Geopersia 2015

Rhaetian strata from the Nayband Formation of the Tabas block, East- Central Iran, were studied palynologically. The materialexamined contained moderately diverse and well-preserved dinoflagellate cyst assemblages which lead to the identification ofRhaetogonyaulax rhaetica Zone. The assigned age of this dinozone (Rhaetian) is justified by plant fossils such as Equisetitesarenaceus, Scytophyllum...

2017
Michelle R. Stocker Li-Jun Zhao Sterling J. Nesbitt Xiao-Chun Wu Chun Li

Following the end-Permian extinction, terrestrial vertebrate diversity recovered by the Middle Triassic, and that diversity was now dominated by reptiles. However, those reptilian clades, including archosaurs and their closest relatives, are not commonly found until ~30 million years post-extinction in Late Triassic deposits despite time-calibrated phylogenetic analyses predicting an Early Tria...

2016
Peter A. Hochuli Anna Sanson-Barrera Elke Schneebeli-Hermann Hugo Bucher

Generally Early Triassic floras are believed to be depauperate, suffering from protracted recovery following the Permian-Triassic extinction event. Here we present palynological data of an expanded East Greenland section documenting recovered floras in the basal Triassic (Griesbachian) and a subsequent fundamental floral turnover, postdating the Permian-Triassic boundary extinction by about 500...

Journal: :Science 1987
P E Olsen N H Shubin M H Anders

The discovery of the first definitively correlated earliest Jurassic (200 million years before present) tetrapod assemblage (Fundy basin, Newark Supergroup, Nova Scotia) allows reevaluation of the duration of the Triassic-Jurassic tetrapod extinction event. Present are tritheledont and mammal-like reptiles, prosauropod, theropod, and ornithischian dinosaurs, protosuchian and sphenosuchian croco...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2017
Lawrence M E Percival Micha Ruhl Stephen P Hesselbo Hugh C Jenkyns Tamsin A Mather Jessica H Whiteside

The Central Atlantic Magmatic Province (CAMP) has long been proposed as having a causal relationship with the end-Triassic extinction event (∼201.5 Ma). In North America and northern Africa, CAMP is preserved as multiple basaltic units interbedded with uppermost Triassic to lowermost Jurassic sediments. However, it has been unclear whether this apparent pulsing was a local feature, or if pulses...

Journal: :تحقیقات اقتصادی 0
غلامرضا کشاورزحداد دانشیار گروه اقتصاد، دانشکدۀ مدیریت و اقتصاد دانشگاه صنعتی شریف الهام محمدی کارشناس ارشد اقتصاد، دانشگاه صنعتی شریف

empirical researches have shown that in highly volatile market, conditional correlation between returns is stronger, so diversification cannot reduce risk. to test this claim in iran’s financial market, quintiles of stock return distribution have been estimated by kernel density and garch models. then, average conditional correlation, error variance and conditional capm has been calculated to t...

M. Ahmad Anuar M. Doaei, Z. Ismail

Firms pursue diversification for sake enhancing financial performance. Some theories state positive relationship between diversification and financial performance. However, there are some theories for negative relationship about the issue. The study has filled the gap that most studies done in developed countries and there are fewer studies in developing country like Malaysia. In this study, re...

Journal: :geopersia 2015
hossein sabbaghiyan ebrahim ghasemi - nejad mohammadreza aria-nasab

rhaetian strata from the nayband formation of the tabas block, east- central iran, were studied palynologically. the materialexamined contained moderately diverse and well-preserved dinoflagellate cyst assemblages which lead to the identification ofrhaetogonyaulax rhaetica zone. the assigned age of this dinozone (rhaetian) is justified by plant fossils such as equisetitesarenaceus, scytophyllum...

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