نتایج جستجو برای: triassic
تعداد نتایج: 3848 فیلتر نتایج به سال:
The vertebrate recovery after the end-Permian mass extinction can be approached through the ichnological record, which is much more abundant than body fossils. The late Olenekian (Early Triassic) tetrapod ichnoassemblage of the Catalan Pyrenean Basin is the most complete and diverse of this age from Western Tethys. This extensional basin, composed of several depocenters, was formed in the lates...
Originally identified as an ornithischian dinosaur, Crosbysaurus harrisae has been found in New Mexico, Arizona, and its type locality in Texas, as well as in North Carolina. The genus has been reassessed by other workers in light of reinterpretations about the postcrania of another putative Triassic ornithischian, Revueltosaurus. The understanding of Triassic dental faunas has become more comp...
This research work introduces the Early Triassic, Late Triassic-Early Jurassic, and Early Cretaceous silica-rich sand levels at east and central Alborz, Kopeh-Dagh, and Central Iran, and compares them with the Permian silica-rich sand level in the Chirouk mine at east Iran. Ghoznavi and Gheshlaq loose sand in Alborz (Early Triassic-Early Jurassic), Soh quartzite in Central Iran (Early Triassic...
Global warming is widely regarded to have played a contributing role in numerous past biotic crises. Here, we show that the end-Permian mass extinction coincided with a rapid temperature rise to exceptionally high values in the Early Triassic that were inimical to life in equatorial latitudes and suppressed ecosystem recovery. This was manifested in the loss of calcareous algae, the near-absenc...
In conjunction with the Permian-Triassic ecologic crisis approximately 250 million years ago, massive dieback of coniferous vegetation resulted in a degradation of terrestrial ecosystems in Europe. A 4- to 5-million-year period of lycopsid dominance followed, and renewed proliferation of conifers did not occur before the transition between Early and Middle Triassic. We document this delayed re-...
Paleotemperature indicators and apatite fission track analysis of Australian continental margin cover sequeRces accreted to the active Banda arc-continent collision indicate little to no heating during rapid late Neogene uplift and exhumation. Thermal maturation patterns of vitrinite reflectance, conodont alteration and' illite crystallinity show that peak paleotemperatures (PPT) increase with ...
The rise and diversification of the dinosaurs in the Late Triassic, from 230 to 200 million years ago, is a classic example of an evolutionary radiation with supposed competitive replacement. A comparison of evolutionary rates and morphological disparity of basal dinosaurs and their chief "competitors," the crurotarsan archosaurs, shows that dinosaurs exhibited lower disparity and an indistingu...
High temperature impact melt breccias from the Rochechouart (France) meteorite crater record a magnetization component with antipodal, normal and reverse polarities. The corresponding paleomagnetic pole for this component lies between the 220 Ma and 210 Ma reference poles on the Eurasian apparent polar wander path, consistent with the 214±8 Ma Ar/Ar age of the crater. Late Triassic tectonic rec...
Carbon and sulfur isotopic data, together with biomarker and iron speciation analyses of the Hovea-3 core that was drilled in the Perth Basin, Western Australia, indicate that euxinic conditions prevailed in the paleowater column during the Permian-Triassic superanoxic event. Biomarkers diagnostic for anoxygenic photosynthesis by Chlorobiaceae are particularly abundant at the boundary and into ...
The Krasiejów locality in the Upper Triassic of southern Poland yields the tetrapod taxa Cyclotosaurus robustus (= C. intermedius), Metoposaurus diagnosticus (we reject proposed subspecies of this species), Stagonolepis robertsoni, Teratosaurus suevicus (= T. silesiacus), Parasuchus bransoni and Silesaurus opolensis. The occurrences of Parasuchus and Metoposaurus indicate the Krasiejów assembla...
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