نتایج جستجو برای: lower triassic
تعداد نتایج: 695069 فیلتر نتایج به سال:
—Delayed biotic recovery from the end-Permian mass extinction has long been interpreted to result from environmental inhibition. Recently, evidence of more rapid recovery has begun to emerge, suggesting the role of environmental inhibition was previously overestimated. However, there have been few high-resolution taxonomic and ecological studies spanning the full Early and Middle Triassic recov...
—Mesozoic marine ecosystems were dominated by several clades of reptiles, including sauropterygians, ichthyosaurs, crocodylomorphs, turtles, and mosasaurs, that repeatedly invaded ocean ecosystems. Previous research has shown that marine reptiles achieved great taxonomic diversity in the Middle Triassic, as they broadly diversified into many feeding modes in the aftermath of the Permo-Triassic ...
Abstract Calcium isotopes (δ 44/40 Ca) are particularly useful in palaeo‐environmental studies due to the key role of carbonate minerals continental weathering and their formation seawater. The calcium isotope ratio can provide hints on past changes fluxes, environmental shifts, ecological factors alternatively diagenesis rocks. investigation Late Triassic record offers a great opportunity eval...
rocks of the Stuhuni and King Salmon Groups; a pre-.Middlm: Triassic unconformity is found througbmt the North American Cordillera (Read and Okulitch, 1977, Siberling, 1973:. In the Stikine Terrane, late Triassic volcanic rocks ar: dominantly fragmental andcommonly alkalic. Based on bul:: rock chemistry, both extensional, ba:k-arc, and Fore-ar: tectonic settings have been suggested tor these r...
The evolutionary radiation of dinosaurs in the Late Triassic and Early Jurassic was a pivotal event in the Earth's history but is poorly understood, as previous studies have focused on vague driving mechanisms and have not untangled different macroevolutionary components (origination, diversity, abundance and disparity). We calculate the morphological disparity (morphospace occupation) of dinos...
In the wake of the end-Permian mass extinction, the Early Triassic (~251.9 to 247 million years ago) is portrayed as an environmentally unstable interval characterized by several biotic crises and heavily depauperate marine benthic ecosystems. We describe a new fossil assemblage-the Paris Biota-from the earliest Spathian (middle Olenekian, ~250.6 million years ago) of the Bear Lake area, southe...
Early Triassic animal body fossils and trace fossils are small relative to those in older and younger intervals. Size decreases sharply through the end-Permian extinction event and Permian/Triassic boundary, and the smallest sizes are encountered in the parvus and isarcica Zones of the earliest Induan. Animals appearing within these two zones are also exceedingly small, compared to younger cong...
The Rochechourt impact structure in south-central France, with maximum diameter of 40–50 km, has previously been dated to within 1% uncertainty of the Triassic– Jurassic boundary, at which time ~30% of global genera became extinct. To evaluate the temporal relationship between the impact and the Triassic–Jurassic boundary at high precision, we have re-examined the structure’s age using multicol...
Premise of research. During the ongoing investigation of Upper Triassic–Lower Cretaceous plant macrofossils from Svalbard, Norway, some ginkgoalean leaf fossils were found from Carnian and Aptian deposits of Spitsbergen and Edgeøya that represent new ginkgophyte species. One new species is described asBaiera aquilonia sp. nov., and one ginkgophyte leaf is assigned to Ginkgoites sp. Along with t...
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