نتایج جستجو برای: early aptian
تعداد نتایج: 686306 فیلتر نتایج به سال:
The Aptian sedimentary deposits of the Castro Urdiales area in north Spain record an episode disoxia/anoxia which postdates Oceanic Anoxic Event 1a (OAE 1a). Carbonate platform and overlying facies are analysed for stratigraphy, sedimentology, total organic carbon isotopes. Lower shallow-water limestones covered by deeper-water marlstones organic-carbon-rich black lutites lower to upper Aptian,...
BACKGROUND The Cretaceous vertebrate assemblages of Romania are famous for geographically endemic dwarfed dinosaur taxa. We report the first complete egg clutches of a dwarf lithostrotian titanosaur, from Toteşti, Romania, and its reproductive adaptation to the "island effect". METHODOLOGY/FINDINGS The egg clutches were discovered in sequential sedimentary layers of the Maastrichtian Sânpetru...
به منظور مطالعات میکروبیواستراتیگرافی و پالئواکولوژی (بر اساس داده های ژئوشیمیایی)و همچنین میکروفاسیس سازند کژدمی، مقطع کوه رحمت واقع در شمال شرق شیراز مورد مطالعه قرار گرفته است. بطور کلی این سازند با ضخامت 66/89 متر بوده که در جهت عمود بر امتداد لایه ها 76 نمونه برداشت شده و 82 مقطع میکروسکوپی از آن تهیه و مورد مطالعه قرار گرفته است. در این تحقیق مطالعات میکروبیواستراتیگرافی از دو منظر، فرامی...
BACKGROUND Large ornithopod tracks are known from the Upper Jurassic to the uppermost Cretaceous rocks of all continents but Antarctica. They include the tracks historically called Iguanodon footprints, iguanodontid footprints, hadrosaur/hadrosaurid footprints, and other large ornithopod tracks that have been used to define ichnotaxa. More than 40 ichnospecies based on large ornithopod tracks h...
Detrital zircon U-Pb ages for 30 Late Jurassic and Cretaceous sandstones from the Eastern Province of eastern New Zealand, combined with previously-published geochronological and palaeontological data, constrain the time of deposition in the Pahau and Waioeka terranes of the Cretaceous accretionary margin of Zealandia, and their adjacent cover strata. The zircon age patterns also constrain poss...
Studies dealing with the response of the continental biosphere to the environmental perturbations associated with Cretaceous oceanic anoxic events (OAEs) are comparatively rare. Here, a quantitative spore-pollen record combined with clay mineral data is presented, which covers the entire early Aptian OAE 1a interval (Forcall Formation, Maestrat basin, east Spain). The well-expressed OAE 1a carb...
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