نتایج جستجو برای: late maastrichtian
تعداد نتایج: 195833 فیلتر نتایج به سال:
In the present study, the sediments of the Gurpi Formation in the Jafarabad section located in the southeast of Ilam were examined from the point of view of calcareous calcareous nannofossils. The sediments of the upper part of Gurpi Formation with a thickness of about 42 m are composed of limy marl sediments. In this study, 34 species belonging to 22 genera from the group of calcareous nannopl...
Late Mesozoic palaeobiogeography has been characterized by a distinction between the northern territories of Laurasia and the southern landmasses of Gondwana. The repeated discovery of Gondwanan lineages in Laurasia has led to the proposal of alternative scenarios to explain these anomalous occurrences. A new biogeographical model for late Mesozoic terrestrial ecosystems is here proposed in whi...
The Late Cretaceous to Early Tertiary subsidence history of the Northern Calcareous Alps (NCA) records the effect of two independent basin formation mechanisms at the northern leading margin of the Austroalpine unit. The terrestrial to shallow-marine sediments of the Lower Gosau Subgroup were deposited mainly within small, fault-bound basins during a phase of strike-slip faulting from the late ...
benthic foraminiferal assemblages from maastrichtian strata, gansserina gansseri-abathamphalus mayaroensis planktonic foraminiferal zone, of the abtalkh formation at aitamir section (west of the kopeh-dagh basin) were investigated in order to evaluate the palaeoenvironmental changes (organic matter flux and bottom-water oxygenation). maastrichtian faunal assemblages are well preserved and diver...
Biostratigraphy has remained a tool for basin and environmental reconstruction in sedimentology. This study aims to further delineate classify the lithology, environment of deposition, biozonation microorganisms found studied well. Thirty-four (34) ditch cutting samples from OMA well, offshore Dahomey Basin, were considered their textural palynomorphs/palynofacies characterization. The observed...
The Quintanilla la Ojada section (Basque-Cantabrian Region, northern Spain) has yielded two assemblages of Late Cretaceous vertebrates, deposited during the Maastrichtian in coastal environments and related to a transgressive lag at base Valdenoceda Formation. Numerous teeth Elasmobranchii Actinopterygii are most prevailing fossil material, although scarce marine reptiles (Mosasauridae) dinosau...
A latest Maastrichtian global warming event, which began approximately 450 k.y. and ended about 22 k.y. prior to the K/T boundary, is associated with the poleward migration of the warm-water planktonic foraminifer Pseudotextularia elegans. The warming event was apparently inititated by greenhouse warming due to the main outpouring of the Deccan Traps in India and is now well documented in the N...
Late Cretaceous (late Campanian) diatom assemblages from the Campbell Plateau (Zealandia), southwest Pacific Ocean, obtained Deep Sea Drilling Project (DSDP) Leg 29 Site 275, contain well-preserved specimens of two enigmatic species currently assigned to genus Ktenodiscus; Micrampulla parvula originally described Maastrichtian-age Moreno Shale, California, and Pterotheca cretacea DSDP 275. In g...
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