نتایج جستجو برای: campanian maastrichtian
تعداد نتایج: 973 فیلتر نتایج به سال:
The biostratigraphy of the Outer Carpathians is based mainly on ranges agglutinated foraminifera. Species acmes provide opportunity to enhance and support existing biozonations. Assemblages foraminifera from Campanian Eocene various tectonic-structural units were analyzed in terms their qualitative quantitative occurrence. In this stratigraphic interval, 19 species display significantly increas...
The eutherian, family-level clade Zhelestidae is consistently although weakly supported in five phylogenetic analyses that we performed on all Cretaceous eutherians. Additionally in the fifth analysis, which included some placentals, Zhelestidae is placed as a stem eutherian clade rather than grouping within the crown clade Placentalia as argued in some previous studies but not others. The subf...
Pterosaurs were the first vertebrates to evolve powered flight and the largest animals to ever take wing. The pterosaurs persisted for over 150 million years before disappearing at the end of the Cretaceous, but the patterns of and processes driving their extinction remain unclear. Only a single family, Azhdarchidae, is definitively known from the late Maastrichtian, suggesting a gradual declin...
The litho-and biostratigraphy of Upper Cretaceous (Gurpi Formation) has been investigated within a well-exposed section at the northern limb of Pey zard anticline, Abnow area, Southern Iran. The studied section consists mainly of grey marl, calcareous pyritic shale, and argillaceous limestones. The Formation unconformably overlies Sarvak Formation and the Tarbur Formation overlies it unconforma...
The controversial European genus Allodaposuchus is currently composed of two species (A. precedens, A. subjuniperus) and it has been traditionally considered a basal eusuchian clade of crocodylomorphs. In the present work, the new species A. palustris is erected on the base of cranial and postcranial remains from the lower Maastrichtian of the southern Pyrenees. Phylogenetic analyses here inclu...
Uranium–Pb ages of detrital zircons taken from seven sandstone samples collected at what were previously called “Paleogene strata” in the Nagasaki and Nishisonogi Peninsula, northwestern Kyushu, SW Japan are measured. Depositional three sandstones peninsula revealed to be e Campanian–Maastrichtian (Late Cretaceous) or younger. two Terashima Island off west coast Peninsula likewise dated as Camp...
Ceratopsid (horned) dinosaurs are an iconic group of large-bodied, quadrupedal, herbivorous dinosaurs that evolved in the Late Cretaceous and were largely restricted to western North America [1-5]. Ceratopsids are easily recognized by their cranial ornamentation in the form of nasal and postorbital horns and frill (capped by epiossifications); these structures show high morphological disparity ...
The Campanian–Maastrichtian (83–66 Ma) was a period of global climate cooling, featuring significant negative carbon-isotope (δ13C) anomalies, such as the Late Campanian Event (LCE) and the Campanian–Maastrichtian Boundary Event (CMBE). A variety of factors, including changes in temperature, oceanic circulation and gateway opening, have been invoked to explain these δ13C perturbations, but no p...
The Campanian–Paleocene Jaworzynka Formation, a part of the Magura Nappe succession in Polish Outer Carpathians, is described terms its detailed litho- and biostratigraphy. formation stretches along marginal Siary Unit, from stratotype area Silesian Beskid Mts up to Mszana Dolna Wyspowy Mts. Its equivalent Moravskoslezske Beskydy the Czech Republic Solaň Formation. In area, displays complex str...
a succession of late campanian- early maastrichtian is analyzed from gurpi formation with regard to the calcareous nannofossils. correlation matrix was applied for the first time to the entire nannofossil assemblage to reconstruct environmental conditions. a detailed quantitative calcareous nannofossil analyses is performed on samples in order to further investigate the climate events, and inte...
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