نتایج جستجو برای: maastrichtian
تعداد نتایج: 629 فیلتر نتایج به سال:
The Gurpi, Tarbur and Sachun formations have been investigated in the studied section in the Fars Province, in order to determine their sequence stratigraphy. On the basis of done studies on the cores of borehole, four main microfacies have been recognized in four stratigraphic sequence deposited during the Campanian to Maastrichtian. The lowermost sequence, was deposited in the early Campanian...
This study presents the nannostratigraphy and nannofossil events in the lower boundary of Kalat Formation in the East and West of the Kopeh- Dagh basin. The Kalat Formation comprises of coarse grained detritus limestone with subordinate sandstone intercalations. In the current study, six sections have been chosen in the East and West of the basin which are as follow: Dobaradar section, Kalat se...
Spherules in sediments across the Cretaceous-Tertiary (K/T) transition in Central America and the Caribbean are commonly interpreted as ejecta from the Chicxulub impact on Yucatan. Their stratigraphic ages, however, are variable spanning from the late Maastrichtian to the early Danian. Figure 1. Locations of spherule-bearing K/T boundary sections in Central America, and the Caribbean. In northe...
Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary...
A comprehensive review and study of the rich dinosaur track record of the Tremp Formation in the southern Pyrenees of Spain (Southwestern Europe) shows a unique succession of footprint localities prior to the end-Cretaceous mass extinction event. A description of some 30 new tracksites and data on sedimentary environments, track occurrence and preservation, ichnology and chronostratigraphy are ...
the larger benthic foraminifera gyroconulina columellifera schroeder & darmoian, 1977 (type-locality: maastrichtian aqra formation of iraq) is described for the first time from two sections of the maastrichtian tarbur formation of the zagros fold-thrust-belt, sw iran. new details on its wall microstructure are provided. the microfacies is represented by bioclastic wacke-/pack-/grainstones with ...
Cretaceous multituberculate mammals of Europe are poorly known, as a rule represented by isolated teeth. The only exception is the Late Cretaceous (Maastrichtian) monotypic genus Kogaionon Riidulescu & Samson, 1996 from Romania, represented by a single skull, without dentaries, assigned to Kogaionidae Rhdulescu & Samson, 1996, Another kogaionid genus is Hainina Vianey-Liaud, 1979, represented b...
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...
Based on a review of troodontid specimens from the territories of the former Soviet Union, including new discoveries from Uzbekistan, two dental morphotypes can be distinguished among Troodontidae from the Cretaceous of Asia: (1) unserrated teeth, present in Mei from Lujiatun (China; Early Cretaceous: Hauterivian-Barremian), an unnamed taxon from Hövöör (Mongolia; Early Cretaceous: Aptian-Albia...
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...
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