نتایج جستجو برای: early maastrichtian
تعداد نتایج: 686539 فیلتر نتایج به سال:
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...
The study of planktonic foraminifera of the Ilam and Gurpi formations at Sarvestan area (SE of Shiraz) enables me to find the most standard biozones defined in mediterranean regions, especially Tethysian domain. Seven biozones were determined. Biozones I (Dicarinella concavata zone) and II (Dicarinella asymetrica zone) belong to the Ilam Formation and indicate the Late Coniacian-Early Santonian...
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...
the study of planktonic foraminifera of the ilam and gurpi formations at sarvestan area (se of shiraz) enables me to find the most standard biozones defined in mediterranean regions, especially tethysian domain. seven biozones were determined. biozones i (dicarinella concavata zone) and ii (dicarinella asymetrica zone) belong to the ilam formation and indicate the late coniacian-early santonian...
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...
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...
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...
The Gurpi Formation with a thickness of 190 m at the Kouh-e sefid anticline is investigated with regard to the calcareous nannofossils. In this section, Gurpi Formation is mainly consists of shale, marls and argillaceous limestones. As a result of this study, 21 genera and 41 species of calcareous nannofossil have been recognized. Based on distribution of index species calcareous nannofossils...
planktonic foraminifera are useful in determining the relative age of the upper cretaceous strata. based on distribution of planktonic foraminifera in kuh-e siah section (212 m thickness), eight biozones have been recognized including dicarinella concavata interval zone (earliest santonian), dicarinella asymetrica total range zone (santonian to earliest campanian), globotruncanita elevata parti...
The Late Cretaceous–Early Paleogene (K–Pg) was a critical period of transition in geological time. This encompassed short-term climatic fluctuations on global scale, changes ocean circulation, and sudden large extinctions marine terrestrial organisms. In the study area, located mid to low latitudes, Cretaceous Early were very tectonically active due positioning site close collision zone two con...
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