Late Maastrichtian And Paleocene Calcareous Nannofossils From Ain Dabadib Section, Nw Kharga Oasis, Egypt
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On terms of calcareous nannofossils, the late Maastrichtian and Paleocene sediments were subdivided into several biozones. The Cretaceous-Tertiary boundary is marked by a hiatus concerning the latest Maastrichtian and the early Danian. To predict the surface water paleotemperature during the late Maastrichtian-Paleocene interval, the warm-water/cool-water; the Micula staurophora/Watz-naueria barnesae, and Discoaster/Chiasmolithus ratios were calculated for each studied samples. There is some nannofossil evidence to suggest that the paleotemperature was already declining in the late Maastrichtian. A slight cooling in the surface-water temperature has occurred at the end of Danian. However, the late Paleocene (Thanetian) is characterized by the predominance of warm-water forms and also by an increased value of the Discoaster/Chiasmolithus ratio. This suggested an increase of the surface-water paleotemperature during this time interval.