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Palaeoclimatic records from the Late Cretaceous calcareous and siliceous planktonic assemblages of Eastern Europeтезисы доклада
- Авторы: Vishnevskaya V.S., Kopaevich L.F.
- Сборник: 2 International Congress on Stratigraphy STRATI-2015, Abstract
- Серия: Austria
- Тезисы
- Год издания: 2015
- Место издания: Berichte des Institutes für Erdwissenschaften Karl-Franzens-Universität Graz Instute of Earth Sciences, Department of Geology and Palaeontology, University of Graz, Heinrichstrasse 26
- Первая страница: 385
- Последняя страница: 385
- Аннотация: The assemblages of planktonic foraminifers and radiolarians are investigated from the same samples that have been collected from Cenomanian-Maastrichtian sequences of East-European platform, Caucasus, as well as the Cenomanian-Campanian of Crimea. The Cenomanian interval was a time of polytaxic development due to warm greenhouse and correlated with sea level rise. The appearance of abundant multichamber cyrtoidal pseudomacrocephalic, as well as cryptocephalic and cryptothoracic forms in the Cenomanian is apparently reflected a changing of hydrological conditions and it was probably caused by the active adaptation. The extinction of singlekeeled rotaliporides in foraminiferal community, reduction of a morphological variety, violation of the correct system of porosity in radiolarians coincides with the Cenomanian–Turonian boundary event. The Turonian-Coniacian diversification of all foraminiferal and radiolarian groups probably is related to a sea-level highstand and hot greenhouse climatic environment. The Tethyan species reached Moscow Region of the Russian Plate. Acme of double-keeled and single-keeled marginotruncanids, concavatotruncanids and their diversification in Turonian-Santonian reflects more stable conditions in a more oligotrophic regime. The replacement of very specialized marginotruncanids/ concavatotruncanids into marginotruncanids by globotruncanids at the Santonian-Campanian boundary probably are related to penetrating of cold water to south up to North Caucasus and Crimea and reflected a cooling episode. The occurrence of temperate and high paleolatitude family Prunobrachidae Pessagno in the North Caucasus locations is also indicative of cool greenhouse environments. The invasion of cold water from Arctic Region through the Russian Plate (Baraboshkin et al., 2003; Naidin et al., 2007; Blakey, 2012; Pugh et al., 2014) to South is confirmed by finding of Genus Prunobrachium in North Caucasus and Crimea Location. Latest Cretaceous family Prunobrachidae Pessagno occurs mostly in temperate and high paleolatitudes. Mass abundance of Prunobrachidae is indicative of cold water environments, which were characterized for Polar Urals, Russian Plate, Siberia, Russian Far East, South PaleoPacific (Tasman Sea) and New Zealand. Analysis of Prunobrachidae paleogeography during Late Santonian-Campanian shows bipolar distribution in temperate and high paleolatitudes. The distribution areas are almost symmetrical relative to theequator: 35º-62º N in the Northern Hemisphere and 50º-52º S in the South. It is very important to use representatives of family Prunobrachidae in the study of paleogeography and ecostratigraphy, as well as stratigraphic correlation of Tethyan and Boreal sequences of the Upper Cretaceous.The finding of calcareous dinocyst Pithonella globosa Futterer widespread in an interval Middle Maastrichtian–early Danian together with Orbiculiforma australis Pessagno, O. renillaeformis ampbellet Clark, Tholodiscus densus (Kozlova), allows to indicate rather warm episode during accumulation of the Late Maastrichtian siliceous clays. This research was supported by the Russian Foundation for Basic Research: 13-05-00447, 15-05-04700, 15-05-04099 and IGCP-609 Project.
- Добавил в систему: Копаевич Людмила Федоровна