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New ammonoid aragonite 87Sr/86Sr records of Mesozoic environmental changeтезисы доклада
- Авторы: Zakharov Y.D., Dril S.I., Tanabe K., Shigeta Y., Baraboshkin E.Y., Michailova I.A.
- Сборник: 35th International Geological Congress, 27 August - 4 September 2016, Cape Town, South Africa, Abstract book
- Тезисы
- Год издания: 2016
- Место издания: 35th International Geological Congress Cape Town
- Первая страница: T47.10.1
- Последняя страница: T47.10.1
- Аннотация: Much of data on Phanerozoic Sr-isotope stratigraphy has been derived from whole-rock samples and calcitic fossils. We focus in this paper on some Mesozoic Sr-isotope oscillations, based on data on the following aragonite-preserved ammonoid shells: (1) Hedenstroemia hedenstroemi from the lowest Olenekian of the Buur River basin, Arctic Siberia (87Sr/86Sr=0.708043); (2) Boreomeekoceras keyserlingi from the uppermost Olenekian of the Olenek River basin, Arctic Siberia (87Sr/86Sr=0.709041), showing very close Sr-isotope composition with Recent Nautilus pompilius from Philippines (0.709148) (10); (3) Arctohungarites sp. from the Anisian of Taimir, Arctic Siberia (87Sr/86Sr=0.707744); (4) Harpoceras falcifer and Hildaites serpentinum from the lower Toacian of western Switzerland (87Sr/86Sr=0.707300-0.707382); (5) Procerites funatus from the lower upper Callovian of the Ulyanovsk area (87Sr/86Sr=0.707429); (6) Deshayesites volgensis – sp. 45/96 and 50/96 from the Lower Aptian of the Ulyanovsk area (87Sr/86Sr=0.707333-0.707382); (7) Douvilleiceras sp., Eotetragonites umbilicostatus and Cleoniceras besairei from the lower Albian of Madagascar (87Sr/86Sr=0.707241-0.707276) (8) Pseudoschloenbachia umbulazi from the upper Santonian of British Columbia (87Sr/86Sr=0.707281); (9) Submortoniceras from the lower Campanian of California (87Sr/86Sr=0.707198) (Fig. 1). Following partly Jones and Jenkins [1], we presume that there is the close correspondence in time between episodes of increased hydrothermal activity at ocean ridges, significantly controlled by negative seawater Sr-isotope excursions, and sea level rises, usually resulted in the OAEs activity and climatic warming. The surprising event, exceedingly large swing in 87Sr/86Sr ratio between the Capitanian minimum and the latest Olenekian maximum, seems to be a result of strongest plate tectonic activity at the end of Palaeozoic time and some contrast conditions of the Early Triassic. References [1] Jones and Jenkyns (2001) Amer J Sci 301: 112-149 [2] McArthur et al. (2012) The Geol Time Scale DOI: 10.1016/B978-0-444-59425-9.00007.X [3] Cochran et al. (2003) Palaepgeogr Palaeoclimatol Palaeoecol 191: 45-64 [4] Cochran et al. (2015) Swiss J Palaeontol 134: 153-165
- Добавил в систему: Барабошкин Евгений Юрьевич