Distribution of calcareous dinoflagellates from the Maastrichtian to early Miocene of DSDP Site 357 (Rio Grande Rise, western South Atlantic Ocean) |
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Authors: | T Hildebrand-Habel H Willems |
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Institution: | Fachbereich Geowissenschaften, Universit?t Bremen, Postfach 330440, D-28334 Bremen, Germany e-mail: hiha@micropal.uni-bremen.de Tel.: +49 (0) 421-2183926 Fax: +49 (0) 421-2184451, DE
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Abstract: | The evolution of calcareous dinoflagellate communities has been investigated for the latest Cretaceous to earliest Neogene
interval of the mid-latitude South Atlantic. In doing so, the response of calcareous dinoflagellates to Cenozoic climatic
change has been addressed for the first time. Trends in species composition and distribution patterns of wall types indicate
significant changes which correlate with major palaeoenvironmental modifications. A first major shift concerning the relative
abundance of species and wall types occurred across the Cretaceous–Tertiary boundary. The associations remained stable during
the entire Paleocene and Eocene. Only in the late Eocene did a dramatic decrease in temperature cause a slight diversification.
A second major shift in the abundance patterns occurred across the Eocene–Oligocene boundary. The early Miocene warming is
possibly reflected in the distinct increase in relative abundance of one species. The assemblages of calcareous dinoflagellates
evidently react to major climatic changes during the Cenozoic. These poorly investigated organisms may thus provide an important
contribution to the understanding of earth's palaeoclimatic evolution.
Received: 9 November 1998 / Accepted: 4 April 1999 |
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Keywords: | Calcareous dinoflagellates Cretaceous Tertiary K/T boundary Eocene– Oligocene boundary Climatic change South Atlantic |
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