The last occurrence of Proboscia curvirostris in the North Atlantic marine isotope stages 9-8 |
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| Institution: | 1. CAGE — Centre for Arctic Gas Hydrate, Environment and Climate, UiT The Arctic University of Norway, 9037 Tromsø, Norway;2. ISMAR — Institute of Marine Sciences, CNR, Bologna, Italy;3. Department of Geological Sciences, University of Alabama, Box 870338, Tuscaloosa, AL 35487, USA;4. Department of Geology & Geophysics, Louisiana State University, LA 70803, USA;5. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale OGS, Trieste, Italy;6. Departament d''Estratigrafia, Paleontologia i Geociències Marines, Facultat de Geologia, Universitat de Barcelona, Barcelona, Spain;1. Dipartimento di Scienze della Terra e dell''Ambiente, Università degli Studi di Pavia, Via Ferrata 1, 27100 Pavia, Italy;2. Department of Earth Sciences, Uppsala Universitet, Villavägen 16, 75236 Uppsala, Sweden;3. National Institute of Water and Atmospheric Research, Greta Point, Wellington, New Zealand;1. Institute of Geology and Palaeontology, Faculty of Science, Charles University, Albertov 6, 128 43, Praha 2, Czech Republic;2. Institute of Geology of the Czech Academy of Sciences, Rozvojová 269, 165 00 Praha, 6 Lysolaje, Czech Republic;3. Earth Science Institute of the Slovak Academy of Sciences, Ďumbierska 1, 974 11 Banská Bystrica, Slovakia;4. Institute of Geological Sciences, Masaryk University, Faculty of Science, Kotlářská 2, 611 37 Brno, Czech Republic |
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| Abstract: | Well-preserved diatoms are present in high sedimentation rate Pleistocene cores retrieved on Ocean Drilling Program (ODP) Legs 151, 152, 162 and IMAGES cruises of R/V Marion Dufresne from the North Atlantic. Investigation of the stratigraphic occurrence of diatom species shows that the youngest diatom event observed in the area is the last occurrence (LO) of Proboscia curvirostris (Jousé) Jordan and Priddle. P. curvirostris is a robust species that can easily be identified in the sediments, and therefore can be a practical biostratigraphic tool. We have mapped its areal distribution, and found that it stretches from 40°N to 80°N in the North Atlantic. Further, we have correlated the LO P. curvirostris to the oxygen isotope records of six cores to refine the age of this biostratigraphic event. The extinction of P. curvirostris is latitudinally diachronous through Marine Isotope Stages (MIS) 9 to 8 within the North Atlantic. This is closely related to the paleoceanography of the area. P. curvirostris first disappeared within interglacial MIS 9 (324 ka) from the northern areas that are most sensitive to climatic forcing, like the East Greenland current and the sea–ice margin. It survived in mid-North Atlantic until the conditions of the MIS 8 (glaciation) became too severe (260 ka). In the North Pacific at ODP Site 883 the LO P. curvirostris falls within MIS 8. The observed overlap in age between the North Atlantic and the North Pacific strongly suggests that the extinction of P. curvirostris is synchronous between these oceans. |
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