Paleoenvironmental evolution of the Eastern Arctic Ocean in the Pleistocene: New results from a multi-proxy study on ODP Hole 910A (Yermak Plateau)
The Pleistocene paleooceanographic and paleoclimate development in the eastern Arctic Ocean is still widely unexplored: this is mainly due to contradictory stratigraphic models and relatively low contents of micropaleontological proxies such as foraminifers, coccoliths and diatoms that are tradional...
| Main Authors: | , , , , , |
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| Format: | Conference Object |
| Language: | unknown |
| Published: |
2004
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| Subjects: | |
| Online Access: | https://epic.awi.de/id/eprint/10748/ https://hdl.handle.net/10013/epic.21217 |
| Summary: | The Pleistocene paleooceanographic and paleoclimate development in the eastern Arctic Ocean is still widely unexplored: this is mainly due to contradictory stratigraphic models and relatively low contents of micropaleontological proxies such as foraminifers, coccoliths and diatoms that are tradionally used to unravel the history of surface and deep waters as well as sea-ice coverage. We have selected ODP Hole 910 for a paleoenvironmental study because presence of biogenic carbonate permits establishment of a relatively continuous stable oxygen isotope stratigraphy on planktic foraminifer Neogloboquadrina pachyderma sin. that is the basic stratigraphic tool in the Pleistocene. Furthermore, the Yermak Plateau is located in the path of inflowing relatively warm North Atlantic waters, and its sediments record the dynamic coupling between the northernmost branch of the Gulf Stream and the Arctic Ocean. Various micropaleontological, sedimentological and organic-geochemical methods are applied on the same sample set to reveal the synchroneity/ asynchroneity of change in the surface water regime and changes in the sediment supply and source areas.The revised chronostratigraphy indicates that the uppermost 20 m of Hole 910A range from Marine Isotope Stages (MIS) 16 to MIS 2. Several stratigraphic age fixpoints support the interpretation of the stable oxygen isotope record that is punctuated by numerous short-term meltwater events. Organic-walled dinoflagellate cysts that have a preservation potential superior to most calcareous and biosiliceous microfossil groups are used to establish a biostratigraphy calibrated vs. the new chronostratigraphy, and to reconstruct the history of surface waters and sea-ice coverage and its interaction with the discharge of freshwater from Eurasia and the growth and decay of the northern Barents Sea ice sheets. Most dinoflagellate cyst samples analysed so far are productive suggesting that Atlantic water inflow into the Arctic Ocean was suppressed only for relatively short periods in the ... |
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