Reconstructing the Plio-Pleistocene evolution of the water mass exchange and climate variability in the Nordic Seas and North Atlantic Ocean
Global climate of the Plio-Pleistocene has been largely impacted by changes of the Atlantic Meridional Overturning Circulation (AMOC), which has most likely to a large extent been controlled by the formation of North Atlantic Deep Water (NADW) ventilating the entire Atlantic Ocean. The main areas co...
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| Format: | Thesis |
| Language: | English |
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2013
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| Online Access: | https://oceanrep.geomar.de/id/eprint/26947/ https://oceanrep.geomar.de/id/eprint/26947/1/Dissertation_Claudia_Teschner.pdf http://macau.uni-kiel.de/receive/dissertation_diss_00013996 |
| Summary: | Global climate of the Plio-Pleistocene has been largely impacted by changes of the Atlantic Meridional Overturning Circulation (AMOC), which has most likely to a large extent been controlled by the formation of North Atlantic Deep Water (NADW) ventilating the entire Atlantic Ocean. The main areas contributing to the formation of NADW have been the Labrador Sea, the Nordic Seas, and North Atlantic Ocean. The circulation pattern in these areas underwent dramatic changes during the Plio – and Pleistocene, in particular during the onset and intensification of the Northern Hemisphere Glaciation (NHG) at 2.7 Ma and the Mid Pleistocene Transition (MPT) 1.5 – 0.6 Ma. The main goal of this study is to improve the understanding of the role of changes in ocean circulation in these key areas and their relationships to glaciations controlling and responding to climate. To investigate the past water mass mixing and erosional input between the climatically important areas of Nordic Seas and North Atlantic Ocean, the radiogenic isotope signatures of neodymium (Nd), lead (Pb) and strontium (Sr) of seawater-derived ferromanganese coatings on sediment particles, as well as of detrital material have been analyzed. Sediments obtained from six ODP (Ocean Drilling Program) Sites covering intermediate to deep waters in the Nordic Seas and North Atlantic Ocean are the basis of this study. Two Sites are located in the North Atlantic Ocean on Bjørn Drift (Site 984) in 1648 m water depth and on Rockall Plateau (Site 982) in 1135 m water depth. The sites in the Nordic Seas are located in the region influenced by Arctic Intermediate Water on Iceland Plateau (Site 907, 1800 m water depth) and of the inflowing Atlantic waters on Vøring Plateau (Site 644, 1220 m water depth), on the Svalbard margin (Site 986, 2051 m deep) and on Yermak Plateau in the Fram Strait (Site 911, 906 m water depth). The extraction of seawater Nd and Pb isotope compositions from authigenic ferromanganese coatings, as well as Nd isotope composition from the calcitic ... |
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