The Northern Transpolar Gateways

• Applicant: Privatdozentin Dr. Mara Weinelt
• Subject Area: Palaeontology
• Term: from 2005 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 20807448

During Phase 3 Theme B1 is planning to expand its focus to the northern transpolar gateway connection between the Nordic Seas and the subpolar North Pacific. This seaway system was only open during rare and short-lasting Plio- / Pleistocene peak interglacials with extreme sealevel highstands, when the Bering Strait, today 45 m deep, was flooded. Two major objectives will be addressed: (1) Potential reversals in the density-driven flow of surface water today streaming from the North Pacific into the Arctic and North Atlantic, to constrain possible implications for the stability of global thermohaline circulation and climate. This target will require a new quality of stable-isotope and trace metal data obtained by laser ablation technique to reconstruct past variations in sea surface stratification. (2) The transpolar exchange of planktic foraminiferal species, which was possible by theory but certainly rare, and more important, the potential ¿race¿ in the evolution and extreme polar adaption of different N. pachyderma sin. (Nps) cryptospecies to both sides of the Arctic Sea, to be reconstructed by morphometric records of Nps and its lineages for the last 3 Myr. (3) In addition, the newly established ¿44/40Ca-based SST proxy of single Nps shells will now be employed to constrain paleo-SST variations to both sides of the Denmark Strait during cold Dansgaard-Oeschger stadials and to establish paleotemperature records for selected Late Pliocene glacial and interglacial stages, necessary for a precise reconstruction of paleodensity gradients.

• DFG Programme: Research Grants
• Participating Persons: Professor Dr. Anton Eisenhauer; Professor Dr. Michael Sarnthein