Holocene surface and deep water variability in the eastern Fram Strait - expanding the multiproxy perspective by radiogenic isotope tracers
Abstract
The Fram Strait between Svalbard and Greenland reacts highly sensitive to the ongoing amplified climate variations in the Arctic Ocean. Through its eastern part large amounts of warm and saline North Atlantic Drift waters flow towards the north hereby providing most of the heat to the Arctic basin. In contrast, sea ice and cold and fresh waters of Arctic origin are transported south into the GIN seas in the western part of the Fram Strait. The resulting water mass gradient is expressed in a year-round ice-free eastern Fram Strait while the western part is perennially covered by sea ice. High-resolution sediment sequences from the Western Svalbard margin covering the last ca 10,000 years have been studied in order to reconstruct variations of Atlantic Water advection to the Arctic, the sea ice extent, and the structure of the water column. For this purpose we established a multiproxy data set including geochemical, micropalaeontological, and sedimentological parameters of surface and deep water masses with centennial to multidecadal time resolution. In addition, sediment cores have been investigated for its neodymium and lead isotope ratios stored in ferromanganese oxyhydroxide coatings of the sediment to derive information on the source of bottom seawater passing the site. A dominant contribution of deep North Atlantic Drift waters is inferred for the relatively warm early and mid-Holocene periods. Cooler conditions and increased sea ice abundances of the late Holocene are reflected in more radiogenic neodymium isotope ratios likely resembling the neoglacial trend of the northern North Atlantic.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMPP43C..08W
- Keywords:
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- 1040 GEOCHEMISTRY / Radiogenic isotope geochemistry;
- 4924 PALEOCEANOGRAPHY / Geochemical tracers;
- 4936 PALEOCEANOGRAPHY / Interglacial;
- 4944 PALEOCEANOGRAPHY / Micropaleontology