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Deglacial to postglacial history of Nares Strait, Northwest Greenland: a marine perspective

This paper is available in a repository.
This paper is available in a repository.

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Abstract

A radiocarbon dated marine sediment core retrieved in Kane Basin, central Nares Strait, was analysed to constrain the timing of the postglacial opening of this Arctic gateway and its Holocene evolution. This study is based on a set of sedimentological and geochemical proxies of changing sedimentary processes and sources that translate into ice sheet configuration in the strait. Proglacial marine sedimentation at the core site initiated ca. 9.0 cal. ka BP following the retreat of grounded ice. Unstable sea surface conditions subsisted until 7.5 cal. ka BP under the combined influence of warm atmospheric temperatures and proglacial cooling induced by the nearby Innuitian (IIS) and Greenland (GIS) ice sheets. The collapse of the ice saddle in Kennedy Channel at 8.3 cal. ka BP marks the complete opening of Nares Strait and the initial connection between the Lincoln Sea and northernmost Baffin Bay. Delivery of sediment by icebergs was strengthened between 8.3 and 7.5 cal. ka BP following the collapse of the buttress of glacial ice in Kennedy Channel that triggered the acceleration of GIS and IIS fluxes toward Nares Strait. The destabilisation in glacial ice eventually led to the rapid retreat of the GIS in eastern Kane Basin at 8.1 cal. ka BP as evidenced by a noticeable change in sediment source in our core. The gradual decrease of carbonate inputs to Kane Basin between 8.1 and 4.1 cal. ka BP reflects the late deglaciation of Washington Land. The shoaling of Kane Basin can be observed in our record by the increased winnowing of lighter particles as the glacio-isostatic rebound brought the seabed closer to subsurface currents. Our dataset suggests reduced iceberg delivery from 7.5 to 1.9 cal. ka BP in relation to the Neoglacial cooling that likely enhanced sea ice occurrence, thus suppressing calving and/or the drifting of icebergs in Nares Strait.

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