Publication Date:
2021-04-05
Description:
Sediment cores from the Northwind Ridge north of the Arctic Chukchi-Alaskan margin were analyzed for
a suite of stratigraphic and provenance proxies. Based on the correlation to previously studied regional
records, cores under study present sedimentary environments of Marine Isotope Stages (MIS) 1e11
(~0.4 Ma) on millennial time scales. Contrasting glacial-interglacial conditions and provenance were
characterized by means of clay-mineral and geochemical (elemental and isotopic) proxies along with
grain size. Interglacial environments are interpreted as sea-ice dominated, with pre-Holocene sediment
transported mostly from the East Siberian to Chukchi-Alaskan margin. In comparison with the recent
conditions, this pattern suggests a stronger Transpolar Drift expanding into the Canada Basin at the
expense of the Beaufort Gyre, or stronger along-shelf currents. Glacial intervals prior to MIS4 have a
predominantly North American signature with carbonaceous or terrigenous source rocks. Carbonaceous
inputs marked by Ca peaks are tracked to the western Canadian Arctic Archipelago eroded by the Laurentide
Ice Sheet (LIS). Terrigenous sources (Zr peaks) are likely related to areas impacted by the
Innuitian Ice Sheet and/or the LIS Mackenzie ice stream. MIS 4 and 2 intervals have a different
composition with the Siberian/Chukchi rather than North American provenance. A stronger winnowing
indicated by grain size in the glacial intervals suggests a stronger mid-depth circulation. Study results
provide new boundary conditions for modeling paleocirculation and glaciations in the western Arctic
Ocean.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
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isiRev