Ocean surface and bottom water conditions, iceberg drift and sediment transport on the North Iceland margin during MIS 3 and MIS 2

Andrews, J.T. and Smik, L. and Belt, S.T. and Sicre, M.-A. and McCave, I.N. (2020) Ocean surface and bottom water conditions, iceberg drift and sediment transport on the North Iceland margin during MIS 3 and MIS 2. Quaternary Science Reviews. p. 106722. ISSN 0277-3791 DOI https://doi.org/10.1016/j.quascirev.2020.106722

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Official URL: https://doi.org/10.1016/j.quascirev.2020.106722

Abstract

Radiocarbon dates and marine tephra suggest that the upper 10 m of core MD99-2274 off North Iceland extends from ∼0 to ∼65 ka BP. A multi-proxy sediment and biomarker study at a ∼0.5 ky resolution is used to derive a paleoclimate scenario for this area of the southwestern Nordic Seas, which during the Holocene had intermittent excursions of icebergs and a seasonal cover of drifting sea ice across the site. The sortable silt mean size (S̅S̅) suggests a bottom current (1000 m depth) flow speed maximum to minimum range of ∼8 cm/s during Marine Isotope Stages 2–3, but the data are unreliable for the Holocene. Slow-down in flow speeds may be associated with massive ice and water discharges linked to the Hudson Strait ice stream (H-events) and to melt of icebergs from Greenland in the Nordic seas where convection would have been suppressed. Five pulses of sediment with a distinct felsic component are associated with iceberg transport from E/NE Greenland. Sea ice, open water and sea surface temperature (SST) biomarker proxies (i.e. IP25, HBI III, brassicasterol and alkenones) all point towards near-perennial sea ice cover during MIS 3 and 2, rather than seasonal sea ice or open water conditions. Indeed, our biomarker and sediment data require that the seas north of Iceland experienced a nearly continuous cover of sea ice, together with icebergs calved from ice stream termini, which drifted southward. The cross-correlation of the quartz % records between MD99-2274 and the well-dated core PS2644 in Blosseville Basin indicates significant coherence in the records at a multi-millennial (∼8 ky) timescale. A transition to open ocean conditions is evident from the early Holocene onwards, albeit with the occurrence of some drift ice and icebergs.

Item Type: Article
Uncontrolled Keywords: 2020AREP, IA76
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
08 - Green Open Access
Journal or Publication Title: Quaternary Science Reviews
Page Range: p. 106722
Identification Number: https://doi.org/10.1016/j.quascirev.2020.106722
Depositing User: Sarah Humbert
Date Deposited: 24 Dec 2020 11:52
Last Modified: 24 Dec 2020 11:52
URI: http://eprints.esc.cam.ac.uk/id/eprint/5980

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