A ~240 ka record of Ice Sheet and Ocean interactions on the Snorri Drift, SW of Iceland

Andrews, J.T. and McCave, I. N. and Syvitski, Jaia (2021) A ~240 ka record of Ice Sheet and Ocean interactions on the Snorri Drift, SW of Iceland. Global and Planetary Change, 201. p. 103498. ISSN 09218181 DOI https://doi.org/10.1016/j.gloplacha.2021.103498

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Official URL: https://doi.org/10.1016/j.gloplacha.2021.103498

Abstract

Core MD99-2323 was extracted from the Snorri Drift at a water depth of 1062 m, just south of the Denmark Strait, and ~120 km from the Last Glacial Maximum (LGM) margins of the Iceland and East Greenland Ice Sheets. The core chronology (~7.5 to 240 cal ka) is derived from radiocarbon dates, marker tephra, paleomagnetic excursion, and correlation with North Atlantic δ18O records on Neogloboquadrina pachyderma (δ18ONp). Sedimentation averaged ~7.5 cm/kyr. Records of proxy flow speed, ice rafted debris (IRD) and oxygen isotopes show that many IRD abundance peaks represent winnowing of the fine fraction by faster flows rather than pulses of increased IRD flux. The overall pattern of flow speed does not resemble the classic fast interglacial/slow glacial pattern seen in records of Nordic Sea overflow, rather the current record is suggested to be partly controlled by the production of brine-driven gravity flows from adjacent ice fronts, especially during cold periods. On a smaller scale the usual glacial/slow – interglacial/fast pattern appears to be the case during ~5 kyr oscillations during Marine Isotope Stage (MIS) 6 where periodic low flow speed is matched by high values of planktonic oxygen isotope ratios. Eight peaks in quartz wt% reflect increased contributions from glacial erosion of Precambrian and Caledonian bedrock from E and NE Greenland; peaks in dolomite may reflect glacial-marine transport from the Laurentide Ice Sheet. Cross wavelet analysis of the δ18ONp versus sortable silt and quartz records indicate significant precession and obliquity periodicities, but with little temporal correlations due to leads and lags in responses.

Item Type: Article
Uncontrolled Keywords: 2021AREP; IA77
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Global and Planetary Change
Volume: 201
Page Range: p. 103498
Identification Number: https://doi.org/10.1016/j.gloplacha.2021.103498
Depositing User: Sarah Humbert
Date Deposited: 14 Jan 2022 13:15
Last Modified: 14 Jan 2022 13:15
URI: http://eprints.esc.cam.ac.uk/id/eprint/6039

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