Terrestrial evidence for ocean forcing of Heinrich events and subglacial hydrologic connectivity of the Laurentide Ice Sheet

During the last glacial period, the Laurentide Ice Sheet (LIS) underwent episodes of rapid iceberg discharge, recorded in ocean sediments as “Heinrich events” (HEs). Two competing models attempt to describe the stimulus for HEs via either internal ice sheet oscillations or external ocean-climate sys...

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Bibliographic Details
Published in:Science Advances
Main Authors: Edwards, Graham H., Blackburn, Terrence, Piccione, Gavin, Tulaczyk, Slawek, Miller, Gifford H., Sikes, Cosmo
Format: Text
Language:English
Published: American Association for the Advancement of Science 2022
Subjects:
Earth
Environmental
Ecological
and Space Sciences
Baffin Island
Hudson
Hudson Strait
Baffin
Ice Sheet
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9581489/
http://www.ncbi.nlm.nih.gov/pubmed/36260662
https://doi.org/10.1126/sciadv.abp9329
Description
Summary:During the last glacial period, the Laurentide Ice Sheet (LIS) underwent episodes of rapid iceberg discharge, recorded in ocean sediments as “Heinrich events” (HEs). Two competing models attempt to describe the stimulus for HEs via either internal ice sheet oscillations or external ocean-climate system forcing. We present a terrestrial record of HEs from the northeastern LIS that strongly supports ocean-climate forcing. Subglacial carbonate precipitates from Baffin Island record episodes of subglacial melting coincident with the three most recent HEs, resulting from acceleration of nearby marine-terminating ice streams. Synchronized ice stream acceleration over Baffin Island and Hudson Strait is inconsistent with internal ice sheet oscillations alone and indicates a shared ocean-climate stimulus to coordinate these different glaciological systems. Isotopic compositions of these precipitates record widespread subglacial groundwater connectivity beneath the LIS. Extensive basal melting and flushing of these aquifers during the last HE may have been a harbinger for terminal deglaciation.

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