Post-LGM deglaciation in Pine Island Bay, West AntarcticaShow others and affiliations
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2012 (English)In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 38, p. 11-26Article in journal (Refereed) Published
Abstract [en]
To date, understanding of ice sheet retreat within Pine Island Bay (PIB) following the Last Glacial Maximum (LGM) was based on seven radiocarbon dates and only fragmentary seafloor geomorphic evidence. During the austral summer 2009-2010, restricted sea ice cover allowed for the collection of 27 sediment cores from the outer PIB trough region. Combining these cores with data from prior cruises, over 133 cores have been used to conduct a detailed sedimentological facies analysis. These results, augmented by 23 new radiocarbon dates, are used to reconstruct the post-LGM deglacial history of PIB. Our results record a clear retreat stratigraphy in PIB composed of, from top to base; terrigenous sandy silt (distal glacimarine), pebbly sandy mud (ice-proximal glacimarine), and till. Initial retreat from the outer-continental shelf began shortly after the LGM and before 16.4 k cal yr BP, as a likely response to rising sea level. Bedforms in outer PIB document episodic retreat in the form of back-stepping grounding zone wedges and are associated with proximal glacimarine sediments. A sub-ice shelf facies is observed in central PIB and spans similar to 12.3-10.6 k cal yr BR It is possible that widespread impingement of warm water onto the continental shelf caused an abrupt and widespread change from sub-ice shelf sedimentation to distal glacimarine sedimentation dominated by widespread dispersal of terrigenous silt between 7.8 and 7.0 k cal yr BP. The final phase of retreat ended before similar to 1.3 k cal yr BP, when the grounding line migrated to a location near the current ice margin. (C) 2012 Elsevier Ltd. All rights reserved.
Place, publisher, year, edition, pages
2012. Vol. 38, p. 11-26
Keywords [en]
Pine Island Bay, Amundsen Sea, Last Glacial Maximum, Pine Island Glacier, Subglacial meltwater, Glacial history, Glacial retreat, Grounding line stability, Ice stream, Warm deep water
National Category
Natural Sciences
Research subject
SWEDARP 2009/10, Oden Southern Ocean 2009/10
Identifiers
URN: urn:nbn:se:polar:diva-2376DOI: 10.1016/j.quascirev.2012.01.017ISI: 000302886700002OAI: oai:DiVA.org:polar-2376DiVA, id: diva2:859009
2015-10-052015-10-052017-12-01