A subglacial hydrologic drainage hypothesis for silt sorting and deposition during retreat in Pine Island Bay

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dc.citation.firstpage14
dc.citation.issueNumber80
dc.citation.journalTitleAnnals of Glaciology
dc.citation.lastpage20
dc.citation.volumeNumber60
dc.contributor.authorSchroeder, Dustin M.
dc.contributor.authorMacKie, Emma J.
dc.contributor.authorCreyts, Timothy T.
dc.contributor.authorAnderson, John B.
dc.date.accessioned2021-10-06T14:15:42Z
dc.date.available2021-10-06T14:15:42Z
dc.date.issued2019
dc.description.abstractLate Holocene sediment deposits in Pine Island Bay, West Antarctica, are hypothesized to be linked to intensive meltwater drainage during the retreat of the paleo-Pine Island Ice Stream after the Last Glacial Maximum. The uppermost sediment units show an abrupt transition from ice-proximal debris to a draped silt during the late Holocene, which is interpreted to coincide with rapid deglaciation. The small scale and fine sorting of the upper unit could be attributed to origins in subglacial meltwater; however the thickness and deposition rate for this unit imply punctuated- rather than continuous-deposition. This, combined with the deposit's location seaward of large, bedrock basins, has led to the interpretation of this unit as the result of subglacial lake outbursts in these basins. However, the fine-scale sorting of the silt unit is problematic for this energetic interpretation, which should mobilize and deposit a wider range of sediment sizes. To resolve this discrepancy, we present an alternative mechanism in which the silt was sorted by a distributed subglacial water system, stored in bedrock basins far inland of the grounding line, and subsequently eroded at higher flow speeds during retreat. We demonstrate that this mechanism is physically plausible given the subglacial conditions during the late Holocene. We hypothesize that similar silt units observed elsewhere in Antarctica downstream of bedrock basins could be the result of the same mechanism.
dc.identifier.citationSchroeder, Dustin M., MacKie, Emma J., Creyts, Timothy T., et al.. "A subglacial hydrologic drainage hypothesis for silt sorting and deposition during retreat in Pine Island Bay." <i>Annals of Glaciology,</i> 60, no. 80 (2019) Cambridge University Press: 14-20. https://doi.org/10.1017/aog.2019.44.
dc.identifier.digitala-subglacial-hydrologic-drainage-hypothesis
dc.identifier.doihttps://doi.org/10.1017/aog.2019.44
dc.identifier.urihttps://hdl.handle.net/1911/111478
dc.language.isoeng
dc.publisherCambridge University Press
dc.rightsThis is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.titleA subglacial hydrologic drainage hypothesis for silt sorting and deposition during retreat in Pine Island Bay
dc.typeJournal article
dc.type.dcmiText
dc.type.publicationpublisher version
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