Testing models of ice cap extent, South Georgia, sub-Antarctic

Natasha Barlow, Michael Bentley, Giorgio Spada, David Evans, James Hansom, Martin Brader, Duanne WHITE, Anja Zander, Sonja Berg

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    The extent of Last Glacial Maximum ice in South Georgia is contested, with two alternative hypotheses: an extensive (maximum) model of ice reaching the edge of the continental shelf, or a restricted (minimum) model with ice constrained within the inner fjords. We present a new relative sea-level dataset for South Georgia, summarising published and new geomorphological evidence for the marine limit and elevations of former sea levels on the island. Using a glacial isostatic adjustment model (ALMA) specifically suited to regional modelling and working at high spatial resolutions, combined with a series of simulated ice-load histories, we use the relative sea-level data to test between the restricted and extensive ice extent scenarios. The model results suggest that there was most likely an extensive Last Glacial Maximum glaciation of South Georgia, implying that the island was covered by thick (>1000 m) ice, probably to the edge of the continental shelf, with deglaciation occurring relatively early (ca. 15 ka BP, though independent data suggest this may have been as early as 18 ka). The presence of an extensive ice cap extending to the shelf edge would imply that if there were any biological refugia around South Georgia, they must have been relatively localised and restricted to the outermost shelf.
    Original languageEnglish
    Pages (from-to)157-168
    Number of pages12
    JournalQuaternary Science Reviews
    Volume154
    DOIs
    Publication statusPublished - 2016

    Fingerprint

    ice cap
    ice
    sea level
    testing
    Last Glacial Maximum
    continental shelf
    South Georgia and South Sandwich Islands
    refugium
    shelf break
    scenario
    fjord
    deglaciation
    glaciation
    Testing
    refuge habitats
    spatial resolution
    history
    evidence
    Sea Level
    modeling

    Cite this

    Barlow, N., Bentley, M., Spada, G., Evans, D., Hansom, J., Brader, M., ... Berg, S. (2016). Testing models of ice cap extent, South Georgia, sub-Antarctic. Quaternary Science Reviews, 154, 157-168. https://doi.org/10.1016/j.quascirev.2016.11.007
    Barlow, Natasha ; Bentley, Michael ; Spada, Giorgio ; Evans, David ; Hansom, James ; Brader, Martin ; WHITE, Duanne ; Zander, Anja ; Berg, Sonja. / Testing models of ice cap extent, South Georgia, sub-Antarctic. In: Quaternary Science Reviews. 2016 ; Vol. 154. pp. 157-168.
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    title = "Testing models of ice cap extent, South Georgia, sub-Antarctic",
    abstract = "The extent of Last Glacial Maximum ice in South Georgia is contested, with two alternative hypotheses: an extensive (maximum) model of ice reaching the edge of the continental shelf, or a restricted (minimum) model with ice constrained within the inner fjords. We present a new relative sea-level dataset for South Georgia, summarising published and new geomorphological evidence for the marine limit and elevations of former sea levels on the island. Using a glacial isostatic adjustment model (ALMA) specifically suited to regional modelling and working at high spatial resolutions, combined with a series of simulated ice-load histories, we use the relative sea-level data to test between the restricted and extensive ice extent scenarios. The model results suggest that there was most likely an extensive Last Glacial Maximum glaciation of South Georgia, implying that the island was covered by thick (>1000 m) ice, probably to the edge of the continental shelf, with deglaciation occurring relatively early (ca. 15 ka BP, though independent data suggest this may have been as early as 18 ka). The presence of an extensive ice cap extending to the shelf edge would imply that if there were any biological refugia around South Georgia, they must have been relatively localised and restricted to the outermost shelf.",
    keywords = "Coastal geomorphology, Glacial isostatic adjustment, Last Glacial Maximum, Sea-level change, South Georgia, sub-Antarctic",
    author = "Natasha Barlow and Michael Bentley and Giorgio Spada and David Evans and James Hansom and Martin Brader and Duanne WHITE and Anja Zander and Sonja Berg",
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    Barlow, N, Bentley, M, Spada, G, Evans, D, Hansom, J, Brader, M, WHITE, D, Zander, A & Berg, S 2016, 'Testing models of ice cap extent, South Georgia, sub-Antarctic', Quaternary Science Reviews, vol. 154, pp. 157-168. https://doi.org/10.1016/j.quascirev.2016.11.007

    Testing models of ice cap extent, South Georgia, sub-Antarctic. / Barlow, Natasha; Bentley, Michael; Spada, Giorgio; Evans, David; Hansom, James; Brader, Martin; WHITE, Duanne; Zander, Anja; Berg, Sonja.

    In: Quaternary Science Reviews, Vol. 154, 2016, p. 157-168.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Testing models of ice cap extent, South Georgia, sub-Antarctic

    AU - Barlow, Natasha

    AU - Bentley, Michael

    AU - Spada, Giorgio

    AU - Evans, David

    AU - Hansom, James

    AU - Brader, Martin

    AU - WHITE, Duanne

    AU - Zander, Anja

    AU - Berg, Sonja

    PY - 2016

    Y1 - 2016

    N2 - The extent of Last Glacial Maximum ice in South Georgia is contested, with two alternative hypotheses: an extensive (maximum) model of ice reaching the edge of the continental shelf, or a restricted (minimum) model with ice constrained within the inner fjords. We present a new relative sea-level dataset for South Georgia, summarising published and new geomorphological evidence for the marine limit and elevations of former sea levels on the island. Using a glacial isostatic adjustment model (ALMA) specifically suited to regional modelling and working at high spatial resolutions, combined with a series of simulated ice-load histories, we use the relative sea-level data to test between the restricted and extensive ice extent scenarios. The model results suggest that there was most likely an extensive Last Glacial Maximum glaciation of South Georgia, implying that the island was covered by thick (>1000 m) ice, probably to the edge of the continental shelf, with deglaciation occurring relatively early (ca. 15 ka BP, though independent data suggest this may have been as early as 18 ka). The presence of an extensive ice cap extending to the shelf edge would imply that if there were any biological refugia around South Georgia, they must have been relatively localised and restricted to the outermost shelf.

    AB - The extent of Last Glacial Maximum ice in South Georgia is contested, with two alternative hypotheses: an extensive (maximum) model of ice reaching the edge of the continental shelf, or a restricted (minimum) model with ice constrained within the inner fjords. We present a new relative sea-level dataset for South Georgia, summarising published and new geomorphological evidence for the marine limit and elevations of former sea levels on the island. Using a glacial isostatic adjustment model (ALMA) specifically suited to regional modelling and working at high spatial resolutions, combined with a series of simulated ice-load histories, we use the relative sea-level data to test between the restricted and extensive ice extent scenarios. The model results suggest that there was most likely an extensive Last Glacial Maximum glaciation of South Georgia, implying that the island was covered by thick (>1000 m) ice, probably to the edge of the continental shelf, with deglaciation occurring relatively early (ca. 15 ka BP, though independent data suggest this may have been as early as 18 ka). The presence of an extensive ice cap extending to the shelf edge would imply that if there were any biological refugia around South Georgia, they must have been relatively localised and restricted to the outermost shelf.

    KW - Coastal geomorphology

    KW - Glacial isostatic adjustment

    KW - Last Glacial Maximum

    KW - Sea-level change

    KW - South Georgia

    KW - sub-Antarctic

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    DO - 10.1016/j.quascirev.2016.11.007

    M3 - Article

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    EP - 168

    JO - Quaternary Science Reviews

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    ER -