Dynamic Antarctic ice sheet during the early to mid-Miocene

Edward Gasson, Robert M. DeConto, David Pollard, Richard H. Levy

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

Geological data indicate that there were major variations in Antarctic ice sheet volume and extent during the early to mid-Miocene. Simulating such large-scale changes is problematic because of a strong hysteresis effect, which results in stability once the ice sheets have reached continental size. A relatively narrow range of atmospheric CO2 concentrations indicated by proxy records exacerbates this problem. Here, we are able to simulate large-scale variability of the early to mid-Miocene Antarctic ice sheet because of three developments in our modeling approach. (i) We use a climate-ice sheet coupling method utilizing a high-resolution atmospheric component to account for ice sheet-climate feedbacks. (ii) The ice sheet model includes recently proposed mechanisms for retreat into deep subglacial basins caused by ice-cliff failure and ice-shelf hydrofracture. (iii)We account for changes in the oxygen isotopic composition of the ice sheet by using isotope-enabled climate and ice sheet models. We compare our modeling results with ice-proximal records emerging from a sedimentological drill core from the Ross Sea (Andrill-2A) that is presented in a companion article. The variability in Antarctic ice volume that we simulate is equivalent to a seawater oxygen isotope signal of 0.52-0.66‰, or a sea level equivalent change of 30-36 m, for a range of atmospheric CO2 between 280 and 500 ppm and a changing astronomical configuration. This result represents a substantial advance in resolving the long-standing model data conflict of Miocene Antarctic ice sheet and sea level variability.

Original languageEnglish (US)
Pages (from-to)3459-3464
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume113
Issue number13
DOIs
StatePublished - Mar 29 2016

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ice sheet
Miocene
ice
sea level
climate feedback
ice shelf
climate
hysteresis
cliff
modeling
oxygen isotope
isotopic composition
isotope
seawater
oxygen
basin

All Science Journal Classification (ASJC) codes

  • General

Cite this

Gasson, Edward ; DeConto, Robert M. ; Pollard, David ; Levy, Richard H. / Dynamic Antarctic ice sheet during the early to mid-Miocene. In: Proceedings of the National Academy of Sciences of the United States of America. 2016 ; Vol. 113, No. 13. pp. 3459-3464.
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Dynamic Antarctic ice sheet during the early to mid-Miocene. / Gasson, Edward; DeConto, Robert M.; Pollard, David; Levy, Richard H.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 113, No. 13, 29.03.2016, p. 3459-3464.

Research output: Contribution to journalArticle

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