TY - JOUR
T1 - Possible Role for Tectonics in the Evolving Stability of the Greenland Ice Sheet
AU - Alley, R. B.
AU - Pollard, D.
AU - Parizek, B. R.
AU - Anandakrishnan, S.
AU - Pourpoint, M.
AU - Stevens, N. T.
AU - MacGregor, J. A.
AU - Christianson, K.
AU - Muto, A.
AU - Holschuh, N.
N1 - Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/1
Y1 - 2019/1
N2 - The history of the Greenland Ice Sheet has been influenced by the geodynamic response to ice sheet fluctuations, and this interaction may help explain past deglaciations under modest climate forcing. We hypothesize that when the Iceland hot spot passed beneath north-central Greenland, it thinned the lithosphere and left anomalous heat likely with partially melted rock; however, it did not break through the crust to supply voluminous flood basalts. Subsequent Plio-Pleistocene glacial-interglacial cycles caused large and rapidly migrating stresses, driving dike formation and other processes that shifted melted rock toward the surface. The resulting increase in surface geothermal flux favored a thinner, faster-responding ice sheet that was more prone to deglaciation. If this hypothesis of control through changes in geothermal flux is correct, then the long-term (10 5 to 10 6 years) trend now is toward lower geothermal flux, but with higher-frequency (≤10 4 to 10 5 years) oscillations linked to glacial-interglacial cycles. Whether the geothermal flux is increasing or decreasing now is not known but is of societal relevance due to its possible impact on ice flow. We infer that projections of the future of the ice sheet and its effect on sea level must integrate geologic and geophysical data as well as glaciological, atmospheric, oceanic, and paleoclimatic information.
AB - The history of the Greenland Ice Sheet has been influenced by the geodynamic response to ice sheet fluctuations, and this interaction may help explain past deglaciations under modest climate forcing. We hypothesize that when the Iceland hot spot passed beneath north-central Greenland, it thinned the lithosphere and left anomalous heat likely with partially melted rock; however, it did not break through the crust to supply voluminous flood basalts. Subsequent Plio-Pleistocene glacial-interglacial cycles caused large and rapidly migrating stresses, driving dike formation and other processes that shifted melted rock toward the surface. The resulting increase in surface geothermal flux favored a thinner, faster-responding ice sheet that was more prone to deglaciation. If this hypothesis of control through changes in geothermal flux is correct, then the long-term (10 5 to 10 6 years) trend now is toward lower geothermal flux, but with higher-frequency (≤10 4 to 10 5 years) oscillations linked to glacial-interglacial cycles. Whether the geothermal flux is increasing or decreasing now is not known but is of societal relevance due to its possible impact on ice flow. We infer that projections of the future of the ice sheet and its effect on sea level must integrate geologic and geophysical data as well as glaciological, atmospheric, oceanic, and paleoclimatic information.
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U2 - 10.1029/2018JF004714
DO - 10.1029/2018JF004714
M3 - Article
AN - SCOPUS:85060354903
SN - 2169-9003
VL - 124
SP - 97
EP - 115
JO - Journal of Geophysical Research: Earth Surface
JF - Journal of Geophysical Research: Earth Surface
IS - 1
ER -