Publication Date:
2019-07-13
Description:
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 northcentral 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 PlioPleistocene glacialinterglacial 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, fasterresponding ice sheet that was more prone to deglaciation. If this hypothesis of control through changes in geothermal flux is correct, then the longterm (10 (sup 5) to 10 (sup 6) years) trend now is toward lower geothermal flux, but with higherfrequency (less than or equal to 10( sup 4) to 10 (sup 5) years) oscillations linked to glacialinterglacial 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.
Keywords:
Geophysics
Type:
GSFC-E-DAA-TN65582
,
Journal of Geophysical Research Earth Surface (ISSN 2169-9003) (e-ISSN 2169-9011); 124; 1; 97-115
Format:
text
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