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Isotopic signature of debris‐rich ice formed by regelation into a subglacial sediment bed
Author(s) -
Iverson N. R.,
Souchez R.
Publication year - 1996
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/96gl01073
Subject(s) - geology , debris , glacier , sediment , geomorphology , entrainment (biomusicology) , ice stream , geochemistry , oceanography , sea ice , cryosphere , philosophy , rhythm , aesthetics
Among the processes that may entrain sediment in the bases of glaciers and ice sheets, basal ice may regelate downward into the pores of unlithified sediment. Laboratory studies suggest that this process leaves interstitial ice with a distribution of δ 18 O and δD that is distinct from that developed due to downward freezing of a semi‐closed water reservoir. Although as a result of both processes these isotopes lie on a freezing slope in a δD‐δ 18 O diagram, debris layers entrained by regelation past grains are both enriched in heavy isotopes with depth and display a downward decrease in deuterium excess, the converse of that due to downward freezing of a water reservoir. Moreover, the extent of enrichment can be significantly larger in the case of regelation into the bed. Reevaluated field data from West Greenland are consistent with regelation into the bed as an entrainment mechanism.