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Evolution of subglacial bedforms along a paleo‐ice stream, Antarctic Peninsula continental shelf
Author(s) -
Ó Cofaigh Colm,
Pudsey Carol J.,
Dowdeswell Julian A.,
Morris Peter
Publication year - 2002
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 - 10.1029/2001gl014488
Subject(s) - geology , bedform , ice stream , continental shelf , ice shelf , geomorphology , trough (economics) , glacial period , ice sheet , sedimentary rock , bedrock , oceanography , paleontology , sediment transport , sediment , sea ice , cryosphere , economics , macroeconomics
Geophysical data from the Antarctic Peninsula continental shelf reveal streamlined subglacial bedforms in a cross‐shelf trough. Bedforms exhibit progressive elongation with distance along the trough, and record flow of a paleo‐ice stream from the Antarctic Peninsula Ice Sheet during the last glacial maximum. Downflow evolution of the bedforms indicates increasing flow velocities as the ice stream traversed the shelf. This, in turn, is related to a transition from crystalline bedrock on the inner shelf to a soft sedimentary substrate on the outer shelf. Although streaming flow operated across both substrates, the highest flow velocities occurred over the soft bed. Spatial variation in the inferred nature of fast‐flow, from sliding to subglacial sediment deformation and/or ploughing, was also lithologically controlled. These data highlight the control of subglacial geology on ice‐stream dynamics in the geological record and demonstrate a direct relationship between the formation of streamlined subglacial bedforms and paleo‐ice streams.