HR: 16:45h
AN: PP32D-04    [PDF]
TI: Evolution of the Antarctic climate system: a synthesis of land and offshore records from southern Victoria Land
AU: * Sugden, D
EM: des@geo.ed.ac.uk
AF: The University of Edinburgh, Geography, School of Geosciences, Edinburgh, EH8 9XP United Kingdom
AU: Denton, G
EM: debbies@maine.maine.edu
AF: The University of Maine, Department of Geological Sciences and Institute for Quaternary and Climate Studies, Orono, Me 04469
AB: We compare the results of geomorphological analysis of a 260-km sector of the Transantarctic Mountains in southern Victoria Land with offshore records of sedimentation in adjacent offshore cores (Cape Roberts and CIROS-1) and seismic results from wider areas of the Ross Sea shelf. Interpretation of the independent records shows good agreement and allows the following synthesis of the climatic evolution of this part of Antarctica. Denudation since rifting at $\sim$ 55 Ma has removed a wedge of rock 4-7 km thick at the coast, declining inland to $\sim$ 1 km. Most denudation occurred in the Eocene under temperate climatic conditions from fluvial planation of the mountains and incision of river valleys near the coast, with sedimentation occurring offshore. A subsequent pulse of denudation, most rapid at 34-31 Ma, and declining until $\sim$17 Ma, coincided with further crustal extension and a change from cool temperate to polar climate. During this interval, local warm-based glaciers first built up on mountain massifs and experienced cyclic periods of expansion and retreat. Glacier temperatures, meltwater, vegetation and chemical weathering progressively decreased and there was a cold polar climate before inundation by a full Antarctic ice sheet. This latter event occurred between 14.8 and 13.6 Ma and the ice sheet was sufficiently thick to override the Transantarctic Mountains and extend to the edge of the continental shelf. Following retreat offshore and thinning of the maximum ice sheet, the last $\sim$ 13.6 Ma have seen little landscape or climatic change under a hyperarid polar climate. Glacier fluctuations in the last $\sim$ 13 Ma owe their variability to internal glacier dynamics or changes in relative sea level.
DE: 1625 Geomorphology and weathering (1824, 1886)
DE: 1827 Glaciology (1863)
DE: 3344 Paleoclimatology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting