DEGLACIATION OF THE VESTFOLD HILLS, EAST ANTARCTICA: PRELIMINARY
EVIDENCE FROM EXPOSURE DATING OF THREE SUBGLACIAL ERRATICS
D. Fabel, J. Stone, L.K. Fifield and R.G. Cresswell
In: Ricci C.A. (ed.) The Antarctic Region: Geological Evolution and
Processes. Proceedings 7th International Symposium on Antarctic Earth
Science, Siena, 1995, 829-834 (1997)
Abstract
Cosmogenic isotope measurements on two subglacially derived erratics
from the Vestfold Hills, East Antarctica indicate retreat of the continental
ice margin from a position at least 5 km west of its present location around
12 - 9 ka. These ages are similar to C-14 dates on the oldest organic sediment
in lakes around the Hills, suggesting that biological colonization of lake
basins coincided with glacial retreat. Whether this indicates recession
of ice that extended across the entire Vestfold Hills, or an amelioration
of climate that simply thawed lakes and melted a much less extensive ice
cover cannot be established from the results so far. Recession appears
to have continued recently, with results from a third sample indicating
emergence of a small nunatak, Ultima Bluff, within the past 2 ka.
