Geological investigations in South Victoria Land, Antarctica

Abstract

Large glaciers derived from the ice plateau cut through the mountain ranges of South Victoria Land to the Ross Sea. In the McMurdo Sound region some glaciers have retreated from portions of their courses leaving almost ice free “dry valleys”. The general geology of one such valley, provisionally named here the Victoria Dry Valley, is discussed in detail. The original ice level of this valley was 1,000 ft to 1,200 ft higher than the present remnants of Victoria Glacier. During the summer months meltwater from remnant cirque and glacier ice accumulates as extensive lakes in the depressions of the moraine-strewn valley floor. The basement is exposed in Victoria Drjf Valley as thick uniform sheets of granite, separated by younger dolerite sills. Acidic and basic dykes antedating sill intrusion are associated with the granite basement. The petrology and field relations of the granite, dykes, and dolerite sills resemble those of similar exposures in the Kukri Hills, 30 miles to the south. It is probable that the rocks of Victoria Dry Valley forrti part of thé northern continuation of the basement complex of South Victoria Land.