OSL Dating of High-Elevation Alluvial Sediments: McMurdo Dry Valleys, Antarctica

Abstract

High-elevation alluvial fans in the McMurdo Dry Valleys are a record of short-term, occasional melting events along the margins of the East Antarctic Ice Sheet. Sediment samples were dated from five fans using Optically Stimulated Luminescence (OSL) dating. OSL dates the time since quartz grains were last exposed to sunlight; all sample preparation takes place in a dark room. Thirteen samples were dated for this thesis, the ages were stratigraphically consistent and ranged from 1.1 ka to 105.9 ka. Clusters of fan activity occurred between 1.1 and 3.1 ka and 8.1 and 11.1 ka. The melting events appear to be linked to insolation, with periods of fan activity occurring usually at times of increased mean annual insolation. The alluvial fans show promise as a possible archive for climate proxies in this region of Antarctica.