Infra-red stimulated luminescence ages from aeolian sand and alluvial fan deposits from the eastern Mojave Desert, California

Abstract

Infra-red stimulated luminescence (IRSL) from coarse-grained (180–212 μm) potassium-rich feldspars has been used to date deposits associated with the western piedmont of the Providence Mountains in the eastern Mojave Desert. These deposits consist of alluvial fans, aeolian sand, which exists in the form of lenses within the fan matrices, and sand from the Kelso dune field which abuts the distal end of the fan sequence. Deposition and subsequent stabilisation of these sand units appears to have occurred in both aird and intermittent climates associated with pluvial phases during the Holocene and Late Pleistocene. Ages of 6600 ± 870 and 7840 ± 1790 years were obtained from dune sand bracketing the Mazama ash at Skull Creek Dunes, Oregon, giving an independent age control on the single aliquot IRSL method which was used on the Mojave samples.