28 Geomorphic Responses to Holocene Climate Change in the Western USA I

Friday, 21 March 2008
8:00 AM - 11:20 AM

HOLOCENE EOLIAN ACTIVITY IN THE MOJAVE DESERT-LINKAGES TO FLUVIAL AND LACUSTRINE SYSTEMS

Paper number: 28-3
Program: SYMPOSIA SESSIONS
Time: 8:40 AM – 9:00 AM

Authors

Abstract

Eolian sediments and landforms are widespread throughout the Mojave Desert of southern California and southern Nevada. In addition, eolian dust forms an important component of many soils in the region. The majority of the sand deposits occur along well-defined regional- and local-scale sand transport corridors that extend from source areas in the western and central Mojave toward depositional sinks that lie to the east and south. Large parts of these systems are stabilized by vegetation and experience little or no eolian activity in present climatic regimes. However, there is an abundance of evidence that eolian activity has been more extensive and more intense than it is at present during periods of the late Quaternary.

Late Pleistocene and early Holocene eolian activity and construction of dune fields and other eolian deposits was controlled mainly by the availability of sediment from paleolake basins and their influent fluvial systems. Once these systems had desiccated in the early Holocene, eolian activity was influenced by extreme events, notably periods of flooding in the Mojave River that provided sediment to its terminal basins; and periods of extended drought that reduced vegetation cover and enhanced eolian mobility throughout the region. The geomorphic response to these events varies spatially, depending on the factors that control the eolian system.

The varied geomorphic response to Holocene climatic events is evaluated in terms of a conceptual model that considers the influence of sediment supply, availability, and mobility on rates of eolian processes to understand Holocene patterns of eolian activity and to provide an assessment of the response of eolian systems to projected future climate change in the region.