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Sand-Dune Dynamics

History And Processes Of Eolian Sand Movement In American Drylands

For additional information, please visit:
http://esp.cr.usgs.gov/info/sw/eolian.html#dune
http://esp.cr.usgs.gov/info/sw/eolian/
http://geochange.er.usgs.gov/sw/impacts/geology/sand/

Eolian sand covers extensive areas over the southwestern United States. Much of this sand is currently stabilized by vegetation but only marginally in areas such as the southern Colorado Plateau. Reactivation of this sand caused by drought, future climate change, or land-use practices could have serious consequences on human and animal populations, agriculture, grazing, and infrastructure. These investigations aim to understand the processes responsible for initiation of eolian sand movement, including controls from source sediment availability, climate, vegetation, and land use. Efforts are focused on eolian sand bodies (dune fields and areas of sheet sands) in the Mojave Desert, the western Sonoran Desert, the Colorado Plateau (particularly deposits within the Navajo Nation), the Southern High Plains, and Great Sand Dunes National Monument.

Previous studies have suggested that, in the Mojave Desert, climate plays a major role in eolian sand dynamics, but more recent studies have suggested that source sediment availability could be more important than climate controls. On the other hand, in the Southern High Plains, eolian sediment movement may be more a function of climate controls. Thus, each subregion of the southwestern U.S. may have different processes controlling the degree of eolian sand movement and dune activity. Detailed stratigraphic, geomorphic, geochemical, and mineralogic studies are needed to understand the most critical controls on eolian sediment movement.

For more information, select from the following topics:

• Navajo dunes
• Eolian sand transport pathways in the Southwest - importance of the Colorado River and local sources
• Dale Lake sand ramps, Mojave Desert
• Southern High Plains dunes
• Great Sand Dunes National Park - Quaternary history and sources of sand