Mojave Desert Geomorphology
Dune dams trigger landscape change in the Mojave Desert
The formation of the Kelso Dunes was a landscape changing event. Analysis of sedimentolology and stratigraphic relations of deposits revealed that dune-blocked drainages accentuated aggradation of alluvium during the Pleistocene-Holocene transition. This occurred along the Kelso Wash, a major axial drainage, and also along alluvial fan channels draining the Providence Mountains. This research demonstrated how eolian-fluvial interactions can exert significant influence on geomorphic development in deserts. Undergraduate student Lucas Chabela (pictured left) contributed to this research.
Publication:
Sweeney, M.R., McDonald, E.V., Chabela, L.P., Hanson, P.R., 2020, The role of eolian-fluvial interactions and dune dams in landscape change, late Pleistocene-Holocene, Mojave Desert, USA. Geological Society of America Bulletin, v. 132, p. 2318-2332, doi:10.1130/B35434.1
Source of dust in vesicular soil horizons
Dust accumulates beneath desert pavements, a surface layer of gravel, creating an vesicular soil horizon that influences plant growth and soil hydrology. Sedimentological (grain size distributions and grain roundness) and geochemical methods (primarily major and trace element compositions) reveal that local dust sources such as alluvial fans and dry washes are more important than far-traveled sources of dust, such as from playas in developing vesicular horizons in the Mojave Desert. Undergraduate Chris Markley (pictured below) contributed to this research
Sweeney, M. R., McDonald, E. V., Markley, C.E., 2013, Alluvial sediment or playas: what is the dominant source of sand and silt in desert soil Av horizons, southwest USA. Journal of Geophysical Research – Earth Surface, 118, doi:10.1002/jgrf.20030.
