Where does desert dust originate? Geomorphic and climatic control on the evolution of dust sources in the Mojave Desert, USA.

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Deserts are by nature dusty environments, and much of the current literature and scientific research has asserted that dry lake beds, or playas, are the major source of dust despite the fact that they make up a very small proportion of the desert landscape. In the eastern Mojave Desert, southwestern United States, ancient lake sediments contributed to the formation of sand dunes and dust during a climatic transition about 10,000 years ago. However, a large amount of dust accumulations are younger in age, suggesting that landforms other than playas have been significant sources of dust in the past. The overall goal of this proposal is three-fold: 1) determine which desert landforms provide sources of dust by using new wind tunnel technology, the Portable In Situ Wind Erosion Lab (PI-SWERL), 2) determine if the dust sources have changed over time by using modern dust sources as analogs to predict which landforms emitted dust in the past, and by comparing temporal changes in the composition of dust and potential sources, and 3) determine if the record of dust in desert soils corresponds to the age of sand dune activity, using optically stimulated luminescence technology to determine the ages of sand grains within the soil dust. From this research, more information will be learned regarding the types of landforms and soil properties associated with dust emissions in desert environments, and how these sources might change in response to geomorphic processes and climate change. Dust is important from a scientific standpoint because dust additions to soils control soil formation, soil hydrology, landscape evolution, and the ecologic function of desert plants. Dust generation is a societal concern related to visibility, safety, and health issues. Broader impacts of this research include collaboration with other universities and researchers, continued development of age control and wind erosion technologies and techniques, and the support of university students who will gain valuable field and scientific experience. The results of this research will be presented at a major conference, published in peer-reviewed scientific journals, and provided to city/road planners and park and recreational area managers for their use.