Abstract

The frequency of dust storms is increasing globally yet it is often difficult to determine dust sources in mixed events. Dust events may negatively impact human health, but the composition of major dust sources is not well characterized in arid regions globally. In the western US, the National Wind Erosion Research Network (NWERN) has various sites evaluating seasonal dust emissions to quantify dust fluxes. We used existing dust samples to characterize the isotopic, chemical, and mineralogical composition of dust over multiple seasons from ten representative NWERN sites and compared with land use, vegetation, and surficial geology. Our results show variability in dust chemistry across the ten sites primarily related to differences in surficial geology (local bedrock and sediment) with other factors playing a minor role. In some cases, seasonal vegetation and wind direction played a role in controlling dust composition. For example, the El Reno site showed seasonal differences in mineralogy related to carbonate precipitation and dissolution in the soil during wet summers and dry winters. The Holloman Air Force Base (HAFB) site had distinct seasonal changes in dust chemistry with spikes in Na, Mg, Ca, Ni, and Sr during the spring months possibly related to changes in wind direction and inputs from neighboring White Sands National Park. The Lordsburg Playa site had distinct chemistry relative to other sites with high concentrations of Li, Na, Ca, and Sr due to the prevalence of evaporite minerals. Mineralogy results show the presence of quartz, phyllosilicates, and feldspar minerals at each of the NWERN sites with HAFB also containing calcium sulfate and iron oxide minerals. The 87Sr/86Sr results showed lower ratios correlating with younger bedrock (e.g., ~0.7075 at the Red Hills site surrounded by Miocene volcanic rocks), but some of the sites with recent surficial sediments had higher ratios (e.g., ~0.714 at the CPER site with Tertiary sediments). By creating a library of isotopic, chemical, and mineralogical data for dust sources across the western US, our dataset has implications for identifying characteristics that may be used for tracking dust sources.

Degree

MS

College and Department

Computational, Mathematical, and Physical Sciences; Geological Sciences

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2023-06-26

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd13329

Keywords

dust chemistry, western US, dust, dust emissions, dust source, strontium isotopes, mineralogy, trace and major element chemistry

Language

english

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