New Mexico Geological Society Annual Spring Meeting — Abstracts

The Chihuahuan Desert, covering much of southern New Mexico, is one of most active areas of aeolian processes in the Western Hemisphere. Blowing sand and dust represents one of the principal environmental hazards in the Chihuahuan Desert and areas downwind. The dynamics of Chihuahuan Desert dust and sand storms are modulated by weather (wind), earth surface dynamics (land cover and sediment characteristics), hydrology (drought and lake-filling floods), and human activities (land use). Sand and dust events from the Chihuahuan Desert have impacts on ecosystems, including those far downwind of the desert: and also have adverse effects on human health (respiratory disease) and safety (highway crashes). More than a decade of research by the authors, detecting hundreds of dust point sources in NASA MODIS and NOAA GOES satellite images coupled with fieldwork at many of those sites, has advanced understanding of drivers and triggers of aeolian processes in the Chihuahuan Desert and beyond.

Aeolian dust and sand not does arise randomly or everywhere within the landscape, but rather is associated with specific landforms (“preferential source areas”). Playas and lake basins cover ~4% of the Chihuahuan Desert surface but emit ~50% of dust plumes visible from satellite. Within basins, contacts between sand sheets/dunes and playas/ephemeral lakes- merging coarse grains for saltation and fines for suspension- are dominant sites of dust emission. Alluvial lowlands, although less active and intense sources than playas, produce more total sediment due to their larger spatial coverage in the Chihuahuan Desert. Sand sheets and dunes produce varied levels of aeolian action based on vegetative stabilization and physical properties. Anthropogenic land disturbance, especially for agriculture (particularly abandoned or fallow croplands just across the border in Chihuahua) initiates additional “hotspots” of dust/sandstorms. Hydrology acts as an on/off switch of dust emission through filling and moistening playa basins, and controlling land cover through soil moisture; dust/sandstorm sources are concentrated in areas of severe to extreme drought. Within New Mexico, aeolian focus areas include the Paleolake Palomas basin connecting with the Mimbres River sinks, and the Lordsburg Playa (site of dozens of fatal dust-related highway crashes). Dust from the White Sands impacts topsoil chemistry in the Sacramento Mountains >100km downwind and is regularly transported downwind to other states: conversely, dust and sand from outside New Mexico (Casas Grandes River Basin in Mexico; Willcox Playa in Arizona) blows into the state causing impacts. Dust and sand storms have a documented association with coccidioidomycosis (valley fever), a sometimes-fatal infection of soilborne fungus; and are associated with increased incidences of cardiovascular and respiratory diseases in Las Cruces.

The Chihuahuan Desert has become a global test bed for understanding the geological and hydrological characteristics and environmental impacts of aeolian processes, continuing to reveal the wind’s secrets.