79-5 2025 QG&G Career Award: Spatial and temporal tempo of aeolian activity and potential fugitive dust generation in former Dust Bowl Drought (DBD) area, Hamilton County, western Kansas, USA

Session: Soil, Dust, and Everything in Between: Current, Quaternary and Earlier Geological Processes and Records

Presenting Author:

Authors:

Abstract:

Aeolian deposits abound on the Southern Great Plains and are particulate sources for epic haboobs during the 1930s. These haboobs occurred at least weekly, often persisted for days, with probable PM2.5 concentrations of >150 µg/cc and are associated with heightened cardiopulmonary mortality and morbidity of rural denizens. Questions remain about the type of source areas that provided source particulates for haboobs, with the oft stated source associated with ruinous agricultural practices, though the role of land-atmosphere interactions with extreme climate variability remains unevaluated. Initially, analyses of agricultural census data questioned the primacy of plowed fields for dust generation with <40% of the DBD area cultivated. We initiated a study of Hamilton County, Kansas to quantify changes in land surface conditions during the DBD by analyses of 1930s aerial images and for other droughts and pluvials in the 20^th and 21^st centuries, as a comparative metric. This remotely sensed analysis used deep learning segmentation models for mosaiced, tonally normalized and georectified aerial images spanning multiple droughts and pluvials from 1936 to 2021 quantified changes in vegetation cover, prevalence of bare-ground, and the initiation and expansion of pivot irrigation. Extreme droughts in the 1930s, 1950s, 2000s, and 2010s increased ground exposure from 26% to a maximum of 47 %. This analysis showed in 1935 that 62% of land area was mostly or fully denuded with uncultivated surfaces serving as potent sources for dust. However, 2 to 5 years post droughts, there was significant vegetation recovery with 50–70 % of the land surfaces nearly or fully vegetated which highlights the resilience of semi-arid ecosystems. Field experiments using the Portable In-Situ Wind Erosion Laboratory measured potential PM10 emissions from various soils in former DBD areas under different wind speeds. Surfaces with vegetation disturbance released significantly greater quantities of dust compared to undisturbed surfaces when exposed to threshold wind velocities. The prevalent sandier rangeland soils in the DBD area are equal to greater dust sources than cultivated fields during periods of severe aridity. This analysis shows that extreme troposphere temperatures (> 35° C) and precipitation deficits (> 20%) are dominant factors that propagate vegetation reduction for dust generation, rather than solely agricultural disturbance, which underscores the sensitivity of former DBD areas to future hydroclimatic deficits and excessive heat.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6623

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.