6 Surficial geology and neotectonics in the West: Celebrating and advancing the legacy of Kirk Bryan through field-based geomorphology studies (Posters)
This session invites and examines recent field-based geomorphology studies in the West. Contributions regarding soils geomorphology, neotectonics, pediments, fluvial terraces, and landscape development are invited.
Monday, 18 May 2026
8:00 AM - 5:30 PM
Alvarado D/E
Dust accumulation and hillslope processes on volcanic basalt
Paper number: 6-1
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM
Authors
Abstract
Volcanic basalt fields are an optimal setting to study dust deposition and local sediment transport processes simultaneously. Dust deposits contain signals of land surface processes and hydroclimate. They can also inform atmospheric model simulations which currently lack sufficient observational data points to accurately represent regional dust movement. Measurements of hillslope sediment transport are also critical to understanding landscape evolution via weathering, erosion, and soil development.
Volcanic cinder cones and lava flows feature enclosed topographic lows that often occupy elevated positions on the general landscape, minimizing contributions from non-eolian sources. Consequently, sediments in these positions originate from either airborne dust or local basalt weathering. Furthermore, dust and basalt differ in geochemical and mineralogical composition. Dust is typically composed of felsic minerals (quartz, zircon, mica) and therefore enriched in elements like Zr, K, and Rb. By comparison, basalt is composed of mafic minerals like ilmenite, olivine, and pyroxene and is enriched in Ti, Mg, and Fe. Importantly, dust and local sediments also differ in grain size; locally derived material is much coarser and more poorly sorted.
With this understanding, mineral dust deposition rate is measured in natural dust traps found in the Lunar Crater (NV), Southwest Utah, and Uinkaret (AZ) Volcanic Fields using a combination of OSL geochronology, XRF geochemistry, XRD mineralogy, laser particle size analysis, and end-member modeling of particle size distributions. Dust flux and particle size appear to vary in space and time according to the proximity, activity, and textural characteristics of upwind geomorphic features including alluvial plains, floodplains, and playas. Local sediment particle size distributions exhibit catenary trends in hillslope soils and stratigraphic trends in small basin samples related to changing basin dimensions over time.
Geological Society of America Abstracts with Programs. Vol. 58, No. 4
doi: 10.1130/abs/2026RM-410568
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