18 Surficial geology and neotectonics in the West: Celebrating and advancing the legacy of Kirk Bryan through field-based geomorphology studies

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.

Tuesday, 19 May 2026
8:00 AM - 12:00 PM
Alvarado A

How to erode a playa by wind: Processes responsible for sand and dust generation, White Sands, New Mexico

Paper number: 18-9
Program: Technical Sessions
Time: 10:30 AM – 10:50 AM

Authors

Abstract

White Sands is one of the most prolific dust sources in North America and is also home to the largest gypsum dune field in the world. The aeolian sediment system state theory explains why White Sands is a dust hot spot. Pleistocene Lake Otero sediment provides an abundant sediment supply, seasonally weak surface crusts and efflorescent salt production make the sediment available to wind erosion, and winds frequently exceed the threshold for sediment transport (>8 m/s), especially in spring, and potentially accelerated by downslope winds from nearby mountains. The erosion of the playa surface at White Sands occurs heterogeneously, concentrated at “erosional hollows”, meter-scale blowouts that likely originate due to small scale variability in the crust thickness and strength, soil moisture, and the availability of loose sand at the surface. We used the Portable in situ Wind Erosion Lab (PI-SWERL) to measure threshold friction velocity and dust emission potential, paired with crust strength measurements, to assess wind erosion potential, and applied geomorphic change detection using high resolution lidar imagery to measure the erosional hollows over time. The erosional hollows create a pock-marked morphology that interrupts the otherwise smooth topography of the playa surface. Geomorphic change detection reveals that the erosional hollows grow over time and merge to form a hummocky topography. The erosion and merging of the hollows eventually results in large scale denudation of the playa floor. The erosional hollows are key sources of sand that sandblasts the playa surface to create dust but also contributes to the formation sand sheets, protodunes and the dune field downwind. The formation and merging of erosional hollows may accelerate in drought and was likely responsible for the main White Sands dune building episode ca. 7 ka, when an extended arid phase resulted in the wind erosion of several meters of playa sediment. Ongoing drought and water table decline could result in higher rates of dust production and dune growth in the future.

Geological Society of America Abstracts with Programs. Vol. 58, No. 4

doi: 10.1130/abs/2026RM-410553

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