Analysis of Dust Trap Sediments Collected on the Southern High Plains

Date

1984

Authors

Machenberg, Marcie D.

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Abstract

Preliminary data derived from six dust traps installed on the Southern High Plains show that dust deposition varies locally and seasonally in response to natural and man-induced factors. Monthly rates of dustfall at individual stations ranged from 0.658 g/m^2 at Muleshoe to 13.4-41 g/m^2 at Palo Duro Canyon. Dust deposition contributes significantly to the renewal of the High Plains surface.

The Southern High Plains has been identified as the dustiest region in the contiguous USA (Orgill and Sehmel, 1976). Sources of dust are numerous and include desiccated playa bottoms, sand dunes, floodplain deposits, plowed fields, overgrazed rangeland, and unpaved roads. Ambient dust deposition is a continuous process augmented by rapid influx of material during duststorms and precipitation events. This study focuses on the amount and characteristics of present-day ambient dustfall. This information is necessary to assess the influence of future eolian deposition and its effect on landscape evolution over the expected lifespan of a high-level nuclear waste repository.

Six dust collectors, consisting of quart-sized, glass canning jars with screened openings, and glycerol as the trapping medium, were installed at pre-established weather-monitoring stations. The traps were designed to collect material deposited by gravitational settling and were mounted at heights of 135 to 147 cm above ground level. The collection sites were chosen to represent natural conditions as accurately as possible. Dust collection was initiated in February 1983 and is expected to continue for 3 to 5 years. Samples are collected monthly (± 3 days) and analyzed for dust quantity, mineralogic composition, and grain-size distribution. Dustfall values are reported as D, g/m^2/month (American Society for Testing and Materials, 1979).

Preliminary results show that the quantity of dust varies greatly between stations. As regional weather patterns are fairly homogeneous over this physiographic province, local differences in soils, land-use practices, vegetation density, topography, and subsequent wind flow account for the variations.

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