Composition of aeolian dust in natural traps on isolated surfaces of the central Mojave Desert - Insights to mixing , sources , and nutrient inputs

R.L Reynolds' , M . Reheis, J. Yount, P. Lamothe US Geologicol Survey. MS 980, P.O. Box 15046, Den~er. CO 80215, USA Received 14 January 2005; received in revised form 17 May 2005; a~~epted 1 June 200S Available online 20 December 2005 The recognition and characterization of aeolian dust in soi l contribute 10 a better understanding of landscape and ecosystem dynamics or dryJands. Results of this study show that recently deposi ted dust, sampled in isolated, mostly high-ground sett ings, is chemically and mineralogically similar on va ried geologic substrates over a large area (ISOOOkml) in the Mojave Deserl. The sill-plus-clay rraction (fines) on these isolated surraces is closely alike in magnetic-mineral composition, in contrast to greatly dissimilar magnctic compositions or rock surraees or vastly different lithologies, on which the fines have accumulatc:d . The fines, thus, are predominantly deposited dust. The amounts of potential nutrients in the sampled dust are much more unironn than might be provided by direct, local weathering o f bedrock or by dust locally derived rrom nearby weathered products. The compositional similarity or the dust on these surraces is interpreted to result from mixing of fines in the atmosphere as well as in fluvial , alluvial, and lacustrine depositional settings prior to dust emission. Published by Elsevier Ltd . KtJ'M·orJs: Aeolian dust; Magnetite; Magnetic p roperties; Plant nutrienlS: Mojave Desert ·Corrcsponding author. Tel .: -+ 1 303 236 1303: rllll : I )03236 S)49. E-mail ulldr"~: rn:[email protected] (R.L. Reynolds), [email protected] (M. Reheis), [email protected] (J. Yount), [email protected](P. Lamothe). 0140-1963/5· see fronl matler Published by Elsevier Ltd. doi: 10.1 0 16/j.ja rideny .2005.06.03 1 RL RtFIQldJ 1.'/ al. I JotJrllal u/ Arid Erw;rQTlmtnls 66 (1006) 42~1 "