How Much is From the Mojave Desert?
INTERPRETATIONS & SUMMARY 1. The fine-grained sediment that mantles much of the Colorado Plateau contains eolian silt, at least some of which has been transported some tens to hundreds of km. 2. The biologic soil crust (BSC) acts as a natural dust trap that records a change in eolian dust source over the past several decades. The magnetic (magnetite enriched relative to titanomagnetite) and chemical (high Zr relative to Ti) patterns suggest enhanced dustfall from source areas more silicic than those that yielded silt to the underlying sediment. Most igneous rocks on the Colorado Plateau are basaltic lavas that occur at the margins of the Plateau. Likely dust-source regions may be areas off the Colorado Plateau, including the Mojave Desert, much of which is underlain by granite and other felsic rocks. The dust record from the Colorado Plateau may reflect increased human disturbance of deserts off the Plateau over the past several decades. Can changing dust composition affect ecosystem p
