Holocene landscape response to seasonality of storms in the Mojave Desert

Quaternary International
By: , and 



New optically stimulated and radiocarbon ages for alluvial fan and lake deposits in the Mojave Desert are presented, which greatly improves the temporal resolution of surface processes. The new Mojave Desert climate-landscape record is particularly detailed for the late Holocene. Evidence from ephemeral lake deposits and landforms indicates times of sustained stream flow during a wet interval of the latter part of the Medieval Warm Period at ca. AD 1290 and during the Little Ice Age at ca. AD 1650. The former lakes postdate megadroughts of the Medieval Warm Period, whereas the latter match the Maunder Minimum of the Little Ice Age. Periods of alluvial fan aggradation across the Mojave Desert are 14–9 cal ka and 6–3 cal ka. This timing largely correlates to times of increased sea-surface temperatures in the Gulf of California and enhanced warm-season monsoons. This correlation suggests that sustained alluvial fan aggradation may be driven by intense summer-season storms. These data suggest that the close proximity of the Mojave Desert to the Pacific Ocean and the Gulf of California promotes a partitioning of landscape-process responses to climate forcings that vary with seasonality of the dominant storms. Cool-season Pacific frontal storms cause river flow, ephemeral lakes, and fan incision, whereas periods of intense warm-season storms cause hillslope erosion and alluvial fan aggradation. The proposed landscape-process partitioning has important implications for hazard mitigation given that climate change may increase sea-surface temperatures in the Gulf of California, which indirectly could increase future alluvial fan aggradation.

    Study Area

    Publication type Article
    Publication Subtype Journal Article
    Title Holocene landscape response to seasonality of storms in the Mojave Desert
    Series title Quaternary International
    DOI 10.1016/j.quaint.2009.10.001
    Volume 215
    Issue 1-2
    Year Published 2010
    Language English
    Publisher Elsevier
    Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
    Description 17 p.
    First page 45
    Last page 61
    Country United States
    State California
    Other Geospatial Mojave Deserrt
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