12 April, 2021
A recent research, published in Geology , by researchers from the Institute of Earth-Sciences (The Hebrew University), the Geological Survey of Israel, NOAA, and The University of Arizona, addresses these questions.
The researchers located an ideal natural dust trap, the Montezuma Well in central Arizona, which is a karst sinkhole and sampled the sediments from a core retrieved from it and dated to the last 12 ka, a time interval characterized in the Southwestern USA by climates shifting from semiarid to a drought and back. This provides a perfect test for examining co-association of dust accumulation (indicating emission and transport) and climate change.
The common hypothesis is that dust emission will increase with increased aridity. The Montezuma Well core results, however, reveal an opposite pattern; minimal dust flux during the arid/drought time interval and highest dust fluxes during the wetter climatic phases. It seems that drought conditions either did not produce enough floods to refill sources with sediments and/or the frequency of windstorms (i.e., there is less active ‘weather’) reduced dust emission and transport, or both.
Field photograph of Montezuma Well, central Arizona, a karst sinkhole acting as an ideal dust-trap.
Field photograph of Kingman Playa, an active dust source in the Sonoran Desert, Arizona.
Guy Tau, Onn Crouvi, Yehouda Enzel, Nadya Teutsch, Paul Ginoux, Craig Rasmussen; Shutting down dust emission during the middle Holocene drought in the Sonoran Desert, Arizona, USA. Geology 2021; doi: https://doi.org/10.1130/G48550.1