Higher interglacial dust fluxes relative to glacial periods in southwestern North American deserts

Lengthy and continuous dust flux records from the deserts of southwestern North America are needed to understand the long-term impacts of climate on dust emissions and the relative influence of regional versus intercontinental dust sources. Here, we perform a particle size end-member analysis of a ~230,000-year sediment record from Stoneman Lake, Arizona, USA, revealing the area directly downwind of this important dust source region is 1.2-10 times dustier during peak interglacial periods compared to glacial maxima. This contrasts with other global dust records and aligns with the region's distinctive dry interglacial and pluvial glacial climates. Our analyses indicate minimal deposition of intercontinental dust and suggest the primary driver of dustiness is regional fine sediment supply, governed by desert alluvial and fluvial system responses to climate change. On the other hand, changes in atmospheric circulation and factors affecting wet and dry fallout appear to exert little control on regional dust flux variability.