Stable dust-transporting winds in Central Asia over the last 1.2 million years

The last 1.2 million years have witnessed fundamental changes in global climate, including substantial intensification of global glaciations and a shift from obliquity-to eccentricity-paced glacial-interglacial cycles. However, the effect of these changes on prevailing wind direction and mineral dust transport pathways remains enigmatic. Here, we utilize anisotropy of magnetic susceptibility (AMS) of Tajik loess over the last 1.2 Ma to constrain past wind regimes in the Afghan-Tajik Basin of southern Central Asia. The area is located at the intersection of the Siberian High pressure system, the Mid-Latitude Westerlies, and the Indian Summer Monsoon, and acts as one of the largest dust-emitting regions globally. AMS measures the magnetic fabric of loess, a function of dust transporting wind directions and post-depositional processes, and here we apply the technique to three different loess-palaeosol sections on the Khovaling Loess Plateau, Tajikistan. In addition to constraining post depositional reworking, we show through comparison to modern modelled and observed wind regimes that AMS does indeed reflect the directions of dust-transporting winds that, while partly affected by meso-scale and local topography, are ultimately driven by regional wind systems. Our results demonstrate that the directions of these dust-transporting winds have remained stable for the last 1.2 million years. This remarkable resilience of the dust transporting wind regime suggests a stability of the wider synoptic wind field despite major global climate transitions and regional orogenic uplift.