Provenance of Neogene eolian red clay in the Altun region of western China—Insights from U[sbnd]Pb detrital zircon age data

Abstract

Aridity of the Asian interior plays an important role in the accumulation of eolian deposits in both eastern (monsoon regime) and western China (westerly wind regime). A better understanding of the provenance of those eolian deposits (loess and red clay) will shed light on the history and mechanisms of Asian aridification. In eastern China, decrease in grain size from northwest to southeast shows that the Neogene red clay of the Chinese Loess Plateau (CLP) was derived from the desert and arid lands of northwestern China by the East Asian winter monsoon. However, in western China, outcrops are limited, and this is an obstacle to studies of the spatial variation of the provenance of eolian deposits. We use UPb geochronology of detrital zircons to determine the provenance of the Altun Red Clay, a recently discovered and continuous eolian deposit in western China. Our comparison of detrital zircon age spectra for the Altun Red Clay with those of potential source regions, and with results for the coeval red clay of the CLP, indicates that: 1. the main zircon age components of the Altun Red Clay are very different from those of the red clay on the CLP, suggesting that these deposits were sourced from different areas, and 2. the Altun Red Clay was likely sourced from the Taklamakan Desert, and transported via westerly winds.