Provenance of Kumtag Desert sands in the Turpan Basin, NW China: insights into alluvial-eolian transport interactions

The origin of eolian sands influences the formation and development of deserts, which in turn have a profound impact on the global climate, local ecosystems, socioeconomic development, and human health. However, the provenance of eolian sediments in the Turpan Basin has been largely untested. In this paper, we report on the sedimentary features and provenance of eolian sediments in the Kumtag Desert using sedimentary structures, grain-size distributions, scanning electron microscopy (SEM), bulk petrography, heavy mineral analysis, detrital zircon U-Pb geochronology, and inverse Monte Carlo models to analyze the data. The eolian deposits, accumulated at a wind stagnation point in the basin, are primarily composed of grainflow and wind-ripple deposits, dominated by medium- to fine-grained sands. Quartz grains are well-rounded and show diagnostic features of eolian transport and abrasion. Provenance analysis reveals that most detrital material originated from the Jurotag Mountain to the south through alluvial transport. The prevailing northwesterly and north-northeasterly winds have reworked and transported sandy components from the alluvial deposits converging along the southern margin of the central Turpan Basin, effectively trapping sand and forming the ~2000 km² Kumtag erg. This study highlights the important role of interactions between alluvial and eolian transport in forming the Kumtag Desert.