New evidence for the provenance and formation of loess deposits in the Ili River Basin, Arid Central Asia

摘要: Abstract Loess deposits are thick and widespread along the piedmonts of Arid Central Asia (ACA), however source (provenance) processes formation these fine-grained aeolian poorly understood. Here we investigate provenance possible distribution mechanisms for loess slopes Ili River basin, located in northwest China southeastern Kazakhstan, using a grain-size mixture model an elemental geochemistry-based fingerprinting technique. Our results indicate that experiences low rates sedimentary recycling downstream within basin piedmont, strongly dependent on local geomorphic context. dominated by proximal sources, indicating short-distance transport from alluvial plains proluvial fans. Local sourcing regardless location catchment, although proportion fluvial input increases proportionally with increasing distance downstream. suggest Asian deserts did not act as significant interim storage reservoirs which contrasts popular piedmont across Asia. Most likely relatively enclosed highly variable topography precluded open desert steppe into upper valley. study provides first clear evidence genetic link between high mountains adjacent piedmonts, based geochemical data, caveat degree topographic variability Tianshan localized influence accumulation.