Factors controlling the Early-Mid Holocene aeolian sediment accumulation in the Pum Qu catchment and environmental implications for the southern Tibetan Plateau

Abstract

Aeolian sediments, a sensitive paleoenvironmental archive, are widely distributed in the river valleys of the southern Tibetan Plateau (TP), mainly including the Pum Qu River (PQR) valley and Yarlung Tsangpo River (YTR) valley. However, factors controlling the Early-Mid Holocene aeolian sediments in the PQR catchment and its relationship with the aeolian accumulation in the YTR catchment are poorly understood. Here, we combine Optically Stimulated Luminescence (OSL) dating, magnetic parameters, grain size parameters, color variations and microscopic characteristics to investigate the factors controlling aeolian accumulation in the PQR catchment. The findings indicate that there is a spatial difference in aeolian accumulation in the PQR catchment. The strong accumulation of aeolian sand mainly occurred between ∼11 and 9.3 ka BP, and the paleosol developed between 9.3 and 4.5 ka BP in the PQR catchment during the Early-Mid Holocene. The results of the comparison show that the ages of strong aeolian accumulation in the PQR catchment and YTR catchment are desynchronized. These desynchronized ages of the Holocene strong aeolian accumulation between these two catchments are mostly caused by different controlling factors. In the PQR catchment, aeolian accumulation is dominantly controlled by multiple factors, mainly including changes in local wind force, source supply, vegetation cover and topographic factors. The Early-Mid Holocene strong aeolian accumulation in the PQR catchment is dominantly controlled by the strong local wind force and rich source supply. In the YTR catchment, the Early-Mid Holocene strong aeolian accumulation may record the interplay between Asian Summer Monsoon (ASM), insolation and westerlies. The desynchronized aeolian accumulation and its controlling factors suggest that there is no simple correspondence between aeolian accumulation and climatic and environmental changes in the southern TP.