Fingerprinting aeolian sediment sources in the Mu Us Sandy Land using the MixSIAR model

Abstract

Understanding and quantifying aeolian sediment sources in sand seas is imperative to elucidate their formation mechanism and promote ecological restoration, particularly in transitional zones between agricultural farming and animal grazing. Despite considerable efforts to identify the provenance of the Mu Us Sandy Land (Mu Us), a clear boundary demarcating the provenance differences between its western and eastern regions remains elusive. Furthermore, the quantitative contributions of its potential source areas are yet to be determined. This study elucidated these aspects using robust source indicators and the MixSIAR fingerprinting model, underpinned by geochemical data. Utilizing provenance indicators such as the K/Ba, K/Rb, Ba/Sr, and Rb/Sr ratios, this study identified the line connecting Angsu and Huanghaojie Town as the clear boundary demarcating the provenance differences between the western and eastern Mu Us. The eastern Mu Us's coarse sand primarily derives from underlying sandstones (70.5%) and local fluvio-lacustrine deposits (29.5%), while the western region's coarse sand predominantly originates from Yellow River (YR) sediments in the Yinchuan Basin, transported from the Northeastern Tibetan Plateau (NTP) (82.2%), and local fluvio-lacustrine deposits (17.8%). Similarly, the Mu Us's fine sand mainly originates from local fluvio-lacustrine deposits, contributing 66.5% and 67.6% to the fine sand in the eastern and western regions, respectively. Under strong westerly winds, Gobi deposits from upwind areas contribute 33.5% and 32.4% of fine sediments to the eastern and western Mu Us, respectively. The spatial heterogeneity of material sources in the Mu Us highlights the combined influence of fluvial and wind processes. Lacustrine deposits play a crucial role in the sediment provenance of the Mu Us. This study demonstrates that the MixSIAR model constitutes an effective approach for quantitative provenance research in deserts located in climatic transitional zones worldwide.