Quantitative analysis of sediment source contributions to the different deposits in the Taklamakan Desert, western China, determined using discriminant function analysis

Provenance analysis of aeolian sediments is key for understanding its origin, transportation and climatic significance. The ability to identify and quantify source contributions of aeolian sediments remains challenging. This study applies a discriminant function analysis (DFA) method to analyze the geochemistry of five different types of sediments (mobile dunes, vegetated dunes, fluvial sands, sandy loess and loess) in the Taklamakan desert and quantify the relative contribution of sediment sources. The geochemical compositions of sediments are influenced by the source rock compositions, chemical weathering and grain size. We analysed the effects of these three factors on the geochemical characteristics of sediments in detail and identified seven source tracers. The seven tracers of potential source areas and target sediments were compared by DFA, to obtain a series of discriminant functions which could identify the sources and their relative contributions. The results show that the aeolian sediments in the Taklamakan Desert are primarily sourced from the Kunlun Mountains and the Tianshan Mountains, with different grain sizes having different sources. The provenance of different types of sediments within the same grain size fractions were found to remain unchanged. The contribution of sediments sourced from the Kunlun Mountain and Tianshan Mountain to the > 63 μm fractions are 60% and 40% respectively, while the contribution to the < 63 μm fractions are 40% and 60% respectively. The findings are valuable for further understanding the source and transport mechanism of sediment in arid and semi-arid areas.