Environmental Significance of the Chemical Composition of Sediments in Groundwater‐Recharged Lakes of the Badain Jaran Desert, NW China

Abstract

For lakes in desert hinterlands that are not recharged by river runoff, sediment is input solely by wind transport; however, the mechanisms that control the spatial variations in geochemical characteristics of sediments in such lakes remain unclear. Moreover, it remains uncertain whether some element ratios can be used as proxies for environmental characteristics. In this study, 100 surface sediment samples were collected from five lakes in the hinterland of the Badain Jaran Desert, NW China, and examined for their major, trace and rare earth element contents and mineral assemblages. Chemical composition and mineral components of the sediments differed significantly between lakes with different total dissolved solids (TDS). Geochemical characteristics of the lake sediments and their spatial variations are influenced by eolian sands, saline minerals, and sediment sorting. Eolian sands dominate the immobile and nonsoluble elements, whereas authigenic minerals are important in influencing variations in the mobile and soluble elements. Sediment sorting is reflected in the spatial variation of the sediment chemical composition. The positive relationship between the SiO 2 /Ti of sediment and lake area indicates that changes in the SiO 2 /Ti ratio can reveal approximate lake area. The Na 2 O/K 2 O ratio in sediments can reveal the TDS of salt lakes more effectively than can the Rb/Sr ratio. However, the key factors and mechanisms governing the chemical composition of sediments at different brine evolution stages vary among lakes with different TDS levels, which should be carefully considered when interpreting the environmental significance of the chemical composition as a proxy for paleoenviroment change.

Weather, Vol. 77, no. 3, March 2022, pp. 73–112

“…Annual average regional precipitation is 70-80mm (Ma et al, 2011). There are more than 110 perennial lakes recharged by groundwater, Warm island effect observed in lake areas of the Badain Jaran Desert, China concentrated in the southeastern part of the desert and they form an interlaced pattern between thousands of megadunes (Wang et al, 2016;Li et al, 2018Li et al, , 2019.…”

Warm island effect observed in lake areas of the Badain Jaran Desert, China

“…Annual average regional precipitation is 70-80mm (Ma et al, 2011). There are more than 110 perennial lakes recharged by groundwater, Warm island effect observed in lake areas of the Badain Jaran Desert, China concentrated in the southeastern part of the desert and they form an interlaced pattern between thousands of megadunes (Wang et al, 2016;Li et al, 2018Li et al, , 2019.…”