Source of aeolian dune sands on the northern margin of Qarhan Salt Lake, Qaidam Basin, NW China

Abstract

The aeolian landforms in the Qaidam Basin have drawn increasing attention from geomorphologists for their morphological and formation mechanisms' similarities with their counterparts on Mars and Titan. Using grain‐size and mineral composition data, this study investigated the source of aeolian dune sands found on the northern margin of Qarhan Salt Lake in the south central part of the Qaidam Basin. Results indicate that linear dune sands and gobi surface sediments are mainly composed of fine and very fine sands, while the yardang corridor sands are much coarser, with medium and fine sands in predominance. The curves of the linear dune sands show a standard normal distribution pattern. This is also the case for the gobi surface sediments and yardang corridor sands located away from linear dunes. However, the curves for these two sediment types show much wider kurtoses. The distribution curves for the yardang corridor sands located near the linear dunes are different from the above‐mentioned sediments, which explicitly display bimodal distributions. More mineral types were detected in the yardang corridor sands and gobi surface sediments than in dune sands. But the major mineral compositions of the three kinds of sediments are similar. Contents of typical very stable and stable heavy minerals differ little among the three sediments, while the contents of some heavy minerals with poor stability differ greatly. The relative proportions of quartz, plagioclase, and orthoclase in all three kinds of sediments demonstrate that they all likely originated from the granite and granodiorite rocks of the Qilian Mountain ranges. Therefore, gobi surface sediments and yardang corridor sands near the study linear dune field could be the source of dune sands. Further investigations are needed to determine whether the yardang corridor sands far away from the study linear dune field feed dunes in the Sebei area.