Comparison of trace elements in modern and ancient sand dunes in the southern Mu Us Desert

Key words: 
• Southern part of the Mu Us Desert /
• Modern sand dune /
• Ancient sand dune /
• Trace elements

Abstract: 【Objective】The trace element records of modern and ancient dunes in the southern part of the Mu Us Desert provide environmental information on their weathering, transportation and deposition processes. The aim of this study is to gain a deeper understanding of the sediment sources and climate environment in this area.【Methods】 Samples of modern and ancient dunes in the southern Mu Us Desert were collected, and the content characteristics and correlations of 14 trace elements including phosphorus (P), lead (Pb), and rubidium (Rb) were analyzed to explore the differences in trace element contents and spatial distribution characteristics among different types of dunes.【Results】 (1) The trace elements in modern and ancient dunes are mainly barium (Ba), strontium (Sr), and phosphorus (P), while the contents of arsenic (As), niobium (Nb), and copper (Cu) are relatively low.Their distribution patterns show certain regional characteristics. (2) The trace element contents in fixed dunes are significantly higher than those in mobile dunes, mainly due to the nature of the dunes and vegetation coverage; while the trace element contents in ancient dunes are higher than those in modern dunes, mainly influenced by sedimentary history, climate change, and special geomorphic positions. (3) The ratios of Sr/Cu, Rb/Sr, and Sr/Ba in modern and ancient dunes are comparable, indicating that they were formed in similar sedimentary environments.【Conclusion】 There are certain similarities and differences in the trace element contents of modern and ancient dunes and different types of dunes. The changes in trace element contents in ancient dunes can provide clues to the sources of modern dunes to a certain extent. The ratios of trace elements in modern and ancient dunes have certain implications for climate and environmental conditions.