毛乌素沙漠南部古今沙丘微量元素对比分析OA

[Objective]Trace elements in modern and ancient dunes from the southern Mu Us Desert record environ-mental information related to weathering,transportation,and deposition.Analysis of this information facilitates a bet-ter understanding of sediment provenance and climatic evolution in the region.[Methods]Samples of modern and an-cient 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 ele-ments in modern and ancient dunes are mainly barium(Ba),strontium(Sr),and phosphorus(P),whereas the con-tents of arsenic(As),niobium(Nb),and copper(Cu)are relatively low.Their distribution patterns show certain re-gional characteristics.(2)The trace element contents in fixed dunes are significantly higher than those in mobile dunes owing to the nature of the dunes and vegetation coverage;however,the trace element contents in ancient dunes are higher than those in modern dunes,owing to the influence of sedimentary history,climate change,and special geomorphic positions.(3)The values of Sr/Cu,Rb/Sr,and Sr/Ba in modern and ancient dunes are comparable,indi-cating that they were formed in similar sedimentary environments.[Conclusion]There are certain similarities and dif-ferences 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.