Climatic Changes Indicated by Trace Elements in the Chagelebulu Stratigraphic Section, Badain Jaran Desert, China, since 150 kyr B.P.

摘要

This paper analyzes the contents of 16 trace elements in the strata of the Chagelebulu Stratigraphic Section, Badain Jaran Desert, since 150 kyr B.P. and discovered that both the contents of the relatively stable elements, such as P, Mn, Zr, Cr, Pb, Rb, Nb, Y, and the relatively active elements, such as V, Sr, Ni, Cu, Zn, As fluctuated with the sedimentary cycles composed of 25 aeolian dune sands, loess, paleosols, lacustrine facies, alluvial, and colluvial sandy gravels, showing 25 cycles of low-high variation and a fluctuant jagged graph of chemical elements' migration and accumulation. The lower contents of the elements in the aeolian sands show the erosion, migration and deposition of wind power in a cold and arid climate. The relative accumulation of sandy-gravel layers, especially the lacustrine facies, loess, and paleosols correlates with the section's position in the special depression relief with a background of warm and humid climate. The above-mentioned variational characteristics were mainly caused by 25 cycles of arid-cold, windy, and warm-humid climatic fluctuation on the southern fringe of the Badain Jaran Desert since 150 kyr B.P. The essential reason bears a relationship with the back and force swing of the East Asia winter monsoon and summer monsoon influenced by climatic vicissitudes during the glacial and interglacial periods.