干旱区生态环境知识资源中心

The CGS1 segment of the Chagelebulu section in the southeast of the Badain Jaran Desert, records sedimentary cycles consisting of alternations between dune sands and overlying paleosol or loess during the Holocene. Based on the analysis of primary chemical elements (78 samples) [SiO2, Al2O3, and Fe2O3 + FeO (TOFE)], we found that the variation of the primary chemical element content shows eleven chemical element cycles, of these, seven cycles are approximately consistent with the sedimentary cycles. This study suggests that the peaks of SiO2 contents and the valleys of Al2O3, TOFE, Al2O3/SiO2, TOFE/SiO2, and (TOFE + Al2O3)/SiO2 contents in the dune sands represent the dominant periods of East Asian winter monsoon, the valleys of SiO2 contents and the peaks of Al2O3, TOFE, Al2O3/SiO2, TOFE/SiO2, and (TOFE + Al2O3)/SiO2 contents in the paleosol and loess reflect the dominant periods of East Asian summer monsoon. The cold periods C1, C2, C3, C4, C7, C9, C10, and C11 revealed by primary chemical element contents in the CGS1 correspond well to the cold events in the North Atlantic. We attributed the climate fluctuations to the combination impact of oceans and atmosphere triggered by the weakened AMOC. Furthermore, we found more cold periods such as C5, C6, and C8 in the CGS1 than those in the North Atlantic, which were also discovered in some other places of China. They serve as new evidence in China’s deserts to support global climate variations during the Holocene.