Quaternary paleoenvironmental evolution of the Tengger Desert and its implications for the provenance of the loess of the Chinese Loess Plateau

摘要

The dust sources of the loess deposits of the Chinese Loess Plateau (CLP) are suggested to be the Gobi-deserts in north China and the Tibetan Plateau in southwest China. The Tengger Desert (TD), a major desert situated to the northeast of the Tibetan Plateau and to the northwest of the CLP, on the western margin of the present-day Asian Summer Monsoon domain, is an ideal area for assessing which of these potential dust source areas may be dominant. A 104-m-long drill core (BJ14) was obtained from the northwestern TD. The magnetostratigraphy, constrained by electron spin resonance dating in the upper part of the core, includes the Brunhes, Matuyama and beginning of the Gauss polarity chrons, with their boundaries at the depths of 44.57 m and 94.31 m, respectively. Sedimentary facies analysis based on lithological, grain-size, magnetic susceptibility and micropaleontological evidences indicates that the core is primarily composed of lacustrine deposits. Combined with the results of previous studies in the eastern TD and the adjacent regions, the sedimentary sequence of core BJ14 indicates that lakes occupied the northern and eastern TD during most of the early Pleistocene and that the onset of a desert environment occurred at similar to 0.9 Ma. Our results suggest that the TD may have contributed only a limited amount of dust to the CLP during the early Pleistocene. (C) 2018 Elsevier Ltd. All rights reserved.