Formation and evolution of mountainous aeolian sediments in the northern Tibet Plateau and their links to the Asian winter monsoon and westerlies since the Last Glacial Maximum

Abstract

The production, transport, and deposition of dust has profound impacts and feedbacks on the regional and global environments. In parallel, the Tibet Plateau (TP) plays an important role in East Asian and global climate systems. Previous studies have shown that the dust can reach the plateau by long-distance transport from the westerlies and by short-distance transport from regional weathering. Here we present three new datasets in the Qilian Mountains of the northern TP, including two mountainous aeolian sedimentary sequences and a surface sample dataset. Proxies include grain size, magnetic susceptibility, mineral composition, total organic carbon, and total nitrogen. Data from surface samples indicate spatial gradient effects in altitude (from low to high) and latitude (from north to south), suggesting dust transport from the Gobi Desert to the plateau. The synthetic analysis of two aeolian sedimentary sequences and paleoclimate simulation data reveals that the northern TP can be a dust transport channel controlled mainly by the Asian winter monsoon and less influenced by the westerlies.

Middle to Late Holocene lake evolution and its links with westerlies and Asian monsoon in the middle part of the Hexi Corridor, NW China

“…The MS in lake sediments documents the sizes and types of magnetic minerals (Wu, 1993). Recently, comprehensive analyses of surface sediments in the Qilian Mountains confirmed that high MS values are usually enriched in fine-grained fractions and are positively correlated with regional precipitation (Y. Li et al, 2022; Peng et al, 2022). Some paleoclimate studies also claimed that high MS values are positively related to silt and clay content and indicate a humid environment (Zhang et al, 1998; Zhao et al, 2005).…”

“…8e, f). In the LH, weakening of the Asian winter monsoon and then the increase in the winter water vapor supplement (Zhang et al, 2022), caused by the increase in winter insolation (Berger and Loutre, 1991), favored the improvement of vegetation growth and the preservation of organic matter (Xiao et al 2002; Peng et al, 2022). Moreover, the increased insolation gradient was conducive to the gradual strengthening of westerlies in the LH, thereby increasing moisture transport to the BHZ section and the middle part of the Hexi Corridor (Jin et al, 2012; Zhang et al, 2016).…”