Atmospheric Dust Variations in the Ili Basin, Northwest China, During the Last Glacial Period as Revealed by a High Mountain Loess-Paleosol Sequence

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Li, Yue, Song, Yougui, Qiang, Mingrui, Miao, Yunfa, Zeng, Mengxiu
• Format: Report
• Language: English
• Published: AMER GEOPHYSICAL UNION 2019
• Subjects: Central Asia; loess; last glacial; dust-climate linkage; dynamic mechanism; ARID CENTRAL-ASIA; CHRONOLOGICALLY ORDERED SAMPLES; HOLOCENE MOISTURE EVOLUTION; QINGHAI-TIBETAN PLATEAU; ABRUPT CLIMATIC EVENTS; MASS ACCUMULATION RATE; LATE QUATERNARY LOESS; GREENLAND ICE-CORE; GRAIN-SIZE; NORTHERN CHINA; Meteorology & Atmospheric Sciences; Greenland; Pacific; Greenland ice core; ice core
• Online Access: http://ir.ieecas.cn/handle/361006/13520; https://doi.org/10.1029/2019JD030470

Atmospheric dust emission is closely related to conditions in the source area. Typically, loess deposits represent the accumulation of locally derived dust, providing the opportunity to reconstruct past variations in dust emission and hence insights into dust-climate linkages and the underlying mechanisms of dust mobilization, transport, and deposition. As yet, however, information on patterns of dust emission in Central Asia is sparse. Here we present the last glacial sedimentological data of a loess section from the Ili Basin, northwest China. Our results show that the variations in sand-sized fraction can indicate frequencies of occurring strong winds, which was likely driven by the Eurasian ice sheets during Marine Isotope Stage Stage 2 (MIS2) and MIS4 and by the boreal summer insolation during MIS3. The mass accumulation rate (MAR) reflects an integration of sediment availability in the provenance, vegetation cover in the deposition area, and wind regime. The differences of driving factors potentially explain the observed mismatches between variations in grain size and MAR. Comparison of dust fluxes observed in Greenland ice core and the North Pacific deep-sea sediment with the Central/East Asian MAR records supports the idea that the high flux of long-distance export of Asian dust is closely associated with the Siberian High and also influenced by changes in the atmospheric transport efficiency and likely by the source strength.