Mountain loess or desert loess? New insight of the sources of Asian atmospheric dust based on mineral magnetic characterization of surface sediments in NW China. (1st July 2020)

• Record Type: Journal Article
• Authors: Xia, Dunsheng; Wang, Youjun; Jia, Jia; Wei, Haitao; Fan, Yijiao; Jin, Ming; Chen, Fahu
• Is Part Of: Atmospheric environment. Volume 232(2020)
• Publication Date: 2020-07-01
• Subjects: Dust emission -- Sediment provenance -- Magnetic fingerprinting -- Northwest China; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2020.117564
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: The arid basins in NW China are one of the most important sources of Asian atmospheric dust. Numerous studies have been conducted of dust flux and its physical and chemical characteristics in terrestrial and marine sediments in East Asia. However, knowledge of the exact sources of the emitted dust is comparatively limited. In this study, we investigated the magnetic characteristics of 541 surface samples collected in NW China. Based on the application of cluster analysis, we propose that the silt in arid basins is sourced from the surrounding high mountains, and that rivers play an important role in transporting the material, whereas sand dunes are only a relatively limited store of silt. Comparison of the results with the magnetic characteristics of loess samples from the Chinese Loess Plateau (CLP) indicates that the slopes of the Kunlun-Alkin-Qilian Mountains System and the surrounding fluvial plains are the major sources of silty dust in NW China, and that the contribution of sediment from sand dunes has been overestimated. In addition, our results indicate that magnetic fingerprinting can be used to trace the pathway of dust transport, and that the loess deposits in central Asia and the CLP are more accurately described as 'mountain loess' rather than 'desert loess'. Highlights: Magnetic characteristics of 541 surface samples in NW China were investigated. Magnetic characteristics used as fingerprint to trace pathways of dust transport. Kunlun-Alkin-Qilian Mountain slopes are major sources of silty dust in NW China. Loess deposits in Chinese Loess Plateau are 'mountain loess' rather than 'desert loess'.