干旱区生态环境知识资源中心

The vast desert area of the Tarim Basin contains a large amount of loose sediment, and consequently, it is one of the most important sources of aeolian dust in the mid-latitudes of the Northern Hemisphere. However, only limited research has been undertaken on the provenance of the desert sediments. In this study, we investigated the iron mineralogy including magnetic (Mt), hematite (Hm), and goethite (Gt) characteristics of desert sediments from the Tarim Basin and used them to determine their provenance. The results show that the sediments are characterized by a high content of Gt that comprises up to 0.16, 0.45, and 0.99 wt.% of the 31-63, 8-31, and 2-8 mu m fractions, respectively. In contrast to Hm and Mt, Gt is significantly enriched in the fine particle size fraction. Consequently, we propose that the desert sediments originate in a cold and humid environment, which favors the formation of Gt and limits the formation of Mt and Hm. The surrounding high mountains appear to be the only location within this vast region with the climatic conditions favoring Gt formation.