ESR Signal Intensity and Crystallinity of Quartz from Three Major Asian Dust Sources: Implication for Tracing the Provenances of Eolian Dust

We measured Electron Spin Resonance(ESR) signal intensity and Crystallinity Index(CI) of fine-(<16 m) and coarse-grained(>16 m) quartz in surface samples collected from the Taklimakan desert in western China, the Badain Juran, Tengger and Mu Us deserts in northern China, and the Gobi desert in southern Mongolia. The aim was to test if these two parameters can be used as the accurate provenance tracers of Asian dust. Coarse-grained quartz displays spatial variability of the ESR signal intensity within each desert and of the CI within the Taklimakan and the Mongolian Gobi deserts. Coarse-grained quartz derived from the Mongolian Gobi and northern China deserts can be differentiated from the Taklimakan desert using the ESR signal intensity. By contrast, variability of ESR signal intensity and CI of fine-grained quartz particles is distinct within the Taklimakan and the Mongolian Gobi deserts, but less significant in three deserts of northern China. Spatially, fine-grained dust originating from three major Asian dust sources(i.e., the Gobi-sandy deserts in western China, northern China and southern Mongolia) can be differentiated using the combination of the ESR and CI signals. Our results suggest that combination of the ESR and CI results can discriminate the sources of fine-grained dust better than coarse-grained dust, providing an effective approach to trace the provenance of fine-grained dust depositions on the land and in the ocean.