Bimodal grain‐size distribution of aeolian quartz in a maar of Cheju Island, Korea, during the last 6500 years: Its flux variation and controlling factor

Aeolian quartz chemically isolated from maar sediments in Cheju Island, Korea, showed bimodal grain‐size distributions. After partitioning into fine and coarse components, fine and coarse quartz fluxes (FQF and CQF) were calculated. The average median grain size of fine quartz was 3 μm and the average FQF was 0.5 mg/cm2/yr with a range of 0.1–1.6 mg/cm2/yr during the last 6500 years. The average CQF was 3 mg/cm2/yr with a range of 1–5.5 mg/cm2/yr and its average median grain size was 15 μm. Comparisons of our results with the present aeolian dust activities and climate changes in dust‐source areas suggest that FQF was influenced by the pathway of the westerlies between Taklimakan Desert and Cheju Island while CQF was affected by the aridity in the source regions including the Gobi Desert in southern Mongolia and the adjoining Gobi and sand deserts in China during the last 6500 years.