Origin and derived courses of eolian dust quartz deposited during marine isotope stage 2 in East Asia, suggested by ESR signal intensity

Abstract

The ESR signal intensity of fine quartz (finer than 20 μm) during marine isotope stage (MIS) 2 in the Japanese Islands is spatially. Under the assumption that the values of ESR signal intensity of eolian fine quartz reflect those of the quartz at the in-source areas, the source area and trajectory of eolian dust are tentatively reconstructed. In northern Japan, where the ESR signal intensity is high (10–12), the eolian dust seems to have originated from Siberia and Mongolia where the Precambrian rocks with a high ESR signal intensity are widely exposed. In central and southern Japan, where the ESR signal intensity is medium (5.8–8.7), the eolian dust seems to be supplied from central Asia where Paleozoic–Mesozoic rocks with a medium ESR signal intensity are widely exposed. For the southernmost islands of Japan, where the ESR intensity signal increases again (9.7–13.4), seem to have an eolian dust supply from areas south of Himalayan Range where the Precambrian rocks are widely exposed. On the basis of ESR intensity signals, three major courses of eolian dust transport in MIS 2 are proposed: the winter monsoon in eastern and northern Japan, the summer subtropical jet in western and southern Japan, and the winter subtropical jet in the southernmost islands of Japan.