3:45 PM - 4:00 PM
[MIS01-07] Provenance changes of dust in the sediments of the Japan Sea associated with westerly jet shifts since 5 Ma.
Keywords: The Japan Sea, Aeolian dust, Provenance changes, Westerly jet
Here we report provenance changes of quartz in the fine silt fraction (4-32 μm) of the Japan Sea sediments, which is basically composed of the aeolian dust, at IODP Site U1425 during the last 5 Ma using electron spin resonance (ESR) intensity and Crystallinity Index (CI) of quartz to specify the dust sources and changes in their relative contributions. Our result suggests that North (larger contribution of dust from the Taklimakan Desert)-South (larger contribution of dust from Mongolian Gobi) shifts of westerly jet seems to be paced by 405-kyr-long eccentricity cycles. We also analyzed grain size and clay mineral composition of the fine silt fraction to further characterize the dust sources. Combined with linear sedimentation rate (LSR), Dry bulk density (DBD), and XRF core scanner (ITRAX) data, we intend to reconstruct dust fluxes from individual sources and their temporal changes during the last 5 Ma.