북서태평양에 운반되는 광물입자의 기원지 및 황사의 운반기작에 관한 고찰

Abstract

The arid and semi-arid regions in the Central-East Asia have supplied a tremendous amount of dust, namely Asian Dust, to nearby continent and the North Pacific Ocean. To date, most studies using pelagic eolian sediment from the North Pacific have focused on understanding the mass flux variation of Asian dust in terms of long-term climate variability, but have not considered specific transport pathways or dust source regions. To characterize the provenance and transport pathways of the Asian Dust deposited in the western tropical/subtropical Pacific and to investigate its changes over the late Quaternary, source regions of mineral dust were investigated with the clay mineral assemblage and the 143Nd/144Nd and 87Sr/86Sr composition of the eolian fractions of deep-sea sediment core retrieved from the Palau-Kyushu Ridge (12°30′N, 134°60′E, 3,728 m water depth) in the Philippine Sea, deposited for the last 600 kyr. The analyzed attributes of the eolian sediment resemble those of dust from the Central Asian deserts (CADs e.g., Taklimakan and nearby deserts) as in the North Central Pacific, but published aerosol data collected near the study site during winter/spring has the mineralogical signature of dust originating from the East Asian deserts (EADs e.g., the Chinese Loess Plateau and nearby deserts). These data indicate that the relative contribution of EAD dust increases with the northeasterly surface winds associc have focused on understanding the mass flux variation of Asian dust in terms of long-term climate variability, but have not considered specific transport pathways or dust source regions. To characterize the provenance and transport pathways of the Asian Dust deposited in the western tropical/subtropical Pacific and to investigate its changes over the late Quaternary, source regions of mineral dust were investigated with the clay mineral assemblage and the 143Nd/144Nd and 87Sr/86Sr composition of the eolian fractions of deep-sea sediment core retrieved from the Palau-Kyushu Ridge (12°30′N, 134°60′E, 3,728 m water depth) in the Philippine Sea, deposited for the last 600 kyr. The analyzed attributes of the eolian sediment resemble those of dust from the Central Asian deserts (CADs e.g., Taklimakan and nearby deserts) as in the North Central Pacific, but published aerosol data collected near the study site during winter/spring has the mineralogical signature of dust originating from the East Asian deserts (EADs e.g., the Chinese Loess Plateau and nearby deserts). These data indicate that the relative contribution of EAD dust increases with the northeasterly surface winds associ