Lithogenic flux in the Japan Sea measured with sediment traps

Otosaka, Shigeyoshi  ; Togawa, Orihiko ; Baba, Masami*; Karasev, E.*; Volkov, Y. N.*; Omata, Nobutaka*; Noriki, Shinichiro*

Spatial and temporal variations of particulate flux were observed by sediment trap experiments at three areas of the Japan Sea (western Japan Basin, eastern Japan Basin and Yamato Basin) during 1999-2002. Mass flux in the Japan Sea showed remarkable regional distribution. Annual mean mass flux at 1 km depth was 455 mg/m/day in the eastern Japan Basin, 252 mg/m/day in the eastern Japan Basin and 147 mg/m/day in the Yamato Basin. Mass fluxes were especially large in spring (March-May). From the distribution of elemental abundance in sediments, La/Yb and Mn/Al ratios as indicators of the origin of aluminosilicates and the "freshness" of particles, respectively. These proxies suggested three sources of lithogenic material for the Japan Sea, (1) atmospheric input of Kosa particles, (2) lateral transport from the East China Sea, and (3) lateral transport from Island-Arc such as the Japan Islands.