Lateral transport of sediment particles in the Okinawa Trough determined by natural radionuclides.

• DOI: 10.2343/geochemj.24.207
• Publication Date: 2011-10-11T04:19:40Z
• Authors: Hisashi Narita; Koh Harada; Shizuo Tsunogai
• Keywords: Settling; Nuclide; Trough (economics); Radiogenic nuclide

Settling particles at 640 m, 1390 and 1920 m depths in the Okinawa Trough bottom sediments six sites East China Sea were analyzed for U Th isotopes, 210Pb, 210Po. Concentrations of 212Th settling higher than those observed open ocean relatively constant with depth compared other radiogenic nuclides. Fluxes concentrations these nuclides increased measured fluxes larger calculated from water column inventories. While sinking through 640-1390 increases 210Pb unsupported 228Th originating intensively shelf region much 230Th produced evenly sea water. The 210Po/210Pb activity ratio was almost unity 228Th/230Th fraction smaller production rates These results suggest that a large deeper particles, as well trough zone continental zone, are transported laterally downward via near layer on time scale approximately 16 years average.