Constraining the transport time of lithogenic sediments to the Okinawa Trough (East China Sea)

Fall AGU Conference on Deciphering Isotope Signatures of Earth Surface and Critical Zone Processes, San Francisco, CA, DEC, 2014International audienceThe transport time of siliciclastic sediments from their continental sites of formation to their final location of deposition on the seafloor is an important parameter bearing on land-sea interactions, climate variability and understanding of marine sediment record. U-234/U-238 activity ratios of the lithogenic fraction from late Quaternary sediment deposited in the Okinawa Trough, East China Sea, were reported in this study. On basis of U-234/U-238 activity ratios, the comminution ages and transport times were calculated using recoil loss factors (f(alpha)) derived from different equations based on grain size distribution. The transport times were longer (approximately 200 +/- 100 kyr) for the Okinawa Trough sediments deposited between 27 and 14 ka, decreased gradually between 14 and 7 ka, and stayed relatively short (