Variability of the intensity of the Tsushima Warm Current and bottom water ventilation in western North Pacific marginal seas during the Pleistocene: preliminary results from IODP Expedition 346 (Sites U1427 and U1428) based on ostracod assemblages

Abstract

IODP Expedition 346 drilled Sites U1427 and U1428 in ideal locations to monitor changes in (i) the intensity of the influx of the Tsushima Warm Current (TWC), and (ii) the intermediate bottom water ventilation from a few hundred thousand years to over a million years in the western North Pacific marginal seas. Site U1427 is located at 330 m water depth in the marginal sea bordered by the Eurasian continent, the Korean peninsula and the Japanese Islands. This semi-enclosed marginal sea has an average water depth of 1350 m and is connected with other marginal seas in the region by shallow, narrow straits. Site U1428 is located at 724 m in the East China Sea and this region is more influenced by continental freshwater runoff derived from the Yangtze River. Both sites are in the path of the TWC, a branch of the Kuroshio Current, the only warm current flowing into …