PROVENANCE CHANGE OF HOLOCENE SEDIMENTS UNDER INFLUENCE OF THE TSUSHIMA WARM CURRENT ON THE SOUTHWESTERN SLOPE OF JAPAN SEA

Synthetic analyses on typical element ratio and source discrimination function were carried out for a sediment core with high sedimentary rate collected along the Tsushima Warm Current (TWC) main stream on the southwestern slope of Japan Sea, in order to trace the sediment provenance change of the study area in the Holocene. Data suggest that the Nakdong River of Korea and Changjiang of China are the main source of the studied sediments. Affected by the TWC strength evolution and sea level rise, their contributions changed with time. There are five stages. In the early Holocene (9.6-6.5 kaBP), especially during the two Melt Water Pulse (MWP) stages including MWP-1C (9.4-8.7 kaBP) and MWP-1D (7.8-7.4 kaBP), the contribution of these rivers was high. Their contribution became lower during 6.5-3.0 kaBP and 2.0-0.7 kaBP, corresponding to the temporally weakening of TWC in the northern East China Sea and southwestern Japan Sea. In 3.0-2.0 kaBP and 0.7-0 kaBP, TWC was strengthened and more fluvial materials from the Nakdong River and Changjiang River were deposited in the study area.