末次冰期以来印尼穿越流对东亚季风变迁和ENSO活动的响应

In this work, we analyzed Mg/Ca ratios and oxygen isotopes in planktonic foraminiferal shells from Core SO18462 that was retrieved from the outflow side of the Indonesian Throughflow (ITF) in the Timor Sea. We then compared our data with those from Core 3cBX that recovered from the western Pacific warm pool (WPWP), in order to investigate response of the ITF to monsoon and ENSO activities since the last glacial. The results display that an apparent difference in surface waters between the Timor Sea and the WPWP occurred in salinity since ~16ka, indicated by much fresher waters in the Timor Sea than in the WPWP. In contrast, there is little change in difference of sea surface temperatures (SSTs). With regard to thermocline temperature (TT), it increased until ~11.5ka since the last glacial, then remained an overall unchanged trend in the WPWP but continuously decreased in the Timor Sea towards the late Holocene. Since ~6ka, thermocline waters have tended to be close to each other in between the Timor Sea and the WPWP. It is indicated that intensified precipitation due to East Asian monsoon and possible ENSO cold phase significantly freshened surface waters over the Indonesian Seas, impeding the ITF surface flow and in turn enhanced subsurface flow during the Holocene. We speculate that increasing ENSO events during the late Holocene likely played an additional role in controlling TT and thermocline depth of the ITF outflow.