Program
 
Special Session 2: Changing ocean environment: from the sedimentary perspective -- processes and records
 

 
 
1400
Intrusion of Kuroshio Current into the East China Sea shelf and Okinawa Trough since the LGM
Wednesday 11th @ 1400-1420
Room 4
Shouye Yang* , State Key Laboratory of Marine Geology, Tongji University
Yanguang Dou, Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Ministry of Land and Resources, Qingdao Institute of Marine Geology
Ergang Lian, State Key Laboratory of Marine Geology, Tongji University
Yun Zhao, State Key Laboratory of Marine Geology, Tongji University
Chao Li, State Key Laboratory of Marine Geology, Tongji University
Presenter Email: syyang@tongji.edu.cn
The Kuroshio Current (KC) has an overwhelming influence on the heat exchange, salt and nutrients balance, and sedimentation on the East China Sea shelf and Okinawa Trough (OT). Despite the numerous research attempts, the spatial and temporal variability of KC during the late Quaternary and its impacts on marine environment remain to be resolved. In particular, the shift of KC pathway since the Last Glacial Maximum (LGM) and the intrusion of its subsurface water onto the inner shelf await more investigations. In this study, we present geochemical evidences including rare earth elements and Nd isotope in the labile fractions of marine sediments, and reconstruct the pathway and evolution of deep-water environment in the OT since the LGM. In addition, we combine H-O stable isotopes with satellite sea surface temperature and hydrographic data, aiming to reveal the intrusion of Kuroshio subsurface water onto the inner shelf. Our data suggest that the Kuroshio-branched water northeast of Taiwan can intrude into the inner shelf near Zhe-Min Coast, manifesting by a pronounced boundary at 50 m isobath around 28 ¡ăN, and thereby feeds the TWC intrusion into the Changjiang Estuary. During the LGM the pathway of KC might have shifted outside the OT but strengthened with the onset of Holocene, accompanied by an oxic depositional environment responding to the enhanced deepwater ventilation with the advection of the North Pacific Intermediate Water and/or South China Sea Intermediate Water into the trough. The intrusion and strengthening of KC in the early Holocene enhanced the water stratification and induced a gradual development of suboxic depositional condition. The KC intrusion complicates the hydrological process in the shelf and OT, and its impact on marine environment deserves more research attention.