Late Quaternary Deep-Water Circulation in the South China Sea

Abstract

A suite of four new benthic foraminiferal (Cibicidoides wuellerstorfe) stable carbon isotope records produced from South China Sea (SCS) sediment cores ranging in water depth from 1515 and 1766m are used here to evaluate deep-water circulation in the SCS over the last complete glacial-interglacial cycle (i.e., the last 200kyrs). A common pattern of benthic£_13C variations is observed between cores, with pronounced £_13C depletions recorded during glacial periods and £_13C enrichments during interglacials. The overall similarity of£_13C values between sites indicates a homogeneous water mass below 1500m in the SCS basin through time, except for the interval between 120 and 65 ka. Temporal changes in ventilation and exchange between SCS and western Pacific are indicated by comparison with records from the Ontong Java Plateau (OJP). The presence of Pacific Intermediate Water can be inferred based on the bathymetric gradient of£_13C between SCS and OJP (¡µ£_13C). The ¡µ£_13C patterns do not appear to be correlated with glacial-interglacial cycle. However, the ¡µ£_18C is greater in warm intervals (late MIS 4 and early MIS 3; MIS 1) than during cold intervals.

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