Influence of the Kuroshio Current intrusion on Holocene environmental transformation in the South China Sea.

Numerous studies have been conducted on the evolutionary history of the Kuroshio Current (KC) and other extensions. However, the history of the KC intrusion into the South China Sea (SCS) through the Luzon Strait has been little studied. Here we trace the Holocene developmental history of the KC intrusion and its impact on environmental transformation in the northern SCS. This study involved a comprehensive analysis of planktonic foraminifera, clay minerals and geochemical elements of core 05E306 sediments from the northeastern SCS. AMS 14C dates indicated that the sedimentation rate at the core site was most rapid (>1000 cm/ka) before ~6.0 ka, relatively rapid (~65 cm/ka) between 6.0 and 4.6 ka and slow (~24 cm/ka) since 4.6 ka. The Pulleniatina minimum event (PME) occurred between 4.6 and 2.7 ka, together with high percentages of Neogloboquadrina dutertrei and Globorotalia menardii. Planktonic foraminifera indicated that the KC intrusion experienced three significant changes at 6.0, 4.6 and 2.7 ka in turn. Depositional environments, including input of terrigenous materials and development of biogenic materials, similarly underwent three important transformations at 6.0, 4.1 and 3.0 ka, respectively. Abrupt changes in sedimentary records at the study core are contemporary with records from the tropical Pacific during the Holocene. This indicates that development of the KC intrusion and its impact on depositional environments in the SCS can be correlated with tropical factors from the low-latitude oceans. [ABSTRACT FROM AUTHOR]