Abrupt variations of the radiolarian fauna at Mid-Pleistocene climate transition in the South China Sea

Based on a detailed study of the radiolarian fauna, the abundance pattern o f planktic foraminifera as well as on isotope and sedimentological records, the Mid-Pleistocene climate transition as a multiple transition phenomenon could be recognized at Core 17957-2 from the South China Sea. Distinct cha nges in the radiolarian/foraminfera ratio, the coarse fraction and the radi olarian assemblages can be related to the global climate cooling observed a t the Mid-Pleistocene revolution (MPR) around 900 ka. A pronounced southwar d shift of the North Equatorial Current that leads to lower sea-surface tem peratures in the South China Sea is documented by the shift of tropical to subtropical radiolarian assemblages at 900 ka. Increasing radiolarian abund ance after the MPR can be interpreted as a result of stronger upwelling and nutrient supply. These abrupt variations could result from the northern tr ade wind system and East Asian monsoon circulation.