南海南部末次冰期以来的古环境变化:YSJD-86GC柱样的证据

Paleo-environment of southern South China Sea since last Glacial:Evidence from planktonic foraminifera of core YSJD-86GC

采自南海南部的YSJD-86GC柱样(113°02.5860′E,10°18.1740′N,水深2 651m,柱长1.68m)提供了该区近27ka以来的古海洋学记录。沉积物岩性特征、浮游有孔虫分布特征、全岩样品AMS14C测年、氧稳定同位素等分析结果表明,南海南部末次冰期以来一直处于稳定的陆坡—半深海沉积环境;氧同位素Ⅱ期以来表层海水古温度逐渐增高;温跃层在氧同位素Ⅱ期相对较浅,之后逐渐变深,全新世中期以来又再次变浅。11—9.5ka BP期间有一次古气候回返事件,与"新仙女木"事件相对应;6—5ka BP期间古气候波动较大,是全新世中期气候波动剧烈阶段的记录。

The core YSJD-86GC, located in the southern South China Sea （113°02.5860′E,10°18.1740′N）, with water depth of 2651m and core length of 1.68m, discloses a paleoceanographic record of the southern South China Sea since about 27 ka BP. The lithology, planktonic foraminifera, AMS14C age and oxygen isotope indicate that this area has been being in a stable slope-bathyal environment and the sea surface temperature has successively in- creased since the last Glacial. The thermocline was comparatively shallow at the stage of oxygen isotope circle Ⅱ, and then gradually deepened. It got shallow again in the middle Holocene. A paleo-climate cold return event took place during 11-9.5 ka BP, which was corresponding to the Younger Dryas Era. Intense changes of paleo-climate occurred during 6--5 ka BP, reflecting the climatic instability of the middle-Holocene.