南海西北部莺琼陆坡36.6 ka以来的浊流沉积

Turbidite records since 36.6 ka at the Yingqiong continental slope in the northwest of South China Sea

对取自南海西北部莺琼陆坡的ZK3岩心进行了AMS14C测年、沉积物粒度分析、地球化学元素分析等,结合萨哈-兰迪姆相浊流环境判别及C-M图的分析结果,识别了南海西北部莺琼陆坡的浊流沉积,讨论了浊流发育的成因及环境气候变化对南海陆坡沉积环境的影响。研究表明:ZK3岩心主要发育了36.6 kaBP以来的晚更新世和全新世地层,浊流沉积发育,初步识别出7.4~8.3、12.8~13.5、15.5~17.2、18.7~20.7 m这4个特征明显的浊积层,其中有3次浊积事件发生于末次冰期。有利的地形、丰富的物源、活跃的海平面变化及气候变化是触发浊流的主要因素。

The cores of ZK3 collected from the Yingqiong slope in the northwest of South China Sea were dated with AMS14C dating,and analyzed for grain sizes and geochemical elements.The Shakha-Landim method for discrimination of turbidity environment and the C-M diagram for turbidite deposits,are also used to recognize the turbidity sediments.Detailed discussion is devoted to the formation of turbidity current and the impacts of the climate change onto the sedimentary environment.The study shows that sediments of core ZK3 were deposited in the time of Pleistocene and Holocene since 36.6 ka.Four layers of turbidite with obvious features occur in the intervals of 7.4~8.3,12.8~13.5,15.5~17.2 and 18.7~20.7 m respectively,corresponding to three turbidity events during the last glacial stage.Favorable topography,abundant material supply,active sea level fluctuation and climate change are the main causes for the origin of the turbidity currents.