南海北部陆坡50 ka 以来黏土矿物来源与输运机制分析

在 AMS14C 定年的基础上,对南海北部 KNG5站和 KNG7站柱状沉积物中的粒度和黏土矿物进行了研究.KNG5孔黏土矿物组合的基本特点是以伊利石、绿泥石和高岭石为主,蒙脱石含量次之.而 KNG7孔黏土矿物组合的基本特点是以伊利石、绿泥石和蒙脱石为主,高岭石含量次之.物源分析进一步表明, KNG5和 KNG7孔高岭石主要来自于珠江,蒙脱石主要由吕宋岛提供,伊利石和绿泥石分别由珠江和台湾提供.相对于 KNG5孔而言, KNG7孔沉积物受珠江影响较小,而受台西南影响较大.由物源分析推测,珠江对南海北部的物源供应存在一个明显的界线,而这一界线可能位于 KNG5孔和KNG7孔之间,越过这一界线随着离岸距离的增加,南海北部陆坡陆源沉积物受珠江影响明显减弱,而主要由台湾贡献.

Clay minerals in core sediments of the northern South China Sea slope since 50 ka and their indication to sources and transport

Precise dating by Accelerator Mass Spectrometry ¹⁴C, grain sizes and clay minerals of the sediments of Core KNG5 and KNG7 from the northern slope of the South China Sea (SCS) were analyzed. Clay minerals of Core KNG5 mainly consisted of illite, chlorite and kaolinite, with minor smectite, whereas clay minerals of Core KNG7 mainly consisted of illite, chlorite and smectite, with minor kaolinite. Sediment source investigations indicated thatkaolinite mainly from the Zhujiang River, smectite mainly from the Luzon River, and illite and chlorite were mainly derived from the Zhujiang River and Taiwan, respectively. Sediment of KNG7 was less affected by the Zhujiang River, but mainly affected by Taiwan compared with KNG5. We speculated from sediment source researches that there was a significant border of the Zhujiang River source supply, and this border may be located between KNG5 and KNG7, and across this line, with the offshore distance increasing, terrigenous sediments in the northern slope of the South China Sea was mainly from Taiwan, while the sediment from the Zhujiang River was severely decreased.