南海西北部表层沉积物黏土矿物分布特征及其来源

发布时间：2018-01-14 13:23

本文关键词：南海西北部表层沉积物黏土矿物分布特征及其来源　出处：《海洋学报》2017年09期 　论文类型：期刊论文

【摘要】：黏土矿物研究在示踪物源、源区风化历史乃至洋流变迁能力等方面具有重要的作用,尽管目前对南海表层沉积物黏土矿物宏观分布特征已获得了较系统的认识,但在受珠江和海南岛物源共同影响的南海西北部其高分辨率的黏土矿物学工作还未开展。本文对南海西北部表层沉积物中的黏土矿物组成、结晶学特征进行了分析,讨论了研究区黏土矿物的物质来源。结果表明,南海西北部表层沉积物的黏土矿物组成以伊利石为主(平均45%),蒙脱石(平均27%)与高岭石(平均21%)次之,绿泥石含量最少(平均6%)。在区域空间分布上,蒙脱石含量呈现西南高东北低的特征,伊利石含量则与之相反;高岭石含量表现为近岸高离岸低,而绿泥石含量呈现离岸高近岸低的特征。总体上,研究区表层沉积物黏土矿物组成与现代珠江沉积物组成差异较大,而与珠江口2.5ka前的沉积物黏土矿物组成比较接近,并且结合研究区岩心揭露的全新世以来极低的沉积速率(4cm/ka)以及上部很薄(小于0.6m)的泥质沉积,推测该区表层沉积物可能并非是现代沉积的结果,更可能主要来自全新世末期古珠江输送的沉积物。除古珠江作为研究区表层沉积物中蒙脱石的一个主要来源外,海南岛北部河流也贡献了少量蒙脱石到其邻近的东南海域。运用高岭石/伊利石比值和伊利石化学指数等进一步对比分析表明,珠江是研究区沉积物中伊利石、高岭石和绿泥石的主要物源,其次台湾和海南岛也可能分别提供了少量富含伊利石/绿泥石和高岭石的沉积物。本工作对于南海西北部沉积物源-汇过程和相应的古环境研究有重要的参考意义。
[Abstract]:The study of clay minerals plays an important role in tracer source, source area weathering history and ocean current transition ability, although the macroscopic distribution characteristics of clay minerals in surface sediments of the South China Sea have been systematically understood. However, the high-resolution clay mineralogy work has not been carried out in the northwestern South China Sea, which is influenced by both the Pearl River and Hainan Island provenances. This paper deals with the clay mineral composition in the surface sediments of the northwest South China Sea. The results show that the clay mineral composition of the surface sediments in the northwest South China Sea is mainly composed of Illite (average 45g). The content of montmorillonite (mean 27) and kaolinite (mean 21) was the second, and the content of chlorite was the least (mean 6%). In the regional spatial distribution, the content of montmorillonite showed the characteristics of high in southwest and low in northeast. The content of Illite is opposite to that of Illite. The content of kaolinite is high offshore and low offshore, while chlorite content is high and low offshore. Generally speaking, the clay mineral composition of surface sediments in the study area is quite different from that of modern Pearl River sediments. The composition of clay mineral in sediment is close to that of sediment before 2.5 ka in the Pearl River Estuary. And combined with the very low deposition rate of 4 cm / ka since Holocene exposed by cores in the study area and the very thin (less than 0.6 m) muddy deposits in the upper part of the study area. It is inferred that the surface sediments in this area may not be the result of modern sedimentation. It is more likely to come mainly from sediments transported from the late Holocene Paleo-Pearl River, except that the Paleo-Pearl River is a major source of montmorillonite in the surface sediments of the study area. The rivers in the northern part of Hainan Island also contributed a little montmorillonite to its adjacent southeast sea area. Further comparative analysis of kaolinite / Illite ratio and Illite chemical index shows that the Pearl River is the Illite in the sediments of the study area. The main source of kaolinite and chlorite. Secondly, Taiwan and Hainan Island may also provide a few sediments rich in Illite / chlorite and kaolinite, respectively. This work has important reference meaning for the study of sediment source-sink process and corresponding paleoenvironment in northwest South China Sea. Righteousness.
【作者单位】：中国科学院海洋研究所海洋地质与环境重点实验室;中国科学院大学;巴黎第十一大学地球科学学院IDES实验室;
【基金】：国家自然科学基金(41622603,41576034)
【分类号】：P736.41
【正文快照】： 十一大学地球科学学院IDES实验室,法国巴黎奥赛91405)1引言南海西北部作为东亚大陆边缘的一部分,与华南大陆接壤,紧邻海南岛、台湾岛以及吕宋岛等岛屿,接受了大量来自陆地和岛屿风化剥蚀的沉积物[1]。该区域作为亚洲大陆与南海深水区之间的过渡地带和陆源物质向海输送的主要通

【相似文献】