Distribution and sources of clay minerals in surface sediments of the northwestern South China Sea
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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2.5 ka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(4 cm/ka)以及上部很薄(小于0.6 m)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: As an effective tracer of sediment provenance, continental weathering and oceanic currents evolution, clay mineral has been widely used in palaeoenvironmental research of the South China Sea in the recent years. The general character of spatial distribution of clay minerals in the surface sediments of the South China Sea basin has been established. However, there remains no detailed knowledge about the distribution and sources of clay minerals in the northwestern South China Sea, which is possibly influenced by terrigenous materials input from both of the Zhujiang River and Hainan Island. Here we analyze assemblages and crystallinity of the clay minerals in the surface sediments of this area, and further investigate the sediment provenance of clay minerals. The clay mineral assemblage in sediments of the northwestern South China Sea mainly consists of illite (average~45%), with associated smectite (~27%) and kaolinite (~21%). Chlorite (~6%) is present in lesser amounts. On the spatial scale of this area, smectite is characterized by higher contents in the southwest South China Sea and lower in the northeast of the study area. On the contrary, illite contents are higher in the northeast and lower in the southwest. The percentage of kaolinite shows a decreasing trend from the coast to the shelf, while the contents of chlorite shows an increasing trend. Generally, clay mineral assemblage in the surface sediments of the study area is distinct from the modern Zhujiang River sediments, but it is more similar to the old Zhujiang River mouth sediments deposited about 2.5 ka ago. Moreover, the seismic and sediment core studies revealed a very low sedimentation rate (4 cm/ka) and thin muddy sediments (<0.6 m) on the surface of the continental shelf of the northwestern South China Sea since the Holocene. Therefore, we suggest that the surface sediment in this area is possibly resulted from reworked old materials which were mainly transported from the old Zhujiang River in the late Holocene. In addition to the old Zhujiang River, the small rivers in the northern Hainan Island could also have contributed smectite to its surrounding area. Further analysis using kaolinite/illite ratio and illite chemical index confirms that the Zhujiang River is the main provenance of illite, kaolinite and chlorite in the study area. Besides, Taiwan and Hainan Island may also provide a minor contribution of illite/chlorite-rich and kaolinite-rich sediments, respectively. This result will be helpful for the future studies especially about the sediment processes from source to sink and palaeoenvironmental evolution in the northwestern South China Sea.
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Key words:
- clay mineral assemblages /
- crystallinity /
- provenance /
- surface sediment /
- northwestern South China Sea
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赵德博, 万世明. 南海沉积物中黏土矿物及其在古气候中的应用研究进展[J]. 海洋地质与第四纪地质, 2014, 34(4):163-171. Zhao Debo, Wan Shiming. Research progress of clay minerals in sediments of the South China Sea and its application to paleoclimatic reconstruction[J]. Marine Geology & Quaternary Geology,2014, 34(4):163-171. Xu Fangjian, Li Anchun, Li Tiegang, et al. Rare earth element geochemistry in the inner shelf of the East China Sea and its implication to sediment provenances[J]. Journal of Rare Earths, 2011, 29(7):702-709. Wang Shuhong, Zhang Nan, Chen Han, et al. The surface sediment types and their rare earth element characteristics from the continental shelf of the northern South China Sea[J]. Continental Shelf Research, 2014, 88:185-202. Liu Z F, Colin C, Li X J, et al. Clay mineral distribution in surface sediments of the northeastern South China Sea and surrounding fluvial drainage basins:source and transport[J]. Marine Geology, 2010, 277(1):48-60. Liu Jianguo, Yan Wen, Chen Zhong, et al. Sediment sources and their contribution along northern coast of the South China Sea:Evidence from clay minerals of surface sediments[J]. Continental Shelf Research, 2012, 47:156-164. 田旭, 徐方建, 吴淑壮, 等. 中全新世以来琼东南陆架黏土矿物特征及物质来源[J]. 地球科学:中国地质大学学报, 2015(9):1497-1504. Tian Xu, Xu Fangjian, Wu Shuzhuang, et al. Clay mineral characteristics and provenance of continental shelf sediments in estern hainan island since middle Holocene[J]. Earth Science:Journal of China University of Geosciences, 2015(9):1497-1504. 闫慧梅, 田旭, 徐方建, 等. 中全新世以来南海琼东南近岸泥质区物质来源[J]. 海洋学报, 2016, 38(7):97-106. Yan Huimei, Tian Xu, Xu Fangjian, et al. Sediment provenance of offshore mud area of the eastern Hainan Island in South China Sea since the Mid-Holocene[J]. Haiyang Xuebao, 2016, 38(7):97-106. Webster P J. The role of hydrological processes in ocean-atmosphere interactions[J]. Reviews of Geophysics, 1994, 32(4):427-476. Wang Bin, Clemens S C, Liu Ping. Contrasting the Indian and East Asian monsoons:implications on geological timescales[J]. Marine Geology, 2003, 201(1/3):5-21. 中国自然地理编委员. 中国自然地理-地表水[J]. 北京:科学出版社, 1981. Editorial Committee of Chinese Physical Geography. Physical Geography of China-Groundwater[J]. Beijing:Science Press, 1981. Liu J, Xiang R, Chen Z, et al. Influence of the Kuroshio current intrusion on depositional environment in the Northern South China Sea:Evidence from surface sediment records[J]. Marine Geology, 2011, 285(1):59-68. Zhao Yulong, Liu Zhifei, Zhang Yanwei, et al. In situ observation of contour currents in the northern South China Sea:Applications for deepwater sediment transport[J]. Earth and Planetary Science Letters, 2015, 430:477-485. Fang Guohong, Fang Wendong, Fang Yue, et al. A survey of studies on the South China Sea upper ocean circulation[J]. Acta Oceanographica Taiwanica, 1998, 37(1):1-16. Wang Ying, Ren Meie, Zhu Dakui. Sediment supply to the continental shelf by the major rivers of China[J]. Journal of the Geological Society, 1986, 143(6):935-944. Wan Shiming, Li Anchun, Clift P D, et al. Development of the East Asian monsoon:mineralogical and sedimentologic records in the northern South China Sea since 20 Ma[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 2007, 254(3):561-582. Biscaye P E. Mineralogy and sedimentation of recent deep-sea clay in the Atlantic Ocean and adjacent seas and oceans[J]. Geological Society of America Bulletin, 1965, 76(7):803-832. Ehrmann W. Implications of late Eocene to early Miocene clay mineral assemblages in McMurdo Sound (Ross Sea, Antarctica) on paleoclimate and ice dynamics[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 1998, 139(3):213-231. Wan S, Tian J, Steinke S, et al. Evolution and variability of the East Asian summer monsoon during the Pliocene:Evidence from clay mineral records of the South China Sea[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 2010, 293(1):237-247. Liu Zhifei, Zhao Yulong, Colin C, et al. Source-to-sink transport processes of fluvial sediments in the South China Sea[J]. Earth-Science Reviews, 2016, 153:238-273. Xu K, Milliman J D, Li A, et al. Yangtze-and Taiwan-derived sediments on the inner shelf of East China Sea[J]. Continental Shelf Research, 2009, 29(18):2240-2256. Clift P D, Long H V, Hinton R, et al. Evolving east Asian river systems reconstructed by trace element and Pb and Nd isotope variations in modern and ancient Red River-Song Hong sediments[J]. Geochemistry, Geophysics, Geosystems, 2008, 9(4):29. Xue Z, Liu J P, DeMaster D, et al. Sedimentary processes on the Mekong subaqueous delta:clay mineral and geochemical analysis[J]. Journal of Asian Earth Sciences, 2014, 79(Part A):520-528. Hu Bangqi, Li Jun, Cui Rurong, et al. Clay mineralogy of the riverine sediments of Hainan Island, South China Sea:Implications for weathering and provenance[J]. Journal of Asian Earth Sciences, 2014, 96:84-92. Li Chuanshun, Shi Xuefa, Kao ShuhJi, et al. Clay mineral composition and their sources for the fluvial sediments of Taiwanese rivers[J]. Chinese Science Bulletin, 2012, 57(6):673-681. Milliman J D, Syvitski J P M. Geomorphic/tectonic control of sediment discharge to the ocean:the importance of small mountainous rivers[J]. The Journal of Geology, 1992, 100(5):525-544. Milliman J D, Farnsworth K L. River Discharge to the Coastal Ocean:A Global Synthesis[M]. Cambridge:Cambridge University Press, 2011:384. Liu Zhifei, Zhao Yulong, Colin C, et al. Chemical weathering in Luzon, Philippines from clay mineralogy and major-element geochemistry of river sediments[J]. Applied Geochemistry, 2009, 24(11):2195-2205. 吴敏, 李胜荣, 初凤友, 等. 海南岛周边海域表层沉积物中黏土矿物组合及其气候环境意义[J]. 矿物岩石, 2007, 27(2):101-107. Wu Min, Li Shengyou, Chu Fengyou, et al. The assemblage and environmental aignificance of clay minerals in the surficial sediments around Hainan Island[J]. Journal of Mineral Petrol, 2007, 27(2):101-107. Hu D, Clift P D, Böning P, et al. Holocene evolution in weathering and erosion patterns in the Pearl River delta[J]. Geochemistry, Geophysics, Geosystems, 2013, 14(7):2349-2368. Liu Yunling, Gao Shu, Wang Yaping, et al. Distal mud deposits associated with the Pearl River over the northwestern continental shelf of the South China Sea[J]. Marine Geology, 2014, 347:43-57. 徐方建, 李安春, 肖尚斌, 等. 末次冰消期以来东海内陆架古环境演化[J]. 沉积学报, 2009, 27(1):118-127. Xu Fangjian, Li Anchun, Xiao Shangbin, et al. Paleoenvironmental evolution in the inner shelf of the East China Sea since the last deglaciation[J]. Acta Sedimentologica Sinica, 2009, 27(1):118-127. 万世明, 李安春, 胥可辉, 等. 南海北部中新世以来黏土矿物特征及东亚古季风记录[J]. 地球科学:中国地质大学学报, 2008, 33(3):289-300. Wan Shiming, Li Anchun, Xu Kehui, et al. Characteristics of clay minerals in the northern South China Sea and its implications for evolution of East Asian Monsoon since Miocene[J]. Earth Science:Journal of China University of Geosciences, 2008, 33(3):289-300. Liu Zhifei, Colin C, Huang Wei, et al. Climatic and tectonic controls on weathering in south China and Indochina Peninsula:Clay mineralogical and geochemical investigations from the Pearl, Red, and Mekong drainage basins[J]. Geochemistry, Geophysics, Geosystems, 2007, 8(5):Q05005. Wan Shiming, Li Anchun, Clift P D, et al. Increased contribution of terrigenous supply from Taiwan to the northern South China Sea since 3Ma[J]. Marine Geology, 2010, 278(1):115-121. Huang Chiyue, Wu Weiyu, Chang Chungpai, et al. Tectonic evolution of accretionary prism in the arc-continent collision terrane of Taiwan[J]. Tectonophysics, 1997, 281(1/2):31-51. Liu J P, Liu C S, Xu K H, et al. Flux and fate of small mountainous rivers derived sediments into the Taiwan Strait[J]. Marine Geology, 2008, 256(1):65-76. Wu J W, Liu Z F, Zhou C. Late Quaternary glacial cycle and precessional period of clay mineral assemblages in the Western Pacific Warm Pool[J]. Chinese Science Bulletin, 2012, 57(28):3748-3760. 陈丽蓉. 中国海沉积矿物学[M]. 北京:海洋出版社, 2008. Chen Lirong. Sedimentary Mineralogy of the China Sea[M]. Beijing:China Ocean Press, 2008. Chamley H. Clay Sedimentology[M]. New York:Springer, 1989:623.
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