东海东北部海域表层沉积物黏土矿物来源及输运

Sources and Transport of Clay Minerals in Surface Sediments of the Northeastern East China Sea

利用X射线衍射,对东海东北部海域80个表层沉积物样品进行黏土矿物的相对含量分析.结果表明:东海东北部海域表层沉积物黏土矿物中伊利石(65.1%)含量最高,其次为绿泥石(26.6%)、高岭石(8.9%)和蒙皂石(4.3%);矿物组合中伊利石-绿泥石-高岭石-蒙皂石型占绝对优势,伊利石-绿泥石-高岭石型较少.由外陆架至冲绳海槽,伊利石含量分布呈低-高-低-高;绿泥石呈低-高-低;高岭石分布趋势明显异于伊利石和绿泥石,含量值分布出现由高到低的趋势;蒙皂石在个别区域缺失,高值区呈斑块状分布在水深小于100 m的外陆架.快速聚类分析显示,黏土矿物可分为"类长江"、"类黄河"和"类台湾"3种类型,呈4个区域相间展布."类黄河"型黏土矿物主要由黄海沿岸流将黄河、废黄河等物质再悬浮搬运而来,分布于29.5°N以北、127°E以西的外陆架区,并未越过东海外陆架进入冲绳海槽.外陆架区"类长江"型黏土矿物主要为低海平面时期古长江物质,并混有少量现代长江源悬浮物质;冲绳海槽区"类长江"型黏土矿物主要来自低海平面时期古长江物质."类台湾"型黏土矿物主要由黑潮控制,由台湾经冲绳海槽南部搬运而来,沿陆坡附近沉积.

The relative contents of clay minerals in 80 surface sediment samples were analyzed by X-ray diffraction.The results showed that the content of illite(65.1%)was the highest in the surface sediment clay minerals in the northeastern part of the east China sea,followed by chlorite(26.6%),kaolinite(8.9%)and smectite(4.3%).In mineral assemblages,illite-chlorite-kaolinitesmectite type is dominant,while illite-chlorite-kaolinite type is less.From the outer shelf to Okinawa Trough,the distribution of illite content was low-high-low-high.Chlorite distribution was low-high-low.The distribution trend of kaolinite is obviously different from that of illite and chlorite.The smectite was absent in some areas and the high value area was patchy in the outer shelf with water depth less than 100 meters.Fast clustering analysis shows that clay minerals can be divided into three types:Yangtze River-like,Yellow River-like and Taiwan-like,which covered in four regions.The"Yellow River-like"clay minerals are mainly transported from the Yellow River and the abandoned Yellow River by the coastal current of the Yellow Sea.They are distributed in the outer shelf area north of 29.5°N and west of 127°E,and don’t cross the East China Sea shelf into the Okinawa Trough.The"Yangtze-like"clay minerals covered in the outer continental shelf were mainly paleo-Yangtze materials in the low sea level period,mixed with a small amount of suspended materials from the modern Yangtze River.The"Yangtze-like"clay minerals covered in the Okinawa Trough were mainly derived from the paleo-Yangtze materials in the low sea level period.The"Taiwan-like"clay minerals are mainly controlled by the Kuroshio,which are transported from Taiwan through the southern Okinawa Trough and deposited along the continental slope.