南通近海表层沉积物粘土矿物含量分布特征及物质来源

摘要

Clay components (<0.002 mm)of 137 surface sediments in Nantong offshore areas were analyzed by XRD.The study was focused on clay assemblages,distribution pattern and provenance.The results show that illite (75.0% ranges from 70.6% to 80.3%)dominates in surface sediments of Nantong offshore areas with kaolinite (12.4% ranges from 9.8% to 14.9%)and chlorite(10.3% ranges from 8.1 to 12.4%)as the second and smec-tite (2.3% ranges from 0 to 4.0%)the lowest.The assemblage of illite-kaolinite-chlorite-smectite is the main type of the clay minerals assemblage in the area,followed by illite-kaolinite-chlorite assemblage.Clay minerals in the surface sediments of Nantong were mostly terrigenous materials and provided by the northeastward extension of Changjiang dilute water.%应用 X 射线衍射（XRD）方法对南通近海137个表层沉积物＜0．002 mm 的粘土组分进行分析，研究了南通近海表层沉积物中粘土矿物的组合特征、分布规律以及物质来源．结果表明，研究区粘土矿物中伊利石相对百分含量最高（70．6％～80．3％，平均值为75．0％），高岭石（9．8％～14．9％，平均值为12．4％）和绿泥石（8．1％～12．4％，平均值为10．3％）次之，蒙脱石含量最低（0～4．0％，平均值为2．3％）；粘土矿物组合类型以伊利石-高岭石-绿泥石-蒙脱石型为主，伊利石-高岭石-绿泥石型次之．南通近海表层沉积物中粘土矿物主要为陆源成因，春夏季（5～9月）东北向扩展的长江冲淡水为研究区提供物源．