苏北闵桥含油玄武岩中粘土矿物的组合特征及其应用

苏北闵桥地区含油玄武岩的主要次生蚀变粘土矿物为：皂石，绿泥石，蒙脱石，伊利石，伊利石／蒙脱石混层，高岭石，方沸石等，不同类型的玄武岩中粘土矿物组合不同，最具特征的组合为：致密玄武岩－皂石（为主）＋其它矿物；淬碎玄武岩－蒙脱石（为主）＋伊利石＋伊利石／蒙脱石混层＋高岭石，碎裂玄武岩－皂石（为主）＋绿泥石＋方沸石，蚀变玄武岩中，随着蚀变作用由弱到强，这些粘土矿物可以分成四个带，皂石带－绿泥石带－蒙脱石带－高岭石带，这种分带性与夏威夷玄武岩中热液成因的粘土矿物的分布性具有可比性，在一个玄武岩岩流单元不同部位，特征粘土矿物为：底部－蒙脱石；中倍位－皂石，顶部位－伊利石＋伊利石／蒙脱石混层，风化带特征粘土矿物为蒙脱石，少量高岭石，本文还对利用粘土矿物组合特征在玄武岩含油性，古地理及古环境等方面的应用进行了探讨。

The association characteristics and the applications of clay minerals from oil-bearing basalts in Minqiao area, northern Jiangsu province

The secondary alteration clay minerals are saponite, chlorite, montmorillonite, illite, mixed-layer illite-montmorillonite, kaolinite and analcite from oil-bearing basalts in Minqiao area ,northern Jiangsu. There are different association characteristics of clay minerals in various lithofacies-structural types of basalt. The typical associations are: saponite (major)+other clay minerals in dense basalts; montmorillonite (major)+illite+mixed-layer illite-montmorillinite+kaolinite in quench-fragmented basalts;saponite+ch1orite+analcite in broken basalts. In altered basalts, the clay mineral association may be divided into four zones with increasing intensity of alteration: (1)saponite zone, (2)ch1orite zone,(3)montmorillonite zone,(4)kaolinite zone.The zonation may be in compared with the clay mineral distributions from thermal liquid origin in Hawaii. In different positions of a basaltic lava-flow unit, the characteristic clay minerals are :montmorillonite in the bottom; saponite in the middle and illite+mixed-layer illite-montmorillonite in the top layer zone. In the weathered zone , clay minerals are mainly montmorillonite with less kaolinite. The paper also deals with the application of the association characteristics of clay minerals in researches of oil-bearing characteristics, palaeogeography and palaeoenvironment.