东海陆架边缘北部玄武岩的矿物及化学特征  

MINERALOGICAL AND CHEMICAL CHARACTERISTICS OF BASALTS FROM THE NORTHERN MARGIN OF THE CONTINENTAL SHELF IN THE EAST CHINA SEA

作　　者：曾志刚[1] 张松梅[2] 常丽华[2] 

机构地区：[1]中国科学院海洋研究所,青岛266071 [2]吉林大学,吉林130026

出　　处：《海洋地质与第四纪地质》2002年第3期47-52,共6页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金资助项目 (4 0 1760 2 0 ) ;国家重点基础研究发展规划项目 (G2 0 0 0 0 4670 3 )

摘　　要：对东海陆架边缘北部一个站位的玄武岩进行了镜下观测、XRD定量分析和电子探针分析。结果表明东海陆架边缘北部玄武岩斑晶主要由拉长石、贵橄榄石和普通辉石组成 ,其中 ,单斜辉石的结晶温度为 110 8.4 9℃ ,岩浆起源深度在 4 2 .9km以深。与冲绳海槽和琉球岛弧玄武岩相比 ,在斜长石 An值、辉石 Ca- Mg- Fe比例与橄榄石 Fo值上均有明显的不同 ,表明三地玄武岩在成因上有一定的差异。Mineral characteristics and mineral chemistry are studied by the microscope, XRD and microprobe analysis for basalt samples from the northern margin of the continental shelf in the East China Sea. The phenocrystal minerals of the basalt mainly consist of labradorstein, augite and chrysolite.Phenocryst accounts for 35% and matrix for about 60%.And An of plagioclase,Ca Mg Fe ratio of pyroxene and Fo of olivine in the basalt samples from the northern margin of the continental shelf in the East China Sea are very different from those of basalts in the Okinawa Trough and the Ryukyu Arc,indicating that basalt origins vary in the three areas.Through calculation,the crystallization temperature of augite is 1 108 49 ℃, the pressure when crystallizing is 1 30 GPa,and the corresponding oxygen fugacity is -8 69.With the help of microscopic observation,it is found that the crystallization sequence of the phenocrystal mineral is clinopyroxene→olivine→plagioclase.The calculated balance temperatures and pressures of olivine and melt mass are 1 011 85 ℃ and 1 24 GPa respectively,and those for clinopyroxene and melt mass are 1 346 ℃ and 1 39 GPa respectively.

关 键 词：玄武岩 矿物 化学特征 东海 陆架边缘 辉石 电子探针 XRD定量分析 

分 类 号：P736.3[天文地球—海洋地质] P588.145[天文地球—海洋科学]