【摘要】 华南地区产于震旦纪地层中的火山岩主要见于震旦纪裂谷盆地两侧的边缘，湖南新化和广东高思火山岩为其中的二个发育地区，镜下鉴定为玄武岩系。在ＳｉＯ２－Ｋ２Ｏ＋Ｎａ２Ｏ的分类图中主要为玄武岩类，有一样品为碧玄岩类，含有较多石英杏仁体玻璃质火山岩角砾的样品为玄武质安山岩类。在ＦｅＯ＊－Ｎａ２Ｏ＋Ｋ２Ｏ－ＭｇＯ三角图中所有样品均为拉斑质岩系。样品的重元素丰度模式具大陆－初始裂谷－Ｅ－ＭＯＲＢ拉斑玄武岩的过渡特征，在Ｎｂ、Ｚｒ、Ｙ、Ｔｉ图上属板内环境。在ＴｉＯ２－Ｋ２Ｏ－Ｐ２Ｏ５三角图上显示以大洋环境为主、大陆环境为次。湖南新化拉斑玄武岩的Ｓｍ、Ｎｄ同位素特征反映岩浆来源于亏损的地幔，并受到了老基底的污染。更多还原

【Abstract】 The volcanic rocks, developed in Sinian terrigenouse clastic strata, were located at the margins of Sinian rift basin in South China. The volcanic rocks in Xinghua, Hunan and Gaosi, Guangdong being two of them are basalt under microscopy. Almost all of samples are mainly basalt in the SiO 2 K 2O+Na 2O diagram, except that one is basanite and two are basaltic andesite that contains some rubbles of vitreous volcanic rocks with quartz amygdale, and all of them are tholeiitic in the FeO * Na 2O+K 2O MgO diagram. The H element abundances of samples have transitional features of continental, initial rifting and E MORB tholeiites being intraplate type in the Nb、Zr、Y、Ti diagrams. They are mainly oceanic and fewer are continental in TiO 2 K 2O P 2O 5 diagram. The tholeiitic basalts in Xinghua, Hunan are derived from depleted mantle with contamination of Pre Sinian basement based on Sm Nd isotopic characteristics.更多还原