江西、福建火山碎屑(斑)熔岩的岩石化学特征及成因探讨

PETROCHEMICAL FEATURES AND ORIGIN OF THE CLASTOLAVA IN JIANGXI AND FUJIAN PROVINCES OF SOUTHEASTERN CHINA

在我国东南部的中生代火山岩中,广泛分布着一种成因特殊的中酸性火山岩——碎屑熔岩,含矿性好,常为U、Cu、Pb、Zn和稀土的找矿标志,笔者对已有的化学分析数据作了处理。从岩石化学特征来看,赣闽两省的火山碎屑熔岩有相似的物质来源和岩浆演化趋势,但赣的来源略深。这些差异还表现在矿物组合和化学成分上。通过计算,得出岩浆房顶部深1.6km,形成温度为1200～1300℃。从岩石特征分析,笔者认为两省碎屑熔岩的成岩过程和成因环境是相似的。

A special genetic mid-acid volcanic rock——clastolava which belongs to Meseozoic era is widely distributed in the southeastern part of China.The mineral-containing property of volcanic lastic rock is good and it is often the mineral-looking symbols of U.Cu.Pb.Zn and rare earth.The author handled with the given data of chemical analysis.From the point of chemical features of rock,there is similar tendency of magmatic evolution and source material between the volcaniclastic rocks of Jiangxi and Fujian provinces,nevertheless magma source of the Jiangxi Province is deeper than the Fu- jian.There are also differences in mineral compositon and chemical components.It is concluded from calculation that the top of magma chamber is about 1.6 km deep,the temperature of rock forming is 1200~1300℃.Analysing from the features of rock,the author believed that the clastolavas of Jianxi and Fujian have had similar genetic environment and magma origin.