鲁西青山组火山岩形成的构造背景及其成因探讨:主元素和微量元素证据  

Tectonic setting and petrogenesis of Qingshan Formation volcanic rocks in western Shangdong Province: Evidence from major elements and trace elements

作　　者：刘 胡瑞忠[1] 赵军红[1] 冯彩霞[1] 

机构地区：[1]中国科学院地球化学研究所矿床地球化学重点实验室

出　　处：《地球化学》2003年第4期306-316,共11页Geochimica

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-102);国家杰出青年科学基金(49925309)

摘　　要：研究区内火山岩从基性—中性—中酸性都有出露,包括橄榄玄武岩、安山岩和英安岩,且都属于非碱性系列。通过对主元素和微量元素的研究,认为本区火山岩为滞后型弧(陆缘弧)火山作用的产物。源区由于存在大量的因俯冲作用进入地幔的陆壳物质以及流体的交代作用,从而出现富含金云母和不相容元素的交代富集型地幔源,并具有壳源的元素组成特征。火山岩的形成是富集地幔部分熔融的结果,但在成岩过程中可能存在单斜辉石、斜长石、橄榄石和Ti-Fe氧化物等矿物的分离结晶作用,以及橄榄石的堆晶作用。The volcanic rocks in the study area all belong to sub alkaline series including olivine basalt, andesite and dacite, from basic to intermediate, and to acid. By studying the characteristics of major and trace elements, we think it is the result of post collision arc (continental margin arc) volcanism, with the characteristics of within plate basalt. Because there are many continental crust minerals and the fluids coming from subducted sediments and lower mantle in upper mantle, contamination and metasomatism can take place in upper mantle, forming the enriched mantle source, which is enriched in phlogopite and incompatible elements, and posses the elemental characteristics of crustal source. The forming of the volcanic rocks is the result of the partial melting of the enriched mantle, however, there can exist fractional crystallization of clinopyroxene, plagioclase, olivine, Ti Fe oxide and other minerals and cumulation of olivine in the magma reservoir during the course of cooling.

关 键 词：鲁西青山组 火山岩 构造背景 岩石成因论 交代作用 熔融 岩相学 地球化学 

分 类 号：P588.1[天文地球—岩石学] P595[天文地球—地质学]