腾冲马鞍山、打鹰山、黑空山火山岩浆来源与演化  

Magma origin and evolution of Maanshan volcano,Dayingshan volcano and Heikongshan volcano in Tengchong area

作　　者：赵勇伟[1] 樊祺诚[1] 

机构地区：[1]中国地震局地质研究所,北京100029

出　　处：《岩石学报》2010年第4期1133-1140,共8页Acta Petrologica Sinica

基　　金：地震行业科研专项(0827)资助

摘　　要：本文对马鞍山、打鹰山、黑空山火山岩主微量和Sr、Nd、Pd同位素地球化学研究认为,腾冲火山岩浆源区具有MORB与富集地幔混合之特征,推测为新特提斯俯冲洋壳重新熔融,导致腾冲地区的高钾钙碱性岩浆的火山活动,解释了腾冲在新生代大陆板内构造环境背景下出现岛弧或活动大陆边缘火山岩地球化学特征的现象。马鞍山、打鹰山和黑空山火山高钾钙碱性岩浆经历了岩浆房阶段辉石、钛铁矿的结晶分离作用和岩浆上升过程中斜长石的结晶分离作用,导致岩浆成分从中基性向中酸性演化,火山岩从玄武质粗安岩→粗安岩→粗面质英安岩演化。On the basis of studies of major elements,trace elements and strontium,neodymium and lead isotopic compositions of Maanshan,Dayingshan and Heikongshan volcanic rocks,it is thought that the magma source of Tengchong volcanoes is the mixture of mid-ocean ridge basalts(MORB) and enriched mantle.It is deduced that the Neotethys subducted ocean crust refused;hence volcanoes were activated with high potassium calc-alkaline magma.This explains why volcanic rocks with geochemical characteristics which suggest tectonic settings of island arcs or active continental margins appeared in the intra-plate background.The magma of Maanshan,Dayingshan and Heikongshan endure crystal fractionation of pyroxene and ilmenite at the chamber stage and plagioclase fractionation at the ascending stage,which induced the magma evolving,from intermediate-basic magma to intermediate-acidic magma, and lava evolving by the course of basaltic trachyandesite-trachyandesite-trachydacite.

关 键 词：高钾钙碱性火山岩 岩石地球化学 新特提斯俯冲洋壳重熔 岩浆演化 腾冲 

分 类 号：P588.14[天文地球—岩石学]