云南省景谷岔河地区火山岩及其构造环境  

CHARACTERISTICS AND TECTONIC ENVIRONMENT OF THE VOLCANIC ROCKS OF CHAHE AREA IN JINGGU,YUNNAN PROVINCE

作　　者：张保民[1] 沈上越[1] 莫宣学[1] 张志斌 张虎 

机构地区：[1]中国地质大学,湖北武汉430074 [2]云南省地质调查院区域地质调查所,云南玉溪653100

出　　处：《地质科技情报》2004年第1期5-10,20,共7页Geological Science and Technology Information

基　　金：中国地质调查局项目"1:25万临沧县幅滚龙幅区域地质调查"(1991300010161);国家自然科学基金资助项目(40372027);国家自然科学基金资助项目(40372105)

摘　　要：岔河地区火山岩属三江构造带澜沧江构造岩浆带的南段。晚二叠世在岔河一带喷发了一套安山岩—流纹岩与粗面岩组合的杂色火山岩系。熔岩普遍为斑状结构,斑晶为斜长石和角闪石。以钙碱性和碱性岩为主,其次是拉斑玄武岩系。据CIPW计算,除碱性岩系外,均含标准石英分子。稀土元素分配模式为无Eu异常的富轻稀土右倾型。微量元素分配形式为亏损P、Ti元素的锯齿状。w(Zr)/w(Y)值大于3.5,w(Ti)/w(Y)值小于500,W(TiO2)平均为0.82%。岩浆来源深度为138km。表明岔河地区火山岩属大陆边缘弧构造环境的产物。The volcanic rocks of Chahe area present in the south of the Lancangjiang magma tectonic zone of the Sanjiang(Jinshajiang,Lancangjiang and Nujiang in China) tectonic belt.A series of the volcanic rocks consisting of andesites-rhyolites and trachites,were extruded in the Chahe area in the Late Permian period.The porphyitic crystals that are plagioclases and amphibales occur in nearly all the lava of volcanic rocks.The volcanic rocks are mostly calc-alkalic and alkalic series with a small amount of tholleiitic series in the rock chemistry.According to the computation of CIPW of volcanic rock,most rocks have standard quartz molecules.The distribution model of REE is right abligue in the orientation,and the Eu element is non abnormal in the abundance.While the distribution model of the trace element is the sawtooth according to Seviell.The P and Ti elements are rare in comparison with mantle-derived rocks.The ratio of w(Zr)/(w(Y)) and w(Ti)/w(Y) is bigger than 3.5 and smaller than 500.w(TiO_2), (0.82) percent on the average.The depth of the magma basin is 138 km.It is suggested that the volcanic rocks in the Chahe area,Jinggu,Yunnan Province should belong to the outcome of continetal margin tectonic environment.

关 键 词：火山岩 大陆边缘孤 构造环境 云南景谷岔河地区 地质构造 

分 类 号：P588.14[天文地球—岩石学]