内蒙古东升庙矿区变质火山岩的地质地球化学特征及其意义

Geological and Geochemical Characteristics of Metamorphic Volcanic Rocks of the Dongshengmiao Ore District,Inner Mongolia and its Significance

为探讨东升庙矿区变质火山岩的地质地球化学特征及其意义,本文对其产出特征、岩石学、岩石化学、地球化学和同位素等方面进行了综合分析研究。结果表明,矿区变质火山岩为一套以玄武岩为主的双峰式火山岩,其原岩为基性的玄武岩和酸性的流纹岩。玄武岩属碱性玄武岩,流纹岩属钙碱性系列,它们具有与火山弧火山岩相似的地球化学特征。基性火山岩的稀土元素分配型式和Nd同位素特征表明其成岩物质来源于(亏损)地幔。构造环境分析表明,矿区变质火山岩的构造环境为大陆边缘火山弧造山带。

In order to investigate the geological and geochemical characteristics of metamorphic volcanic rocks of Dongshengmiao ore district and its significance, this paper studied the occurrence characteristics, petrology, petrochemistry, geochemistry and isotopes of metamorphic volcanic rocks. The results showed that the metamorphic volcanic rocks were bimodal volcanic rocks, and its primary rocks were the alkali-basalt and the calc-alkaline rhyolite which both had the similar geochemical characteristics with those of the volcanic arc volcanic rocks. The model of rare earth element （REE） and Nd isotope geochemical characteristics of the basaltic volcanic rocks showed that its rock-forming elements came from depleted mantle. On the basis of researches of the rock--forming environment and the regional geology, it was confirmed that the metamorphic volcanic rocks of Dongshengmiao ore district was formed in continental marginal volcanic arc orogenic belt environment.