冈底斯构造岩浆带中段措勤地区中新生代岩浆岩构造组合分析

在新一轮1:25万区域地质调查成果的基础上, 根据研究区岩浆岩的时空分布、产状、岩石学和地球化学特征以及形成的构造环境, 将其划分为6种岩石构造组合:①弧间扩张型组合; ②洋岛型蛇绿岩组合; ③岛弧与陆缘弧型组合; ④碰撞型组合; ⑤陆内俯冲、碰撞型组合; ⑥陆内拉张型组合.进而对构造岩浆组合的地球动力学机制进行了剖析, 尤其是对喜马拉雅中期的岩浆作用进行了深入探讨; 提出了冈底斯构造岩浆带是由俯冲型、碰撞型和隆升型岩浆岩组合成的复合体, 它们在空间上明显分带, 在时间上呈现由相对基性向酸性的演化趋势和规律. 

MESOZOIC-CENOZOIC TECTONIC MAGMATICPORTFOLIO ANALYSIS IN CUOQIN AREA OFTHE MIDDLE GANGDISE

On the basis of 1：250000 regional geological mapping in the blank areas of the Qinghai-Tibet Plateau, the magmatic rocks in Cuoqin area are divided into six kinds of petrotectonic assemblage through their time-spatial distribution, occurrence, petrology, geochemistry and tectonic settings as follows ： （ 1 ） the combination of inter-arc dilated, （2） the Oceanic-island ophiolite portfolio, （3） the portfolio of island and margin arcs, （4） the combination of collision-type, （5） the inland subduction and collisiontype combination, and （6） the intracontinental extensional type combination. Then, the geodynamic mechanism of tectono-magmatic portfolios, especially the mid-Himalayan magmatism, is discussed. It is proposed that the Gangdise tectono-magmatic belt is comprised by the subduction-, collision- and uplifttype magmatic rocks clearly zoned in space and evolution from base to acidic in time.