【摘要】 通过对野外地质特征、岩石学、矿物学、地球化学和同位素年代学的研究,对沙德盖岩体形成时代和形成构造环境进行了探讨。锆石U-Pb分析结果表明,206Pb/238U表面年龄统计权重平均值为198.5Ma,代表沙德盖岩体侵位时代。岩体位于印支期逆冲推覆构造的前缘挤压区,矿物学、岩石学和地球化学研究结果表明,该岩体为高钾钙碱性系列,属于造山后A型花岗岩。岩浆可能起源于由逆冲推覆构造加厚的地壳下部岩石的熔融,岩浆活动是印支运动的重要表现形式。更多还原

【Abstract】 The age and tectonic setting of the Shadegai pluton are discussed based on field investigation and the detailed petrological,mineralogical,geochemical and isotopic geo-chronological studies.Zircon U-Pb dating gives a weighted mean of 206Pb/238U apparent age of 198.5 Ma,which is interpreted to represent the emplacement age of the Shadegai pluton.The pluton was sited at the frontal compressive area of an Indosinian thrust nappe.The pluton is also concluded to be high-k calc-alkaline,post-orogenic A-type granite based on petrological,mineralogical and geochemical studies and on tectonic setting analysis.The thrusting-related thicken crust resulted in the melting and emplacement of the magmas responsible for the formation of the Shadegai pluton.Magmatic activity made up an important part of the Indosinian movement in the area.更多还原