滇西哀牢山构造岩浆岩带阿扎鲁花岗岩岩石地球化学特征及构造背景浅析

Geochemical Characteristics and Tectonic Setting of A Zhalu Granite in Ailaoshan Structure Magmatic Belt,Western Yunnan Province

阿扎鲁岩体分布于哀牢山构造岩浆岩带中,通过野外地质调查与岩体剖面测量、岩石样品采集分析、薄片显微镜下鉴定等手段与方法,对其野外地质特征、岩石学特征及岩石地球化学特征进行了系统研究,并探讨了其形成的构造环境。研究结果表明,阿扎鲁岩体的岩性为花岗岩,岩体分布明显受断裂控制;岩石局部可见后期变质的片岩及糜棱岩,岩石具浅层侵入的特点;阿扎鲁花岗岩的A/NCK多大于1.0,为铝饱和型;具有富硅钾、低钙、贫铁、镁、钛的特点,岩石为高钾钙碱性系列。其主量元素、微量元素及稀土元素地球化学特征均表明,该岩体形成于造山期碰撞后期的弧陆碰撞阶段。

A Zhalu granite is located in the Ailaoshan structure magmatic belt. The granite is studied in the aspects of its geochemical characteristics and tectonic setting. The study shows that its distribution is obvi-ously controlled by faults and the rock is characterized by shallow intrusion. Locally, the rock body is found with visible schist and mylonite of synantexis metamorphosed in the later period.. The A/NCK of A Zbalu granite is mostly more thanl, belonging to aluminum saturation. The granite has the characteristics of rich Si and K, low Ca, and poor Fe, Mg and Ti, indicating that it belongs to the high K Ca alkaline se- ries. The geochemical analysis of major elements, trace elements, and rare elements show that the rock was formed in the arc continent collision stage of late stage orogenic collision.