云南省卓潘碱性杂岩体矿物学、地球化学特征及其地质意义

卓潘杂岩体是金沙江—哀牢山富碱侵入岩带的重要组成部分，位于兰坪盆地西部。岩体主要由辉长岩、辉石岩及正长岩组成，各岩石的K2O含量为096%～736%，Na2O含量为052%～662%，Na2O+K2O含量为198%～897%，K2O/Na2O比值介于035～1115之间，属于高钾、富碱的钾玄岩系列。岩石中的辉石为透辉石，长石主要为钠长石(An＜5)和正长石，黑云母为镁质黑云母。计算获得辉石的结晶温度范围介于1 070～1 490 ℃之间。各矿物成分特征表明卓潘杂岩体属于富铁、高氧逸度的岩浆体系，形成于后碰撞的挤压环境向伸展环境转换的构造背景。

Mineralogical and Geochemical Characteristics of the Zhuopan Alkaline Complex in Yunnan Province and Their Geological Significance

The Zhuopan alkaline complex is located in the western Lanping basin and is an important part of the Jinshajiang Ailaoshan alkali rich intrusion belt. The Zhuopan alkaline complex is mainly composed of gabbro, pyroxenolite and syenite,and their K2O contents of the whole rock vary from 198% to 897%; the Na2O contents are from 052% to 662%, the Na2O+K2O contents are from 198% to 897% and the K2O/Na2O ratios change between 035 and 1115, indicating that they belong to the high K, alkali rich shoshonite series.Electron microprobe analysis(EMPA)indicates that the pyroxene is dominated by the diopside; the feldspar is mainly albite (An<5) and orthoclase feldspar; and biotite is Mg biotite in the complex rock.Pyroxene thermometer calculation shows that the crystallization temperature was from 1,070 to 1,490 ℃.According to the geochemical characteristics of the different rocks and minerals,we deduce that the Zhuopan alkaline complex was sourced from a magmatic system with high oxygen fugacity and iron content and formed in a transition tectonic setting changing from post collisional compression to extensional environment.