滇东南薄竹山花岗岩岩石学及其稀土-微量元素地球化学  

Petrology and REE-Trace Element Geochemistry of Bozhushan Granite Pluton in Southeastern Yunnan Province,China

作　　者：解洪晶[1,2] 张乾[1] 祝朝辉[1,2] 范良伍[1,2] 王大鹏[1,2] 

机构地区：[1]中国科学院地球化学研究所,贵州贵阳550002 [2]中国科学院研究生院,北京100049

出　　处：《矿物学报》2009年第4期481-490,共10页Acta Mineralogica Sinica

基　　金：国家重点基础研究发展计划项目(2007CB411408);中国科学院重要方向项目(KZCX2-YW-111)

摘　　要：薄竹山花岗岩体分两期侵入,第一期岩石类型主要为中粒黑云母二长花岗岩,SiO2含量介于64.82%～72.01%,平均68.72%,总碱度K2O+Na2O=5.51%～8.2%,平均6.92%,A/CNK平均1.14,富集Rb、U、Th等微量元素和轻稀土元素,中等的Eu负异常,δEu=0.37～0.55,属过铝质花岗岩,主要形成于同碰撞阶段;第二期主要为细粒二长花岗岩,SiO2含量变化范围75.94%～76.89%,平均76.33%,总碱度K2O+Na2O=7.58%～8.82%,平均8.22%,A/CNK-A/NK图上主要落在准铝质范围,微量元素Nb、Ta、Y富集,显著亏损Sr、Ba,强烈的Eu负异常,δEu=0.06～0.11,形成于板内的伸展环境。第二期花岗岩Ba、Sr亏损明显,这与强烈的Eu负异常相对应,说明第二期花岗岩经历了高度演化。Bozhushan granite comprises two intrusive bodies. The first intrusion is dominated by medium grained bio- tite monzogranite. Their SiO2 and total alkaline contents are in the ranges of 64. 82% -72. 01% （average 68.72% ） and 5.51% -8. 2% （average 6. 92% ）, respectively. The rocks display positive Rb, U, Th, and LREE, and medium strong negative Eu anomalies （δEu = 0. 37 - 0. 55 ）. Most of rocks belong to peraluminous（ average A/CNK = 1.14） granite and generated in syn-collisional setting. The second intrusion mainly consists of fine grained monzogranite, most of which belongs to metaluminous rocks and is characterized by high SiO2 （75.94% -76. 89% ） and total alkaline （7. 58% -8.82% ）. These rocks are enriched in Nb, Ta, Y, and significant depleted in St, Ba, and Eu （ δEu = 0. 06 - 0. 11 ）. This intrusion is formed in an extensional setting. Compared with the first intrusion, the second is mostly depleted in Ba, Sr, and Eu, indicating the higher evolvement.

关 键 词：花岗岩 岩石学 地球化学 薄竹山岩体 滇东南 

分 类 号：P581[天文地球—岩石学] P595[天文地球—地质学]