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.
出处
《矿物学报》
CAS
CSCD
北大核心
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)
关键词
花岗岩
岩石学
地球化学
薄竹山岩体
滇东南
granite
petrology
geochemistry
Bozhushan granite
Southeastern Yunnan Province
