东昆仑热水钼矿区似斑状黑云母二长花岗岩元素地球化学及年代学研究  

Geochemical characteristics and geochronology of porphyroid biotite monzogranite from the Reshui Mo polymetallic deposit,East Kunlun Mountains

作　　者：国显正 贾群子[2] 李金超[2] 孔会磊[2] 栗亚芝[2] 许荣科[1] 南卡俄吾 

机构地区：[1]中国地质大学(武汉)地质调查研究院,湖北武汉430074 [2]中国地质调查局西安地质调查中心,陕西西安710054 [3]陕西省土地工程建设集团有限责任公司,陕西西安710075

出　　处：《中国地质》2016年第4期1165-1177,共13页Geology in China

基　　金：中国地质调查局地质调查项目(12120113029000;12120115021501;DD20160013)资助~~

摘　　要：热水钼矿区处于东昆仑造山带东段,大地构造位置位于北昆仑岩浆弧,区内侵入岩较发育,其中与热水钼多金属矿密切相关的矿化似斑状黑云母二长花岗岩岩相学及地球化学数据显示,Si O2含量在67.64%~71.09%,铝饱和指数（A/CNK）为0.86~1.11,为准铝质到过铝质,K2O/Na2O值1.35~2.32,里特曼指数为1.73~1.99,属于高钾钙碱性I型花岗岩。岩石总体上富集大离子亲石元素Rb、Th、U、K、Pb等,明显亏损高场强元素Ta、Nb、Ce等,贫P、Ti。稀土元素总量（ΣREE）为94.27×10^-6~127.44×10^-6,平均为110.92×10^-6,稀土元素配分曲线呈右倾型,具有较明显的轻稀土富集、重稀土亏损的特征,弱到中等程度的负铕异常。LA-ICP-MS锆石U-Pb年龄为（230.9±1.4）Ma,形成于印支期,钼多金属矿与这一时期岩浆活动密切相关。综合分析表明,似斑状黑云母二长花岗岩形成构造体制转换阶段,在热水地区具有寻找斑岩型矿床潜力。The Reshui Mo polymetallic deposit is located at the North Kunlun magmatic arc, where lots of intrusive rocks occur. Geochemical data reveal that the porphyroid biotite monzogranite from East Kunlun is rich in silicon （67.64%- 71.09%）, Al2O3 （13.8%-14.57%）,Na2O（2.23%-3.02%）,and K2O（3.95%-5.18%）,with ratios of K2O/Na2O being 1.35-2.32 and A/CNK being0.86- 1.11,1.01 on average, suggesting that the granite should belong to high potassic calc- alkaline and I type granite. Theporphyroid biotite monzogranite is intensively depleted in HFSE （Ta, Nb, mCe）, enriched in LILE （Rb, Th, U, K, Pb）, and poor in P,Ti. The total rare earth elements （Σ REE） are 94.27 ×10^- 6-127.44 ×10^- 6, with an average of 110.92×10^- 6. The rare earth elementdistribution curve shows the right-inclined type, and has characteristics of obvious enrichment of light rare earth and depletion ofheavy rare earth elements. LA-ICP-MS zircon U-Pb dating shows that the formation age of the rock is （230.9±1.4） Ma, belongingto Indosinian stage. The molybdenum polymetallic deposit is closely related to the magmatic activity during this period. Based ontectonic history and the structure environment in combination with the geochemical characteristics, the authors hold that theporphyritic biotite monzonitic granite of the Reshui deposit was formed at the structural transformation stage, and Rershui area haspotential for finding porphyry deposits.

关 键 词：似斑状黑云母二长花岗岩 地球化学 锆石U-PB定年 热水钼矿区 

分 类 号：P588.121[天文地球—岩石学] P597[天文地球—地质学]