| 付治国.东天山东戈壁超大型钼矿床地质地球化学特征与成因分析[J].矿产勘查,2012,3(6):745-754 |
| 东天山东戈壁超大型钼矿床地质地球化学特征与成因分析 |
| Geological,geochemical characteristics and genesis of super-large size Dong Gobi molybdenum deposit in eastern Tianshan, Xinjiang |
| 投稿时间：2012-05-08 |
| DOI： |
| 中文关键词: 东天山 斑岩型钼矿床 矿床地球化学 综合异常 矿床成因 新疆哈密 |
| 英文关键词: eastern Tianshan porphyry molybdenum deposit deposit geochemistry integrated anomaly deposit genesis Hami, Xinjiang |
| 基金项目: |
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| 中文摘要: |
| 新疆哈密东戈壁超大型钼矿床是2006—2011年发现并探明的超大型钼矿床。赋矿围岩是下石炭统干墩组地层,为斑岩型钼矿床。成矿母岩为斑状花岗岩,其岩石化学特征:SiO2为74.42%、K2O/Na2O为1.71、K2O+Na2O为7.54%(高碱)、K2O 4.76%(高钾)、里特曼指数为1.81；A/NCK值在0.95～1.16之间,平均值为1.06,显示铝饱和。稀土总量132×10-6,LREE/HREE比值为1.9～2.9,平均2.2,轻稀土略显富集。δEu为0.289,铕强烈亏损,显示壳源型特征,岩石稀土地球化学分类属S型花岗岩类。斑状花岗岩δ18O值为10.5‰～12.5‰,石英脉中流体包裹体压力平均值为531.04×105～752.10×105 Pa,成矿深度范围1.68～2.39 km。斑状花岗岩锆石U-Pb年龄测定结果为(227.6±1.3) Ma,为晚三叠世,东戈壁斑岩型钼矿床形成于印支期。 |
| 英文摘要: |
| The super-large size Dong Gobi ( i.e., Hami, Xinjiang ) molybdenum deposit in the eastern Tianshan Mountain is discovered and explored in the period from 2006 to 2011 and rank one of the top ten largest molybdenum deposit in China. The country rocks are Gandun Group of Upper-Carboniferous System, and the host rock is the porphyritic granite. Thus Dong Gobi molybdenum deposit is recognized as heporphyry type deposit.The chemical compositions of the porphyritic granite are as followings:high SiO2(average 74.42%), high alkali (the average value of K2O+Na2O is 7.54%), high potassium (average K2O:4.76%) and the ratio of the K2O/Na2O is 1.71, the A/NCK value is between 0.95and 1.16, the average value is 1.06. The content of the REE is about 132×10-6 and the average value of the LREE/HREE is 2.2, it indicated that there is slight enrichment of the LREE.The porphyritic granite is strongly depleted in Eu and the δEu value is 0.289. All of these geochemical parameters imply that the porphyritic granite originated from the melt of the crust, and classified as S-type granite. According to the study results of the fluid inclusions, the δ18O value of the porphyritic granite is between 10.5‰ and 12.5‰, it is predicted that the deposit was formed at the pressure between 531.04×105 Pa and 752.10×105 Pa, equal to the crust depth of 1.68～2.39 km. Based on the measurement of U-Pb isotope of the zircon mineral from the porphyritic granite, the host rock is formed around 227.6±1.3Ma, equal to Late Triassic epoch, therefore, it is predicated that the porphyritic mineralization occurred in Indonian period. |
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