新疆巴里坤小加山地区钨矿床成矿规律及远景评价

发布时间：2018-02-27 04:07

  本文关键词： 小加山 石英脉型钨矿 成矿流体 地球化学 远景评价　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：小加山钨矿床位于新疆巴里坤地区,属石英脉型钨矿床。该区基础地质资料缺少,勘查工作程度低,成因研究薄弱,制约了成矿机理研究的深度。本文在地质特征基础上,对小加山钨矿床不同类型的含钨石英脉开展岩相学、流体包裹体研究,通过岩体地球化学特征讨论矿化蚀变特点,查明成矿流体来源,获得成因认识,分析成矿作用,总结成矿规律。矿区位于东准噶尔成矿区中部南缘,处于博格达-哈尔里克构造带上。构造位置上矿区处于哈尔里克复式背斜中,构造线方向以EW向为主。矿区出露地层主要为中泥盆统大南湖组第一亚组第一段(D2d11)、第二段(D2d12)。主要岩浆岩有石英闪长岩、黑云母花岗岩、钾长花岗岩及少量中酸性花岗闪长岩脉。矿体赋存于邻近海西晚期花岗岩侵入体附近的中泥盆统大南湖组第一亚组第二段(D2d12)的变质晶屑凝灰岩中。与成矿有关的小加山侵入岩体主要岩石类型为黑云母花岗岩,其围岩主要为蚀变闪长岩和变晶屑凝灰岩。该花岗岩属于高钾钙碱性准铝质—A型花岗岩,岩体均属于轻稀土富集型。微量元素特征揭示出岩浆成岩的过程中可能发生强烈地分离结晶作用,岩浆物质来源可能与富集岩石圈地幔有关。花岗岩为后碰撞伸展花岗岩区,岩体形成于伸展构造环境,是后碰撞环境下岩浆活动的产物。黑钨矿石英脉分为灰色含钨石英脉和白色含钨石英脉两种。岩相学观察含矿石英脉中流体包裹体主要为两相水溶液包裹体,EW走向的灰色石英脉包裹体气液比大,SN走向的白色石英脉包裹体气液比较小。显微测温结果显示灰色石英脉均一温度(Th)范围为143～354℃,白色石英脉Th范围为154～312℃。激光拉曼探针显示小加山钨矿含黑钨矿石英脉中流体包裹体含有少量CO2组分。H、O同位素研究表明：钨矿床成矿流体来源以岩浆水为主。成矿演化过程为：岩浆岩侵入活动→岩浆水运移分离→含钨络合物迁移搬运→冷却富集成矿,成矿晚期流体有大气降水的混合。受海西期构造活动影响,钨的花岗质岩浆自下而上发生侵入,花岗岩高度分异演化,冷凝后形成黑云母花岗岩,富含W元素岩浆热液过渡性流体沿裂隙向上流动,在上部地层中引发硅化和绢云母化,随着成矿流体温度降低,含钨络合物分解,形成了石英脉型黑钨矿床。结合钨矿床的矿物共生组合和围岩蚀变特征、成矿流体和岩浆作用等研究结果,认为小加山钨矿床与赣南钨矿构造环境具有相似性,可能存在“三层搂”结构,从而建立了成矿模式。进行了化探数据W、Mo含量等值线图分析,综合地质特征以及东南矿点和化工西矿区W、Mo含量等值线与异常带吻合区域,反映出东南矿点和化工西矿区深部和外围存在钨矿潜力很大。
[Abstract]:The Xiaojiashan tungsten deposit is located in the Balikun area of Xinjiang and belongs to the quartz vein tungsten deposit. The basic geological data are scarce, the exploration work is low and the genetic study is weak in this area, which restricts the depth of the study of metallogenic mechanism. The petrographic and fluid inclusions of different types of tungsten bearing quartz veins in the Xiaojiashan tungsten deposit are studied. Through the geochemical characteristics of the rock mass, the characteristics of mineralization and alteration are discussed, the source of the ore-forming fluid is found, the genetic understanding is obtained, and the metallogenic process is analyzed. The ore area is located in the southern margin of the middle part of the East Junggar metallogenic deposit, and is located in the Bogda-Halrick structural belt. The main direction of the tectonic line is EW. The exposed strata of the mining area are the first member of the first subformation of the Dananhu formation of the Middle Devonian, the first member of the first subformation, and the second stage of the second member of the D2d12. The main magmatic rocks are quartz diorite and biotite granite, and the main magmatic rocks are quartz diorite and biotite granite. Potassium feldspar granodiorite and a small amount of intermediate-acid granodiorite diorite. The orebody occurs in metamorphic tuff tuff of the first sub-formation of the Dananhu formation in the Middle Devonian near the late Hercynian granite intrusion. The main rock types of Xiaogashan intrusive body are biotite granite. The surrounding rocks are mainly altered diorite and metamorphic tuff. The characteristics of trace elements indicate that the magmatic diagenesis may have strong separation and crystallization, and the source of magmatic material may be related to the enriched lithospheric mantle. The granite is a post-collisional extensional granite area. The rock mass was formed in an extensional tectonic environment, The quartz vein of wolframite is divided into gray tungsten quartz vein and white tungsten bearing quartz vein. The gas-liquid content of gray quartz vein inclusions is smaller than that of white quartz vein inclusions with large SN strike. The results of microthermometry show that the homogenization temperature of grey quartz veins is in the range of 143 ~ 354 鈩，

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