滇东南南秧田白钨矿床电气石石英岩的成因研究

发布时间：2018-03-16 02:33

  本文选题：滇东南　切入点：南秧田　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：南秧田矿床位于“越北地块”北部,是我国滇东南地区最大的以钨为主的金属矿床。矿区电气石石英岩(脉)大量发育并具广泛的白钨矿矿化,对矿区主矿体的叠加富集作用明显。本文以电气石着手,以南秧田白钨矿床中的条带状电气石石英岩和电气石石英脉为研究对象,通过详细的野外调查研究、岩相学研究、地球化学及B等同位素研究,结合电气石石英岩(脉)流体包裹体的资料,对电气石石英岩(脉)的流体性质、流体来源及矿床成因展开了深入研究。取得的主要成如下:1、针对电气石的成因矿物学、B同位素研究和其在矿床研究中的应用等三个方面,系统梳理和论述了电气石的研究进展。2、通过对南秧田矿区电气石的主量、微量和B同位素等地球化学研究,查明了矿区电气石的物质来源、B来源和成因。矿床电气石均属于碱性电气石中镁电气石,没有明显的光学分带和组成分带,以富Mg及Y位中无Al或低Al为特征,具有相对高的Fe O/(Fe O+Mg O)比值(0.46-0.65,平均0.53);稀土元素配分曲线与研究区内晚白垩纪老君山花岗岩稀土元素配分曲线接近;B同位素δ11B值与平均地壳的δ11B值非常接近(-10±3‰),集中在-14‰。这些特征与岩浆期后热液成因的电气石特征一致,为与老君山花岗岩有关的热液电气石,其B来源于贫Ca的变质泥岩、砂岩。3、厘定了矿区含矿电气石石英岩的流体性质。流体包裹体特征表明,其均一温度集中在250~340℃,盐度3~10 wt%Na Cleq;显示为中-高温、低盐度的成矿流体,推测其主要是演化的中-低盐度岩浆来源流体与低盐度大气降水混合的产物。4、肯定了晚白垩纪岩浆期后热液对矿区主矿体的叠加富集作用,认为晚白垩世(80-96Ma)华南西部与岩石圈伸展作用有关的成岩-成矿事件对本区钨矿形成具有重要影响。5、提出了距晚白垩纪花岗岩体中部距离为有利矿化区,电气石石英岩(脉)为寻找富矿体的重要标志,为矿区外围及深部勘查评价指明了找矿方向。
[Abstract]:The Nanyangtian deposit is located in the northern part of the "Yubei block", and is the largest tungsten deposit in southeast Yunnan of China. The tourmaline quartzite (vein) in the mining area is extensively developed and widely mineralized in scheelite. The superposition and enrichment of the main orebody in the mining area is obvious. In this paper, the tourmaline quartzite and tourmaline quartz veins in the southern Yangtian scheelite deposit are taken as the objects of study, and the detailed field investigation and petrographic study are carried out. Geochemistry and B isotopic studies, combined with the data of fluid inclusions in tourmaline quartzite (vein), are used to study the fluid properties of tourmaline quartzite (vein). The origin of fluids and the genesis of the deposit have been studied in depth. The main results are as follows: 1. Aiming at the mineralogical B isotope study of tourmaline and its application in ore deposit research, The research progress of tourmaline is systematically reviewed and discussed. 2. The main quantity, trace and B isotopes of tourmaline are studied in Nanyangtian mining area. The material source and origin of tourmaline in mining area have been found out. The tourmaline of ore deposit belongs to magnesium tourmaline in alkaline tourmaline. There is no obvious optical zonation and compositional zone, which is characterized by the absence of Al or low Al in rich mg and Y sites. The REE partition curve of Laojunshan granites in late Cretaceous is close to B isotope 未 11B and the average crustal 未 11B is very close to that of the average crustal 未 -10 卤3 鈥，

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