云南省麻栗坡县南温河钨矿矿床地质特征及成因探讨

发布时间：2018-04-29 12:30

本文选题：南温河 + 矽卡岩　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：云南麻栗坡县南温河白钨矿床是近年发现的超大型钨矿床,位于麻栗坡县南西方向,呈似层状产出于元古代区域变质岩地层中。该区的地质环境较为复杂,前人对矿区的矿床成因仍存在着较大争议。本文通过较为深入的矿区考察、详细的岩相学分析、精确的地球化学测试以及年代学研究,较为系统地总结了该矿区含白钨矿的赋矿岩石的矿物生成顺序、变质岩的变质等级等,并进行了矿床成因探讨。通过对该区区域变质岩的研究,广泛分布于区内的二云石英片岩作为含矿矽卡岩的围岩出现,其原岩为砂质岩和杂砂岩。区别于含白钨矿矽卡岩的原岩具有钙质岩石的特征。矿区赋矿岩石主要为矽卡岩和云英岩,根据矽卡岩中的矿物共生组合,将矽卡岩型白钨矿的成矿过程划分为3期5个阶段:(1)矽卡岩期,分为矽卡岩阶段和退化蚀变阶段;(2)云英岩期,分为早期的硅化阶段和晚期的云母阶段;(3)石英硫化物期,即石英硫化物阶段。通过观察发现两种岩石中都具有石英硫化物阶段,都在最晚的阶段形成,且都沿裂隙充填于早期矿物中。推测白钨矿主要形成于退化蚀变阶段和硅化阶段。结合野外观察和镜下看到的云英岩型和矽卡岩型两种类型的矿体的接触关系,再结合矿区中云英岩型白钨矿的成矿年龄在102 Ma左右的早白垩世,而同项目组人员的研究结果含白钨矿矽卡岩形成于距今155±0.96 Ma的晚侏罗世。可初步推断这两种类型的白钨矿为不同期次岩浆活动的产物,是燕山早期的岩浆熔体同化钙质岩石(推测有海相沉积的成分)并顺层侵入区域变质岩的裂隙中而形成的。
[Abstract]:Nanwenhe scheelite deposit in Malipo County Yunnan Province is a very large tungsten deposit discovered in recent years. It is located in the southwest direction of Malipo County and occurs in the metamorphic strata of the Proterozoic region. The geological environment in this area is complex, and there are still some controversies about the genesis of ore deposits. In this paper, the sequence of mineralogical formation of the scheelite bearing rocks in this area is systematically summarized through more in-depth investigation, detailed petrographic analysis, accurate geochemical testing and chronological study. The metamorphic grade of metamorphic rock and the origin of ore deposit are discussed. Through the study of the regional metamorphic rocks in this area, the Eryun quartz schist widely distributed in the area appears as the surrounding rock of skarn bearing ore, and its original rocks are sandstones and complex sandstones. The source rock, which is different from the skarn bearing scheelite, has the characteristics of calcareous rock. The ore-bearing rocks are mainly skarn and quartzite. According to the mineral symbiotic assemblage in skarn, the metallogenic process of skarn type scheelite is divided into 3 stages and 5 stages: 1) skarn. It can be divided into skarn stage and degenerative alteration stage, quartz sulfide stage, early silicification stage and late mica stage, I. E. quartz sulfide stage. It is found that both rocks have quartz sulphide stage, both of which are formed at the latest stage, and are filled with early minerals along the fissure. It is inferred that scheelite is mainly formed in the degenerative alteration and silicification stages. Combined with the contact relationship between the quartzite type and skarn type seen in the field and under the microscope, combined with the early Cretaceous of the metamorphic quartz type scheelite deposit at about 102 Ma in the ore area, However, the results of the same project team show that the skarn bearing scheelite was formed in the late Jurassic period 155 卤0.96 Ma ago. It can be preliminarily inferred that these two types of scheelite are the product of magmatic activity in different periods and formed by assimilating calcareous rocks (conjectured marine sedimentary compositions) from early Yanshanian magma melt and intruding into the fractures of regional metamorphic rocks.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.67

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