沱沱河地区多才玛铅锌矿床矿化富集规律及矿床成因

发布时间：2018-02-23 21:33

  本文关键词： 沱沱河地区 多才玛矿床 中低温热液脉型矿床 矿床成因 矿化富集规律　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：在沱沱河地区,多才玛铅锌矿床是近年来新发现的超大型矿床。据最新的报告显示,矿体储量已经超过600万吨,并且找矿潜力仍有待挖掘。但是目前矿床类型尚存争议,矿化富集规律不明,这些因素严重制约了下一步的找矿工作。因此急需对该矿床进行系统且全面的研究,旨在为沱沱河地区找矿突破提供新的资料。本文基于野外的实地考查,结合沱沱河地区的区域地质背景、对多才玛矿区的地质特征和矿体特征进行了详细的研究,并进行了构造地质学、流体地质学、地球化学等方面的研究,查明了矿体特征、流体特征和演化规律,矿化富集规律并确定了矿床成因。多才玛铅锌矿床大地构造分区属于青藏高原上羌塘地块的东北部,北部是松潘-甘孜地块,南部是拉萨地块,区域上NWW向的大型断裂构造带主导着矿体的形成与展布。矿体主要赋存在九十道班组,其次是沱沱河组和五道梁组,岩性主要为碎屑灰岩、泥晶灰岩和粉砂岩中。矿体呈脉状和透镜状产于北西西向的张性的构造破碎带内。南北向的断裂构造切断矿体,造成差异性抬升的现象。矿石矿物主要以方铅矿、闪锌矿、黄铁矿和黄铜矿为主,脉石矿物主要以方解石、石英和重晶石为主,矿石的结构主要是粒状结构、碎裂结构和交代结构,矿石构造主要是块状构造、脉状构造和浸染状构造。矿体和赋矿围岩的碳酸盐化、硅化和重晶石化明显,体现了中低温热液蚀变的特征。成矿可以大致分成以下3个阶段,石英-黄铁矿阶段,玉髓—重晶石—碳酸盐—方铅矿阶段,碳酸盐-石膏阶段。流体包裹体的测温结果显示多才玛矿区主要以气液两相的盐水溶液包裹体为主,成矿流体具有中低温(108～423.6℃)、中低盐度(1.2～17.1%)、中低密度(0.58g/cm3～1.03g/cm3)的特征,从早到晚温度、压力和盐度逐渐降低,成矿晚期流体有大气降水的参与,主成矿压力范围9.87～26.03MPa,成矿深度0.99～2.60km。碳氧同位素结果表明起源于深部的流体在上升的过程中与围岩发生了水岩反应。硫同位素特征表明成矿流体主要来自岩浆热液和地层硫的细菌还原作用。铅同位素结果表明,铅具有混合铅特征,以壳源铅为主混合少量深源地幔铅。成矿流体温度逐渐降低,不同流体的混合以及以灰岩为主的围岩消耗掉H+使得成矿流体PH增加是成矿物质卸载沉淀成矿的主要机制。综合分析认为,多才玛铅锌矿床属于中低温热液脉型矿床,成矿时间在40～20Ma之间,晚于区域逆冲推覆构造的形成时间,成矿构造背景是印度-亚洲大陆的晚碰撞阶段。
[Abstract]:In Tuotuohe area, the Duocima Pb-Zn deposit is a newly discovered superlarge deposit in recent years. According to the latest report, the ore body reserves have exceeded 6 million tons, and the prospecting potential is still to be excavated. However, the type of deposit is still controversial. The regularity of mineralization and enrichment is unknown, these factors seriously restrict the next prospecting work. Therefore, it is urgent to carry out systematic and comprehensive research on the deposit, in order to provide new information for the breakthrough of prospecting in Tuotuohe area. This paper is based on field investigation in the field. Combined with the regional geological background of Tuotuo River area, the geological characteristics and orebody characteristics of Duocima mining area are studied in detail, and structural geology, fluid geology, geochemistry and other aspects are studied, and the orebody characteristics are found out. Fluid characteristics and evolution rules, mineralization and enrichment rules, and the genesis of the deposit have been determined. The tectonic zoning of the Docima Lead-Zinc deposit belongs to the northeast of the Qiangtang block on the Qinghai-Xizang Plateau, the Songpan-Ganzi block in the north and the Lhasa block to the south. The formation and distribution of orebodies are dominated by the large fault structural belts of NWW direction in the region. The orebodies mainly occur in the 90 Daban formation, followed by Tuotuohe formation and Wudaoliang formation, and the lithology is mainly clastic limestone. In mudstone and siltstone, the orebody is veined and lenticular in the extensional structural fracture zone of NW direction. The fault structure of the north and south direction cuts off the orebody, which results in the differential uplift. The ore minerals are mainly galena and sphalerite, the main ore minerals are galena and sphalerite, and the ore minerals are mainly galena and sphalerite. Pyrite and chalcopyrite are dominant, gangue minerals are mainly calcite, quartz and barite, ore structure is mainly granular structure, cataclastic structure and metasomatic structure, ore structure is mainly block structure. Vein structure and disseminated structure. Carbonation, silicification and barite formation of orebody and ore-bearing rock show the characteristics of hydrothermal alteration at middle and low temperature. Ore formation can be divided into the following three stages, quartz pyrite stage. The temperature measurement results of fluid inclusions show that the fluid inclusions are mainly composed of gas-liquid two-phase saline solution inclusions in the chalcedone-barite-carbonate-galena stage, carbonate gypsum stage, and carbonate-gypsum stage, and the temperature measurement results of fluid inclusions show that the fluid inclusions are mainly gas-liquid brine solution inclusions. The ore-forming fluid has the characteristics of moderate and low temperature (108U 423.6 鈩，

本文编号：1527721