滇中昆阳群中典型铅锌矿床地球化学特征对比分析

发布时间：2018-05-26 00:00

本文选题：矿床地质特征 + 矿床地球化学　；参考：《昆明理工大学》2016年硕士论文

【摘要】：滇中前震旦系主要位于扬子地块西南缘,元谋—绿汁江断裂以东、普渡河—滇池断裂以西,岩浆活动强烈导致该区地壳结构复杂,具有“多层结构”的特点。据统计赋存在昆阳群中的铅锌矿床(点)有近二十余处,其赋矿地层主要为：大龙口组(Pt2d)、黑山头组(Pt2hst)、鹅头厂组(Pt2e)。本次研究工作在导师的指导下选定赋存于昆阳群中的典型矿床：大笑、热水塘铅锌矿床,深入实地进行了严谨的野外地质调查工作,通过典型矿床的成矿地质背景、矿床地质特征、流体包裹体特征、同位素地球化学、同位素年代学等方面的研究,并结合前人地质资料以及本次所测数据,总结出滇中前震旦纪铅锌成矿域内铅锌矿床(点)的空间分布、赋矿层位、赋矿岩性、成矿物质来源和成矿年代。本论文取得了以下主要结论：1.滇中前震旦纪地质构造、岩浆活动较为活跃,变质作用十分复杂,矿区铅锌矿体主要赋存在黑山头组(Pt2hst)、鹅头厂组(Pt2e)碳酸盐岩中,所选典型矿床矿体均呈现出似层状、脉状、透镜状产出的特点。2.所采集矿石中的矿物组分较简单,主要矿物为方铅矿、闪锌矿、黄铁矿、黄铜矿,次生矿物有：褐铁矿、铅矾、白铅矿等。经鉴定矿区内矿石的结构以自形、半自形、他形粒状结构,溶蚀残余结构,交代残余交叉结构,乳浊状结构为主；局部可见叶片状结构,变晶结构,压碎结构,填隙结构,固溶体分解结构；网状结构；偶见揉皱结构,胶结状结构,交代残余结构,嵌晶结构-交代溶蚀结构,包含结构。3.围岩蚀变主要以硅化、黄铁矿化和碳酸盐化为主,局部可见重晶石化和白云石化。4.大笑铅锌矿床与热水塘铅锌矿床硫、铅同位素均表现出多来源的特征：大笑矿石铅来源于地幔与造山带、热水塘矿石铅来源于上地壳与造山带,结合单矿物锶、钕同位素的研究表明,大笑、热水塘铅锌矿床成矿物质可能主要源自赋矿围岩的碳酸盐岩中或基底地层之中,而且有数据表明有深部的流体参与成矿。其所选典型矿床成矿年代大致相当于印支晚期—燕山早期之间。5.流体包裹体地球化学特征则表现出所选滇中前震旦纪铅锌矿床成矿流体为：中—低温、低盐度、中—低密度、地表浅层的特点。6.滇中地区铅锌矿床具有多期次、成矿物质多来源的特点,在印支期构造活动强烈作用下,使深部岩浆上侵,岩浆热液沿早期构造形成的裂隙运移,并对地层内的成矿物质进行萃取,在有利部位聚集成矿。
[Abstract]:The preSinian system in central Yunnan is mainly located in the southwestern margin of Yangtze block, east of Yuanmou-Luzhujiang fault and west of Puduhe-Dianchi fault. Magmatic activity strongly causes the crustal structure in this area to be complicated and has the characteristics of "multi-layer structure". According to statistics, there are more than 20 Pb-Zn deposits (points) in Kunyang Group. The main ore-bearing strata are: Pt2dPt2DU in Dalong mouth formation, Pt2hsti in Heshantou formation and Pt2etein in Yetouchang formation. Under the guidance of my tutor, this study selected typical deposits in Kunyang group: laughter, hot water pond lead-zinc deposit, and carried out rigorous field geological survey in the field, through the metallogenic geological background of typical deposits. Geological characteristics of ore deposits, characteristics of fluid inclusions, isotopic geochemistry, isotopic chronology and so on. The spatial distribution, ore-bearing horizon, ore-bearing rock, ore-forming material source and metallogenic age of lead-zinc deposits in the Precinian lead-zinc metallogenic region in central Yunnan are summarized. In this paper, the main conclusions are as follows: 1. The Precinian geological structure of central Yunnan is characterized by active magmatic activity and complex metamorphism. The lead-zinc orebodies in the mining area are mainly located in the carbonate rocks of the Keshantou formation (Pt2hsthe) and the Yetouchang formation (Pt2e). The orebodies of the selected typical deposits are laminar and vein-like. Characteristics of lenticular production. The main minerals are galena sphalerite pyrite chalcopyrite and secondary minerals such as limonite lead alum and white lead ore. The ore structures in the mining area are identified as self-shape, semi-automorphism, heteromorphic granular structure, dissolved residual structure, metasomatic residual cross structure, opacifying structure, locally visible vane structure, metamorphic structure, crushing structure, filling structure, etc. Solid solution decomposition structure; network structure; occasional crinkle structure, cemented structure, metasomatic residual structure, embedded crystal structure-metasomatic solution structure, including structure. 3. The main alteration of surrounding rock is silicification, pyrite and carbonization, barite and dolomitization. 4. The sulfur and lead isotopes of the Kuai lead-zinc deposit and the Yuantang lead-zinc deposit both show the characteristics of multiple sources: lead from the mantle and orogenic belt, and lead from the upper crust and orogenic belt from the Huantang ore, combined with strontium, a single mineral. The study of neodymium isotopes shows that the ore-forming material of the Yuantang lead-zinc deposit may originate mainly from carbonate rocks or basement strata of ore-bearing surrounding rock, and there are some data indicating that deep fluids are involved in mineralization. The metallogenic age of the typical deposit is approximately equal to that of the late Indosinian to the early Yanshanian. The geochemical characteristics of fluid inclusions show that the ore-forming fluids of the Precinian lead-zinc deposits in central Yunnan are: moderate-low temperature, low salinity, medium-low density, and shallow surface features .6. The Pb-Zn deposits in central Yunnan are characterized by multiple stages and multiple sources of ore-forming materials. Under the strong action of Indosinian tectonic activities, the deep magma is invaded and magmatic hydrothermal fluid migrates along the cracks formed by the early tectonics. The ore-forming materials in the strata are extracted and formed in favorable areas.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P618.4

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