贵州盘县架底金矿地质地球化学特征初步研究

发布时间：2018-07-25 21:06

【摘要】：架底金矿位于扬子准地台西南缘与华南褶皱带接合部位的莲花山背斜南东翼北东向强构造变形区,是贵州省地质矿产勘查开发局一○五地质大队在贵州西部峨眉山玄武岩分布区继大麦地金矿之后新发现的又一个中型原生金矿床。本文在前人研究基础上,采用光薄片镜下鉴定、X射线荧光光谱、ICP-MS和Linkam THMSG600型冷-热台分别对架底金矿的矿床地质、元素地球化学特征和流体包裹体地球化学特征等进行研究,并与区内典型的水银洞金矿进行对比,探讨区域成矿模式及找矿前景,对区内原生型金矿找矿预测具有重要意义。通过研究取得了如下主要成果:(1)金矿体产出于茅口组与峨眉山玄武岩组之间的构造蚀变体(SBT)和峨眉山玄武岩组第二段火山碎屑岩中,容矿岩石主要为凝灰岩、玄武质凝灰岩和玄武质火山角砾岩。矿体呈似层状、透镜状,其形态简单—中等,矿体平均品位为3.17×10-6。(2)矿石结构主要有碎裂结构、半自形—它形结构和交代结构等;矿石构造主要有浸染状、块状、条带状和细脉状等。围岩蚀变主要以硅化、黄铁矿化为主,另有少量毒砂化、粘土化。(3)常量元素地球化学特征研究表明,该金矿石的常量元素地球化学特征与峨眉山玄武岩相似,可能与其容矿岩石为峨眉山玄武岩有关。(4)微量元素地球化学特征显示,矿石中Au、As、Sb、Hg、Tl相对围岩异常富集,反映Au、As、Sb、Hg、Tl为热液作用所带入。(5)稀土元素地球化学特征显示,矿石与围岩的REE含量和特征参数存在一定差异,但其球粒陨石标准化曲线则相当吻合,总体表现出负Ce异常、无明显Eu异常,富轻稀土、贫重稀土、配分曲线平缓右倾的特征,可能说明成矿流体尚未能导致岩石的稀土元素发生变化。(6)流体包裹体地球化学研究显示,成矿流体的均一温度范围为193~227℃,平均值为211℃、盐度变化为4.03~8.28wt%NaCl,平均值为6.3wt%NaC1、密度变化为0.87~0.92 g/cm3,平均值为0.9g/cm3,具中-低温度、低盐度和中等密度的特点。初步显示架底金矿具中-低温热液成矿的特征。(7)对比研究发现,架底金矿地质特征、地球化学特征与水银洞卡林型金矿相似,说明架底金矿与水银洞卡林型金矿可能具有相似的矿床成因,同属于一个成矿体系。综上所述,架底金矿受有利的岩性组合、背斜构造和构造蚀变体(SBT)所控制,与水银洞卡林型金矿具有相同的成矿模式,可能显示贵州西部峨眉山玄武岩区具有巨大的找矿前景。
[Abstract]:The Jaidi gold deposit is located in the strong tectonic deformation area of the south east wing of the Lianhuashan anticline at the junction between the southwestern margin of the Yangtze quasi platform and the South China fold belt. It is a new medium primary gold deposit discovered by the 105th geological team of Guizhou Provincial Geological Exploration and Development Bureau in the basalt distribution area of Emeishan, west of Guizhou Province, after the barley gold deposit. On the basis of previous studies, ICP-MS and Linkam THMSG600 type cold-hot platform were used to identify the deposit geology, elemental geochemical characteristics and fluid inclusion geochemical characteristics of Gedi gold deposit, respectively. Compared with the typical Shuiyindong gold deposit in this area, the regional metallogenic model and prospecting prospect are discussed, which is of great significance for the prospecting and prediction of the primary gold deposits in the region. The main results are as follows: (1) among the structural alteration (SBT) and the second member of the Emeishan basalt formation, the host rocks are mainly tuff, which occurred between the Maokou formation and the Emeishan basalt formation. Black Tortoise tuff and Black Tortoise volcanic breccia. The ore body is layered, lenticular, simple to medium in shape, with an average grade of 3.17 脳 10 ~ (-6). (2) the ore structure mainly consists of cataclastic structure, hemiform-isomorphic structure and metasomatic structure, and the ore structures are mainly disseminated and massive. Stripes and veins, etc. The main alteration of the surrounding rock is silicification, pyritization, and there are a little arsenopyrite and clay. (3) the geochemical characteristics of the major elements of the gold ore are similar to those of the Emeishan basalt. It may be related to the ore-bearing rock is Emeishan basalt. (4) the geochemical characteristics of trace elements show that the ore is abnormally enriched in relation to the surrounding rock, which indicates that the Au-As-SbSbSbHgTl is brought into the ore by hydrothermal process. (5) the geochemical characteristics of rare earth elements show that, There are some differences in REE content and characteristic parameters between ore and surrounding rock, but the normalized curve of chondrites is quite consistent, showing negative ce anomaly, no obvious EU anomaly, rich in light rare earth, poor in heavy rare earth, and the distribution curve is gently right tilting. It may indicate that the ore-forming fluid has not been able to cause the change of rare earth elements in rocks. (6) the geochemical study of fluid inclusions shows that the homogenization temperature range of ore-forming fluid is in the range of 1931 ~ 227 鈩，

本文编号：2145086