利用锌同位素测试分析研究边家大院铅锌银多金属矿床形成过程

发布时间：2018-08-31 17:50

【摘要】：内蒙古林西边家大院铅锌银多金属矿床是近年新发现的多金属矿床,矿区由三种类型矿床组成:西部斑岩钨-锡-钼矿床,中部角砾岩型铜-铅-锌矿床及东部热液脉型铅-锌-银矿床。本文通过对整个矿床29个闪锌矿样品进行锌同位素值测试分析,并结合前人对边家大院铅锌银多金属矿床地质特征、成矿流体的物理性质总结,取得如下认识:(1)梳理了边家大院矿床地质特征,通过岩石地球化学测试、岩石主微量元素、H-0、C-0同位素等研究了矿床的成矿物质来源。(2)通过对边家大院铅锌银多金属矿床29块闪锌矿研究得出,样品中锌同位素的值从西到东呈现增长趋势(+0.17%到+0. 36%),但在角砾岩型矿床中也观察到较轻的锌同位素样品。系统增长表明这三个小矿床应来自于同一个成矿系统,它们在时间和空间上存在一定联系;较轻的锌同位素样品,可能是成矿之后由于大气降水引起的淋滤作用而改变了闪锌矿中锌同位素的值。(3)利用边家大院矿床中的锌同位素值测试分析,直接揭示出三种类型矿床属于同一个热液系统,并且之间存在相互联系。该矿集区三类矿床形成于太平洋俯冲下陆内伸展的构造背景,是早白垩世深源岩浆上侵构造-岩浆作用的产物。这一研究也为下一步进行矿床预测、开展找矿工作指出了方向。
[Abstract]:The Lead-Zinc-Ag polymetallic deposit in Jiayuan, west of Inner Mongolia, is a newly discovered polymetallic deposit, which is composed of three types of deposits: the western porphyry tungsten-tin molybdenum deposit. The central breccia type copper-lead-zinc deposit and the eastern hydrothermal vein-type lead-zinc-silver deposit. In this paper, 29 sphalerite samples of the whole deposit are tested and analyzed, and the physical properties of ore-forming fluids are summarized according to the geological characteristics of the lead, zinc and silver polymetallic deposits in Bian Jia Yuan. The results are as follows: (1) the geological characteristics of the Bian Jia Yuan deposit are combed, and the rock geochemistry is measured. The source of ore-forming material has been studied by the main trace element of rocks, such as H-0C _ 0 isotopes. (2) through the study of 29 sphalerite deposits in Bian Jia Yuan Pb-Zn Ag polymetallic deposit, it is found that the values of zinc isotopes in the samples show an increasing trend from west to east (0.17% to 0. 7%). But lighter zinc isotopic samples were also observed in breccia deposits. The systematic growth indicates that these three small deposits should come from the same ore-forming system, and they have some relationship in time and space. It is possible that the zinc isotope values in sphalerite have been changed due to the leaching caused by atmospheric precipitation after mineralization. (3) by using the zinc isotopic values of the Bian Jia Yuan deposit, it is directly revealed that the three types of deposits belong to the same hydrothermal system. And there is a correlation between them. The three types of deposits formed in the tectonic setting of the subduction and subcontinental extension in the Pacific Ocean are the product of the early Cretaceous deep source magma transgression tectonic-magmatism. This study also points out the direction for further ore deposit prediction and prospecting.
【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】：2017
【分类号】：P618.2

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