| 李益智,胡家刚,蔡明海,彭振安,李强,张文兵.广西大厂铜坑矿床流体包裹体研究[J].矿产勘查,2017,8(1):37-53 |
| 广西大厂铜坑矿床流体包裹体研究 |
| Study on fluid inclusions of Tongkeng deposit in Dachang tin ore field, Guangxi |
| 投稿时间：2016-03-26 |
| DOI： |
| 中文关键词: 广西大厂 流体包裹体 锡多金属矿 锌铜矿 |
| 英文关键词: fluid inclusions, tin-polymetallic ore deposit, zinc-copper ore, Dachang, Guangxi |
| 基金项目:国土资源部公益性行业科研专项(编号:200911007-13)资助。 |
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| 中文摘要: |
| 铜坑矿床是大厂矿田代表性矿床之一,由上部的锡石—硫化物型锡多金属矿体和深部新发现的夕卡岩型锌铜矿体组成。文章通过对比研究两类矿体成矿流体特征,发现主成矿阶段流体包裹体类型基本相似,主要有CO2-H2O型、NaCl-H2O型和纯CO2型。锡多金属矿成矿阶段早期到晚期均一温度变化为270～390℃→110～210℃,成矿流体盐度w(NaCl)变化为3%～8%→1%～4%,流体密度变化为0.56～0.86 g·cm-3→0.86～0.96 g·cm-3；锌铜矿在主成矿阶段均一温度变化为285～435℃,盐度w(NaCl)变化为3%～12%,含NaCl子矿物的盐水包裹体盐度达到30%～39%,流体密度变化为0.59～0.98 g·cm-3。锡多金属矿体与锌铜矿体流体成分基本相似,主要成分为CO2和H2O,其次含有部分CH4气体以及少量气相H2,但锌铜矿中CO2含量低于锡多金属矿体中CO2含量。锡多金属矿成矿流体的捕获压力为44.46～109.9 MPa,换算成深度为1.68～4.15 km；锌铜矿成矿流体捕获的压力为67.6～114.7 MPa,换算成深度为2.55～4.33 km。大厂矿田锡多金属矿的剥蚀程度相对较高,达中等剥蚀程度,而锌铜矿剥蚀程度较低。两类矿体在成因上具有本质联系,又存在一定差异,锡多金属矿主成矿期有岩浆流体和幔源流体混入；锌铜矿主成矿期主要为岩浆流体参与。 |
| 英文摘要: |
| Tongkeng tin deposit is one of the most representative tin deposits in the Dachang ore field, it is composed of two parts, i.e., cassiterite-sulfide type tin-polymetallic ore body in the upper part and skarn type zinc-copper ore body in the deep part which is newly discovered. Based on the comparative study of characteristics of ore-forming fluid inclusions of two types ore bodies, it was found that the two types of fluid inclusions are basically similar, the main types of fluid inclusions are CO2-H2O type, NaCl-H2O type and CO2-rich type. The variation ranges of homogeneous temperature, mineralizated fluid salinity and fluid density are from 270～390℃ to 110～210℃, from 3%-8% to 1%-4% and from 0.56-0.86g/cm3 to 0.86-0.96g/cm3 from early tin-polymetallic mineralization stage to late stage respectively. The homogeneous temperature variation range is from 285 to 435℃and the fluid salinity changes from 3% to 12% in main tin-polymetallic stage in the copper-zinc orebody. The salinity of brine inclusion containing NaCl subcrystal reached 30%-39%, and the ore-forming fluid density changes from 0.59 to 0.98g/cm3. The fluid compositions of tin-polymetallic ore bodies and zinc copper ore bodies are basically similar, the main components of fluid inclusions are CO2 and H2O, part of CH4 gas and minor H2 gas. However, the content of CO2 in zinc-copper orebody is lower than that of CO2 in the tin-polymetallic orebody. The ore-forming fluid capture pressure of tin-polymetallic orebody is 44.46-110MPa and metallogenic depth is 1.68-4.15 km; the capture of ore forming fluid pressure of zinc-copper ore is 67.7-114.7MPa and metallogenic depth is 2.55-4.33 km. The denudation degree of tin-polymetallic ore is relatively high to moderate level; the denudation degree of zinc-cooper is lower. In Genesis, there is a certain difference and essential relation in the two types of ore bodies, the metallogenic period of tin-polymetallic are magmatic and mantle derived fluids, the main mineralization stage of the copper deposit is magmatic fluid. |
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