中国有色金属学报
中國有色金屬學報
중국유색금속학보
The Chinese Journal of Nonferrous Metals
2015年
10期
2871-2882
,共12页
流体包裹体%成矿流体%铜矿床%成矿作用%矽卡岩
流體包裹體%成礦流體%銅礦床%成礦作用%矽卡巖
류체포과체%성광류체%동광상%성광작용%석잡암
fluid inclusion%ore-forming fluid%copper deposit%metallogenesis%skarn
老鸦岭铜矿床是安徽省铜陵冬瓜山矿田内的一个矽卡岩型矿床。矿体赋存于远离主接触带的下二叠统到下三叠统大理岩地层中。原生成矿过程分为矽卡岩期的早矽卡岩阶段(A1)、晚矽卡岩阶段(A2)、氧化物阶段(A3)和热液期的石英硫化物阶段(B1)、碳酸盐阶段(B2)。包裹体岩相学分析表明:石榴子石、透辉石、石英和方解石中发育着气液两相包裹体(Ⅰ型)和含子矿物包裹体(Ⅱ型)。显微测温结果显示:早矽卡岩阶段,包裹体均一温度为434~579℃或者>600℃,盐度连续分布在20.80%~56.70%,显示其成矿流体具有高温、高盐度的特征,体系处于超高压环境;氧化物阶段,流体减压沸腾,最低沸腾温度为298℃,包裹体具有不均一捕获特征,地下水的混入导致盐度从59.36%到3.76%显著变化,由于处于开放体系,受静水压力影响,估算成矿压力范围为16~37 MPa,结合上覆地层的厚度判断成矿深度约为1.6 km;石英硫化物阶段,包裹体均一温度集中于250~350℃,盐度在3.92%到49.22%之间;碳酸盐阶段,包裹体均一温度为160~193℃,盐度为2.63%~4.39%,成矿流体显示出从高温到低温、从高盐度到低盐度、从均一到不混溶分离的演化过程。基于以上研究,推断老鸦岭铜矿床的成矿流体以高温、高盐度的岩浆流体为开端,在上侵和沿大隆组地层快速运移过程中逐渐演化,伴随沸腾作用和两次地下水的混入,成矿流体温度、盐度、压力不断下降,最终在青山脚背斜轴部卸载成矿。
老鴉嶺銅礦床是安徽省銅陵鼕瓜山礦田內的一箇矽卡巖型礦床。礦體賦存于遠離主接觸帶的下二疊統到下三疊統大理巖地層中。原生成礦過程分為矽卡巖期的早矽卡巖階段(A1)、晚矽卡巖階段(A2)、氧化物階段(A3)和熱液期的石英硫化物階段(B1)、碳痠鹽階段(B2)。包裹體巖相學分析錶明:石榴子石、透輝石、石英和方解石中髮育著氣液兩相包裹體(Ⅰ型)和含子礦物包裹體(Ⅱ型)。顯微測溫結果顯示:早矽卡巖階段,包裹體均一溫度為434~579℃或者>600℃,鹽度連續分佈在20.80%~56.70%,顯示其成礦流體具有高溫、高鹽度的特徵,體繫處于超高壓環境;氧化物階段,流體減壓沸騰,最低沸騰溫度為298℃,包裹體具有不均一捕穫特徵,地下水的混入導緻鹽度從59.36%到3.76%顯著變化,由于處于開放體繫,受靜水壓力影響,估算成礦壓力範圍為16~37 MPa,結閤上覆地層的厚度判斷成礦深度約為1.6 km;石英硫化物階段,包裹體均一溫度集中于250~350℃,鹽度在3.92%到49.22%之間;碳痠鹽階段,包裹體均一溫度為160~193℃,鹽度為2.63%~4.39%,成礦流體顯示齣從高溫到低溫、從高鹽度到低鹽度、從均一到不混溶分離的縯化過程。基于以上研究,推斷老鴉嶺銅礦床的成礦流體以高溫、高鹽度的巖漿流體為開耑,在上侵和沿大隆組地層快速運移過程中逐漸縯化,伴隨沸騰作用和兩次地下水的混入,成礦流體溫度、鹽度、壓力不斷下降,最終在青山腳揹斜軸部卸載成礦。
로아령동광상시안휘성동릉동과산광전내적일개석잡암형광상。광체부존우원리주접촉대적하이첩통도하삼첩통대리암지층중。원생성광과정분위석잡암기적조석잡암계단(A1)、만석잡암계단(A2)、양화물계단(A3)화열액기적석영류화물계단(B1)、탄산염계단(B2)。포과체암상학분석표명:석류자석、투휘석、석영화방해석중발육착기액량상포과체(Ⅰ형)화함자광물포과체(Ⅱ형)。현미측온결과현시:조석잡암계단,포과체균일온도위434~579℃혹자>600℃,염도련속분포재20.80%~56.70%,현시기성광류체구유고온、고염도적특정,체계처우초고압배경;양화물계단,류체감압비등,최저비등온도위298℃,포과체구유불균일포획특정,지하수적혼입도치염도종59.36%도3.76%현저변화,유우처우개방체계,수정수압력영향,고산성광압력범위위16~37 MPa,결합상복지층적후도판단성광심도약위1.6 km;석영류화물계단,포과체균일온도집중우250~350℃,염도재3.92%도49.22%지간;탄산염계단,포과체균일온도위160~193℃,염도위2.63%~4.39%,성광류체현시출종고온도저온、종고염도도저염도、종균일도불혼용분리적연화과정。기우이상연구,추단로아령동광상적성광류체이고온、고염도적암장류체위개단,재상침화연대륭조지층쾌속운이과정중축점연화,반수비등작용화량차지하수적혼입,성광류체온도、염도、압력불단하강,최종재청산각배사축부사재성광。
The Laoyaling copper deposit, located at the Dongguashan mining area, Tongling, Anhui Province, China, is a skarn deposit. The orebodies are mainly located in the marble of the Lower Permain to the Lower Triassic strata, which is far from the contact zone. The primary ore-forming process is divided into skarn period and hydrothermal period. The former period can be subdivided into early skarn stage(A1), late skarn stage(A2) and oxide stage(A3), and the latter period can be subdivided into quartz sulfide stage(B1) and carbonate stage(B2). The characteristic of ore-forming fluids and mineralization were discussed by petrographical and micro thermometric data of the fluid inclusion. Two types of inclusions, gas-liquid two-phase aqueous inclusions (typeⅠ) and aqueous inclusions with daughter mineral (typeⅡ), are hosted in garnet, diopside, quartz and calcite. The inclusions of early skarn period homogenize at temperatures of 434?579℃or >600℃and have salinities of 20.80%?56.70%, indicating that the ore-forming fluids in this stage have the characteristics of high temperature, high salinity, and ultrahigh pressure. The oxide period, owing to the decrease of pressure, ore-forming fluids started to boil at the lowest temperature of 298 ℃, which shows the characteristics of heterogeneous capture of inclusions, and changes the salinity from 59.36%to 3.76%obviously by inburst of groud water. The system is affected by the hydrostatic pressure in the open system with metallogenic pressure changing from 16 MPa to 37 MPa, together with thickness of the overly strata, the metallogenic depth is deduced to be 1.6 km. The inclusions of quartz-sulfide period homogenizing at temperature of 250?350 ℃ have salinities of 3.92%?49.22%, and in carbonate period homogenizing at temperatures of 160?193 ℃, the inclusions have salinities of 2.64%?4.39%. The results demonstrates that the ore-forming fluids evolve from high-temperature to low-temperature, from high-salinity to low-salinity and from homogenization to immiscible separation. The ore-forming fluid is originated from different evolutional stages of the primitive fluids derived from the magmatic intrusion, and started with characteristics of high temperature and high salinity. The ore-forming components were precipitated in Qingshanjiao anticline due to twice boiling and fluid mixing as well as the decrease in salinity, temperature and pressure of the fluids.