新疆阿尔泰铁木尔特铅锌矿床流体包裹体研究及地质意义

Characteristics of fluid inclusions in the Tiemurte Pb-Zn deposit,Altay,Xinjiang and its geological significance

铁木尔特中型铅锌矿是阿尔泰山南缘克兰盆地内的重要VMS型矿床。矿床赋存于上志留统-下泥盆统康布铁堡组上亚组第二岩性段,容矿岩石为大理岩、绿泥石英片岩、变钙质粉砂岩、夕卡岩。矿体呈似层状和透镜状。矿床的形成经历了喷流沉积期、叠加改造期和表生期。石英、长石、方解石和石榴子石中包裹体类型主要为液体包裹体,在石英中另出现了气体包裹体、纯气体包裹体、含子矿物多相包裹体、含液体CO2的三相包裹体和两相CO2包裹体。喷流沉积期成矿流体均一温度变化于150～330℃,其峰值是165℃和285℃,成矿流体盐度(NaCleq)为4%～16%,流体密度为0.77～0.97g/cm3,流体阳离子主要以Na+为主,次之为K+,阴离子以Cl-为主,其次是SO42-,气相成分主要是H2O和CO2。叠加改造期均一温度范围是150～480℃,峰值为285℃,盐度(NaCleq)为2.2%～17.08%和33.93%～47.2%,流体密度变化于0.61～1.03g/cm3之间,流体阳离子主要以Na+为主,次为K+、Mg2+、Ca2+,阴离子以Cl-为主,其次是SO42-,气相成分主要是H2O和CO2,其次为N2、CH4,含有少量C2H6。

The Tiemurte middle-size lead-zinc deposit occurs in Kelang basin on the southern margin of Altay and it is an important VMS style. The Tiemurte deposit occurs in second lithological unit of Upper Silurian-Lower Devonian Kangbutiebao Formation,with the host rocks being marble,greenschist,meta-calcareous siltstone and skarn. The ore bodies show bed-like or lenticular. The lead-zinc deposit is subjected to three stages:Sedimentary exhalative stage,superposed rebuilding stage and hypergenesis stage. The inclusions in quartz,feldspar,calcite and garnet are dominantly liquid inclusions type. In addition,the inclusions in quartz including rich gas phase inclusions,single gas inclusions,daughter mineral-bearing inclusions,CO2-bearing three-phase and aqueous two-phase. In sedimentary exhalative stage,homogenization temperatures of inclusions vary from 150℃ to 330℃ with peak temperature of 165℃ and 285℃,the salinity from 4% to 16% NaCl equiv,the density ranges from 0.77g/cm3 to 0.97g/cm3,the cations in inclusions are dominanted by Na+ and K+,the anions are Cl-and SO42-and the gases in fluid inclusions are chiefly composed of H2O and CO2. In superposed rebuilding stage,homogenization temperatures are 150~480℃,the salinity is 2.2% to 17.08% NaCl equiv and 33.93% to 47.2% NaCl equiv,the density ranges from 0.61g/cm3 to 1.03g/cm3,the cations in inclusions are Na+ and K+,the anions are Cl-and SO42-and the gases in fluid inclusions are chiefly composed of H2O and CO2,the secondary components are N2,CH4.