新疆马热勒铁金矿床特征及其流体成矿作用

Fluid mineralization and characteristics of the Mareletie gold deposit in Xinjiang

马热勒铁金矿床产于中泥盆统北塔山组安山岩和安山质凝灰岩间的韧性剪切带中。矿体呈脉状 ,主要为蚀变岩和含金石英脉。矿石由黄铁矿、黄铜矿、方铅矿、黝铜矿、自然金、银金矿、毒砂、辉铋矿、磁铁矿、石英、绢云母、绿泥石、方解石等矿物组成 ,围岩蚀变有硅化、碳酸盐化、黄铁矿化和绢云母化。金矿成矿主要经历黄铁矿—石英—金、石英—金属硫化物—金、石英—碳酸盐—金三个阶段。成矿物质主要来源于中泥盆统北塔山组含金建造。流体包裹体研究显示 ,成矿温度为 16 0℃～ 2 80℃ ,成矿压力为 (73.4～ 12 1.9)× 10 5Pa ,成矿时成矿流体pH为 4 .2 0～ 5 .0 1,呈酸性 ,Eh为 - 0 .6 6～ - 0 .4 5eV ,属还原环境 ;流体为Na+ —Ca2 + —HCO3 -—Cl-型体系和Na+ —Ca2 + —HCO3 -—SO42 -—Cl-型体系的酸性—弱酸性流体 ,流体中成矿物质金主要以[AuCl2 ]-、[Au(HS) 2 ]0 等络合物形式存在并运移 ;流体的溶液来自岩石建造水、古大气降水及变质水组成的混合水。区域构造应力作用、成矿流体环境物理化学条件的改变、古大气水不断加入、成矿流体与围岩的蚀变反应等引起成矿流体周围一系列环境物理化学条件的变化 。

The Mareletie gold deposit is located in the southeastern Ertix mineralization region. Ore bodies occur in the ductile shear zone of the middle Devonian system Beitashan group, which is a formation of andesite and andesite-tuff, controlled by the Jiamante-Mareletie fault system. The orebodies are vein, lenticular and stratoid forms. The ores consist of pyrite, arsenopyrite, galena, sphalerite, tetrahedrite, nature gold, electrum, quartz, sericite and chlorite. The wall rock alteration includes silication, pyritization, sericitization, chloritization and carbonization. The ore deposit underwent mainly three stages: pyrite-quartz-gold stage, metal-sulfide-gold stage and quartz-carbonate-gold. The temperate of mineralization is 160℃～280℃ and pressure is 73.4×10 5 ～121.9×10 5 Pa. The chemical component of the fluid inclusion suggests that the ore materials translated in -?Au(HS) 2 0, which were derived from the ore-bearing formation of the middle Devonian system Beitashan group. The ore-bearing fluid is acidity, pH=4.20～5.01, Eh=-0.66～-0.45eV, which consists of formation stored-water, metamorphic water and rain water. It belongs to the gold deposits that are controlled by ductile shear-zone structures.