摘要:
东五家子金矿所处大地构造位置为华北克拉通北缘中段,其北侧以赤峰-开原深大断裂与内蒙-兴安褶皱造山带相隔,南侧以凌源-北票深断裂与燕山沉降带为邻.北西向断层为矿区内最主要的容矿构造,脉岩中的闪斜煌斑岩与矿化关系最为密切.矿石自然类型为石英脉型,矿石中硫化物主要为黄铁矿,其次为黄铜矿和方铅矿.贵金属矿物有自然金和碲银矿.围岩蚀变为硅化、绢云母化和碳酸盐化等,蚀变分带明显.矿石中明显出现碲化物,与矿化关系密切的闪斜煌斑岩发育,矿石硫同位素δ34S‰接近零值等表明成矿流体具幔源流体特征.石英流体包裹体发育较差,包裹体为单一的气液两相包裹体,属H2O-NaCl体系类型.流体盐度为9.86%～16.72%,且随着温度降低盐度出现升高的趋势.流体密度为0.936～1.017g/cm3,成矿温度为172.3～212.6℃,成矿压力为19～24MPa,形成深度为1.9～2.4km.与国内典型的造山型金矿对比表明,该矿床属浅成的造山型金矿,成矿动力学背景为早燕山期华北与西伯利亚克拉通碰撞后的陆内造山.
Abstract:
The tectonic position of Dongwujiazi gold deposit is in the middle section of the north margin of North China Craton,Chifeng-Chaoyang gold mineralization concentration area.In the north,it separates the Inner Mongolia-Xing an Fold-orogenic Belt from the Chifeng-Kaiyuan deep fault,and its south border with Yanshan subsidence zone is the Lingyuan-Beipiao deep fault.The NW trending faults are the main ore-hosting structure in the mining area,the spessartite in the vein rock is greatly related with the mineralization.The natural type of the ore is quartz-vein type,the sulfide in the ore is mostly pyrite,while chalcopyrite and galena are in the second place,noble metal minerals include native gold and hessite.The wall-rock alterations include silicification,sericitization,and carbonatization,the zoning of the alterations is obvious.The telluride can be easily found in the ore.The developing of spessar tite closely related with mineralization and the δ34S‰ value of the ore is nearly zero which implies that the ore-forming fluid has the features of mantle-derived fluid.The fluid inclusions in quartz are poorly developed.The inclusions are all aqueous two-phase inclusions,which belong to the H2O-NaCl system.The fluid salinity is between 9.86WB% NaCl.eqv and 16.92WB% NaCl.eqv,and it increases with t he decrease of temperature.The fluid density is between 0.94g/cm3 and 1.08g/cm3 and the ore-forming temperature is between 172.3℃ and 212.6℃.The ore-forming pressure is between 19Ma and 24M Pa,and the forming depth is between 1.9km and 2.4km.Compared to the typical or ogenic gold deposit from home and abroad,it belongs to the hy pabyssal orogenic gold deposit.The metallo genic dynamics background is North China craton and Siberian craton intra-ontinental orogeny after ollision in early Yanshanian.
百度学术
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