【摘要】 Humedo金矿床位于安第斯山脉北部的Cangrejos-Zaruma地区,该地区发育斑岩型铜金矿床和浅成热液型金银矿床。已探明矿体分布在Humedo金矿区露天采场,产于岩体内外接触带中,主要赋矿围岩为英安斑岩和闪长岩,其次为片麻岩。矿石中金属矿物主要为银金矿、铁闪锌矿、毒砂、黄铁矿等,脉石矿物主要为石英、绢云母、电气石,围岩蚀变类型主要有黄铁绢英岩化、电气石化、磁黄铁矿化、碳酸盐化、绿泥石化和褪色化等。矿石中金矿物以银金矿为主,多呈包体分布于毒砂、铁闪锌矿和黄铁矿中,少数呈晶隙金分布于石英等矿物晶隙中。银金矿中Au质量分数为66. 127%～78. 209%,Ag质量分数为22. 103%～31. 593%。电气石常与含金多金属硫化物伴生,形成晶洞状构造和角砾状构造,微区X射线衍射分析和电子探针分析结果显示该电气石类型属于黑电气石。毒砂是主要载金矿物之一,利用毒砂温度计求得其形成温度为330℃～400℃。英安斑岩和闪长岩锆石U-Pb年龄为(16. 75±0. 17)～(17. 30±0. 21) Ma,表明成矿母岩侵位和成矿时代为新近纪中新世。Humedo金矿床的形成主要受大地构造条件、成矿物源与热源条件、矿田构造条件、大地电场条件和物理化学条件制约。更多还原

【Abstract】 The Humedo Gold Deposit is located in the Cangrejos-Zaruma area in northern Andes,where porphyry Cu-Au deposits and epithermal Au-Ag deposits develop. The proven gold ore bodies are mainly distributed in the open pit of the Humedo Gold District. The ore bodies are produced in the inner and outer contact zone of the rock body. The main ore-bearing wall rocks are dacite porphyry and diorite,followed by gneiss. The main metal minerals in the ore are electrum,sphalerite,arsenopyrite,pyrite,etc.; the main gangue minerals are mainly quartz,sericite,tourmaline; the main wall rock alteration types are beresitization,tourmalinization,pyrrhotitization,carbonatization,chloritization and bleaching alteration,etc. The gold minerals in the ore are mainly electrum,most of which are distributed in arsenopyrite,sphalerite and pyrite as inclusions,and a small part is interstitial gold distributed in the crystal gaps of minerals such as quartz. The Au mass concentration in the electrum is 66. 127 %-78. 209 %,and the Ag mass concentration is 22. 103 %-31. 593 %. Tourmaline is often associated with gold-bearing polymetallic sulfides,forming crystal-like structures and breccia-like structures. Micro-area X-ray diffraction analysis and electron probe analysis show that the tourmaline belongs to schorl. Arsenopyrite is one of the main gold-bearing minerals. According to the arsenopyrite thermometer,its formation temperature is between 330 ℃ and 400 ℃ . The U-Pb ages of the ore-bearing dacite porphyry and diorite zircon range from( 16. 75 ± 0. 17) Ma to( 17. 30 ± 0. 21) Ma,indicating that the emplacement and mineralization age of the ore-forming parent rock is the Tertiary Miocene. The formation of the Humedo Gold Deposit is mainly restricted by geotectonic conditions,mineralization material source and heat source conditions,ore field tectonic conditions,geoelectric field conditions and physical and chemical conditions.更多还原