胶西北大尹格金矿床成矿机理:载金黄铁矿标型及硫同位素地球化学约束  

Metallognic mechanism of Dayingezhuang gold deposit,northwestern Jiaodong Peninsula: Geochemistry constrains from the gold bearing pyrite typomorph and sulfur isotope

作　　者：张瑞忠[1,2] 王中亮[1] 王偲瑞 刘育[1] 秦文凯 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]招金矿业股份有限公司,招远265400 [3]招金矿业股份有限公司大尹格庄金矿,招远265413

出　　处：《岩石学报》2016年第8期2451-2464,共14页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(41230311;41572069);国家重点研发计划(2016YFC0600100);国家科技支撑计划课题(2011BAB04B09);公益性行业科研专项(201511029);高等学校学科创新引智计划(B07011);地质过程与矿产资源国家重点实验室开放课题(GPMR201307)联合资助

摘　　要：胶东是我国最重要的金矿集中区,破碎带蚀变岩型金矿床是区内最主要的金矿床类型,该类型金矿床已探明金资源量占全区的90%以上,其巨量金的来源是引人瞩目的关键科学问题。招平断裂带是该区内规模最大的断裂-成矿带,位于招平金矿带中段的大尹格庄金矿床是该金矿带最具代表性的破碎带蚀变岩型金矿床之一,已探明金金属量约283t。大尹格庄金矿床严格受沿胶东群与玲珑花岗岩接触带发育的NNE向招平断裂带控制,矿体赋存在招平断裂下盘黄铁绢英岩化和碎裂岩化玲珑花岗岩中,主要由Ⅰ号和Ⅱ号矿体组成,其具有相似的矿物组成,矿石主要矿物是绢云母、石英、黄铁矿,次要矿物是钾长石、斜长石、黑云母、方解石、黄铜矿、方铅矿、闪锌矿、磁黄铁矿、黝铜矿和自然金、自然银、金银矿、碲银矿等;其中黄铁矿是最主要的载金矿物。根据穿插关系和矿物共生组合,大尹格庄金矿床内成矿作用可划分为4个成矿阶段,分别是黄铁矿-石英-绢云母阶段(I)、石英-黄铁矿阶段(Ⅱ)、石英-多金属硫化物阶段(Ⅲ)和石英-方解石-多金属硫化物阶段(Ⅳ)。各个成矿阶段的黄铁矿的晶体形态标型研究表明,成矿Ⅰ阶段黄铁矿以粗粒自形立方体为主,含有少量五角十二面体;成矿Ⅱ和Ⅲ阶段黄铁矿以细粒五角十二面体为主,且具有更多五角十二面体、八面体和立方体形成的聚形;成矿Ⅳ阶段主要为细粒立方体晶形。不同矿体各个成矿阶段的硫化物的δ^(34)S值集中在4.58‰~7.54‰,具有一定的塔式效应,正向偏离陨石硫,与胶东地区胶东群变质岩、围岩花岗岩类δ^(34)S比较接近,指示大尹格庄金矿床各个成矿阶段的矿石硫源总体一致,与胶东群变质岩和中生代花岗岩间具有继承演化关系。此外,从成矿Ⅰ阶段→Ⅱ阶段→Ⅲ阶段→Ⅳ阶段,大尹格庄金矿床矿石硫化物δ^(34)S呈现出逐�Jiaodong is the most important gold ore-concentrated region of China, and the fracture zone altered-type gold deposit is the most important gold deposit type of the region, which takes up over 90% the proven amount of gold, the source of the huge amount of gold remains an impressive key scientific problem. The Zhaoping fault zone is the largest fracture-mineralization belt of the region and the Dayingezhuang gold deposit, which locates at the middle part of the Zhaoping gold belt, is one of the most typical fracture zone altered-type gold deposits, with a proven amount of gold of 283t. The Dayingezhuang gold deposit is strictly controlled by the NNE trending Zhaoping fault zone, ore bodies occur in the disintegrated and beresitization altered Linglong garnet at footwalls of the Zhaoping fault zone, are made up by ore body Ⅰ and ore body Ⅱ, and share a similar mineral composition of sericite, quartz and pyrite as major minerals and potassium feldspar, anorthose, biotite, calcite, chalcopyrite, galena, pyrrhotite, tetrahedrite, native gold, native silver, kustelite and hessite as minor minerals, among which pyrite is the leading gold-bearing mineral. According to the interspersed relationship and the paragenetic association of the minerals, the stages of mineralization can be divided into four, which are pyrite-quartz-sericite stage （stage Ⅰ）, quartz-pyrite stage （stage Ⅱ）, quartz-polysulfide stage （stage Ⅲ） and quartz-carbonate stage （stage Ⅳ）. The researches on crystal form of pyrite in different stages show that, pyrite in stage Ⅰ is primarily coarse-grained euhedral cube and little pentagonal dodecahedron; pyrite in stage Ⅱ and stage Ⅲ is primarily fine-grained pentagonal dodecahedron with more combinate form of pentagonal dodecahedron, octahedral and cube; pyrite in stage Ⅲ is mainly fine-grained cube. The values of δ34S of different stages and ore bodies center at 4.58‰～7.54‰, show a tower style distribution, positive deviate from meteorite sulfur and approach the δ

关 键 词：黄铁矿晶形 硫同位素 成矿环境 大尹格庄金矿床 胶西北 

分 类 号：P597.2[天文地球—地球化学] P618.51[天文地球—地质学]