吉林省敦化市松江河金矿地质特征及矿床成因

发布时间：2018-02-15 11:45

  本文关键词： 松江河金矿 矿床地质特征 流体包裹体 造山型金矿　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：松江河金矿位于吉林省敦化市,地处天山-兴蒙造山带南端,华北板块北缘东段,夹皮沟—海沟金及多金属成矿带中部,成矿地质条件优越,是吉林省内重要的金及有色金属成矿区矿区地层主要出露中元古界色洛河岩群,一套高金含量的的绿片岩相-角闪石岩相的变质岩系,原岩为玄武岩、安山岩、流纹岩以及含砾泥砂质陆源碎屑沉积岩。矿区内断裂构造发育,区域性北西向青茶馆—白水滩断裂带斜贯全区,为区内主要控岩控矿构造。矿体主要受近北南向次级断裂控制。本区岩浆活动较为频繁,岩浆岩分布十分广泛,矿区内岩浆岩主要有辉石角闪岩、印支早期黑云母斜长花岗岩及燕山早期钾长花岗岩。矿区内发现的矿脉主要有10条。编号为Ⅱ-1~Ⅱ-10,其中,Ⅱ-1号矿体是区内的主要矿体,其它为次要矿体。矿石类型为蚀变岩型,局部见石英脉型。矿石矿物主要有钛铁矿、黄铁矿、黄铜矿、磁黄铁矿、自然金等。矿石结构主要有自形—半自形结构、他形粒状结构、包含结构、碎裂结构。矿石构造主要有浸染状—星散浸染状构造和片状—条带状构造。矿体围岩蚀变较发育,主要有硅化、钾化、绿帘石化、绿泥石化及星点状黄铁矿化等。成矿期次可以划分为四个阶段:Ⅰ石英-氧化物阶段,Ⅱ黄铁绢英岩阶段,Ⅲ石英-方解石多金属硫化物阶段,Ⅳ碳酸盐阶段,其中Ⅱ和Ⅲ阶段为主成矿阶段。松江河金矿成矿区域上与燕山早期敦化-密山深大断裂大规模左旋平移有关。成矿期主控矿的SN向断裂表现为以压为主的左旋压扭特征,在断裂走向偏左和产状变缓部位为局部张开部位,含矿性好。松江河金矿成矿流体包裹体类型有:含CO2相包裹体、气液两相包裹体、纯液相包裹体;具有低盐度(5~9wt%NaCl.eqv)、低密度(0.66~0.72g/cm3)、中温(173.7~345.2℃)的特点;成矿压力84~106Mpa,成矿深度7.50~8.52km。松江河金矿成矿与空间上密切相关的中侏罗世五道溜河岩株状产出的二长花岗岩有关,岩浆源区为下地壳,岩石形成于大陆边缘岩浆弧环境,成岩时代为173Ma±。矿床形成于古太平洋板块俯冲过程中挤压向伸展转换的构造背景。矿体受压扭性断裂构造控制,矿石金属矿物组合简单,中温、低盐度、低密度流体和典型的富CO2包裹体发育等特征与典型的造山型金矿特征相似,按照成矿动力学背景分类,属于中成造山型金矿。与成矿有关的侵入岩为二道溜河二长花岗岩,流体演化方面,成矿Ⅰ阶段为偏高温的氧化环境,钛铁矿和锐钛矿。成矿Ⅱ阶段随着氧化物的析出,流体表现为还原环境,出现大量黄铁矿和磁黄铁矿,伴随有金的析出。成矿Ⅲ阶段随着温度降低,气相的溢出和沸腾作用,大量多金属硫化物发生沉淀,金的Au(HS)2-分解,大量金沉淀于石英、方解石和硫化物裂隙和晶隙中。成矿Ⅳ阶段大气水的加入流体变为中性和偏碱性,主要发育碳酸盐。综合矿床地质特征和流体演化特征,矿床成因类型为中温热液脉型金矿。
[Abstract]:Jilin province is located in the city of Dunhua Songjianghe gold deposit, located in the Tianshan Xingmeng orogenic belt at the southern end, the eastern section of the northern margin of North China plate, the trench - gold and polymetallic metallogenic belt, the metallogenic geological condition is superior, is the Jilin Province gold and nonferrous metal metallogenic district important strata outcropped mainly middle Proterozoic Seluohe group metamorphic rocks. A set of greenschist - high gold content of amphibole facies, the original rock is basalt, andesite, rhyolite and gravelly sandy muddy terrigenous sedimentary rocks within the mining area. The faults, regional NW - Qing teahouse baishuitan fault zone for oblique penetration of the region, the main control of rocks ore structure. The ore body is mainly controlled by the North South secondary faults. Magmatic activities in this area are more frequent, magmatite are widely distributed within the mining area, magmatite mainly pyroxene amphibolite, plagioclase granite and biotite early Indosinian early Yanshan Moyite. There are 10 main mining areas found in the vein. No. II -1~ II -10 II, which is the main orebody No. -1 orebody in the region, the other is the secondary deposit. The ore type is altered rock type, local quartz vein type. Ore minerals are mainly pyrite ore, ilmenite, brass, pyrrhotite, natural gold. Ore textures are mainly euhedral subhedral - structure, xenomorphic granular structure, including structure, cataclastic structure. There are disseminated - scattered disseminated structure and sheet - banded structure ore structure. The ore rock alteration is developed, mainly include silicon, potassium, epidote petrochemical, chloritization and star like pyritization. Metallogenic period can be divided into four stages: the first stage II oxide quartz, pyrite sericite quartz rock phase III quartz calcite polymetallic sulfide stage and carbonate stage IV, the main ore-forming stage II and III stage in Songjiang. 娌抽噾鐭挎垚鐭垮尯鍩熶笂涓庣嚂灞辨棭鏈熸暒鍖，

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