东天山小尖山金矿床成矿流体特征及成矿模式探讨

小尖山金矿床产于东天山康古尔韧性剪切带南缘,对该矿床流体特征和矿床成因类型了解较少。矿区普遍发育低绿片岩相变质,矿床由多条走向为100°~120°的陡倾斜蚀变岩型矿体组成,金平均品位3.11×10^-6~24.99×10^-6;成矿过程可划分为3个阶段:(1)黄铁矿-磁铁矿-绿泥石-绢云母-石英阶段;(2)黄铁矿-黄铜矿-自然金-石英-绿泥石阶段;(3)石英-方解石-贫硫化物阶段。本文通过对矿床不同成矿阶段石英脉内发育的流体包裹体进行了岩相学、显微测温与氢氧同位素研究分析,发现矿床主要发育H₂O-CO₂及气液两相流体包裹体,从早至晚成矿过程中流体内CO₂包裹体逐渐减少,气液两相包裹体内气液比逐渐减小。各成矿阶段包裹体显微测温结果表明,从早至晚成矿流体均一温度分别为216.9~396.4℃、183.1~319.2℃与145.1~220.8℃;成矿流体盐度分别为1.40%~10.11%NaCleq、1.91%~11.22%NaCleq与1.63%~6.74%NaCleq,成矿流体属于中低温、中低盐度的NaCl-H₂O-CO₂体系,并经历了从中温、中盐度流体向低温、低盐度流体的演化过程;成矿早阶段流体的δD_V-SMOW值为-22.550‰,δ¹⁸O_水值为9.44‰,指示变质水成因;成矿晚阶段δD_V-SMOW值介于-41.913‰~-34.796‰之间,平均值为-37.413‰,δ¹⁸O_水值介于1.99‰~3.98‰之间,平均值为2.99‰,指示混合水成因,但接近变质水;成矿流体主要为变质水,成矿早阶段至晚阶段具有从变质水向混合水演化的特征。综合分析,小尖山金矿床成因类型为造山型金矿,其成矿模式为早期韧性剪切变形过程中产生的变质流体在运移过程中萃取岩石中成矿物质,形成含金成矿流体,并在糜棱岩面理等裂隙处发生结晶作用,导致金的初步富集;晚期地壳快速抬升,地质体由韧性变形向脆-韧性、脆性变形转变,伴随有花岗岩脉的侵入,变质流体在运移过程中从流经岩石中淋滤萃取金等成矿物质,形成含矿流体,岩浆水、大气降水的混入以及深度、压力的降低使得流体内的成矿物质在裂隙或断层发育的有利地段卸载沉淀,形成金矿体。     

北阿尔金地区大平沟金矿H-O-S-Pb同位素地球化学特征对金矿成因的启示

大平沟金矿床是北阿尔金地区典型金矿床之一,矿化类型以钾长石-石英脉型和蚀变岩型为主,矿体赋存于近东西向韧性剪切带中,围岩为太古宇米兰岩群钾长变粒岩。矿石矿物以黄铁矿为主,另有少量褐铁矿和自然金等。大平沟金矿床含金石英脉中石英的δ¹⁸O_VSMOW值为12.4‰~15.3‰,估算的流体δ¹⁸O_H2O值介于7.4‰~10.3‰之间,石英中流体包裹体的氢同位素为-97‰~-66‰,表明成矿流体以变质流体来源为主;含金石英脉中硫化物的δ³⁴S_VCDT值为6.9‰~8.3‰,主要为壳源硫,与典型造山型金矿的硫值一致;硫化物的²⁰⁶Pb/²⁰⁴Pb值为18.310 1~19.373 9,²⁰⁷Pb/²⁰⁴Pb值为15.587 2~15.654 1,而²⁰⁸Pb/²⁰⁴Pb值为38.119 1~39.143 9,反映硫化物的铅来源具有造山带铅特征。综合分析认为,大平沟金矿床属于造山型金矿,其形成受近东西向次级断裂和韧性剪切带控制,成矿流体以变质流体为主,成矿物质来源于太古宙深变质岩。     

吉尔吉斯斯坦布丘克造山型金矿床：来自流体包裹体、H- O- S同位素证据

吉尔吉斯斯坦北天山构造带的矿床学数据缺乏,制约了天山造山带境内外成矿对比。布丘克金矿床位于吉尔吉斯斯坦北天山构造带中部。金矿体为石英复脉,呈带状发育于NWW向韧性剪切带中。矿体倾向SSW,倾角60°～70°,赋矿围岩主要为侵入于早古生代变质碎屑杂岩中的正长斑岩。布丘克金矿床成矿期石英流体包裹体观察、石英H-O同位素、硫化物S同位素测试结果显示,布丘克金矿床石英脉中包裹体大小集中在2～10μm之间,类型以H₂O-CO₂型、富CO₂型、水溶液型包裹体为主,成分以富CO₂、含CH₄为特征。成矿流体具有中温(200～320℃)、低盐度(3%～7%NaCl_eqv)特征;石英δD_V-SMOW值介于-108.1‰～-90.2‰之间,δ¹⁸O_流体值介于4.86‰～9.26‰之间;黄铁矿δ³⁴S分布在0‰左右(-0.9‰～1.6‰)。综合本文数据、矿床地质特征、区域地质资料,本文认为布丘...     

北祁连西段牛毛泉东金矿地质特征、成矿时代及成因分析

牛毛泉东金矿位于北祁连造山带与阿尔金断裂的结合部位,该地区被誉为西北的"金三角"。牛毛泉东金矿为该地区近年来新发现的受脆韧性剪切带控制的金矿床,金矿体产于阴沟群安山质凝灰岩、安山质凝灰熔岩中的近东西向脆韧性剪切蚀变带,矿化受构造控制显著,成矿具有多阶段性,金主要形成于硫化物-石英-金矿化阶段。矿脉两侧热液蚀变强烈,与成矿有关的蚀变主要为硅化。通过石英流体包裹体测得金矿石中流体包裹体的均一温度112～191℃;成矿流体盐度0.35%～7.86%,平均4.77%;密度为0.92～0.96 g/cm^3,平均0.95 g/cm^3,显示成矿流体具有浅层低温热液特征。对黄铁绢英岩型矿石中绢云母⁴⁰Ar-³⁹Ar测年获得坪年龄为(296.7±2.8) Ma,对应于北祁连陆内伸展拉张构造演化过程。矿床的地质特征及成矿时代与邻近的寒山金矿类似,并受同一条韧性脆性断裂构造带控制,均为低硫浅成低温热液型金矿,主成矿时代为华力西晚期。牛毛泉东金矿的发现及成因研究对指导区域找矿方向具有重要的意义。     

新疆阿尔泰南缘托库孜巴依金矿成矿演化：石英脉系、同位素地球化学及其Ar-Ar年代学证据

托库孜巴依金矿区赋存于玛尔卡库里大型韧性剪切带及其次级构造中,含矿构造演化经历了5个主要变形阶段:D1推覆挤压变形与紧闭褶皱,D2左行走滑韧性剪切带,D3造山带的抬升与脆-韧性变形,D4伸展体制下的张性构造,伴生有多金属硫化物-石英脉充填与闪长岩脉贯入;D5晚期近东西向及北西向等多组压扭或张扭性次级断裂。相应地,在构造变形过程中形成一系列形态和矿物组合各异的石英脉,初步划分出8种脉系、4个主要成矿阶段,识别出两个主要成矿事件:①与脆-韧性剪切作用有关的含金黄铁矿-石英脉,②与走滑-伸展转换体制有关的含金多金属-石英脉。氢、氧同位素研究结果显示从早阶段向晚阶段,成矿流体由以变质热液为主向以大气降水为主的方向演化,硫同位素主要为深源硫特征,铅同位素分析结果显示来源于造山带和上地幔之间,并向造山带演化,且与阿舍勒铜矿的围岩和矿石有一定的成因联系,说明早期的火山作用对成矿有一定的贡献。对构造变形形成的黑云母进行Ar-Ar法定年,获得黑云母的坪年龄为(269.94±2.54)Ma,反等时线年龄为(269.38±2.63)Ma,结合已发表的年龄数据,该矿床可能由两个成矿事件形成,分别为290Ma左右和270Ma左右,对应于额尔齐斯构造带的两幕变形,早期主要与其大规模左行走滑有关,而第二成矿事件可能与后碰撞走滑-伸展转换体制有关。     

辽宁清原南龙王庙金矿流体包裹体研究

南龙王庙金矿位于华北克拉通北缘,产在清原群表壳岩的北东端.主要容矿岩石为新太古代的磁铁石英岩,控矿构造为葫芦头沟-大荒沟韧性剪切带.矿石以细脉-浸染状构造为主.主要蚀变类型有白云母化、硅化、绿泥石化、碳酸盐化和绿帘石化.对矿区细脉-浸染状矿石石英中的流体包裹体进行了系统的岩相学、显微测温分析.结果显示,矿石石英中存在两个不同阶段的流体包裹体：早阶段形成的包裹体主要为含子矿物的三相包裹体（I）;晚阶段形成的包裹体包括气液两相包裹体（II）、纯CO₂包裹体（III）和含CO₂三相包裹体（IV）三种类型.流体演化过程为：早阶段的中温、高盐度、中等密度的流体,萃取清原群表壳岩中的Au;晚阶段在剪切带韧性变形向脆性变形转化过程中,流体演化为中温、中低盐度、低密度的特征,Au成矿元素达到饱和,在有利的构造空间沉淀成矿.成矿作用的方式由早期的扩散交代逐渐转变为晚期的充填作用,分别形成细脉-浸染状矿体和含金黄铁矿石英脉型矿体.     

新疆东准噶尔金水泉金矿床地质特征、成矿时代及其地质意义

新疆奇台县金水泉金矿床是东准噶尔卡拉麦里成矿带上一个典型的造山型金矿床,产于清水-苏吉泉大断裂和卡拉麦里深断裂之间的次级断裂带中,其成矿时代尚无确切的年代学资料。通过阴极发光(CL)、背散射图像(BSE)和矿物包体确定含金石英脉中的锆石种类,进行LA-ICP-MS锆石U-Pb同位素定年。捕获锆石主要呈柱状、长柱状,振荡环带清晰,粒径较热液锆石大,包括岩浆锆石和变质锆石;~(206)Pb/~(238)U年龄为365~418Ma、265Ma。热液锆石呈短柱状、棱角状、不规则状、双锥状,常含继承锆石内核,内部包裹体为磷灰石或含金磷灰石,发育不明显的波缓状振荡环带或无振荡环带;~(206)Pb/~(238)U年龄加权平均值为314.9±3.2Ma,指示金矿化作用发生于晚石炭世早期碰撞造山向造山后伸展转变的构造环境。成矿时代晚于赋矿围岩姜巴斯套组的年龄(约343Ma),与总结区域构造演化规律所限定的时间范围(320~310Ma)吻合。综合研究认为,金水泉金矿床成矿作用可划分为350~320Ma造山阶段含金流体生成、315Ma挤压-伸展转换阶段金迁移就位、二叠纪陆内变形阶段金矿体破碎变形3个阶段。     

陕西葫芦沟金矿成矿断裂的构造地球化学特征

本区的成矿断裂是发育在太古代太华群中韧性剪切带之上的一系列脆－韧性、脆性剪滑断裂。在成矿过程中，不同类型断裂、不同类型构造岩带显示出不同的断裂动力蚀变特征和成矿元素组合。活化的金等元素在构造应力驱动下，于不同构造部位以不同形式沉淀并富集成矿，从而形成了蚀变岩型和石英脉型金矿体。     

东天山中段晚古生代面状剪切带形成机制与金成矿关系研究

东天山晚古生代康古尔塔格构造—金矿带的中段南带开展构造控矿研究,为区域金矿定位预测与勘探提供依据。采用区域构造分析和构造解析方法,在雅满苏北部厘定出一类已发生变形改造的大型面状脆韧性—韧性剪切带,构造恢复表明,其形成于晚古生代造山早期向北的分层剪切或低角度逆冲剪切(S₁//S₀)作用,并作为区域金矿的一级控矿构造而成为俯冲带深源成矿流体向上运移成矿的主通道。在造山过程中递进变形的分层剪切或低角度逆冲剪切晚期、向南北向横向缩短转换阶段,伴随区域抬升和断褶作用,拆离剪切带分支断裂开始成生并向上突破,导致封闭在拆离带内运移的深源含矿流体以断层阀方式分流排泄,成矿流体沿分支断裂向上运移,在断裂上盘或上盘背斜枢纽处的低序次的断裂、破裂中聚集卸载,形成充填石英脉和交代蚀变岩型(造山型)金矿,并有时限为276.5±2.9Ma的石英闪长斑岩侵入产出;晚期褶皱、断裂等叠加构造则对矿床(体)破坏、改造及保存起了重要作用。     

东准噶尔卡拉麦里地区金铜多金属成矿系统和地球动力学

卡拉麦里地区处于中亚—兴蒙成矿域东准噶尔成矿带的南段,晚古生代增生—碰撞过程明显、构造和岩浆活动强烈、矿产资源丰富。晚古生代增生—碰撞成矿作用集中在两个时期,卡拉麦里北缘至野马泉为主的泥盆纪和卡拉麦里构造带为主的早石炭世中晚期—二叠纪。本文在综合研究基础上,根据卡拉麦里地区晚古生代增生—碰撞过程的地球动力学和成矿特征,将成矿系统划分为:泥盆纪活动大陆边缘斑岩型金成矿系统,早石炭世中晚期后碰撞挤压—伸展转换阶段浅成低温热液—斑岩型金铜成矿系统,晚石炭世—二叠纪后碰撞伸展阶段造山型金铜成矿系统和岩浆热液型锡金成矿系统,以后3类为主。矿床组合包括:韧性剪切带型金矿、浅成低温热液型金矿、岩浆期后热液脉型金矿、斑岩型铜金矿、构造控制脉型铜矿和云英岩—石英脉型锡矿。认为该地区的泥盆纪活动大陆边缘成矿系统可能被晚石炭世—二叠纪后碰撞造山型金成矿系统所叠置而不易识别,后碰撞作用主导了该地区主要成矿系统,大陆岩石圈拆沉和软流圈地幔上涌产生的走滑伸展构造—壳幔岩浆作用—混合流体作用是卡拉麦里地区金属成矿作用的地球动力学机制。     

青海东昆仑阿斯哈金矿Ⅰ号脉成矿流体地球化学特征和矿床成因

阿斯哈金矿位于东昆中隆起带东段,是东昆仑重要的金、铁多金属成矿带。金矿的容矿围岩为印支早期闪长岩和黑云母花岗岩,NNE向和NW向断裂为主要的容矿构造,Ⅰ号脉为该金矿主要的矿脉之一,云煌岩与金矿脉空间关系密切。流体包裹体主要有富CO₂三相和气液两相2种类型。流体盐度（w(NaCl)）为1.83%~8.13%,流体密度为0.69~0.87 g/cm³,成矿温度为155.3~425.6 ℃。成矿Ⅰ阶段流体为低盐度、富CO₂的高温流体;成矿Ⅱ阶段富CO₂型和气液两相流体包裹体共存,发生了以CO₂逸失为特征的不混溶或沸腾,致使残余流体盐度升高;成矿Ⅲ阶段为气液两相包裹体。激光拉曼光谱分析表明,流体气相成分主要有CO₂、CH4、N₂。结合氢、氧和硫同位素组成分析认为,成矿流体主要为幔源流体,晚期有大气水的加入。通过等容线图解法估算成矿压力为98~132 MPa,估算成矿深度为8.16~9.58 km。通过与典型造山型金矿特征对比,阿斯哈金矿为中成造山型金矿,矿床形成于早印支期陆内造山由挤压向伸展转换时期。     

广西平南新坪金矿成矿流体特征及矿床成因初探

广西新坪金矿地处大瑶山多金属成矿带六岑矿田,矿体主要受新坪复式背斜和近东西向的断裂破碎带控制,赋存于寒武系黄洞口组砂岩、砂泥岩中。石英流体包裹体数据显示,成矿流体为中温低盐度低密度含CO₂的流体;流体中阳离子以Na⁺、Ca²⁺、Mg²⁺、K⁺为主,阴离子以Cl^-为主。氢氧同位素分析表明,成矿流体中水可能主要来源于岩浆,并叠加有变质水,且不排除有少量大气水加入的特征;矿石硫化物的硫同位素组成范围较窄,多为距离零轴很近的负值,推断可能是深源硫与地层硫的混合。根据本次分析及结合前人研究表明,Au来源具有多源性,主要来源于寒武系地层,但区内深源岩浆岩也有提供Au的可能性。据以上分析,结合前人对该地区矿床成因的研究,初步认为新坪金矿属于变质-岩浆热液叠加成矿。     

黔东南平秋金矿成因研究:来自氢、氧、硫同位素的制约

黔东南地处江南造山带西南段雪峰隆起西南端,区内金矿床(点)广布,是湘黔金矿集中区的重要组成部分。平秋金矿是该区金矿床的典型代表,其矿体产于下江群番召组浅变质火山-沉积岩,严格受北东向断裂褶皱控制。为理清其成因,对平秋金矿床含矿石英脉中的石英包裹体进行了氢、氧同位素测试。结果显示,其δD为-51.3‰~-59‰,δ18OH2O-SMOW为4.46‰~8.16‰,表明平秋金矿成矿期流体以变质水为主。对成矿期黄铁矿的硫同位素分析结果表明,其δ34S值为-1.86‰~4.55‰,而围岩下江群浅变质岩中黄铁矿的δ34S值为9.63‰~13.56‰,二者相差巨大,表明矿床中硫不是直接来自于赋矿围岩。根据上述氢、氧、硫同位素测定结果并结合区域地质背景,本文认为平秋金矿的成矿流体和成矿物质源自下伏地层的变质脱水作用,成矿作用与加里东运动造成的变质变形有关。     

Gold mineralization in the Jiangnan Orogenic Belt of South China: Geological,geochemical and geochronological characteristics,ore deposit-type and geodynamic setting

Located in the southeastern margin of the Yangtze Block and generally interpreted as the Neoproterozoic collisional product of the Yangtze with the Cathaysia Blocks of South China, the Jiangnan Orogenic Belt (JOB) contains a number of gold (Au) (-polymetallic) ore deposits and mineral showings, mostly hosted by Neoproterozoic low-grade metamorphic volcaniclastic and sedimentary rocks. The mineralization styles mainly include auriferous quartz veins and disseminated mineralization in altered mylonite and cataclasite that are developed along shear zones, fracture zones and inter- or intra-formational fault zones closely related to regional folding and shearing deformation. Three gold mineralizing epochs are recognized in the JOB. The ca. 423–397 Ma mineralization was associated with the early Paleozoic tectonothermal event(s), which induced widespread emplacement of Silurian S-type granites, low-grade metamorphism and enrichment of gold in the Neoproterozoic rocks (i.e., forming Au source beds). The second Au mineralization epoch, occurring at ca. 176–170 Ma (Jurassic), was related to the subduction of the Paleo-Pacific plate beneath the South China continental margin. The third and most important Au mineralization epoch took place at ca. 144–130 Ma (early Cretaceous), when a Basin-and-Range tectonic pattern was developed, characterized by NE–NNE-trending strike-slip faults, granitic domes and metamorphic core complexes (MCC), and basins filled with red bed lithologies. C, H, O, He-Ar, S and Pb isotopic and fluid-inclusion data suggest that the ore fluids were predominantly metamorphic and/or magmatic, with variable input of mantle-derived fluids and the progressive involvement of meteoric waters in the later stages of mineralization. Ore materials were mostly contributed by the Neoproterozoic source beds, plus a possible contribution from mantle- or magma-derived components. The Au (-polymetallic) deposits in the JOB, particularly those formed in the early Cretaceous, share many geological and geochemical features with the orogenic-type and Carlin-type deposits. In the context of tectonic evolution of South China, the gold mineralization in the JOB may be considered an “intracontinental reactivation type”, characterized by synchronous development of Au–polymetallic mineralization, reactivation of stuctures developed in Neoproterozoic metamorphic rocks, and widespread granite emplacement in the late Mesozoic.     

陕川丁家林-太阳坪金矿带成矿机理

丁家林-太阳坪金矿带与丁家林-太阳坪脆-韧性剪切带同位分布、同能源作用、同步生成，是脆-韧性剪切变形形成的石英脉型金矿，总体走向NE，主要由丁家林和太阳坪2个金矿床组成，分石英单脉、单脉密集带、复脉带3个亚型。丁家林以含Au石英复脉为主，太阳坪以含Au石英单脉为主；成矿物质来源于富含Si质的志留系黄坪组，成矿流体主要是构造水；内生成矿作用分脆．韧性剪切变形-构造分异热液期和韧-脆性剪切变形-构造分异热液期，与2期脆-韧性剪切变形相对应，第2期为主成矿期。其成矿机理是脆-韧性剪切变形动力成岩成矿。     

Geology and Genesis of the Superlarge Jinchang Gold Deposit, NE China

The superlarge Jinchang gold deposit is located in the joint area between the Taipingling uplift and the Laoheishan depression of the Xingkai Block in both eastern Jilin and eastern Heilongjiang Province. Wall rocks of the gold deposits are the Neoproterozoic Huangsong Group of metamorphic rocks. Yanshanian magmatism in this region can be divided into 5 phases, the diorite, the graphic granite, the granite, the granite porphyry and the diorite porphyrite, which resulted in the magmatic domes and cryptoexplosive breecia chimney followed by large-scale hydrothermal alteration. Gold mineralization is closely related to the fourth and fifth phase of magmatism. According to the occurrences, gold ores can be subdivided into auriferous pyritized quartz vein, auriferous quartz-pyrite vein, auriferous polymetailic sulfide quartz vein and auriferous pyritized calcite vein. The ages of the gold deposit are ranging from 122.53 to 119.40 Ma. The ore bodies were controlled by a uniform tectono-magmatic hydrothermal alteration system that the ore-forming materials were deep derived from and the ore-forming fluids were dominated by magmatic waters with addition of some atmospheric water in the later phase of mineralization. Gold mineralization took place in an environment of medium to high temperatures and medium pressures. Ore-forming fluids were the K^＋-Na^＋-Ca^2＋-Cl^--SO4^2- type and characterized by medium salinity or a slightly higher, weak alkaline and weak reductive. Au in the ore-forming fluids was transported as complexes of [Au （HS）2]^-, [AuCl2]^-, [Au（CO2）]^- and [Au（HCO3）2]^-. Along with the decline of temperatures and pressures, the ore-forming fluids varied from acidic to weak acidic and then to weak alkaline, which resulted in the dissociation of the complex and finally the precipitation of the gold.     

Trace element and REE geochemistry of the Zhewang gold deposit,southeastern Guizhou Province,China

The quartz vein-type gold deposits are widely hosted by the Neoproterozoic （Xiajiang Group） epimeta- morphic clastic rock series in southeastern Guizhou Province, China. The Zhewang gold deposit studied in this paper occurs in the second lithologieal member of the Pinglue Formation of the Xiajiang Group. Trace element geochemis- try of host rocks, quartz veins and arsenopyrite has revealed that ore-forming fluid was enriched in sulphophile ele- ments such as Au, Ag, As, Sb, Pb and Zn, and simultaneously concentrated some magmaphile elements such as W and Mo, which probably provides some evidence for multi-stage mineralization or overprinting of magmatic hydro- therm. Quartz veins and arsenopyrite were characterized by depletion in HFSE and enrichment in LREE. Hf/Sm, Nb/La and Th/La imply that the ore-forming fluid was probably a NaC1-H20 solution system enriched in more C1 than F; Th/U values reflect the strong reducibility of the ore-forming fluid, coincident with the sulfide assemblages. The values of Co/Ni reflect that magmatic fluids may have partly participated in the ore-forming process and Y/Ho values have proved that the ore-forming fluid was associated with metamorphism and exotic hydrotherm which has reformed former quartz veins during late mineralization. The concentrations of REE, Eu anomalies and Ce anomalies of this deposit display that ore-forming elements mainly were derived from host rocks and possibly from a mixed deep source, and the ore-forming fluid was mixed by dominant metamorphic fluid and minor other sources. The physical-chemical conditions of ore-forming fluid changed from the initial stage to the late stage. The metamorphic fluid is responsible for the mineralization. Therefore, the Zhewang gold deposit is classified as a quartz vein-type gold deposit which may have been reformed by magmatic fluids during the late stage.     

富湾超大型银矿床Ar-Ar年龄、铅同位素特征及形成条件分析

富湾超大型银矿床主要为脉状,产于下石炭统灰岩与长坑赋金硅质岩接触带及其下的破碎带中。银矿床矿化石英⁴⁰Ar-³⁹Ar年龄为(64.3±0.1) Ma。矿床铅同位素μ值（10.67~10.95）与赋矿地层的μ值(9.79~10.33)不同,而与粤西地区元古宇基底中矿床的μ值(10.62~10.66)相似。富湾超大型银矿床成矿物质主要来自元古宙变质基底,矿床形成与三水盆地晚白垩世到早第三纪强烈火山活动形成的有利成矿环境有关。有利于形成富湾超大型银矿床地质条件包括：（1）深大断裂构造交汇及盆地边缘同生断裂构造组成的连通网;（2）特殊岩性组合形成的聚矿-圈闭环境;（3）丰富成矿物质源区、多期矿化及成矿元素多次活化迁移;（4）多期次火山活动形成的循环地热系统。     

青田-仙居地区金银矿化特征及找矿远景分析

浙江青田-仙居地区位于华南褶皱系浙东南褶皱带之温州-临海拗陷内.金银矿化的直接围岩是上侏罗统西山头组晶屑、玻屑熔结凝灰岩.主控矿构造为火山机构及有关的断裂构造.多期次的火山活动、岩浆侵入活动为金银成矿提供热源、热液及成矿物质来源.该区与龙泉遂昌金银成矿带同处于地幔陡变带内,深部构造特征相同或相似.区内构造活动、火山喷发及岩浆侵入频繁而强烈,伴随的多期次热液活动明显.基底岩系为含金变质岩系(陈蔡群、龙泉群),盖层岩系是由基底含金变质岩系重熔或部分同熔形成的中生代火山喷发-沉积岩系.在基底岩系演化过程中,金银等成矿物质发生了活化、迁移、富集或再分配作用,部分在构造有利部位富集成矿,部分则以自然态、游离吸附态赋存在凝灰质岩石中,经多期次热液作用再次被活化、迁移,最终在成矿有利部位沉淀富集成矿.因此,青田-仙居地区具备较好的金银成矿条件,是金银矿找矿的良好远景区.