新疆达尔布特构造带多元信息综合找矿研究

在新疆达尔布特构造带附近展开多元信息综合找矿时．以遥感方法为先导,采用ETM数据多光谱假彩色合成、主成分分析、HSI编码、边缘增强以及Crosta法蚀变矿物填图等技术,结合化探异常及地质综合分析,圈定找矿靶区;经过部分地表检查验证,新发现矿化点8处,主要位于达尔布特断裂带的下盘,矿化多与花岗闪长岩小岩体有关,突破了前人认为成矿主要位于该断裂带上盘的认识,为区内找矿提供了重要线索,并为研究成矿规律、完善成矿理论提供了有益证据。     

陕西省宁陕县太山庙金矿床地质特征及找矿标志

太山庙金矿床位于胭脂坝岩体南接触带附近,近东西向的断裂带控制着含金构造带及金矿体的分布。矿区圈出3个金矿体,金矿物为微粒金,以包裹金为主。金矿石自然类型主要为黄铁矿化石英脉型、褐铁矿化石英脉型、黄铁矿化蚀变绢云母石英片岩型。地球化学异常、石英片岩、次级断裂、石英脉、褐铁矿化蚀变带等为本区主要找矿标志。     

赣南上围地区控矿断裂特征与铀成矿关系

位于江西省龙南县上围地区出露的燕山期花岗质复式岩体明显受北东向马屎山硅化断裂带和鹅形石英断裂夹持控制,是有利的产铀岩体,已探明291铀矿床和292矿点。岩体内断裂作用强烈,热液蚀变和铀矿化现象普遍。经地质调查,在岩体内识别出北东向断裂6条和北北东向断裂11条及若干北西—北西西向断裂。其中,北东向断裂主要包括岩体西部的硅化带和东部的石英断裂;北北东向断裂主要包括岩体东部的蚀变碎裂岩带和西部硅化破碎带;北西—北西西向断裂多被中基性岩脉充填,主要包括501～504号脉。北北东向断裂与铀成矿关系最密切,是容矿断裂。断裂的规模和产状控制了铀矿体的空间分布和展布形态,断裂性质控制了铀矿化类型,断裂变形程度控制铀矿化蚀变分带,断裂与中基性岩脉复合控制了富铀矿体的产出形态。     

新疆包古图地区金矿床矿化类型和与围岩关系研究

西准噶尔包古图地区是新疆北部重要的金铜产地,已发现中型金矿床1处,金矿点20余处,大型斑岩铜（金、钼）矿床1处。金矿床按矿化类型可分为石英脉-蚀变岩型、蚀变岩型、辉锑矿-石英脉型、富硫化物型以及产于斑岩型铜矿中的伴生金。石英脉-蚀变岩型是最主要的矿石类型,构成包古图地区最主要的经济矿体。蚀变岩型是包古图地区近年来发现的新矿化类型,矿体由就位于NW向断裂中的蚀变凝灰质细砂岩和蚀变凝灰岩组成。辉锑矿-石英脉型矿石中含自然砷、自然锑、Paakkonenite、方锑金矿和硫锑金银矿等罕见矿物,这些矿物都与金矿化直接相关。富硫化物型矿石中,自然铋和辉铋矿与金矿化紧密相关。这些金矿化在空间上与中酸性岩体和岩体附近的岩脉关系紧密,成因上金矿化与岩体密切相关,而与岩脉关系不大。成矿元素在岩体中含量最高,其次为岩体附近的火山碎屑沉积岩,同一区域内岩脉的成矿元素含量最低,离岩体越远,成矿元素含量越低。Au与As、Sb、Bi之间具有不同程度的正相关性,As、Sb、Bi异常是该区找金的重要化探标志。中酸性岩体是最重要的找矿标志,岩体附近的断裂系统是金矿最有利的就位空间。     

新疆富蕴县金水泉金矿地质特征和矿床成因规律分析

金水泉金矿赋矿地层为中泥盆地层,位于两条断裂交汇部位。中、酸性浅成小岩体或岩脉附近,以及碳酸盐化、硅化、褐铁矿化等蚀变,是重要的找矿标志。该矿为与韧性剪切带有关的中低温变质热液型蚀变岩型+石英脉型金矿床。     

陕西凤县金矿类型与金的预富集及找矿方向

陕西凤县地区金矿主要有蚀变岩与石英脉型。地层预富集是金矿形成的物质基础；岩体为金矿形成提供了Au源，而且沿构造蚀变带提供了热源，是Au活化成矿的一个重要条件；多期次热液沿构造破碎带进行交代改造形成蚀变预富集，是金矿成矿的关键。庞家河成矿模式为层预富集＋蚀变预富集＋后期多次热液交代富集成矿；佐家庄成矿模式为岩体（脉）预富集＋构造蚀变预富集＋多种热液叠加成矿。NNW向断裂带是寻找蚀变岩型金矿的主要标志；印支期与华力西期花岗岩－闪长岩带的内外接触带是寻找石英脉型及蚀变岩型金矿的主要构造带；金的预富集带是金矿成矿的有利部位，紧靠商丹大断裂南侧续分布的残余存小岩块旁侧都发现金矿床。     

甘肃北祁连西段金矿成矿地质条件及分布规律

区内金矿床划分为两个矿带：阿尔金断裂金矿化带和北祁连北缘金矿化带。又细分为５个亚带和３种矿化类型：鹰嘴山亚带——与超基性岩有关的蚀变岩型金矿;牛毛泉—寒山亚带——与中酸性火山岩破碎蚀变有关的金矿;雄子沟—河大坂亚带——热液充填的石英脉型金矿及金湾子—大风沟金矿亚带;石油河金铜矿亚带——断裂蚀变带和热液交代型为主的金矿。矿化类型：蚀变岩型、石英脉型、热液交代型     

双旗山金矿床的地质特征及找矿方向

双旗山金矿床的矿化主岩是中元古界变质岩,可分为两类金矿化:片岩+石英脉型金矿化和蚀变岩型金矿化。片岩+石英脉型金矿化主要受NW320°～340°断裂构造控制。蚀变岩型金矿化主要受近SN或NNE向断裂构造控制,双旗山金矿床的矿石属少硫化物金矿石,其硫化物含量少于2%,主要是黄铁矿,偶见方铅矿、闪锌矿和黄铜矿。与金矿化关系密切的近矿热液蚀变作用是硅化、绢云母化、黄铁绢英岩化。受近SN或NNE向断裂构造控制的蚀变岩型金矿化是双旗山金矿床找矿的主要目标。     

新疆谢米斯台地区小岩体型矿化遥感探测

中酸性小岩体易被地质填图遗漏,严重制约了该类型矿化的发现。在新疆西准噶尔谢米斯台地区找矿工作中,首先利用ETM+数据进行小岩体扫面,进而选取重点区采用ETM+和中巴资源卫星02B HR数据进行分辨率融合后解译、识别中酸性小岩体,并利用主成分分析法提取蚀变遥感异常,结合地质、化探信息综合分析后确定重点检查区域。利用此方法共解译出14个钾质花岗岩和3个黑云母花岗岩小岩体,这些小岩体大多被野外检查所证实。经野外检查发现了5处铜、金矿化点,证实了该方法的有效性。本研究中采用的方法可以为西部地区地质填图和中酸性小岩体型矿产资源勘查提供借鉴。     

新疆包古图地区金矿床地质特征及成矿模型研究

包古图地区是新疆西准噶尔重要的金矿集区之一,根据矿床地质和矿化类型,可将区内金矿化分为2类:以阔个沙也金矿床(包古图金矿Ⅰ~Ⅳ号点)为代表的石英脉型金矿化,产于部分中酸性斑岩体周边地层中,赋矿围岩为下石炭统包古图组凝灰质砂岩、凝灰岩等,围岩蚀变以硅化、绢云母化、黄铁矿化、毒砂化和碳酸盐化为主,矿体为黄铁矿_石英脉型、辉锑矿_石英脉型和自然砷_石英脉型或石英网脉型/蚀变岩型,受NE向断裂控制,与矿区密集分布的中酸性脉岩伴生,主要矿物组合为黄铁矿_毒砂_自然砷_辉锑矿_自然金_银金矿,矿化元素组合为Au_As_Sb,是中酸性斑岩系统热液演化晚期的产物;另一类金矿化产于中酸性斑岩与下石炭统火山_沉积地层的接触带中,以包古图金矿Ⅺ号点为代表,矿体为石英_硫化物脉型,矿物组合为黄铁矿_毒砂_自然铋_辉铋矿_自然金_黄铜矿,是斑岩系统热液演化较早期的产物。结合已有研究资料,可将区内金矿床的成矿模型总结如下:斑岩岩浆系统演化晚期分异出含Au_Cu_Bi_As_Sb的岩浆热液,在岩体内部形成斑岩型铜矿化,岩体与围岩接触带形成高温石英_硫化物脉型Au_As_Bi矿化,部分含矿热液随中酸性岩脉向外围迁移,并逐渐与大气水混合,最终在NE向断裂中形成石英脉型Au_As_Sb矿化。基于此成矿模型,认为包古图地区金矿找矿工作的重点应该放在中酸性斑岩体与围岩接触带和斑岩体外围NE向断裂(中酸性脉岩)密集分布区,尤其是As_Sb、As_Bi化探异常叠加区。矿床地质和地球化学特征对比显示,包古图金矿成矿系统与侵入岩有关的金矿成矿系统非常相似。     

西准噶尔布兰萨拉地区金成矿条件及找矿方向探讨

西准噶尔布兰萨拉地区位于谢米斯台-沙尔布提铜多金属成矿带的西段,区内已发现金矿床、金矿点、矿化点数十处,但目前尚无人对区内的金成矿条件进行系统总结和分析,下一步找矿方向不明确。本文在前人工作基础上,通过收集、整理已有的钻探、槽探、化探等资料,结合实地勘察及样品采集等工作,初步梳理出石英脉型和蚀变岩型两种金矿化成因类型。赋矿地层主要为古生界下志留统谢米斯台组,赋矿岩系为火山碎屑岩,岩性以石英脉、硅化凝灰岩等为主。晚志留世中酸性侵入岩与金矿的关系密切。北东向孟布拉克断裂为研究区内主干断裂,为导矿构造,控制着带内金矿的分布及规模,北东向、近东西向、北北东向的第二级次级断裂是主要的成矿、容矿构造。不同方向构造交汇地段、中酸性侵入体发育地段及金地球化学晕圈分布地段是研究区内下一步金矿找矿方向。     

Multi-stage pyrite and hydrothermal mineral assemblage of the Hatu gold district (west Junggar,Xinjiang, NW China): Implications for metallogenic evolution

The Hatu, Qi-III, and Qi-V gold deposits in the Hatu–Baobei volcanic–sedimentary basin (west Junggar, Xinjiang) represent the proximal, middle, and distal parts of the Hatu gold district, respectively. Orebodies of these deposits mainly consist of Au-bearing quartz veins and altered host rocks with disseminated sulfide minerals. Six types of pyrite in these mines are studied here to illustrate ore-formation processes. Sedimentary pyrite, including framboidal and fine-grained pyrite, occurs in mudstone-bearing sedimentary rocks or altered volcanic–sedimentary rocks. Framboidal pyrite formed during redox changes in sedimentary layers. Hydrothermal pyrite contains five subgroups, from Py1 to Py5. Porous Py1 formed prior to gold mineralization, and is overgrown by Py2 that contains inclusions of sulfide minerals and native gold. Coarser Py3 coexists with arsenopyrite and native gold, and contains the greatest As concentrations. Gold and antimony are also preferentially concentrated in arsenian Py2 and Py3. The Au–As-deficient Py4 and Py5 formed during the post-ore process. There is a negative correlation between the As and S contents in Py1, Py2, and Py3, implying the substitution of sulfur by arsenic. Gold precipitated under relatively reducing condition in framboid- and graphite-bearing tuffaceous rocks. Cesium, Rb, Sr, La, Ce, Au, As, Sb, Cu, and Pb are concentrated in altered host rocks. The Au-bearing quartz veins and disseminated sulfide mineral orebodies were formed via a co-genetic hydrothermal fluid and formed during different stages. The variation of fO₂ during fluid/rock interactions, and crystallization of arsenian pyrite were major factors that controlled gold precipitation.     

Early Tertiary epithermal gold mineralization, Bahcecik prospect, northeastern Turkey

The Bahcecik prospect is located in the eastern Pontide tectonic province of the eastern Black Sea region of Turkey. It is one of the first low sulfidation epithermal systems to be described from this area of Turkey. Gold mineralization occurred within Late Cretaceous to early Tertiary volcanic rocks and is localized along east-trending normal faults and lithologic contacts. An early quartz–sericite alteration event was focused along the major fault in the area and resulted in precipitation of arsenian (?) pyrite with anomalous gold. A later, more spatially extensive, advanced argillic alteration event overprinted the quartz–sericite event. Native gold was precipitated during this event as disseminations and fracture fillings in quartz. Gold mineralization is restricted to the high-temperature portion of the alteration zone characterized by quartz veins with diaspore–pyrophyllite selvages. The prospect area was subjected to Tertiary to Holocene supergene alteration.     

阿尔及利亚Hoggar地盾金矿成矿特征——以Tin-Zakri金矿为例

阿尔及利亚金矿主要分布于南部地区Hoggar地盾.受泛非运动影响,Hoggar地盾与西非克拉通挤压碰撞,区内金矿沿南北向断裂带分布.Tin-Zakri金矿位于Hoggar地盾近南北向Tiririnienne成矿带上,受区内北西向主构造控制.目前发现与矿化有关的矿化蚀变带30条,其中规模较大的有2条（27、30号脉）,矿体赋存在片理化岩带内,呈北西向或近南北向脉状展布,以石英脉的形式断续分布在韧性剪切带中.围岩蚀变特征明显,绢云母化为金矿的直接找矿标志,绿泥石化片理化带是金矿找矿的重要线索.     

内蒙古东部喀喇沁旗地区金矿围岩蚀变遥感信息提取及成矿预测

内蒙古东部喀喇沁旗地区位于燕山造山带东段的成矿带之上,金矿资源丰富.本文运用遥感技术,结合野外调查,对这一地区金矿围岩矿化异常信息进行了提取和分析.研究表明,本区现有矿床分布与明显受区域构造控制,区内金矿床围岩蚀变以硅化和含铁矿物为主,粘土矿物蚀变较少.区内主要发育3个成矿带,即南北各存在一个近E-W向的成矿带,喀喇沁旗东南发育一个NE-SW向的成矿带,且明显受断裂控制.成矿有利区主要位于本区东南部,且在本区南部NE-SW向断裂和近EW向断裂交汇地带围岩蚀变信息较强,可能为富矿部位.研究表明围岩蚀变遥感异     

GENERAL CHARACTER OF MULTISTAGES OF METALLOGENESIS FOR MICRO-MESOTHERMAL GOLD DEPOSITS:EXAMPLES FROM ZHANG-BALING TECTONIC BELT,ANHUI,CHINA

In Zhangbaling Tectonic Belt,two types of mineralization,auriferous quartz veins and alteration halos,can observed within many deposits.The pressure of metallogenesis of auriferous alteration halos is much higher than that of quartz vein,the temperatures of metallogeneses of these two types of orebodies are don't the same Geochemistry study indicates that both of them are micro-mesothermal deposits related to Yanshanian granites.The results of proton microprobe analysis of sulphides from the gold deposits in the area show that the "invisible" gold existed in sulphides is in the form of micro inclusions,and the concentration of "invisible" gold in sulphide minerals within quartz vein is poorer than that from alteration halos.Field observation shows that the structural modality of the fractures controlling the orebodies of auriferous quartz vein is different from that of the auriferous alteration zones.The fracture controlling the orebodies of auriferous alteration halos is compress-shear fracture,auriferous quartz vein is controlled by extensive fault.The alteration halos crosscut by auriferous quartz vein.The wallrocks of the former altered strongly and developed alteration zones well.The wallrocks of auriferous quartz vein altered slightly.The results of tectonogeochemical study shows that the concentration of associated metallogenesis elements and intensity of alteration are positively correlated with tectonic deformation strength for auriferous alteration halos.It indicates that it is probably a general character for micro-mesothermal gold deposits due to the multistages of metallogeneses took place.The tectonic environment is the most important fact determining the mechanism of fluid flow and precipitation of gold,and then the types of mineralization and modes of gold.     

Intrusion-Related Gold Deposits of North China Craton, People's Republic of China

Abstract. Intrusion‐related gold deposits are widely distributed within the North China craton or along its marginal fold belts. Presently, about 200 individual intrusion‐related gold deposits (prospects) have been discovered, among which Yuerya, Anjia‐yingzi, Linglong, Jiaojia, Chenjiazhangzi, Qiyugou, Jinjiazhuang, Dongping, Hougou, Huangtuliang, Guilaizhuang, Wulashan and Donghuofang are the most important ones. In general, the intrusion‐related gold deposits can be classified into three major groups according to their host rocks: (1) hosted by or related to felsic intrusions, including (la) calc‐alkaline granitoid intrusions and (lb) cryptoexplosion breccia pipes; (2) related to ultramafic intrusions, and (3) hosted by or related to alkaline intrusions. The first group contains the Yuerya, Anjiayingzi, Linglong, Jiaojia, Chenjiazhangzi and Qiyugou gold deposits. Gold mineralization at these deposits occurs within Mesozoic Yanshanian calc‐alkaline granitoid intrusions or cryptoexplosion breccia pipes as gold‐bearing quartz veins and replacement bodies. Pyrite, galena, sphalerite, chalcopyrite, native gold and electrum are major metallic minerals. The Jinjiazhuang deposit belongs to the second group, and occurs within Hercynian diopsidite and peridotite as quartz veins and replacement bodies. Pyrite, marcasite, arsenopyrite, native gold and electrum are identified. The third group includes the Dongping, Hougou, Huangtuliang, Guilaizhuang, Wulashan and Donghuofang deposits. Gold mineralization at these deposits occurs predominantly within the Hercynian alkaline intrusive complexes as K‐feldspar‐quartz veins and replacement bodies. Major metal minerals are pyrite, galena, chalcopyrite, tellurides, native gold and electrum. All these pyrite separates from Hercynian and Yanshanian intrusions or cryptoexplosion pipes associated with the gold deposits show a broad range in δ³⁴S value, which is overall higher than those Precambrian rocks and their hosted gold deposits. For the alkaline intrusion‐related gold deposits, the δ³⁴S values of the sulfides (pyrite, galena and chalcopyrite) from the deposits increase systematically from orebodies to the alkaline intrusions. All of these intrusion‐related gold deposits show relatively radiogenic lead isotopic compositions compared to mantle or lower crust curves. Most lead isotope data of sulfides from the gold ores plot in between the fields of the intrusions and Precambrian metamorphic rocks. Data are interpreted as indicative of a mixing of sulfur and lead from magma with those from Precambrian metamorphic rocks. Isotopic age data, geological and geochemical evidences suggest that the ore‐forming materials for the intrusion‐related gold deposits were generated during the emplacement of the Hercynian or Yanshanian intrusion. The calc‐alkaline or alkaline magma may provide heat, volatiles and metals for the intrusion‐related gold deposits. Evolved meteoric water, which circulated the wall rocks, was also progressively involved in the magmatic hydrothermal system, and may have dominated the ore fluids during late stage of ore‐forming processes. Therefore, the ore fluid may have resulted from the mixing of calc‐alkaline or alkaline magmatic fluids and evolved meteoric water. All these intrusion‐related gold deposits are believed to be products of Hercynian or Yanshanian calc‐alkaline and alkaline igneous processes along deep‐seated fault zones within the North China craton or along its marginal belts.     

新疆乌什塔拉地区遥感、化探、地质综合找矿研究

新疆乌什塔拉地区位于中亚天山成矿带的东南部,该成矿带上已发现众多矿床。在乌什塔拉地区开展地质矿产调查时,为快速确定找矿靶区,以遥感技术为先导,利用ETM+自然彩色合成、最小噪声分离等方法解译岩体、断层;之后对ETM+数据采用掩膜技术剔除干扰后,利用主成分分析法提取矿化蚀变信息;并将地质、化探、遥感等多元信息叠合进行综合分析。结果表明,利用主成分分析法提取的蚀变信息与化探异常、岩体、断层吻合较好,蚀变信息在工作区西北部、北部(喀拉塔格附近)及南部(阿拉塔格附近)具有面状、带状分布特征,而在工作区西南部、中部(阿勒格乌拉西)及东南部(扎合布拉格北沟附近)等地具有线状特征。经综合分析、筛选,共圈定了19处找矿靶区,对其中5处重点部位进行野外检查,发现利用主成分分析法提取的蚀变异常多由岩脉、断层、夕卡岩化、黏土化、褐铁矿化等引起。对蚀变带取样化学分析,确定了金、铜、铁矿化点3处。     

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。     

山东栖霞金矿的空间分布及其矿化特征

破碎蚀变岩型金矿与裂隙充填石英脉型金矿是栖霞地区主要金矿化类型,破碎蚀变岩型金矿分布于郭家岭超单元西石硼单元或玲珑超单元郭家店单元二长花岗岩体内外接触带附近;而裂隙充填石英脉型金矿主要分布于栖霞-桃村一带的古老基底构造轴部附近,且集中分布于该地区南北宽不超过20km的范围内。而大部分含金矿脉其附近往往发育有成群成带的中基性岩脉,中基性岩脉特别是煌斑岩为该区找金的一个间接标志。