滇西大平掌铜多金属矿床火山喷流沉积原因

大平掌矿床由上部层状块状硫化物矿体和下部细脉浸染状矿体组成,双层结构清楚。块状矿体中发育典型的草莓状和鲕状硫化物。成矿地质背景和矿石中的金属元素及REE配分形式、S同位素组成、流体包裹体特征等均与黑矿型矿床及现代海底热液活动区硫化物矿床相似。矿床典型的火山喷流沉积成因。     

含铜黄铁矿型矿床研究中的几个问题

含铜黄铁矿型矿床包括块状硫化物型铜矿床及别子型矿床。一般认为其形成与海底火山喷气-沉积作用有关。但对这类矿床的认识却存在很多争议。 1.对含铜黄铁矿型矿床的新认识。过去很多人都把这类矿床与块状硫化物矿床联系在一起。近年来作者研究表明,很多这类矿床不仅有块状硫化物矿石,而且还含有浸染状、细脉状、网脉状以及条带状矿石。且这些矿石往往是属同一成因的,因此将这类矿床统统以块状硫化物矿床命名是不符合实际的。比如加拿大Gold-Stream地区与基性火山岩有关的铜锌矿床;其中包含两种矿石,一种是产于绿色和暗色钙质千枚岩中薄层浸染状硫化物矿石,另一种为产于绿岩带地层间隙中的块状硫化物矿石,其间含有磁黄铁矿和黄铜矿的薄层紧密混合     

浅海环境下的喷流沉积块状硫化物矿床——以广东玉水铜矿为例

广东玉水铜矿是一个以斑铜矿、黄铜矿为主的高品位铜矿床,主矿体呈层状沿中石炭统白云岩/下石炭统石英砂岩界面产出.本文在详细的野外地质工作基础上,确认了块状矿体下盘存在石炭纪凝灰岩、火山丘状体及火山通道;确认了以红色赤铁矿-菱铁矿-碧玉岩为组合的喷气沉积岩,其稳定覆盖在块状矿层的顶部,并延伸出矿体外围.层状矿体层序由下往上为:(含砾)石英砂岩夹凝灰岩→块状铜铅锌硫化物矿层→赤铁矿-菱铁矿-碧玉岩等喷气沉积岩→白云岩,证实含矿岩系具有火山岩—矿体—喷气岩"三位一体"特征.层状矿体具有典型的"双层"结构:上部为块状矿体;下部为筒状含矿蚀变体,由呈漏斗状的流体通道系统及其浸染状、网脉状矿化体组成.围绕主流体通道发育扇形含硫化物石英细脉,且不穿过上覆块状矿体和上盘白云岩.本文还首次报道了控制矿体和凝灰岩厚度及铜矿体塑性流变的同生断层(同火山断层).综合矿床地质及地球化学研究表明玉水铜矿是形成于浅海环境下的喷流沉积块状硫化物矿床.这一新认识表明V MS型矿床可以形成于浅海水环境下,这对丰富和完善V MS型矿床的成因模式具有重要的科学价值;同时可为华南寻找类似地质背景区的隐伏V MS型铜多金属矿床提供借鉴.     

滇西大平掌铜矿成矿地质条件及找矿前景

大平掌铜矿位于滇西澜沧江火山岩带的中南段,矿体呈层状、似层状赋存于泥盆纪-石炭纪的一套细碧-石英角斑岩系中,矿体具明显的"上层下脉"双层结构特征,即上部为块状矿体,下部为细脉-浸染状矿体。矿床为火山岩型块状硫化物(VHMS)特征矿床。矿石的金属矿物为铜-铅-锌-金-银矿物组合为主,矿化及蚀变具明显的分带性。沿矿区北西向控岩控矿构造带南北两端及西侧具有较好的找矿前景。     

云南省老许寨铜及多金属矿床成因及找矿潜力分析

老许寨铜及多金属床位于云南"三江"成矿带南段,形成于岛弧环境中,是一处较为典型的火山喷流—沉积型矿床。矿床形成主要受海相火山裂陷盆地控制,盆地中发育较为典型的"双峰式"火山岩。矿区成矿条件优越,含矿层位为上石炭统龙洞河组上段(C3l2)中的第二段,含矿岩性主要为角砾状流纹岩、沉凝灰岩及部分硅质岩。矿(化)体主要由位于上部的块状硫化物矿体及下部的细脉浸染状矿体组成,共同构成典型的"双层结构"。本文通过研究区域地质背景和成矿地质特征,结合矿区演化特点及矿床成因,对矿区找矿潜力进行分析,为本矿区进一步深部找矿提供理论依据。     

闪锌矿与方铅矿的LA-ICPMS微量元素地球化学对江西冷水坑银铅锌矿田的成因制约

冷水坑银铅锌矿田位于江西省贵溪市,是我国重要的银铅锌矿集区。矿田中产有两类特征迥异的矿体,一类为赋存于花岗斑岩体内的细脉浸染状-大脉状矿体,另一类为产于火山碎屑岩夹层中的块状硫化物矿体。然而,目前关于两类矿体的成因及联系还存在争议。本文采用激光剥蚀电感耦合等离子体质谱仪对两类矿体中的闪锌矿和方铅矿进行了微区原位成分的测试,试图根据它们的微量元素特征约束矿床的成因问题。分析结果表明,产于细脉浸染状-大脉状矿体中的闪锌矿具有相对较高的Fe、Mn、Pb、Ag、Cu、Sb、Sn和Tl含量,而产于层控块状硫化物矿体中的闪锌矿具有相对略高的Cd含量。两类矿体中方铅矿的微量元素也存在一定差别,前者具有相对较高的Ag、Sb、Sn和Au含量,而后者具有相对较高的Cd、Bi、Se和Tl。通过与国内外不同成因类型铅锌矿床的综合对比,我们发现冷水坑矿田的闪锌矿具有较低的Zn/Cd比(66~131)、Cd/Fe比(0.06~0.31)和Co含量(多数10×10~(-6)),以及相对较高的Sn含量(多数1×10~(-6)),这些特征与火山成因块状硫化物矿床中闪锌矿的特征十分类似,表明它们可能具有类似成因。此外,我们的研究结果表明冷水坑矿田闪锌矿中Fe、Cd、Ag、Sb和Tl等元素主要以类质同象的形式存在,而Cu、Pb和Sn等元素主要以显微包裹体的形式存在。方铅矿中的Ag、Sb、Cd、Sn和Tl等元素以类质同象的形式存在,而Mn、Bi和Se等元素可能以显微包裹体的形式存在。此外,基于闪锌矿-方铅矿共生矿物对的Cd分配系数温度计,获得层控块状硫化物矿体的形成温度为238~246℃,而细脉浸染状-大脉状矿体的形成温度略低,为209~224℃,前者闪锌矿中相对较低的Fe和Mn含量,可能由氧逸度的影响造成。综上所述,我们认为冷水坑矿田两类矿体具有相同的成因机制,成矿流体和成矿物质都主要来自深部岩浆热液,温度、围岩性质及氧逸度是控制两类矿床金属硫化物微量元素差别的重要因素。     

东天山卡拉塔格矿带红海VMS型矿床S、Pb同位素地球化学研究

红海早古生代块状硫化物矿床是近年来在东天山新发现的典型VMS型矿床,赋存在一套早古生代海相岛弧火山岩-火山碎屑岩中,是由上部透镜状块状矿体和深部脉状-网脉状矿体组成。文章对该矿床开展了系统的S、Pb同位素地球化学研究,拟揭示其成矿物质来源。本次分析获得金属硫化物的硫同位素δ34 S值:黄铁矿闪锌矿黄铜矿,且接近于0‰(-0.8‰~6.0‰);而重晶石的δ34 S值为高正值(27.4‰~29.9‰),这与世界大部分VMS型矿床的硫化物δ34 S值一致;矿床硫主要来自于下盘岛弧火山岩硫及与少量海水硫酸盐无机还原硫的混合。金属硫化物的Pb同位素组成比较集中,其中206 Pb/204 Pb为17.886~18.144,207 Pb/204 Pb为15.465~15.506,208Pb/204Pb为37.325~37.684,硫化物Pb同位素类似于MORB亏损地幔Pb同位素特征,具有地幔和造山带来源特征,显示其金属成矿物质主要来源于矿体下盘发育的具亏损地幔特征的岛弧火山岩。总之,红海VMS矿床硫化物S、Pb同位素研究显示其成矿物质主要来自岛弧火山岩,少量来自海水,它们为深入研究VMS矿床成矿物质来源和成矿过程中流体间相互作用提供了资料。     

青海治多县多彩铜铅锌矿床蚀变矿化分带性与成因类型

多彩铜铅锌矿床位于"三江"多金属成矿带北段青海省南部的治多县,是目前该地区新发现的唯一一个与古特提斯火山作用有关的大型矿床。矿体产于晚三叠世巴塘群火山岩地层中,直接赋矿围岩为英安质凝灰岩。矿区内主要发育硅化、绢云母化、黄铁矿化、绿泥石化、重晶石化、白云石化、方解石化等蚀变,矿化类型以块状及浸染状铜铅锌矿化和纹层状及星点状铜矿化为主,其次为细脉状铜铅锌矿化等。蚀变矿化在空间上具有明显分带性,以白云石-重晶石固结壳为界,下盘依次出现硅化-重晶石化-块状及细脉状矿化带、硅化-黄铁矿化-稠密浸染状矿化带、黄铁矿化-硅化-绢云母化-稀疏浸染状矿化带、硅化-弱绿泥石化带、绿泥石化带。上盘则多为成矿后中低温蚀变组合,如弱硅化-弱绢云母化-绿泥石化等。成矿演化上,矿床经历了3期主要成矿作用:火山沉积-气液矿化期、海底喷流热液矿化期及表生期。矿床地质特征、蚀变矿化分带及成矿演化等的综合分析表明,多彩铜铅锌矿床与日本黑矿及同一构造带的"三江"中段川西呷村VMS矿床极为相似,属于火山岩容矿的块状硫化物矿床。     

思茅大豆掌铜多金属矿床地质特征及成矿机制

大平掌铜矿属火山成因铜多金属矿床。主矿体－－浸染状矿体为次火山热液型，受英安岩等组成的火山穹窿构造及隐爆角砾岩筒构造所控制，赋存部位为火山管道之隐爆角砾－次火山岩相；块状矿体是在D2－C1海相火山喷发时期形成，受后期构造及火山－次火山岩体侵位破坏，呈角砾状分布在构造破碎带中。矿床总体为海底火山喷流喷气沉积及次火山热液叠加改造的复合型铜矿床。     

新疆阿尔泰山南缘产于泥盆纪火山-沉积盆地铅锌矿床地质特征--以可可塔勒铅锌矿为例

可可塔勒矿床位于新疆阿尔泰造山带南缘,产于泥盆纪火山-沉积盆地内铅锌矿(可可塔勒)体呈似层状、透镜状,矿石构造以条纹条带状、块状、斑杂状为主,矿物成分相对简单,矿体直接容矿围岩为火山-沉积岩.矿床属火山-沉积岩容矿的块状硫化物矿床.为介于典型的火山岩容矿的块状硫化物型矿床(VHMS)和典型沉积岩容矿的硫化物矿床(SEDEX型)之间的过渡类型(一种新类型块状硫化物矿床),其矿化特征与伊比利亚型矿床相类似.     

Ore Genesis for Stratiform Ore Bodies of the Dongfengnanshan Copper Polymetallic Deposit in the Yanbian Area, NE China：Constraints from LA-ICP-MS in situ Trace Elements and Sulfide S–Pb Isotopes

The Dongfengnanshan Cu polymetallic deposit is one representative deposit of the Tianbaoshan ore district in the Yanbian area, northeast(NE) China. There occur two types of ore bodies in this deposit, the stratiform ore bodies and veintype ones, controlled by the Early Permian strata and the Late Hercynian diorite intrusion, respectively. Due to the ambiguous genetic type of the stratiform ore bodies, there has been controversy on the relationship between them and veintype ore bodies. To determine the genetic type of stratiform ore bodies, laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) in situ trace elements and S–Pb isotope analysis have been carried on the sulfides in the stratiform ore bodies. Compared with that in skarn, Mississippi Valley-type(MVT), and epithermal deposits, sphalerite samples in the stratiform ore bodies of the Dongfengnanshan deposit are significantly enriched in Fe, Mn, and In, while depleted in Ga, Ge, and Cd, which is similar to the sphalerite in volcanic-associated massive sulfide(VMS) deposits. Co/Ni ratio of pyrrhotites in the stratiform ore bodies is similar to that in VMS-type deposits. The concentrations of Zn and Cd of chalcopyrites are similar to those of recrystallized VMS-type deposits. These characteristics also reflect the intermediate ore-forming temperature of the stratiform ore bodies in this deposit. Sulfur isotope compositions of sulfides are similar to those of VMS-type deposits, reflecting that sulfur originated from the Permian Miaoling Formation. Lead isotope compositions indicate mixed-source for lead. Moreover, the comparison of the Dongfengnanshan stratiform ore bodies with some VMStype deposits in China and abroad, on the trace elements and S–Pb isotope characteristics of the sulfides reveals that the stratiform ore bodies of the Dongfengnanshan deposit belong to the VMS-type, and have closely genetic relationship with the early Permian marine volcanic sedimentary rocks.     

Comparative Study of Gacun and Youre Silver–Lead–Zinc–Copper Deposits in Sichuan, SW China, and their Mineralization Significance

The large Gacun silver–lead–zinc–copper deposit in Sichuan Province is one of the largest volcanogenic massive sulfide(VMS) deposits in China. The deposit consists of western and central ore bodies, which form a vein–stockwork mineralization system corresponding to hydrothermal channels, and eastern ore bodies, which form an exhalative chemical sedimentary system derived from a brine pool in a submarine basin. The Youre lead–zinc deposit, which is currently under exploration and lies adjacent to the southern part of the Gacun deposit, is characterized by intense silicification and vein–stockwork structures and consists of massive silicified rhyolitic volcanics, banded rhyolitic tuff, and phyllitic sericite tuff. From a comparison of their ore-bearing horizons, the Gacun and Youre deposits have a continuous and stable hanging wall(calcareous slate and overlying andesite) and foot wall(rhyolite–dacite breccia and agglomerate), and the lithologic sequence includes lower intermediate to felsic rocks and upper felsic rocks. Thus, the Youre deposit, which comprises relatively thinly layered low–grade ore, is regarded as forming a southward extension of the Gacun deposit. A further comparison of the structures of the ore-bearing belts between the two deposits suggests that the Youre ore bodies are similar to the western ore bodies of the Gacun deposit. Moreover, the characteristics of fluid inclusions and stable isotopes in the Youre deposit are also similar to those of the western ore bodies of the Gacun deposit. Genetic models of the deposits are proposed for the Gacun–Youre ore district, and massive concealed ore bodies may occcur in the Youre deposit at depths that are similar to those of the eastern ore bodies of the Gacun deposit.     

The Palaeoproterozoic Kristineberg VMS deposit, Skellefte district, northern Sweden, part I: geology

The Kristineberg volcanic-hosted massive sulphide (VMS) deposit, located in the westernmost part of the Palaeoproterozoic Skellefte district, northern Sweden, has yielded 22.4 Mt of ore, grading 1.0% Cu, 3.64% Zn, 0.24% Pb, 1.24 g/t Au, 36 g/t Ag and 25.9% S, since the mine opened in 1941, and is the largest past and present VMS mine in the district. The deposit is hosted in a thick pile of felsic to intermediate and minor mafic metavolcanic rocks of the Skellefte Group, which forms the lowest stratigraphic unit in the district and hosts more than 85 known massive sulphide deposits. The Kristineberg deposit is situated lower in the Skellefte Group than most other deposits. It comprises three main ore zones: (1) massive sulphide lenses of the A-ore (historically the main ore), having a strike length of about 1,400 m, and extending from surface to about 1,200 m depth, (2) massive sulphide lenses of the B-ore, situated 100–150 m structurally above the A-ore, and extending from surface to about 1,000 m depth, (3) the recently discovered Einarsson zone, which occurs in the vicinity of the B-ore at about 1,000 m depth, and consists mainly of Au–Cu-rich veins and heavily disseminated sulphides, together with massive sulphide lenses. On a regional scale the Kristineberg deposit is flanked by two major felsic rock units: massive rhyolite A to the south and the mine porphyry to the north. The three main ore zones lie within a schistose, deformed and metamorphosed package of hydrothermally altered, dominantly felsic volcanic rocks, which contain varying proportions of quartz, muscovite, chlorite, phlogopite, pyrite, cordierite and andalusite. The strongest alteration occurs within 5–10 m of the ore lenses. Stratigraphic younging within the mine area is uncertain as primary bedding and volcanic textures are absent due to strong alteration, and tectonic folding and shearing. In the vicinity of the ore lenses, hydrothermal alteration has produced both Mg-rich assemblages (Mg-chlorite, cordierite, phlogopite and locally talc) and quartz–muscovite–andalusite assemblages. Both types of assemblages commonly contain disseminated pyrite. The sequence of volcanic and ore-forming events at Kristineberg is poorly constrained, as the ages of the massive rhyolite and mine porphyry are unknown, and younging indicators are absent apart from local metal zoning in the A-ores. Regional structural trends, however, suggest that the sequence youngs to the south. The A- and B-ores are interpreted to have formed as synvolcanic sulphide sheets that were originally separated by some 100–150 m of volcanic rocks. The Einarsson zone, which is developed close to the 1,000 m level, is interpreted to have resulted in part from folding and dislocation of the B-ore sulphide sheet, and in part from remobilisation of sulphides into small Zn-rich massive sulphide lenses and late Au–Cu-rich veins. However, the abundance of strongly altered, andalusite-bearing rocks in the Einarsson zone, coupled with the occurrence of Au–Cu-rich disseminated sulphides in these rocks, suggests that some of the mineralisation was synvolcanic and formed from strongly acidic hydrothermal fluids. Editorial handling: P. Weihed     

祁连优地槽区块状硫化物矿床形成地质环境的初步对比研究和探讨

在成矿规律学的研究中,许多研究者常把优地槽的发展演化与矿床形成阶段相结合并力图给予模式化,认为块状硫化物矿床是优地槽发展初期的坳陷阶段,地槽基底下坳带来巨厚沉积和强烈火山作用时期,与火山和沉积作用有关的形成物(毕利宾,1950;斯米尔诺夫,1973)。     

湖北银洞沟银矿床地质特征与成因类型

湖北银洞沟矿床是中国为数不多的较为典型的大型银矿床。文中系统总结了该矿床的地质特征,初步提出了矿床的成因类型。研究结果表明:银洞沟矿床产于秦岭造山带东南部武当群变质火山岩中,矿体受韧性剪切带控制,矿石类型主要为石英脉型和少量蚀变岩型,围岩蚀变矿物组合主要为石英、铁白云石、白云母、钠长石、绿泥石、黄铁矿等,成矿流体特征为低盐度、低密度、富含CO2±CH4±N2的水溶液,矿床上部为低品位银金矿体,中部为高品位银金矿体和少量铅锌矿体,深部银品位降低,金品位增高,同时出现较厚大铅锌矿体。其地质特征与典型的造山型矿床一致,表明其为一造山型银矿床,矿床矿化分带符合造山型矿床成矿模式——地壳连续模型,因此应该充分重视寻找矿山深部金、铅、锌、铜、钼等接替资源。     

云南鲁春VMS 锌铅铜多金属矿床的成矿金属来源

鲁春VMS 锌铅铜多金属矿床产于金沙江构造带内鲁春-红坡牛场伸展裂谷盆地中,是三江地区典型的火山成因块状硫化物矿床,其含矿层位为双峰式火山岩系中的流纹质火山--沉积岩系。通过研究该矿床的主成矿元素、双峰式火山岩和矿石的稀土元素特征,对其成矿金属来源、赋矿火山岩及构造环境进行研究表明,鲁春多金属矿床属Zn --Pb --Cu 型火山成因块状硫化物矿床,形成于碰撞造山后在薄陆壳( 陆缘弧) 基底上伸展而成的裂谷盆地环境; 矿石的主成矿元素含量特征w ( Zn) /w ( Pb + Zn) 均值为0. 64,与日本黑矿和四川呷村矿床较为接近; ΣREE 为( 15. 99 ～ 144. 43) × 10 － 6,平均73. 99 × 10 － 6,LREE/ HREE 为3. 59 ～ 11. 40,平均6. 30,呈典型的LREE 富集型; δEu 为0. 13 ～ 0. 46,平均0. 28,Eu 负异常明显,与矿区流纹岩极为相似。矿体与流纹岩空间上的密切关系以及地球化学特征的一致性表明,成矿金属元素源自下伏的长英质岩系。     

阿尔金山喀腊达坂一带火山成因块状硫化物型铅锌矿床地质特征及找矿前景

阿尔金山北缘喀腊达坂地区位于红柳沟-拉配泉弧后盆地(裂谷)内,中酸性火山岩及近东西向断裂构造十分发育,在喀腊达坂断裂分布的褐铁矿化、黄钾铁矾蚀变带内已发现多处地质特征相似的铅锌矿床;通过分析喀腊达坂铅锌矿床地质特征,认为该区铅锌矿床均属火山成因块状硫化物型;。分析了该区的控矿因素,总结了找矿标志,认为该区硫化物型铅锌矿具有优越的成矿条件和巨大的找矿前景。     

海南石碌铁钴铜( 金) 矿床与 国内外IOCG 型矿床的对比研究

[摘 要] IOCG 矿床是近些年来被认知的一种重要矿床类型,因其巨大的经济和理论研究价值受到 国内外矿业界和学术界的重视。海南石碌铁钴铜(金)矿床在构造环境、与岩浆岩的关系、矿体特征、元 素和矿物组合、围岩蚀变等方面与国外典型的IOCG 矿床有相似之处。该矿床处于大陆边缘拉张的裂 谷环境,早期火山沉积岩为成矿提供初始矿源,后期侵入岩对成矿具有重要的改造富集作用,矿体基本 呈层状、似层状及少量脉状产于石碌群第六层中,一般铁矿体在上,钴铜矿体在下,具Fe-Cu-Co( -Au) 多元素组合,铁氧化物主要为赤铁矿,蚀变以透辉石化、透闪石化为主;在成矿时代方面区别于多数产在 元古宙的IOCG 矿床,而是经历了新元古代海相火山喷流沉积阶段、加里东期区域变质阶段、海西-印支 期热液改造阶段和燕山晚期热液改造阶段。文章认为石碌铁钴铜(金)矿床不仅与IOCG 矿床有较多相 似之处,与国内内蒙古白云鄂博铁稀土铌矿床、四川拉拉铜铁金钴钼稀土矿床、新疆乔夏哈拉铁铜金矿 床、云南迤纳厂铁铜稀土矿床和东川稀矿山铁铜矿床等也有相似之处。因此,在中国开展寻找IOCG 矿 床尤其是大型矿床,是很有前景的。     

阿舍勒铜锌块状硫化物矿床地质特征和成因

阿舍勒矿床与早－中泥盆世双峰式火山活动有着成因联系，产于火山洼地中，它在喷气－沉积阶段形成，后又细历了变质改造和岩浆热液叠加。矿床具有双层结构，很好的矿化分带和刨变分带。成矿流体的温度，压力和酸碱度等物理化学条件变化引起了围岩蚀变和矿石堆积，在海底界面上下形成了具有成因联系的两套矿化。