甘肃大水金矿床铅同位素组成与成矿物质来源探讨

通过对矿床矿石铅同位素组成的分析,并与矿区岩浆岩脉和围岩地层中的岩石铅同位素组成进行对比,借以示踪矿床成矿物质来源。研究表明,矿石铅与矿区岩石铅(灰岩和脉岩)的铅同位素组成具有较相近和较窄的变化范围,暗示铅可能属同一铅源。在铅同位素构造模式图及不同成因类型矿石铅的Δγ-Δβ成因分类图解中,显示出造山带铅、地壳与地幔混合的俯冲带岩浆作用铅特征,说明铅不是单一来源的正常铅,而是混合型多来源的异常铅。成矿物质是多来源的,赋矿地层和岩浆岩共同提供了铅源及成矿物质,但以岩浆为主,地层为辅,地幔铅参与了成矿。     

西秦岭李坝金矿床地质、同位素地球化学及其成因探讨

李坝金矿床位于西秦岭造山带中的礼-岷矿集区内,赋矿围岩为泥盆系浅变质细碎屑岩,矿床产于中川岩体的外侧热接触变质带内,矿体主要受断裂破碎带控制。本文在李坝金矿床地质特征研究的基础上,对赋矿围岩、花岗斑岩岩脉、矿石硫化物进行了LA-MC-ICPMS原位微区硫同位素测试及化学溶样法分析,对不同地质体的铅同位素进行了系统测定与示踪,测定了成矿流体的氢-氧同位素组成,并对与矿体相伴产出花岗斑岩脉进行了LA-ICP-MS锆石U-Pb定年。研究表明,李坝金矿床花岗斑岩脉中黄铁矿δ34S值范围为8.19‰~10.06‰,赋矿围岩中金属硫化物δ34S值范围为4.94‰~9.81‰,矿石硫化物的δ34S值范围为4.94‰~10.82‰,矿石硫化物的硫同位素组成与矿区花岗斑岩及赋矿围岩的硫同位素组成相似,暗示成矿流体中的硫源主要来自受改造或变质的地层岩石与岩浆热液硫的混合。不同地质体的铅同位素组成变化范围较小,在Zartman铅构造模式图解中,样品投影点均落于造山带与上地壳演化线附近,矿石铅投影点与赋矿围岩及矿区岩脉的投影点重合,表明矿石中的铅可能来源于赋矿围岩和岩浆作用的混合。氢-氧同位素研究表明,成矿流体可能为变质流体、岩浆流体及地层建造水的混合热流体。矿区花岗斑岩脉与矿体相伴产出,花岗斑岩的LA-ICP-MS锆石U-Pb年龄为223 Ma,与金矿化时间一致,暗示成矿作用与岩浆活动同时发生。李坝金矿床与矿区岩浆岩同为造山作用的产物,并且其矿床地质特征、同位素地球化学特征与造山型金矿床相似,为形成于秦岭造山带由碰撞向伸展转变环境下成矿物质来源复杂的造山型金矿床。     

桂东龙水金矿床地质特征及成因

龙水金矿是赋存于大宁花岗闪长岩体外接触带的破碎蚀变岩型金矿。从矿床地质、矿石物质成分及金的赋存状态、围岩蚀变、矿物流体包裹体、稳定同位素等不同方面阐明金矿床的地球化学特征,认为龙水金矿的形成是在变质热液成矿的基础上叠加后期岩浆热液成矿作用的复合成因金矿床。矿区外围还具有找矿远景。     

老挝爬奔金矿床稳定同位素、稀土元素地球化学特征

爬奔金矿位于丰沙里-帕府(泰国)中生代拗陷带与琅勃拉邦-梨府(泰国)华力西褶皱带的交接部位,属于岩浆期后低温热液型矿床。文章通过对爬奔金矿床含金方解石氢、氧、碳同位素组成和稀土元素地球化学特征的研究,探讨成矿溶液中水、碳来源以及成矿溶液的演化问题。研究表明,热液流体来源主要是岩浆水与地层封存的古大气降水。矿石中方解石的碳、氧同位素~(13)C_(V-PDB)(‰)值分布在-4.5~-5.2之间,~(18)O_(V-SMOW)(‰)值分布于20.0~20.8之间,表明含金方解石矿物为热液流体与二叠纪海相碳酸盐岩相互作用的产物。     

陕西铧厂沟金矿床成矿特征及物质来源研究

陕西略阳铧厂沟金矿床为小型金矿.矿床赋存于南秦岭地区中下泥盆统三河口群地层的细碧岩和海相碳酸盐岩中:矿体明显受层间断裂构造控制.金矿石主要有细碧岩型金矿石、灰岩-石英脉型金矿石和石英砂岩型金矿石三种,分别赋存在主矿带、北矿带、南矿带和南南矿带中.本文通过硫、铅、碳、氢、氧等同位素以及微量元素、稀土配分型式等方面的系统研究发现,铧厂沟金矿中的细碧岩矿石与灰岩矿石在同位素组成、微量元素Q型聚类以及稀土配分型式上均有较大差异,前者成矿物质来源为深源特征,后者成矿物质来源为地壳(沉积)特征,且两种矿石分别显示出与赋矿围岩的紧密联系,表明成矿金属物质、硫、铅和碳主要来自赋矿的基性火山岩系和海相碳酸盐岩地层.氢、氧同位素显示成矿溶液主要来自加热的循环地下水,部分流体来源与岩浆水有关.     

新疆青河县薛夏巴斯套金矿地质特征

文章论述了新疆青河县薛夏巴斯套矿区金矿地质特征。介绍了金矿产出的地质背景,赋矿层位及赋矿岩石特征,蚀变与矿化,矿(化)体特征及矿石质量,矿物组合等。探讨了矿床成因,指出金矿形成于岩浆侵入阶段,为岩浆气液型金矿床。后期受构造变质作用、热液作用叠加,使矿体形态、矿石组构、矿物成分发生变化,最终形成岩浆-热液改造型金矿床。     

内蒙古柴胡栏子金矿田燕山期岩浆岩与金矿床

岩相学、岩石化学及稀土元素和微量元素研究证明, 柴胡栏子金矿田的燕山期火成岩组合具有活动大陆边缘弧火成岩组合的特点, 介于典型的靠近海沟的钙碱性弧火成岩与陆内造山火成岩之间的过渡类型。流体包裹体测温 （１８０℃～２９０℃）, 硫同位素 （δ３４ Ｓ＝ ３１‰～７８‰）, 氢氧同位素 （成矿流体以岩浆水为主, 有大气水参与）, 岩石、矿石稀土元素配分特点的相似性等说明金的成矿主要与岩浆作用有关。燕山期岩浆构造作用引起原始矿源层太古界建平群中的金发生活化、迁移, 并在岩浆热液的进一步作用和大气水的参与下, 发生富集沉淀, 形成金矿床。柴胡栏子金矿田的北矿区金矿成矿主要与闪长岩有关, 以蚀变岩型为主。王府矿区金矿化与闪长玢岩脉关系最密切, 以石英脉型为主。岩浆作用为金矿床的形成提供了热源和大部分热液来源, 并且是成矿物质活化和转移的载体。本区金矿床应属与岩浆作用有关的中温热液矿床。     

新疆天格尔金矿带成矿物质来源探讨

天格尔金矿带是近年来在中天山发现的一个大型金矿带。本文从金矿围岩的含金性、岩石和矿石的稀土元素和微量元素特征、黄铁矿的硫同位素特征及矿化带中金含量的分形结构因子（ＦＳＦ）等方面探讨了金矿带的成矿物质来源。研究表明，长英质糜棱岩既是金矿脉的围岩，也是金的矿源岩，在走滑剪切作用过程中，金从矿源岩中活化并迁移出来，形成一系列剪切带型金矿床。     

青海卡尔却卡铜多金属矿床地球化学特征与成矿物质来源

为了解卡尔却卡铜多金属矿床的物质来源, 探讨其成岩、成矿机制, 通过现场调查, 结合矿床地质成矿条件, 对矿区典型的岩浆岩、围岩及矿石进行了主量元素、微量元素分析及S、Pb同位素分析.结果表明: 矿区岩体属中酸性岩, 为高钾钙碱性系列岩石, 源于深部, 上侵时受地壳混染, 具同源特征.不同地质体稀土配分曲线均为右倾轻稀土富集型, 岩浆岩、矽卡岩和矿石为同一成矿系统.微量元素地球化学显示矿区花岗岩产于火山弧环境.矿石硫同位素δ34S_CDT值为4.4×10-3~11.0×10-3, 处于岩浆硫跟围岩混合硫范围内, 成矿物质具多源性.矿石铅同位素Th/U值范围为3.46~3.69, μ值为9.46~9.52, 均低于9.58, 介于地壳与原始地幔值之间, 反应矿石铅具深源铅和壳源铅特征.铅同位素特征参数示踪、构造模式示踪和Δβ-Δγ图解示踪的结果表明: 铅来源与岩浆作用有关, 以壳源铅为主并混合少量深源地幔铅.总结矿床地球化学特征表明成矿物质主要来源于岩浆, 少量来源于周围地层.矿区岩体成矿演化过程复杂, 在岩体中形成斑岩型铜、钼矿化, 在与碳酸盐岩接触带形成矽卡岩型铅、锌矿化, 及至后期热液作用形成中低温热液脉型金矿化, 是一个多因复成矿床.      

老挝爬奔金矿围岩蚀变特征及其与金矿化的关系

爬奔金矿位于琅勃拉邦岛弧带中段西侧,矿体赋存于石炭-下二叠统厚层-巨厚层灰岩中,受NW-NNW向断裂构造控制,是少硫化物型中-低温热液矿床。野外调研及室内研究结果表明:爬奔金矿的围岩蚀变以中-低温蚀变矿物组合为特征,主要有硅化、褐铁矿化、菱铁矿化、方解石化,随着岩石蚀变强度的增加,Au与Si、Fe同步增加,而Ca减少。蚀变受断裂构造控制,分带明显,不同的矿化蚀变对应不同的矿石类型。多种蚀变叠加部位是成矿有利地段。"红化"蚀变和"褪色"蚀变是区内独特的围岩蚀变现象,找矿指示作用明显,结合构造、地层、化探异常等其他条件,可作为矿区外围及邻区的找矿标志。     

老挝爬奔金矿床红土型金矿化地质特征及成因分析

老挝爬奔金矿床存在两类金矿化,即产于二叠系灰岩及其接触带上,受断裂构造控制的碳酸盐化低温热液型原生金矿化和产于凹陷地形中,与原生金矿化伴生的红土型金矿化。两类矿化在空间上紧密相关,空间结构自上而下为红土型金矿化和碳酸盐化构造蚀变岩型金矿。矿区土壤地球化学Au异常区、红土型金矿以及原生型金矿体常具"三位一体"的对应关系。     

新疆维权银多金属矿床地质特征及找矿方向

文章通过对维权银多金属矿床地质特征的认识,结合矿区矿石、岩石地球化学、稀土元素、微量元素以及硫同位素特征,初步认为该矿床为一个钙矽卡岩型银多金属矿床。区域性韧-脆性大断裂影响带中的华力西晚期花岗岩类岩体与石炭纪含钙质岩系的接触带附近是成矿有利部位;钙矽卡岩带、多金属矿化(孔雀石化、铅锌矿化等)、化探Cu、Pb、Zn、Ag等多金属异常组合、高磁 高重力 高极化 低阻的物探"三高一低"异常组合是最佳找矿标志。区内北部应主要寻找与剪切带成矿作用有关的金矿,南部应主要寻找矽卡岩型铜银多金属矿。     

Migration paths and precipitation mechanisms of ore-forming fluids at the Shuiyindong Carlin-type gold deposit,Guizhou, China

Shuiyindong is one of the largest and highest grade stratabound Carlin-type gold deposits in China. This paper reports on the results of petrographic studies, electron microprobe analyses (EMPA) of arsenian pyrite, and the mass transfer during mineralization and alteration, and it presents the deposit-scale distributions of Au, As, Sb, Hg, Tl, and trace elements in a representative cross section across the Shuiyindong Carlin-type gold deposit, Guizhou Province. The main objectives were to identify the precipitation mechanisms of minerals, or elements from fluids, and the migration paths of ore-forming fluids.Petrographic and EMPA studies indicate that gold in the primary ores is mainly hosted by arsenian pyrite. Mass transfer associated with alteration and mineralization shows that Au, As, Sb, Hg, Tl, and S were significantly added to all mineralized rocks, Fe₂O₃ and SiO₂ were immobile in the main orebodies that are hosted in bioclastic limestone, and CaO, Na₂O, Sr, and Li were removed from country rocks. The relations between Fe and S indicate that the sedimentary rocks at the Shuiyindong deposit contain more iron than is needed to combine with all of their contained sulfur to form pyrite. This suggests that sulfidation and decarbonation were the principal mechanism of gold precipitation at the Shuiyindong deposit. Hg, Sb, and As commonly formed sulfide minerals, such as stibnite, realgar, and orpiment, in late-stage quartz–calcite veins, or absorbed by organic matter in argillite. Fluid cooling presumably led to depositions of stibnite, realgar, and orpiment in late-stage quartz–calcite veins. Organic matter likely served as a reductant in argillite for the ore fluids, causing the precipitation of As, Sb, Hg, and S, as well as Au.Deposit-scale distributions of gold and other relevant elements reflect the passage of fluids through the rocks. Rock strata and structures allowed the ore-forming fluids to migrate horizontally along the unconformity surface of the Middle–Upper Permian, converge on the high position of an anticline, and then ascend into the overlying strata along the anticlinal axis. The distributions of the major and trace elements show that elements that accompanied the ore-forming fluids include Au, As, Sb, Hg, Tl, and S, and that Na₂O and Li were exhausted in the Longtan Formation at the anticlinal core during gold mineralization. The enrichment of Co, Cr, and Ni in the Longtan Formation at the anticlinal core might be associated with deformation that formed the anticline, or with gold mineralization. Different host rocks were preferentially mineralized by different elements. The bioclastic limestone is commonly enriched in Au, whereas the argillite is preferentially enriched in As, Hg, Sb, and Tl. The zonation of ore-forming elements in the deposit appears to be Sb–Tl–As–Hg–Au–Hg–As (from bottom to top). Enrichment of Au, As, Sb, Hg, and Tl provides useful guidance for the exploration for Carlin-type gold deposits in Guizhou. Anomalies of As and Hg in soil or stream sediment might be an important clue and these elements can be used as indicator elements. Ore-forming fluids migrated along the unconformity surface of the Middle–Upper Permian and the anticlinal axis, so these are favorable sites for exploration for Carlin-type gold deposits in Guizhou.     

桂西巴马料屯金矿床成矿年代上限的确定——对滇黔桂“金三角”卡林型金矿年代学研究的启示

广西巴马料屯金矿床是较为典型的卡林型金矿床,金矿体与燕山晚期石英斑岩脉空间上相关。矿床勘查成果和野外露头观察均表明石英斑岩脉切割金矿体,说明岩浆岩形成于矿体之后。成矿元素地球化学测量结果表明,Au、As元素沿石英斑岩脉走向出现明显的分异,表现为在导矿和容矿断层区段Au、As质量分数高,局部形成矿（化）体;远离矿体的砂泥岩和灰岩围岩地段,则逐渐降低至正常背景值,说明石英斑岩侵位过程中切割早期的矿体或含矿断层,萃取了矿（化）体中成矿元素Au、As,从而在这些断层之间形成一定宽度的高值带。成矿元素地球化学测量支持岩浆岩形成于矿体之后的结论。石英斑岩脉白云母斑晶的⁴⁰Ar/³⁹Ar坪年龄为（95.5±0.7） Ma,代表了岩浆侵位年龄,由于岩脉形成于矿体之后,此年龄可以作为成矿年代的上限年龄。本矿床及滇黔桂"金三角"其他卡林型金矿的确切成矿年代,尚需更多高精度直接成矿年龄数据的约束。     

河南庄金矿地球化学特征及成矿流体探讨

河南庄金矿位于华北板块最南端的秦岭构造带上,赋矿围岩为一套碳酸盐岩钙泥质建造,矿化受地层和构造发育控制.通过微量元素、稀土元素、C-H-O-S同位素分析对成矿流体来源和成矿条件进行了研究.其中微量元素、稀土元素、氢-氧同位素分析都指示成矿流体来自岩浆,后期受到变质作用和沉积改造作用影响;碳-氧同位素数据表明碳和部分氧元素来自海相碳酸盐的溶解作用,并催化了金元素的富集;硫同位素与微量元素分析得出成矿环境为缺氧的还原环境,并指示成矿流体来自深地壳或地幔.河南庄金矿同蚀变岩型金矿的矿床地质-地球化学特征相似,应属于蚀变岩型金矿.     

Trace Elements in Fluid Inclusions in the Carlin—Type Gold Deposits,Southwestern Guizhou Province

Fluid inclusions in quartz from the Lannigou and Yata Carlin-type gold deposits in southwestern Guizhou were analyzed by inductively coupled plasma-mass spectrometry for their trace elements(Co,Ni,Cu,Pb,Zn,Pt,etc.).The results show that quartz fluid inclusions entrapped at different ore-forming stages contain higher Co,Ni,Cu,Pb and Zn.It has been found for the first time that the ore-forming fluids responsible for the Carlin-type gold deposits are rich in Pt.From this it can be concluded that basic volcanic rocks seem to be one of the important sources of ore-forming materials for the Carlin-type gold deposits.     

新疆霍什布拉克铅锌矿床微量元素地球化学

霍什布拉克铅锌矿床是新疆西南天山地区晚古生代碳酸盐岩容矿的重要矿床。本文采用高精度电感耦合等离子质谱(ICP-MS)对主要矿石矿物(黄铁矿、方铅矿、闪锌矿)和热液脉石矿物方解石进行了微量元素地球化学研究。研究表明,黄铁矿、方铅矿、闪锌矿、方解石具有较为相似的稀土元素特征,Eu正异常明显,弱负或弱正Ce异常指示成矿流体最初由相对氧化的条件演化为还原条件。与霍什布拉克岩体、容矿围岩的稀土元素组成进行对比后发现,硫化物及热液方解石稀土元素配分曲线部分与重结晶泥晶灰岩重合,结合前人同位素地球化学研究,认为容矿坦盖塔尔组碳酸盐岩为成矿提供了必要的成矿物质及成矿流体组分。Ga/In值显示闪锌矿为低温成矿;硫化物明显富集LREE,Hf/Sm、Nb/La和Th/La值小于1,显示铅锌成矿过程中成矿流体主体以富Cl为特征;Y/Ho、Zr/Hf和Nb/Ta值变化范围相对较小,表明成矿期流体性质相对较为稳定,基本未混入外来流体。     

Yangshan Gold Deposit: The Largest Carlin and Carlin-like Type Gold Deposit in China

Gold Headquarter of the CAPF has discovered the Yangshan super large-scale gold depositin Gansu Province, which is a great breakthrough of gold exploration and prospecting in WesternQiniing Mountains of China. The gold resources of this deposit achieved 308 tons with increasingpotentials. Preliminary geological investigations indicate that the Yangshan gold deposit is located inthe intra-continental collision orogenic belt; and the deposit was formed during the continent-continentcollision orogenic processes. The geological characteristics of the deposit are similar to that of thetypical Carlin-type gold deposits, while differences still exist. The ore-forming background is notablydifferent from the Carlin gold deposit province in the United States; and the ore-forming fluids aresimilar with that of the orogenic-type gold deposit. Accordingly, the Yangshan gold deposit is atransitional type between the Carlin-type and the orogenic type gold deposits. At present, the Yangshangold deposit is the largest Carlin and Carlin-like type gold deposit that is ever discovered in China.Researches on metaliogeny, metaliogenic model and ore-enrichment regularities of the Yangshan golddeposit are crucial to meet the pressing needs of the current geological investigation and oreexploration of the deposit.     

云南勐海勐满金矿床的地球化学特征及成因

云南勐满金矿床是"三江"褶皱系南端的一个微细粒—红土复合型金矿床,矿床达中型规模,并具有成为大型金矿的找矿远景。赋矿层位为上元古界澜沧群片岩和中侏罗统碎屑岩及第四纪残坡积层。文章提供了勐满金矿的矿床地质特征、流体包裹体以及S、H、O和Pb同位素地球化学研究资料,并对矿床成因和成矿作用进行了分析。研究表明:勐满原生金矿床具有与卡林型金矿床类似的地质和地球化学特征;其成矿物源主要是上元古界澜沧群曼来组浅变质岩系和中侏罗统花开左组碎屑岩系;流体包裹体及S、H、O同位素研究一致显示成矿流体主要为大气降水。成矿作用经历了原始含矿岩系(矿源层)的形成阶段及金的活化、迁移和富集阶段。区域构造及岩浆活动是引起金矿活化迁移和富集的主要因素。进一步加强对含矿层位的岩相古地理与岩石学研究、加强控矿构造的分析、确定控矿构造的力学性质及与区域主干断裂之间的配套关系,是今后找矿工作中需要特别注意的问题。     

河南省桐柏银洞岭银矿床地质地球化学特征

银洞岭银矿床属变质碎屑岩型银(金)矿床, 其成矿元素含量变化与歪头山岩组地层层序、岩石类型密切相关, 歪头山岩组下部变粒岩、云母石英片岩Ag含量相对较高, 成为银矿体的直接赋矿围岩;蚀变作用导致成矿元素显著带入, 而对稀土元素的迁移影响不大;成矿热液的运移以渗流作用为主、渗透作用为辅;通过对银洞岭银矿床地质地球化学评价标志的建立, 为该类型矿床的普查评价起到借鉴作用。