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哈达门沟金矿床产于华北克拉通北缘西段，形成于伸展构造背景中，成矿流体富钾高碱且氧化性强，矿石建造中铁氧化物含量高，并且可见铁氧化物被硫化物交代的现象。文章拟揭示金在铁氧化物中的含量和赋存状态，并探讨金矿床成因。对哈达门沟金矿3种类型矿石中的黄铁矿、铁氧化物(磁铁矿和赤铁矿)单矿物进行金、铁浸取实验，结果表明：铁氧化物含金较高；黄铁矿中的金和铁的浸出曲线不同步，金浸出率与铁浸出率呈负相关，表明黄铁矿中的金主要以颗粒金形式存在；铁氧化物中金、铁同步浸出，浸出率为正相关，表明铁氧化物中的金主要以品格金和(或)胶体吸附金形式存在。哈达门沟金矿床的上述特征均表明其具铁氧化物型金矿床的特点。 相似文献
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位于右江盆地南部的滇东南底圩金矿床是近年来新发现的一处金矿床,为理清其成因,对不同类型矿石和赋矿围岩进行了主、微量元素及硫化物的硫同位素分析。结果表明,相较于赋矿围岩,矿石中明显富集Au、As、Sb、Hg、Tl、S、K、C元素,应为热液带入;而Si、Mg、Fe、Zr和Th在矿石和围岩中变化不大,Fe主要来源于赋矿围岩。对矿床中的主要金属硫化物黄铁矿和毒砂进行的矿物学和硫同位素分析表明,载金矿物主要为含砷黄铁矿和毒砂,金可能主要以Au+的形式赋存在含砷黄铁矿和毒砂之中;含金硫化物具有较高的硫同位素组成(5.93‰~11.99‰),表明成矿所需的S主要为地壳来源。结合前人对于右江盆地南部相似金矿的研究,认为印支期造山作用使沉积物脱水形成的变质流体交代玄武岩,容矿岩石的硫化物化作用是底圩金矿床形成最重要的成矿作用之一。 相似文献
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陕西省铧厂沟金矿床位于勉略缝合带以南,矿体受控于近东西向逆冲断层和韧脆性剪切带。本文以细碧岩矿带为例,系统研究了围岩蚀变分带及蚀变矿物组合,总结了矿床的蚀变分带模式。围岩蚀变以穿切细碧岩透镜体的剪切带为中心向外依次可划分为黄铁绢英岩化带、绢云碳酸盐化带和绿泥赤铁矿化带。蚀变矿物组合分别为黄铁矿＋铁白云石＋铬云母＋绢云母＋钠长石＋石英＋方解石、铁白云石＋绢云母＋钠长石＋石英±黄铁矿、（铁）绿泥石＋钠长石＋铁白云石＋赤铁矿＋钛铁氧化物＋石英±绿帘石。蚀变岩石组分迁移分析表明,在围岩蚀变过程中, SiO2、Na2O、Fe2O3T、MgO与Y等组分发生不同程度的迁出, K2O、CaO、Ba、Rb、Sr、Cr、Cu、Pb和挥发组分等迁入,并以黄铁绢英岩化带最为显著。金在成矿流体中以Au（HS）–2络合物迁移,成矿流体与富铁细碧岩之间的反应是金沉淀重要机制。 相似文献
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甘肃李坝金矿围岩蚀变与金成矿关系 总被引：1，自引：0，他引：1
西秦岭地区是目前国内造山型和卡林型金矿找矿的热点地区之一,已发现的甘肃李坝造山型金矿为超大型规模。以李坝金矿6号矿带为例,系统地研究了其蚀变矿物组合、近矿围岩蚀变分带及相应的金矿化特征,总结了矿床(带)的蚀变分带模式。该模式具典型的中心式环带结构,可分为3个蚀变带,由中心向外依次为黄铁绢英岩化带、绢云母化带和绿泥石化带。蚀变矿物组合分别为黄铁矿+绢云母+石英±毒砂±白云母±电气石±方解石、绢云母+绿泥石+石英+黄铁矿±黑云母及绿泥石+黑云母±绢云母±黄铁矿;与这3个蚀变带相对应的是金的富集带、矿化带和无矿带。蚀变岩石物质组分迁移分析表明,围岩蚀变及其分带是热水流体/岩石反应时岩石化学组分发生迁移的结果,矿化伴随着蚀变发生,且金矿化与黄铁矿化和浸染状硅化关系最为密切。 相似文献
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Alteration and mineralization styles of the orogenic disseminated Zhenyuan gold deposit,southeastern Tibet: Contrast with carlin gold deposit 总被引：1，自引：0，他引：1
Orogenic disseminated and Carlin gold deposits share much similarity in alteration and mineralization.The disseminated orogenic Zhenyuan Au deposit along the Ailaoshan shear zone,southeastern Tibet,was selected to clarify their difference.The alteration and mineralization from the different lithologies,including meta-quartz sandstone,carbonaceous slate,meta-(ultra)mafic rock,quartz porphyry and lamprophyre were researched.According to the mineral assemblage and replacement relationship in all types of host rocks,two reactions show general control on gold deposition:(1)replacement of earlier magnetite by pyrite and carbonaceous material;(2)alteration of biotite and phlogopite phenocrysts in quartz porphyry and lamprophyre into dolomite/ankerite and sericite.Despite the lamprophyre is volumetrically minor and much less fractured than other host rocks,it contains a large portion of Au reserve,indicating that the chemically active lithology has played a more important role in gold precipitation compared to structure.LA-ICP-MS analysis shows that Au mainly occurs as invisible gold in fine-grained pyrite disseminated in the host rocks,with Au content reaching to 258.95 ppm.The diagenetic core of pyrite in meta-quartz sandstone enriched in Co,Ni,Mo,Ag and Hg is wrapped by hydrothermal pyrite enriched in Cu,As,Sb,Au,Tl,Pb and Bi.Different host rock lithology has much impact on the alteration and mineralization features.Carbonate and sericite in altered lamprophyre show they have higher Mg than those developed in other of host rocks denoting that the carbonate and sericite incorporated Mg from phlogopite phenocrysts in the primary lamprophyre during alteration.The ore fluid activated the diagenetic pyrite in meta-quartz sandstone leading the hydrothermal pyrite enriched in Cu,Mo,Ag,Sb,Te,Hg,Tl,Pb and Bi,but the hydrothermal pyrite in meta-(ultra)mafic rock is enriched in Co and Ni as the meta-(ultra)mafic rock host rock contain high content of Co and Ni.However,Au and As shear similar range in both types of host rocks indicating that these two elements most likely come from the deep source fluid rather than the host rocks.It was shown in the disseminated orogenic gold deposit that similar hydrothermal alteration with mineral assemblage of carbonate(mainly dolomite and ankerite),sericite,pyrite and arsenopyrite develops in all types of host rocks.This is different from the Nevada Carlin type,in which alteration is mainly dissolution and silicification of carbonate host rock.On the other hand,Au mainly occur as invisible gold in both disseminated orogenic and Carlin gold deposits. 相似文献
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The Nature of Ore‐forming Fluids of the Carlin‐type Gold Deposit in Southwest China: A Case from the Zimudang Gold Deposit 
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下载免费PDF全文 The Zimudang gold deposit is a large Carlin‐type gold deposit in the Southwest Guizhou Province, China, with an average Au content of 6.2 g/t. Gold is mainly hosted in the fault zone and surrounding strata of the F1 fault and Permian Longtan Formation, and the ore bodies are strictly controlled by both the faults and strata. Detailed mineralogy and geochemistry studies are conducted to help judge the nature of ore‐forming fluids. The results indicate that the Au is generally rich in the sulfides of both ores and wall rocks in the deposit, and the arsenian pyrite and arsenopyrite are the main gold‐bearing sulfides. Four subtypes of arsenian pyrite are found in the deposit, including the euhedral and subhedral pyrite, framboidal pyrite, pyrite aggregates and pyrite veins. The euhedral and subhedral pyrite, which can take up about 80% of total pyrite grains, is the dominant type. Au distributed unevenly in the euhedral and subhedral pyrite, and the content of the Au in the rim is relatively higher than in the core. Au in the pyrite veins and pyrite aggregates is lower than the euhedral and subhedral pyrite. No Au has been detected in the points of framboidal pyrites in this study. An obvious highly enriched As rim exists in the X‐ray images of euhedral pyrites, implying the ore‐forming fluids may be rich in As. The relationship between Au and As reveals that the Au may host as a solid solution (Au+) and nanoparticles of native gold (Au0) in the sulfides. The high Co/Ni ratio (>1) of sulfides and the enrichment of W in the ores all reflect that the gold‐bearing minerals and ore‐forming process were mainly related to the hydrothermal fluids, but the magmatic and volcanic activities cannot be neglected. The general existence of Au and As in the sulfides of both ores and wall rocks and the REE results suggest that the ore‐forming fluids may mainly be derived from the basin itself. The enrichment of Tl suggests that the ore‐forming fluids may be enriched in Cl. The Ce and Eu show slightly or apparently negative anomalies, which means the ore fluids were probably formed under reducing environment. The Y/Ho ratios of ore samples fluctuate around 28, implying the bicarbonate complexation and fluorine were both involved in the ore‐forming process. Combined with the previous studies and our results, we infer that the ore‐forming fluids enriched Au, As, HS? and halogen (F, Cl) were derived from the mixture of reducing basinal fluids and magmatic or volcanic hydrothermal fluids. 相似文献
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Hong Hanlie Wang Qinyan The Center for Material Research Testing Wuhan University of Technology Wuhan Bian Qiujuan Faculty of Earth Sciences China University of Geosciences Wuhan 《中国地质大学学报(英文版)》2001,12(1)
1The Shewushan gold dePOsit consists of a series of mineralized faults containing high gold grades (1. OX 10-6 to 19. 5 X10-s ) in a larger lower 'grade zone (0. 2 X 10-8 to 1. 0 X 10-6 )peripheral to these. The total reserve was approximately I X10,tons with an average grade around 2. 2 X 10-s. The discovery outcrop is of intense silicification and anomalous gold values(up tO 3. 4 X 10-e ). Hubei No. 4 Geological Party investigatedthe data from Hubei Regional Measuring Party and Hubei… 相似文献
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铜厂铜-铁矿床是勉略宁矿集区具有代表性的矿床之一,主要由上部的铜厂铜矿床和下部的杨家坝铁矿床(铜厂铁矿床)组成。根据磁铁矿和硫化物的相对含量,铜厂铜-铁矿床的矿石可分为磁铁矿矿石、含硫化物磁铁矿矿石和硫化物矿石三类。系统的岩相学和矿相学研究表明,其矿石矿物主要为磁铁矿、黄铜矿、黄铁矿和磁黄铁矿;矿石结构包括自形-半自形-他形粒状结构、交代残余结构和包含结构,矿石构造包括块状、浸染状、脉状和条带状构造。铜厂铜-铁矿床的围岩蚀变种类较多,且具有一定的分带性,上部铜矿体围岩蚀变以硅化、碳酸盐化和黑云母化为主,以石英、方解石和黑云母为主的蚀变矿物组合显示钾化特征;下部铁矿体围岩蚀变有钠长石化、蛇纹石化、滑石化、透闪石化、碳酸盐化、绿泥石化等,以钠长石、蛇纹石、滑石、透闪石、方解石、白云石、菱铁矿、绿泥石、黑云母和磷灰石等为主的蚀变矿物组合显示钠化特征。铜厂铜-铁矿床中磁铁矿的TiO2含量小于1.72%,Al2O3含量小于1.81%,均显示热液磁铁矿的特征,结合铜矿石脉穿插铜厂闪长岩及二者突变接触的地质特征,说明铜厂铜-铁矿床的形成与热液活动密切相关。同时,铜厂铜-铁矿床形成于早古生代加里东期,勉略宁矿集区在该时期处于大陆裂谷的扩张环境中,与铁氧化物-铜-金(Iron Oxide-Copper-Gold,简称IOCG)矿床的形成环境类似。通过与典型IOCG矿床地质特征、矿化蚀变特征、矿物组合特征、矿物地球化学特征及大地构造背景的系统对比,初步提出铜厂铜-铁矿床应属于IOCG矿床。 相似文献
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Kofi Adomako‐Ansah Toshio Mizuta Napoleon Q. Hammond Daizo Ishiyama Takeyuki Ogata Hitoshi Chiba 《Resource Geology》2013,63(2):119-140
The Blue Dot gold deposit, located in the Archean Amalia greenstone belt of South Africa, is hosted in an oxide (± carbonate) facies banded iron formation (BIF). It consists of three stratabound orebodies; Goudplaats, Abelskop, and Bothmasrust. The orebodies are flanked by quartz‐chlorite‐ferroan dolomite‐albite schist in the hanging wall and mafic (volcanic) schists in the footwall. Alteration minerals associated with the main hydrothermal stage in the BIF are dominated by quartz, ankerite‐dolomite series, siderite, chlorite, muscovite, sericite, hematite, pyrite, and minor amounts of chalcopyrite and arsenopyrite. This study investigates the characteristics of gold mineralization in the Amalia BIF based on ore textures, mineral‐chemical data and sulfur isotope analysis. Gold mineralization of the Blue Dot deposit is associated with quartz‐carbonate veins that crosscut the BIF layering. In contrast to previous works, petrographic evidence suggests that the gold mineralization is not solely attributed to replacement reactions between ore fluid and the magnetite or hematite in the host BIF because coarse hydrothermal pyrite grains do not show mutual replacement textures of the oxide minerals. Rather, the parallel‐bedded and generally chert‐hosted pyrites are in sharp contact with re‐crystallized euhedral to subhedral magnetite ± hematite grains, and the nature of their coexistence suggests that pyrite (and gold) precipitation was contemporaneous with magnetite–hematite re‐crystallization. The Fe/(Fe+Mg) ratio of the dolomite–ankerite series and chlorite decreased from veins through mineralized BIF and non‐mineralized BIF, in contrast to most Archean BIF‐hosted gold deposits. This is interpreted to be due to the effect of a high sulfur activity and increase in fO2 in a H2S‐dominant fluid during progressive fluid‐rock interaction. High sulfur activity of the hydrothermal fluid fixed pyrite in the BIF by consuming Fe2+ released into the chert layers and leaving the co‐precipitating carbonates and chlorites with less available ferrous iron content. Alternatively, the occurrence of hematite in the alteration assemblage of the host BIF caused a structural limitation in the assignment of Fe3+ in chlorite which favored the incorporation of magnesium (rather than ferric iron) in chlorite under increasing fO2 conditions, and is consistent with deposits hosted in hematite‐bearing rocks. The combined effects of reduction in sulfur contents due to sulfide precipitation and increasing fO2 during progressive fluid‐rock interactions are likely to be the principal factors to have caused gold deposition. Arsenopyrite–pyrite geothermometry indicated a temperature range of 300–350°C for the associated gold mineralization. The estimated δ34SΣS (= +1.8 to +2.5‰) and low base metal contents of the sulfide ore mineralogy are consistent with sulfides that have been sourced from magma or derived by the dissolution of magmatic sulfides from volcanic rocks during fluid migration. 相似文献
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内蒙古哈达门沟金矿13号矿体以含金石英钾长石脉为主,金大部分以包体金形式存在,少数存在于黄铁矿间隙中。金的颗粒大小为0.05~0.25 mm。成矿元素组合特征中Au与Ag、Bi、Pb等亲硫元素具有很高的相关性,显示金的成矿与多金属硫化物联系很密切。通过数据分析,绘制了元素空间分布图,并建立了原生晕轴向垂直分带序列:Au-Pb-(Ni-Co-Ag-Zn-As-Hg )-Cu-W-Bi-Sb-Mo。由于成矿多期叠加特点导致Ag、Sb、As等元素异常同时存在和部分轴向分带序列分带特征不明显。与典型金矿分带序列对比发现,前缘晕元素Sb出现在分带序列的下部,地球化学参数在矿体下方(标高658 m附近)发生转折,这些都暗示深部有隐伏矿体存在,通过后续实际生产实践也验证了本文推测。 相似文献
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大白阳金矿床位于华北克拉通北缘张家口地区，为一中型金矿床。矿床产于太古宇桑干群化家营组和涧沟河组变质地层中，受区内断裂和褶皱控制，金矿脉总体走向北北西。矿石类型为含金石英脉型和蚀变岩型，矿石矿物主要为磁铁矿、赤铁矿、黄铁矿、方铅矿、闪锌矿、黄铜矿、斑铜矿、自然金、银金矿及少量碲化物。矿床的成矿期可划分为4个成矿阶段，分别为石英-钾长石阶段、石英-黄铁矿阶段、石英-多硫化物阶段和石英-碳酸盐-硫酸盐阶段。矿床硫化物的δ34SV-CDT为-16.2‰~-10.5‰，为高氧逸度成矿流体所致；Pb同位素组成206Pb/204Pb=16.762~17.293、207Pb/204Pb=15.350~15.463、208Pb/204Pb=36.777~37.328，与区内岩浆岩Pb同位素组成一致。黄铁矿微量元素低，主要赋存于黄铁矿晶格中。黄铁矿中低的Co、Ni质量分数表明，黄铁矿从岩浆流体中沉淀。桑干群斜长角闪岩在蚀变过程中为流体提供部分成矿物质，为矿源层之一。大白阳金矿床属于与岩浆有关的热液矿床，其形成经历了泥盆纪金的初始矿化和侏罗纪-白垩纪的叠加成矿，由此也导致了张宣地区大量金矿床的出现。 相似文献
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Qingyan Tang Pengfei Di Man Yu Jian Bao Ying Zhao Dongxiao Liu Yuxi Wang 《Resource Geology》2019,69(3):314-332
The Zaozigou gold deposit lies in the West Qinling orogenic belt, Gansu Province, China. It is one of the largest gold deposits, and the orebodies are hosted in fine‐grained slates intercalated with limestone of the Middle‐Triassic Gulangdi Formation and varied dykes. The gold orebodies are strictly controlled by the NE‐, NW‐, and SN‐trending tensional and shearing faults with high dipping angle. The mineralogy and geochemistry of pyrite and arsenopyrite are measured by electron microprobe. Pyrite has up to 0.12 wt.% Au, and arsenopyrite contains up to 0.17 wt.% Au. The antithetic correlation between S and As indicates the substitution of As for S in pyrite, and arsenic occurs in anionic As1? state in the pyrite structure under the reduced conditions. Pyrite has relatively high Co (~364–2248 ppm) but relatively low Ni (~109–497 ppm) contents, with Co/Ni ratios ranging from ~1.63 to 10.50, indicating that the deposit originated from a volcanogenic fluid and remobilized by hydrothermal fluid. Au in arsenopyrite occurs as cationic Au in solid solution, whereas Au in pyrite is in solid solution and metal nanoparticles (Au0). The texture characteristics and trace element geochemistry among cores, transition zones, and rims of pyrites demonstrate that there are at least four pulses of fluid participating in the generation of pyrite in the deposit. The calculated formation temperatures of the Zaozigou deposit vary from 148°C to 304°C, with an average temperature of 213°C based on Au contents in pyrite. The Pb isotopic compositions of pyrite samples suggest that the metallogenic materials of the Zaozigou deposit were derived from the mantle and upper crust. All the characteristics above lead us to draw the conclusion that the Zaozigou gold deposit is classified as an epithermal deposit. 相似文献
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甘肃岷县寨上特大型金矿次显微金的赋存状态研究 总被引：4，自引：0，他引：4
寨上金矿是一微细浸染型超大型金矿床。通过光学显微镜、人工重砂、电子探针、扫描电镜等显微测试手段对寨上矿区主要载金矿物进行分析测试得出：黄铁矿、白钨矿是最主要的载金矿物之一,石英、褐铁矿、辉铜矿是次要的载金矿物．方解石、菱铁矿、重晶石等不含金。由于受检测手段所限,在含金黄铁矿、白钨矿、石英等矿物中未发现独立金颗粒,所以寨上金矿次显微金呈微包裹体形式存在于载金矿物中或呈类质同象替代的原子形式存在。通过研究主要载金矿物黄铁矿中Au、As的关系得出：Au与As呈正相关关系;从具有增生环带结构黄铁矿的内核向增生体S、Fe呈对数下降趋势,Au、As呈对数上升趋势。对比沉积期、热液期形成的黄铁矿主量、微量元素得出S、Fe变化不大,微量As呈线性递增,而Au呈线性递减。 相似文献
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桂西北明山卡林型金矿床热液矿物的显微组构与化学成分特征及其对成矿作用的指示 总被引：1，自引：0，他引：1
桂西北明山金矿是滇黔桂地区代表性的卡林型金矿之一,矿体受平行于区域性断裂右江断裂的北西西向次级断层控制,赋存于二叠系灰岩之上的中三叠统钙质细砂岩、碳钙质泥质粉砂质岩中。地质、岩相学特征和阴极发光、背散射电子影像、电子探针等分析研究表明,明山金矿发育了3个成矿阶段的热液矿物组合,不同热液矿物普遍具有多世代的特点。热液矿物中见有波状消光、带状消光、毕姆纹、压溶劈理、位错滑移等韧性剪切带粒内应变特征,坑道中也见有黄铁矿石英脉发生韧性变形、又被后期石英脉切断的现象,说明矿床经历了多次的脆-韧性变形。不同矿化期（阶段）的黄铁矿中Au和As的含量表明:沉积期黄铁矿Au、As的含量较低;成岩期黄铁矿中Au的含量高但As含量不高;而成矿期3个阶段的热液黄铁矿中都含较高的As和Au;热液黄铁矿核部包裹的交代残余黄铁矿Au、As含量较高,但变化范围较大,可能是变质成因。紧邻矿体的围岩中成岩黄铁矿从中心向外Au和As的含量逐渐降低,说明其中的As和Au在后来的构造和（或）热液事件中发生了活化迁移,越靠近颗粒边缘元素的活化迁移越强,这表明成矿物质来自于围岩。根据这些事实,推断明山矿区可能在成岩期发生了金的预富集,变形变质早期富含有机质的变质流体活动又使As发生了富集,主变质期流体的广泛渗透交代、活化出先存含金富砷黄铁矿中的Au和As,形成成矿流体。当成矿流体遇到富含活性铁的炭钙质泥质粉砂岩时,形成黄铁矿的同时发生Au的沉淀。 相似文献
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多不杂铜(金)矿床是西藏多龙矿集区重要的斑岩型铜矿床之一。详细的岩心编录和岩相学研究显示,多不杂铜(金)矿床发育4类磁铁矿:磁铁矿-1(Mt1)反射色呈灰白色,它形粒状,部分颗粒包含在黑云母内部;磁铁矿-2(Mt2)反射色呈粉棕色,半自形-它形粒状,边缘被赤铁矿交代,颗粒内部见少量黄铜矿;磁铁矿-3(Mt3)反射色呈粉棕色,自形-半自形,粒度小,表面平整,主要产于角岩化蚀变内;磁铁矿-4(Mt4)反射色呈深灰色,颗粒间隙被黄铁矿、黄铜矿交代。Mt1、Mt2属岩浆磁铁矿或岩浆-热液磁铁矿的过渡类型;Mt3、Mt4属岩浆-热液磁铁矿的过渡类型。Mt1、Mt2、Mt4磁铁矿形成温度大致在300～500℃,Mt3形成温度明显低于其他三类磁铁矿,大致在200～500℃。4类磁铁矿具有明显的地球化学差异,其中Mt1具... 相似文献