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1.
西秦岭降扎地区寒武系层控金矿床中 Au-Se共同富集成矿机制 总被引：2，自引：0，他引：2
西秦岭降扎地区寒武系中的层控金矿床,产于由碳质硅岩和碳质板岩组成的硅岩建造中,研究表明,无论是围岩还是金矿,匀普遍含有国高的硒,达到工业综合利用的要求,在局部地段甚至可以圈出独立的硒矿体,在金矿石中,矿主要呈独立矿物和以类质同象形式存在于硫化物中,且硒与金呈密切的正相关关系,尤为重要的是,在金矿石中常常见到自然金与一些硒矿物紧密共生,说明Au,Se可能以Au-S-Se或Au-Se络合物形式进行迁移,由于沸腾的成矿流体与下渗的富氧冷水混合而发生氧化还原作用,导致了Au和Se的共同富集成矿。 相似文献
2.
《International Geology Review》2012,54(11):1037-1045
Cambrian stratabound gold deposits in the western Qinling Mountains are hosted in a siliceous formation composed of black chert and carbonaceous slate. Studies have shown that Se is sufficiently high in abundance either in wall rocks or in gold ores as to reach economic grade. Locally, some independent Se ore bodies (Se >500 ppm) can be delineated. In gold ores, Se is present mainly as separate minerals, or as isomorphous solutions in sulfides. In addition, Se is positively correlated with Au. What is more important is that in the gold ores, native gold is commonly intimately inter-grown with selenium minerals. On the basis of this unique phenomenon, the authors hypothesize that gold and selenium may be transported by Au-S-Se or Au-Se complexes. The co-enrichment of Au and Se is attributed mainly to the boiling of ore fluids and their mixing with shallow-seated oxygen-bearing water. 相似文献
3.
拉尔玛-邛莫金矿床产于西秦岭南亚带寒武系硅岩建造中,受地层、岩性、构造控制十分明显.但与其它层控金矿床相比较,该矿床不仅含矿主岩特殊,而且矿石矿物和元素组合十分复杂.矿床中除Au外,Cu、U、Mo、Sb、V、Zn等元素在局部地段亦可圈出独立矿体.同时,矿床中存在铂族元素(PGE)、铟的高异常以及硒的矿化富集体,从而构成了Au-Cu-U-Mo-Se-PGE建造矿床.研究表明,金矿床的形成,至少经历了喷流沉积和地下水热液活动改造两个成矿期.前者表现为硅岩建造中出现了众多成矿元素的高异常和黄铁矿等条带状、层纹状构造的形成,显示出矿质的初步聚集;后者则促使矿质富集层中的成矿物质组分发生活化、迁移和再聚集,并最终导致工业矿床的形成.矿床属与海底喷流作用有关的喷流型层控金矿床. 相似文献
4.
The gold deposits,occurring in the south subzone of western Qinling,are the only typical and important strata-bound gold deposits,which are associated with submarine exhalative sedimentation.The gold deposits include the La‘erma ore deposit,the Qiongmo ore deposit and the Yaxiang ore occurrence.They are hosted i the Cambrian silicalite formation composed of black chert and slate.The presence of typical chert offers important evidence to evaluate the possible submarine exhalative system and its role in the formation of the gold deposits,which are closely associated with peroclation and diffusion in the horizontal,vertical and axial directions,Element-assemblage zonation is clearly seen due to differences in element concentrations in different directions,Such a zonation makes gold.selenium,uranium,copper,stibium,molybdenum,mercury,etc,precipitate in the form of simple or composite orebodies.The establishent of the element-assemblage zonation is highly helpful for evaluating directly the metallogenesis of gold deposits. 相似文献
5.
西南寒武、二叠系富硒碳质岩中硒结合态的比较研究 总被引：6，自引：0，他引：6
使用硒的7步连续化学提取技术,对采自贵州寒武纪牛蹄塘组和湖北恩施二叠纪茅口组富硒碳质岩中的水溶态、可交换态、有机态、元素态、酸性提取态、硫化物/硒化物态和残渣态硒进行了比较研究,应用氢化物－原子荧光法测定了岩石总硒和各结合态硒。结果表明,恩施二叠纪沙地新鲜富硒碳质硅质岩和碳质页岩中的硒主要以有机结合态和硫化物/硒化物态硒为主,残渣态硒较低;遵义松林早寒武世碳质硅质岩中的硒主要以有机结合态和硫化物态硒为主,碳质页岩与镍钼矿层中则以有机结合态、残渣态和硫化物态硒为主,斑脱岩中主要以有机结合态、元素态和可交换态硒为主。根据硒结合态的这种分布特征,推测二叠纪、寒武纪富硒碳质岩中硒初始富集的生物地球化学过程略有差异：前者碳质硅质岩中主要以微生物还原为主,碳质页岩中则是微生物还原作用和生物同化吸收或吸附兼而有之;后者主要以生物同化吸收或吸附为主,微生物还原次之。 相似文献
6.
西秦岭寒武系层控金矿床中成矿元素富集规律 总被引：2，自引：0，他引：2
产于西秦岭南亚带寒武系硅岩建造中的金矿床, 是我国境内发现的一种与海底喷流作用有关的、具有独特地质特征的层控金矿床。成矿元素富集规律研究表明, 矿床中富集的元素种类十分丰富, 不仅含有具基性、超基性特征的元素群, 而且含有具酸性特征的元素群, 元素组合相当复杂。除Ａｕ 外, Ｃｕ、Ｕ、Ｍｏ、Ｓｂ、Ｖ、Ｚｎ等在局部地段亦可圈出独立的矿体。尤为重要的是, 矿床中铂族元素（ＰＧＥ）、分散元素（Ｓｅ、Ｉｎ） 的富集程度达到了综合利用的程度, 从而构成特殊的Ａｕ－Ｃｕ－Ｕ－Ｍｏ－Ｓｅ－ＰＧＥ建造矿床。 相似文献
7.
In western Victoria, a widespread stratiform style of gold enrichment in Palaeozoic black mudstone and chert—clearly different from the classic mesothermal quartz vein deposits of the Victorian goldfields—has been confirmed by whole-rock geochemistry and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). This enrichment pre-dates compaction, deformation and low-grade metamorphism of the sedimentary host-rocks, and therefore possibly developed diagenetically during slow deposition of the thin carbonaceous black mudstone beds and the thinner layers of chert. These paired strata have been documented at many locations in three regional outcrop areas of chevron-folded Cambrian and Lower Ordovician metasediments in the Stawell and Bendigo Zones, where they are interbedded with quartz-rich turbidites. The layers were named ‘indicators’ by the early miners, who found locally rich nuggety gold deposits at intersections between these layers and mesothermal quartz veins. Gold is present in euhedral pyrite crystals in both black shale and chert. LA-ICPMS analysis of individual pyrite crystals in the indicator beds shows that pyrite is enriched in Au, As, Sb, Se, Te and Bi. The Au content of pyrite varies from 0.03 to 2.69 ppm with a mean of 0.58 ppm and shows a positive correlation with As, which varies from 1000 to 6000 ppm. Many pyrite crystals show enrichment of gold in their cores and depletion in their rims, confirming the likely syngenetic or syndiagenetic accumulation of gold during pyrite formation in the sediments. Prior to regional metamorphism, folding and faulting, the many indicator strata in the outcrop areas were parts of an extensive marine sequence of Late Cambrian and Early Ordovician age. The former primary source of this mineralisation is considered to have been one or more contemporaneously exhalative submarine hydrothermal systems. Thus, the older Palaeozoic sediments of the western Lachlan Fold Belt were significantly enriched in syngenetic gold in the Early Palaeozoic, at least 40 million years before emplacement of the quartz – gold vein deposits of the goldfields. 相似文献
8.
广东河台金矿中Se和Te及其找矿意义 总被引：1，自引：0，他引：1
本文研究了河台金矿Se和Te的地球化学特征。金矿中Se和Te一般作为矿化剂出现,是金矿床中常见元素。尽管Se、Te作为金矿指示元素已有一些报道,但多缺乏系统性。文中研究了河台金矿矿床矿体、围岩及土壤中Se、Te分布特征,初步搞清了Se、Te与金矿化的关系,指出了Se,Te的找矿意义和进一步找矿的方向。 相似文献
9.
10.
粤西古水剖面震旦系顶部层状硅岩的热水成因属性:岩石学和地球化学证据 总被引：30，自引：1，他引：29
古水剖面震旦系顶部硅岩主要发育层状构造、纹理状构造、块状构造和假角砾状构造,化学成份以ＴｉＯ２、Ａｌ２Ｏ３和大部分微量元素亏损（相对地壳克拉克值）为特征。但Ｂａ、Ａｓ和Ｓｂ等少数已知的热水沉积特征元素显示富集。在Ａｌ－Ｆｅ－Ｍｎ三元图上,古水硅岩投映在“热水沉积”域内。因子分析和对应分析显示了大部分金属元素在代表热水淋滤作用的因子上均有反映。稀土元素以低含量为特征,在对北美页岩组合样（ＮＡＳＣ）正规化后的稀土配分模式落在典型热水沉积的上、下限之间,而在正常沉积的之外。各种岩性和地球化学证据表明,古水硅岩具有热水成因。 相似文献
11.
12.
微细浸染型（卡林型）金矿成矿过程中碳和有机质的作用 总被引：10，自引：2，他引：10
在众多关于黔滇桂微细浸染型（卡林型）金矿研究成果的基础上，本文通过本类型金矿含碳及有机质的特征；金能形成金属有机化合物及原子簇化合物的特征的研究。提出金以金属有机化合物形式在本区上二叠统富含生物成因有机质的煤系地层中形成预富集；在区域热变质作用中，金以气相金属有机化合物方式向上运移，蓄积在上二叠统至中三叠统各层位的背斜和穹隆部位；动力变质带的断裂活动引起物理化学突变，使金的气相金属有机化合物在构造断裂带解体、裂化从而形成了含细分散碳质的微细浸染型含金硫化物原生矿化；并探讨了主成矿期后与有机质解体有关的叠加热液活动和表生氧化作用对原生矿化的改造。从而从有机质演化角度初步建立了此类型的成矿模式 相似文献
13.
恩施渔塘坝富硒碳质岩石中硒的形态分析 总被引：2，自引：0，他引：2
湖北恩施渔塘坝是中国人群硒中毒爆发性流行的地区，也是恩施较为典型的高硒地区之一。其北部出露的富硒碳质岩石，通常认为是渔塘坝硒的主要来源。采用7步连续化学浸提技术，将富硒碳质岩石中硒分为水溶态、可交换态、有机态、元素态、酸性提取态、硫化物／硒化物态和残渣态硒，使用氢化物-原子荧光法测定了岩石总硒和硒形态。结果表明，碳质页岩和碳质硅质岩中硒主要以有机态、硫化物／硒化物态和可交换态硒为主，碳质泥岩中硒以有机态、元素态和硫化物／硒化物态硒为主。碳质泥岩中的水溶态硒显著低于碳质页岩和碳质硅质岩中的水溶态硒，但元素态硒的比例显著高于后两者，说明碳质泥岩是富硒碳质岩层中硒易于富集的场所。富硒碳质岩中的可利用态硒主要以Se^4＋为主，而非是Se^6＋和有机硒。可交换态和有机结合态硒中Se^4＋与岩石总硒的显著正相关关系表明，Se^4＋离子的分布影响着岩石总硒，有机质与粘土在硒富集的地球化学过程中承担了重要作用。 相似文献
14.
青海省东昆仑成矿带主要金矿床特征与及关键控矿因素分析 总被引：2，自引：0，他引：2
青海东昆仑地区近年来沟里金矿、五龙沟金矿等老矿区取得了新进展和新突破,到继续开发,黑海北等多个新矿区（点）取得新发现。本文分析了区域成矿条件和典型矿床,总结出东昆仑地区金矿床的主要控矿因素,认为该地区金矿床主要形成于海西期-印支期,其次为加里东期;岩浆活动为金矿床形成提供了成矿流体和成矿物质来源;北西西-北西向构造及次级构造控制了金矿体的展布。成矿分析表明,东昆仑地区具有良好的金矿床成矿潜力与找矿前景。 相似文献
15.
David L. Huston Leon Vandenberg Andrew S. Wygralak Terrence P. Mernagh Leon Bagas Andrew Crispe Alexis Lambeck Andrew Cross Geoff Fraser Nick Williams Kurt Worden Tony Meixner Bruce Goleby Leonie Jones Pat Lyons David Maidment 《Mineralium Deposita》2007,42(1-2):175-204
The Tanami region of northern Australia has emerged over the last two decades as the largest gold-producing region in the Northern Territory. Gold is hosted by epigenetic quartz veins in sedimentary and mafic rocks, and by sulfide-rich replacement zones within iron formation. Although limited, geochronological data suggest that most mineralization occurred at about 1,805–1,790 Ma, during a period of extensive granite intrusion, although structural relationships suggest that some deposits predate this period. There are three main goldfields in the Tanami region: the Dead Bullock Soak goldfield, which hosts the world-class Callie deposit; The Granites goldfield; and the Tanami goldfield. In the Dead Bullock Soak goldfield, deposits are hosted by carbonaceous siltstone and iron formation where a late (D5) structural corridor intersects an early F1 anticlinorium. In The Granites goldfield, deposits are hosted by highly sheared iron formation and are interpreted to predate D5. The Tanami goldfield consists of a large number of small, mostly basalt-hosted deposits that probably formed at a high structural level during D5. The D5 structures that host most deposits formed in a convergent structural regime with σ 1 oriented between E–W and ENE–WSW. Structures active during D5 include NE-trending oblique thrust (dextral) faults and ESE-trending (sinistral) faults that curve into N- to NNW-trending reverse faults localized in supracrustal belts between and around granite complexes. Granite intrusions also locally perturbed the stress field, possibly localizing structures and deposits. Forward modeling and preliminary interpretations of reflection seismic data indicate that all faults extend into the mid-crust. In areas characterized by the N- to NW-trending faults, orebodies also tend to be N- to NW-trending, localized in dilational jogs or in fractured, competent rock units. In areas characterized by ESE-trending faults, the orebodies and veins tend to strike broadly east at an angle consistent with tensional fractures opened during E–W- to ENE–WSW-directed transpression. Many of these deposits are hosted by reactive rock units such as carbonaceous siltstone and iron formation. Ore deposition occurred at depths ranging from 1.5 to 11 km from generally low to moderate salinity carbonic fluids with temperatures from 200 to 430°C, similar to lode–gold fluids elsewhere in the world. These fluids are interpreted as the product of metamorphic dewatering caused by enhanced heat flow, although it is also possible that the fluids were derived from coeval granites. Lead isotope data suggest that lead in the ore fluids had multiple sources. Hydrogen and oxygen isotope data are consistent with both metamorphic and magmatic origins for ore fluids. Gold deposition is interpreted to be caused by fluid unmixing and sulfidation of host rocks. Fluid unmixing is caused by three different processes: (1) CO2 unmixing caused by interaction of ore fluids with carbonaceous siltstone; (2) depressurization caused by pressure cycling in shear zones; and (3) boiling as ore fluids move to shallow levels. Deposits in the Tanami region may illustrate the continuum model of lode–gold deposition suggested by Groves (Mineralium Deposita 28:366–374, 1993) for Archean districts. 相似文献
16.
《International Geology Review》2012,54(5):438-448
Structural, geochemical, and isotope studies were carried out on the gold deposits of the Pontes e Lacerda region (Mato Grosso state, Brazil), where rocks of the Aguapei and Rondoniano mobile belts (southwestern Amazonian craton) occur. The orebodies are hosted in metavolcanic, gneiss-granite, quartzite, tonalite, and granite units. Tectonics involve oblique overthrusting (from northeast to southwest), which led to the formation of recumbent folds and thrusts (pathways for the mineralizing fluids), upright folds, and faults with dominant strike-slip component. These unconformities represent potential sites for mineralization. During geological mapping, it was observed that the orebodies consist of quartz, pyrite, and gold, and that the hydrothermal alteration zone contains quartz, sericite, pyrite (altered to limonite), and magnetite (altered to hematite). Chalcopyrite, galena, and sphalerite occur only in the Onca deposit. Chemical analysis of sulfides indicates high contents of Bi, Se, and Te in sulfides and gold, suggesting plutonic involvement in the origin of hydrothermal solutions. K-Ar dating of hydrothermal sericites from gold veins yielded ages in the range from 960 to 840 Ma, which may indicate the age of original crystallization of sericite. Pb-Pb dating in galenas yielded model ages in the range from 1000 to 800 Ma for the Onca deposit, which is in agreement with K-Ar ages. Pb-isotopic ratios indicate high U/Pb and low Th/Pb for the upper-crustal Pb source before incorporation in galena crystals. The Pontes e Lacerda gold deposits yielded ages correlated to the Aguapei event and probably were formed during a Proterozoic contractional tectonic period in the southwestern part of the Amazon craton, which may characterize an important metallogenic epoch in the Pontes e Lacerda region. 相似文献
17.
恩施渔塘坝富硒碳质岩中硒的赋存状态 总被引：6，自引：1，他引：5
在渔塘坝富硒碳质岩中发现了自然硒及其系列硒矿物的组合.这些硒矿物有自然硒、方硒铜矿、硒铜蓝、水硒铁石、硒银矿、含硒黄铁矿、含硒黄铜矿和难以确定名称的Fe-Se矿物.其中自然硒、方硒铜矿和硒铜蓝的矿物组合主要分布在断层面附近的碳质硅质岩中,自然硒与方硒铜矿的矿物组合主要分布在高碳质泥岩中,水硒铁石及未确定的Fe-Se矿物主要赋存于露头处的富硒碳质岩中.硒矿物中除自然硒较普遍地存在外,其他矿物并不是均匀地分布于富硒碳质岩中,而是局部性地出现.Cu-Se矿物的大量发育表明铜可能在硒的表生迁移转化中起着某种重要的作用. 相似文献
18.
XIE Hongyuan SHEN Yuanchao WANG Yuejun LI Guangming LIU Tiebing ZHANG Qirui ZEN QingdongInstitute of Geology Chinese Academy of Sciences Beijing Zhang Yuxu Fei Zhenbi 《《地质学报》英文版》1998,72(1):77-86
According to the differences in ore-controlling structural systems and the characteristics of host rocks, textures and structures of ores and mineral associations of ores, quartz vein-type gold deposits in the Rushan area can be divided into the Rushan and Tongling styles. Rushan style gold deposits, occurring in the Kunyushan complex, include Rushan, Tangjiagou and Tongxishan gold mines. They are distributed along four NNE-trending and sinistral, compresso-shear faults with a right stepping array. A prominent characteristic of the gold mineralization is that the orebodies in neighbouring gold deposits distributed in a single ore-controlling fault zone take opposite pitches. Study of the locating structures of the quartz vein gold deposits shows that the Rushan-style gold deposits are characterized by NNE and NE zoning. Therefore, the intersections of the NE direction of the known gold deposit and the neighbouring NNE-trending fault zones are favourable for looking for gold deposits, and the ends of the 相似文献
19.
陕南秦巴山区是我国重要的金矿产区,尤其是安康西北部的羊坪湾-流芳金成矿带更是秦巴山区的典型代表,硝璜洞金矿就位于这一成矿带上.硝璜洞金矿产于志留纪大贵坪组第一岩性段的含炭质云英片岩夹薄层炭质石英岩内,显示岩性对金矿化的制约.矿体严格受韧性剪切带控制,主要赋存于与主剪切带呈“入”字形相交的次级韧性断裂带中.矿体呈似层状、透镜状、脉状产出.金矿物以自然金形式赋存,自然金粒度呈粗粒、巨粒.野外可识别出3期硅化蚀变,金矿化与第1期蚀变关系密切.矿床成因为韧性剪切带控制的变质热液型金矿床. 相似文献
20.
磨坊沟式金矿是指鲁西铜石地区赋存在早寒武世朱砂洞组灰质白云岩和白云质灰岩中的碲金矿床，近期地质勘查表明，矿体产出层位相对稳定，分布面积较广，矿化较为连续，具有很大的资源潜力和找矿远景。其围岩具明显的黄铁绢英岩化、高岭土化、方解石化和萤石化。碲金矿的形成与黄铁绢英岩化密切相关。矿床产出的构造部位为鲁西幔枝构造核部，铜石隆起外围太古宙结晶基底与寒武纪盖层间主拆离带之上的次级拆离带中。成矿物质来自深源（地幔），矿体就位受主、次级拆离滑脱带控制。由于次级拆离带断坪顺层展布，故矿体亦表现出似层状特征。 相似文献