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1.
Mercuriferous gold and amalgams of two types have been detected in the Lower Triassic, Middle Jurassic, and Holocene alluvial deposits in the sedimentary cover of the Vyatka-Kama depression. Electron microscopic studies revealed that some of these aggregates represent intergrowths of individual segregations (globules) ranging in size from 1 to 300 μm. At high magnifications (up to 100 000 times or more), electron photomicrographs show that the smallest globules include tiny (up to nanoscale) gold particles. Microprobe analysis made it possible to detect significant chemical variations in the globules mainly due to alterations in the Hg content (from 0 to 58.25 wt %). The major part of such aggregates belongs to solid Au-Hg solid solutions. Amalgams with Hg >19.8 at % are represented by several phases: (Au,Ag)3Hg and (Au,Ag)2Hg prevail; (Au,Ag)3Hg2, (Au,Ag)5Hg4, and (Au,Ag)Hg are subordinate. In terms of composition, some globules correspond to argentiferous gold (without Hg), mercuriferous electrum, and Au-Pb intermetallides with Hg, Ag and Cu. Another, more widespread type is represented by lumpy massive grains (with mercuriferous gold shell) and porous amalgam. Their formation is related to natural amalgamation initiated by the Early Mesozoic tectonomagmatic activation of the platform and adjacent deep faults. The results obtained can be used in prospecting for Au-Hg mineralization in the sedimentary cover of the Vyatka-Kama depression. 相似文献
2.
黔东内生金矿自然金成色及其研究 总被引：5，自引：0，他引：5
研究区13个金矿床／点，24个自然金样品，161个点的电子探针测试表明，区内自然金成色平均值几乎均大于900％0，属高成色；自形晶比它形晶的金银含量均匀；位于交代前峰的金成色比尾部低，包体金随主矿物的种类不同成色不同。银是金中最主要的杂质元素；铋在该区金中具有很高的富集程度，是影响成色的主要因素。本区与湖南相比，具有地层越老、成色越高、银含量越低的共同规律，而成色高低与成矿时间和温度的关系较前人总结的规律出入甚大；比值关系表明，前者变化范围很小，后者很大，碱金属含量变化对前者影响不大。 相似文献
3.
湘西沃溪钨锑金矿床超纯自然金 总被引：2，自引：0，他引：2
湘西沃溪钨锑金矿床产有自然界中十分罕见的超纯自然金。超纯自然金的Au含量在99 %以上 ,Fisher成色接近1000。自然金中含有Ag、Pb、Zn、Cu、As、Sb、Hg、Bi等显微化学组分。与一般自然金相比 ,超纯自然金的Ag 含量显著偏低 ,而Pb、Zn、As、Sb、Hg、Bi等显微化学组分含量趋于偏高 ,且较稳定。理论分析表明 ,超纯自然金的形成与强氧化性的酸性成矿流体有关。流体中金、银主要以MeCl2-(Me=Au或Ag)的络合物形式迁移。推断矿床成矿可能与区域中酸性岩浆活动有成因联系。 相似文献
4.
K. von Gehlen 《Mineralium Deposita》1983,18(3):529-534
The contents of silver and mercury in 323 spots on gold grains from seven localities of the Witwatersrand palaeo-placer and Archaean vein deposits from Barberton were measured using an electron microprobe. The objective was to obtain information on the extent of gold alteration during fluvial transport and post-depositional geological processes. The results, however, show that Ag and Hg are distributed homogeneously in the gold grains studied. No indications were found that the gold was transported in solution nor that leaching took place in an oxidizing fluvial environment. This strongly suggests that the Ag and Hg contents in Witwatersrand gold grains represent geochemical ‘fingerprints’ inherited from their eroded primary sources. Combined analysis for Ag and Hg in Witwatersrand gold grains by electron microprobe can therefore be a valuable tool in establishing the types of primary sources for the gold. 相似文献
5.
W. Crone L.T. Larson R.H. Carpenter T.T. Chao R.F. Sanzolone 《Journal of Geochemical Exploration》1984,20(2):161-178
We evaluated the effectiveness of iron oxide-rich fracture coatings as a geochemical sampling medium for disseminated gold deposits, as compared with conventional lithogeochemical methods, for samples from the Pinson mine and Preble prospect in southeastern Humboldt County, Nevada. That disseminated gold mineralization is associated with Hg, As, and Sb is clearly demonstrated in these deposits for both fracture coatings and rock chip samples. However, the relationship is more pronounced for fracture coatings. Fracture coatings at Pinson contain an average of 3.61, 5.13, 14.37, and 3.42 times more Au, As, Sb and Hg, respectively, than adjacent rock samples. At Preble, fracture coatings contain 3.13, 9.72, 9.18, and 1.85 times more Au, As, Sb and Hg, respectively, than do adjacent rock samples. Geochemical anomalies determined from fracture coatings are thus typically more intense than those determined from rock samples for these elements. The sizes of anomalies indicated by fracture coatings are also somewhat larger, but this is less obvious. In both areas, Sb anomalies are more extensive in fracture coatings. At Preble, some Hg and Au anomalies are also more extensive in fracture coatings. In addition to halos formed by the Hg, As and Sb, high values for Au/Ag and Zn/(Fe + Mn) are closely associated with gold mineralization at the Pinson mine. The large enhancement in geochemical response afforded by fracture coatings indicates a definite potential in the search for buried disseminated gold deposits. 相似文献
6.
在进行原生晕元素分带研究时,所选元素多未进行筛选,不利于正确认识分带规律及指导矿产预测。本文基于扎家同哪金矿2779个钻孔样品数据,拟通过定量评价不同金属元素在围岩、矿化围岩、矿石等中的富集程度,研究不同元素在矿化过程中形成原生晕的能力差异。研究发现,扎家同哪金矿Au、As、Sb、Hg、W、Ag在围岩、矿化围岩和矿石中富集程度递增,易形成原生晕,Zn仅在矿石中富集,成晕规模有限,Mo、Cu、Pb、Sn富集微弱或表现为亏损,较难形成原生晕;扎家同哪金矿不同位置与成矿有关的富集元素为Au、As、Sb(围岩)—Au、As、Sb、W、Hg(Ag)(矿化围岩)—Au、As、Ag、Sb、W、Hg、Zn(矿石),成矿过程中元素在矿化围岩中富集的权重由大至小为As、Hg、Au、Sb、W、Mo、Sn、Pb、Zn、Cu、Ag,进入围岩能力总体表现为低—高—中温元素递减的趋势。对于扎家同哪金矿,在研究原生晕分带特征、指导进一步找矿时,宜优先选用As、Hg、Au、Sb和W等元素。 相似文献
7.
8.
也金嘎波金矿位于冈底斯成矿带上,是对区域化探发现的Au、As多元素组合异常进行追踪发现的,属于热液型金矿床。矿区各类岩石Au、As、Sb、W、Hg、Ag、Bi、Pb元素平均值高于中国丰度值数倍以上,表明矿区具有丰富的物质来源基础。岩石地球化学研究证明,矿床地表发育Au、As、Sb等10多个元素组合异常。其中Au是成矿指示元素,As、Sb、W是密切伴生元素,Bi、Ag、Pb、Hg是一般的伴生元素。多元素组合异常浓度带发育,浓集中心互相套合叠置部位指示金矿(化)体位置。矿体指示元素(Au、As、Sb、W、Hg、Bi、Ag、Pb)异常分布在岩体、地层接触带和构造交汇处,显示金矿与岩浆活动、热液作用和断裂构造相关,属多次构造作用、岩浆热液叠加富集而成。该金矿床处在冈底斯成矿带内,此研究对该成矿带金异常的识别和查证,寻找新的金矿具有借鉴意义。 相似文献
9.
三家金矿发现Hg—Au—Ag矿物—α—汞金银矿 总被引：1，自引：0，他引：1
a-汞金银矿是1986年笔者在河北省青龙县三家金矿某富矿带采集的金矿石标本中发现的,见于矿石光片及人工重砂中。经电子探针分析,平均含Ag 41.53%,Au 22.34%,Hg 36.09%,简化化学式为:(Ag,Au)3Hg。其x射线粉晶数据为:2.382(9) (111),2.060(6)(200),1.461(7)(220),1.245(10)(311),1.194(5)(222),与1929年Pabst等人合成的a汞金矿(含Au 82.75%)可以比较,属等轴晶系。笔者确定它为Hg、Au、Ag金属互化物,且是Hg-Au-Ag系列矿物的新变种。 相似文献
10.
《Russian Geology and Geophysics》2014,55(2):252-258
The mineral and geochemical compositions of noble-metal (first of all, gold) deposits of the Fennoscandian, Siberian, and Northeast Asian orogenic belts are considered. These deposits are of several types: Au (disseminated Au–sulfide and Au–quartz), Au–Bi, Au–Ag, Au–Sb, Ag–Sb, Au–Sb–Hg, and Ag–Hg. They formed in different geodynamic settings as a result of the active motion of crustal tectonic blocks of different nature. Subduction processes (both at the front and at the rear of continent-marginal and island-arc magmatic arcs) resulted in Au–Ag, Ag–Sb, Ag–Hg, Au–Sb–Hg, and Au–Bi deposits. Collision events gave rise to Au and Au–Bi deposits. Intraplate continental rifting and formation of orogenic belts along the boundaries of block (plate) sliding led to the origin of Au and Au–Bi ores in association with Au–Ag, Au–Sb–Hg, and complex ores. In all cases, the formation of noble-metal mineralization was accompanied by magmatism of different types and metamorphism. Because of this diversity of ores, there is no single concept of the genesis of noble-metal mineralization. Several competing models of genesis exist: hydrothermal-metamorphic, pluton-metamorphic, plutonic, activity of mantle fluid flows, and multistage concentration during the crust–mantle interaction with the leading role of sedimentary complexes. 相似文献
11.
槐树坪金矿床位于河南省洛阳市嵩县境内,是豫西熊耳山地区近年来新发现的大型金矿床。本次研究对槐树坪金矿区地表及井下不同类型的较新鲜围岩、蚀变岩和矿石以及地表1∶20000面积性土壤采样,分析29项微量元素,从岩石和土壤两种采样介质来确定槐树坪金矿床的地球化学找矿指示元素。一方面基于较新鲜围岩的元素含量特征确定每个微量元素在该区岩石中的异常下限,进而分别计算了蚀变岩和矿石中微量元素平均含量与异常下限的比值,即异常衬度。按照异常衬度大于1.4的标尺确定了蚀变岩与矿石中明显富集的微量元素组合。另一方面,基于Au与28项微量元素在较新鲜围岩、蚀变岩、矿石三种介质中含量关系散点图直观确定了指示金成矿的微量元素组合。综合二者确定出槐树坪金矿区岩石地球化学找矿的指示元素组合为Au、Ag、As、Sb、Hg、Sn、Mo、Bi、Cu、Pb、Zn、Cd、Nb计13项。针对地表1∶20000面积性土壤调查,采用上述岩石中异常衬度为1.4作为土壤异常下限绘制了槐树坪金矿区微量元素的地球化学异常剖析图,以槐树坪金矿区已探明鸡公山一带的主成矿段为模型确定了土壤地球化学找矿的指示元素组合为Au、Ag、As、Sb、Hg、Bi、Cu、Pb、Zn、Cd、B计11项。综合上述结果认为在找矿指示元素组合方面土壤对岩石具有明显的继承性。基于岩石与土壤介质中共同的10项找矿指示元素,构建了归一化的综合异常指标,以鸡公山矿段为标准对整个槐树坪矿区进行了综合评价,发现槐树坪矿区内马蹄沟、秦佛爷沟、姜疙瘩和天坪西4处具有类似鸡公山矿段的找矿潜力。 相似文献
12.
We report the morphological, textural and chemical characteristics of gold grains in stream gravels from the Siruvani River in Attappadi Valley, southern India. The placer gold deposits contain both primary grains with jagged grain contours and secondary grains with smooth grain margins. The primary and secondary gold grains are also distinguished by marked contrast in microtextures with the latter displaying a range of corrosion textures including striations, etch pits and chemical corrosion cavities that coalesce to form honey-comb patterns. Some of these cavities are filled with fine clay derived from lateritic weathering front. While the primary grains are characterized by high silver content (up to 35.77 wt.%) with marginal overgrowths of high purity gold, the secondary grains show exceedingly high fineness (1000 Au/Au+Ag) levels (up to 984) with no marked compositional variation indicating selective extraction of Ag and/or reprecipitation of Au. From morphological and chemical characteristics, we propose that the high purity gold grains were not derived directly from primary sources, but underwent chemical refinement in the weathering front before they were transferred to the fluvial systems. Our findings have important implications for gold exploration in the Attappadi Valley. 相似文献
13.
The «Selektor-C» software package and standard thermodynamic functions of ternary Ag–Au–Hg solid solutions were used for developing physicochemical models in natural processes with participation of gold, silver and mercury. On the example of the Kyuchyus Au–Sb–Hg deposit we have worked out hypogene and hypergene models of formation of native gold, including mercuric gold. We obtained thermodynamic evidence that the Kyuchyus deposit ores formed with the origin of electrum at the early main productive quartz–sulfide stage and ternary Au–Ag–Hg solid solutions at the late non-substantive Au-bearing stages. 相似文献
14.
15.
We carried out experiments on crystallization of Fe-containing melts FeS2Ag0.1–0.1xAu0.1x (x = 0.05, 0.2, 0.4, and 0.8) with Ag/Au weight ratios from 10 to 0.1. Mixtures prepared from elements in corresponding proportions were heated in evacuated quartz ampoules to 1050 ºC and kept at this temperature for 12 h; then they were cooled to 150 ºC, annealed for 30 days, and cooled to room temperature. The solid-phase products were studied by optical and electron microscopy and X-ray spectroscopy. The crystallization products were mainly from iron sulfides: monoclinic pyrrhotite (Fe0.47S0.53 or Fe7S8) and pyrite (Fe0.99S2.01). Gold–silver sulfides (low-temperature modifications) are present in all synthesized samples. Depending on Ag/Au, the following sulfides are produced: acanthite (Ag/Au = 10), solid solutions Ag2–xAuxS (Ag/Au = 10, 2), uytenbogaardtite (Ag/Au = 2, 0.75), and petrovskaite (Ag/Au = 0.75, 0.12). They contain iron impurities (up to 3.3 wt.%). Xenomorphic micro- (<1–5 μm) and macrograins (5–50 μm) of Au–Ag sulfides are localized in pyrite or between the grains of pyrite and pyrrhotite. High-fineness gold was detected in the samples with initial ratio Ag/Au ≤ 2. It is present as fine and large rounded microinclusions or as intergrowths with Au–Ag sulfides in pyrite or, more seldom, at the boundary of pyrite and pyrrhotite grains. This gold contains up to 5.7 wt.% Fe. Based on the sample textures and phase relations, a sequence of their crystallization was determined. At ~1050 ºC, there are probably iron sulfide melt L1 (Fe,S ? Ag,Au), gold–silver sulfide melt L2 (Au,Ag,S ? Fe), and liquid sulfur LS. On cooling, melt L1 produces pyrrhotite; further cooling leads to the crystallization of high-fineness gold (macrograins from L1 and micrograins from L2) and Au–Ag sulfides (micrograins from L1 and macrograins from L2). Pyrite crystallizes after gold–silver sulfides by the peritectic reaction FeS + LS = FeS2 at ~743 ºC. Elemental sulfur is the last to crystallize. Gold–silver sulfides are stable and dominate over native gold and silver, especially in pyrite-containing ores with high Ag/Au ratios. 相似文献
16.
该文以山东招远大尹格庄金矿床中微量元素为研究对象,通过对矿床围岩、矿石等微量元素的研究,表明大尹格庄金矿围岩中微量元素以富含 Bi,Au,Pb,W,Ag,Sn 为特点,矿体和矿化体中元素组合为 Au,Ag,As,Sb,Hg,B, Cu,Zn,Bi,Mo,Mn,Co,Ni,W。在5个成矿阶段中,第二阶段与第三阶段微量元素的富集程度较明显,表现为 Au, Ag,As,Co,Bi,Cu,Pb,Zn 等的富集,成矿元素可分为2个分带序列,主成矿元素为 Au Ag Cu Pb Zn Bi 组合、头晕元素 As Sb Hg 组合和尾晕元素 Co Ni 组合。 相似文献
17.
Robert John Chapman James Keith Mortensen William P. LeBarge 《Mineralium Deposita》2011,46(8):881-903
Between 1978 and 2009, approximately 430,000 oz of placer gold were obtained from the Indian River and Black Hills Creek,
which equates to roughly 20% of the production for the entire Yukon Territory during that period. The area is unglaciated,
exposure is poor, and there are few known lode gold occurrences present. The technique of microchemical characterization of
placer gold grains has been applied to illuminate the style(s) of source mineralization and their relationship to placer gold
from the Klondike gold district immediately to the north. A total of 2,613 placer gold grains from 22 localities were characterised
in terms of the Au, Ag, Cu, and Hg content of their alloy and associated suite of opaque mineral inclusions. A combination
of alloy and inclusion mineralogy was used to define gold signatures which augmented the previous classification of orogenic
gold in the Klondike. Gold type 3b (8–25% Ag) is the main component of the placers in lower Dominion Creek but is augmented
and eventually replaced by type 3a gold (10–40% Ag) in placers in the main Indian River valley, probably through erosion of
gold-bearing veins in the valley floor. Type 4 gold exhibits highly variable Ag which may contain Hg to a maximum of 11 wt.%.
This gold type also hosts a distinctive inclusion assemblage of complex polymetallic sulphides, tellurides, sulfotellurides,
and sulfosalts and has previously been ascribed to local low sulfidation epithermal mineralization. Placer gold in drainages
radiating from Eureka Dome exhibits various proportions of types 3 and 4 gold depending on location, but type 3 gold forms
the major component in Black Hills Creek and northerly flowing tributaries of the Indian River with the exception of Eureka
and Montana creeks. Type 5 gold is found only in placers in the middle and lower Indian River. It is distinguished by slightly
elevated (0.05–0.17%) Cu in the gold alloy, together with low (5–9%) Ag contents. Inclusions of Bi minerals, Cr-bearing magnetite
and molybdenite within type 5 gold suggest derivation from an intrusion-related source. Candidates for such a source include
undiscovered lode occurrences associated with Cretaceous age intrusions to the south of the Indian River, or deformed Cu-Au
(−Mo) porphyry occurrences which are known to be present in the same area. This analysis of placer gold has indicated that
the contribution of low sulfidation epithermal gold from Eureka Creek to the larger placers of the Indian River is minor.
Consequently, the placer gold inventory of the Indian River is primarily orogenic in origin. Similarly, the characterization
of placer gold in Blackhills Creek strongly suggests an orogenic source. This study has demonstrated for the first time that
orogenic lode gold mineralization extends a considerable distance to the south of the southern Klondike goldfield. This information
contributes to the regional models of gold mineralization in an area which is currently the focus of intensive exploration. 相似文献
18.
Sewage sludges are dewatered end products of human sewage waste and are recognised repositories of organic pollutants and heavy metals. They may be considered targets for economic extraction of Au because of the documented Au content of sewage sludges worldwide which are of the order of some ore deposits currently mined for Au. They are also highly nutrient enriched (nitrogen and phosphorus) and therefore amenable to use as agricultural fertiliser or as covers for mine wastes. The sewage of Melbourne, Australia, a city with a current population of 3.3 million, was stockpiled in large, closed, lagoonal tanks from 1898 until 1980. In 1995 Echidna Mining, an Australian gold exploration company, acquired the exploration rights to the ground surrounding the historic sludge reserves and commenced a program of resource evaluation, utilising RNAA, INAA, GFAAS, ICP–MS and FLAAS to determine 31 elements, including Au, Ag, Sb, As, Cd, Hg, Zn, Cu, and Pb. The study was initiated to determine Au, Ag and other metal variations in both space and time and to investigate the economics of chemical extraction of the precious metals. A total of 149 samples from over 50 hand-auger drillholes to a depth up to 4 m have been analysed from the stockpiles, with Au assays yielding remarkably consistent results. Average grades of 0.77 g/t Au and 18.8 g/t Ag have been documented for a measured resource of 770,000 m3 (of an estimated 1.6–2.5 million m3 contained) at a density of 1.0 g/cm3 and an average moisture content of around 40%. Laboratory-based extractive metallurgy of the Werribee sludges has demonstrated that Au, Ag and Zn can be removed with relative ease by heap-leaching using modified conventional technology, albeit with prohibitive reagent consumption. The extraction of the precious metals also results in the variable removal of contaminant metals such as Cd, As, Sb, Hg and Cr which may render the sludges fit for sale as agricultural fertiliser, provided organic pollutants and pathogenic organisms are below governmental environmental protection limits, an area beyond the scope of this paper. Another potential avenue of the exploitation of sewage sludges is discussed: that of the utilisation of sludges to extract contaminant metals from waste water and contaminated mine waters, which we demonstrate on pure aqueous synthetic samples. This paper presents a study of the exploitation of an historic sludge resource for its contained Au and residue post-metal extraction. 相似文献
19.
Mi?raç Akçay H.Mustafa Özkan Charles J. Moon Barry C. Scott 《Journal of Geochemical Exploration》1996,56(3):197-218
Orientation studies over the Sarpda? prospect in the Biga peninsula and the Arapdagi deposit near Izmir have provided elear evidence for elemental dispersion around west Turkish gold prospects. Although these deposits are of different types, silicification associated with the deposits results in the main part of both deposits forming topographic highs.At Sarpda? gold mineralisation is relatively weak compared with nearby prospects and associated with a silicified cap on the main hill. Comparison of coarse and fine fractions, based on a 190 μm size split of 8 kg of -2 mm material, suggests that gold disperses clastically on the steep slopes, probably within silica, but coarse grains break down giving Au concentrations in the finer fractions at the base of the main slope. Discrete gold grains, that can be panned, only occur 1–2 km downstream within the streams and heavy mineral concentrations are very limited. This interpretation of Au dispersion is consistent with the data from 1 kg samples collected at the higher primary grade, but more contaminated, Arapda?i prospect.Antimony is the most consistent pathfinder both for the silicified cap at Sarpda? and for gold-rich veins at Arpada?i. It gives high contrast anomalies. Arsenic is useful being more mobile than Sb, although contrast may be low. High resolution Ag data can be useful but base metal enrichments are also often associated with Ag anomalies. Most prospects have some base metal enrichments although they can be displaced from the main gold-rich parts of the deposit and anomalies may be weak. Lead and Cu are the more consistently useful elements.The use of large (> 8 kg of -2 mm material) samples produces consistent stream sediment data that can be used to reliably interpret single samples and quantify Au anomalies. A survey around the Halíköy Hg and Emirli Sb mines, using these large samples, confirmed the extension of the known gold-bearing Emirli structure. In contrast the major Hg-bearing Halíköy Fault is gold poor although a structure parallel to it is auriferous. 相似文献
20.
Steven D. Bussey Paul M. Taufen Bart J. Suchomel Malcolm Ward 《Journal of Geochemical Exploration》1993,47(1-3)
The Bell Springs deposit is a bulk-tonnage, low-grade gold deposit, formed in a hot-spring environment, that is hosted by middle Miocene weakly peralkaline, high-silica rhyolite ash flows and rheomorphic tuffs. Ore grade mineralization over about 460 × 460 m was controlled by northeast- and northwest-trending structures. Sixty-nine soil samples collected along a traverse across the Bell Springs deposit, screened into six mesh size fractions, +10, −10+35, −35+80, −80+120, −120+200, and −200, were treated by low-detection-limit acid digestion/organic extraction procedures, and analyzed by ICP or graphite furnace techniques for Au, Ag, As, Bi, Cd, Cu, Ga, Hg, Mo, Pb, Sb, Se, Te, Tl, and Zn. Twenty-five stream-sediment samples were collected from a drainage crossing mineralization and from a nearby tributary. Sediment size fractions of −200 mesh and −10+200 mesh were analyzed by the same procedures used for soils. In addition, analyses of bulk leachable gold via cyanide leach method (BLEG) was done on bulk −10 mesh sediments.Anomalous Au, Ag, As, Sb, and Mo in all soil size fractions revealed the underlying ore. Areas with anomalous Sb and As were about three times larger than areas with anomalous Au and Ag. Analyses of fine-fractions of stream sediments provided the best-defined Au anomalies in drainages. A multi-element factor calculated by multiplying Au, As, Sb, and Mo reinforced anomalous Au in drainages and correlated well with Bell Springs mineralization. 相似文献