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1.
The Lega Dembi deposit is the largest gold producer in Ethiopia. It is situated in late-Precambrian metamorphosed sediments
of the N-S trending, volcano-sedimentary Megado belt, which forms part of the late-Proterozoic Adola granite-greenstone terrane
in southern Ethiopia. The lode-gold mineralization occurs in a N-S trending, steep westerly dipping quartz-vein system that
follows the structural contact between underlying feldspathic gneisses and the volcanosedimentary sequence of the Megado belt.
This contact also marks the northernmost extension of the regional-scale, sinistral strike-slip Lega Dembi-Aflata shear zone.
Mineralization and intense quartz-veining is best developed in graphite-rich sediments within an area not more than 80 m away
from this tectonic contact. Hydrothermal wall-rock alteration includes actinolite/tremolite-biotite-calcite-sericite and chlorite-calcite-epidote
assemblages. Gold occurs preferentially in the sericite alteration zone, where it is closely associated and intergrown with
galena. The variable deformation of the gold-quartz veins suggests a syn-kinematic timing for the gold mineralization during
transcurrent shearing in a dilational segment of the shear zone. In addition to the structural control, lithological control
on gold deposition is indicated by the almost exclusive occurrence of the gold mineralization in graphite-rich metasediments.
This close relationship suggests that gold precipitation was the result of chemical reduction of regional ore-bearing fluids.
Temperature conditions of mineralization are constrained by the actinolite-biotite alteration assemblage and by arsenopyrite
chemistry, which indicate that ore deposition occurred at or close to peak metamorphic conditions at upper-greenschist to
lower-amphibolite metamorphic grades. Rb-Sr dating of sericite indicates an age of about 545 Ma. for hydrothermal alteration
and, thus, for gold mineralization. The style of gold mineralization, structural pattern and lithological assemblages at Lega
Dembi are very similar to lode-gold deposits most commonly reported from Archaean granite-greenstone terranes. These similarities
may open new perspectives for the exploration of lode-gold deposits, which has previously primarily focused on Archaean greenstone
belts rather than Proterozoic or even Phanerozoic meta-volcanosedimentary belts.
Received: 26 July 1996 / Accepted: 8 January 1997 相似文献
2.
中国胶东焦家式金矿类型及其成矿理论 总被引：8，自引：0，他引：8
胶东焦家式金矿是中国最重要的金矿类型,是受构造控制的热液型金矿,可分为破碎带蚀变岩型、含金石英脉型、破碎带石英网脉带型、硫化物石英脉型、层间滑动构造带型、蚀变砾岩型和盆缘断裂角砾岩型等亚类。金矿成矿时期为早白垩世,成矿物质来源于强烈的壳幔相互作用,常具有绢英岩化、黄铁矿化、硅化、钾化等矿化蚀变,金矿体产出具有尖灭再现、分支复合、侧伏、斜列、叠瓦规律。岩浆热隆、流体活动、伸展拆离是导致胶东大规模金矿形成的三大关键要素;早白垩世壳幔同熔岩浆活动分凝和激活的围岩流体是金矿迁移、富集的载体;岩浆上隆产生的伸展拆离构造为金矿成矿提供了有利空间。据此,提出了焦家式金矿“热隆-伸展”成矿理论。焦家式金矿形成于早白垩世中国东部岩石圈大规模减薄阶段,受伸展构造系统控制。控矿构造沿倾向呈现陡缓相间的倾角变化规律,金矿主要沿断裂倾角变化的平缓部位和陡、缓转折部位富集,构成“阶梯式”分布型式。 相似文献
3.
Preliminary isotopic data for Late Proterozoic (～ 1100 Ma) granulite-facies metamorphics of the Prydz Bay coast indicate only very minor reworking (i.e., remetamorphism) of Archaean continental crustal rocks. Only two orthopyroxene—quartz—feldspar gneisses from the Rauer Group of islands, immediately adjacent to the Archaean Vestfold Block, show evidence for an Early Archaean origin (～ 3700—3800 Ma), whereas the vast majority of samples have Middle Proterozoic crustal formation ages (～ 1600–1800 Ma). The Prydz Bay rocks consist largely of garnet-bearing felsic gneisses and interlayered aluminous metasediments, although orthopyroxene-bearing gneisses are common in the Rauer Group; in contrast, Vestfold Block gneisses are predominantly orthopyroxene-bearing orthogneisses. The extensive Prydz Bay metasediments may have been derived by erosion of Middle Proterozoic rocks, such as the predominantly orthogneiss terrain of the Rauer Group, and deposited not long before the Late Proterozoic metamorphism. Data from nearby parts of the East Antarctic shield also suggest only limited Proterozoic reworking of the margins of the Archaean cratons.As in the Prydz Bay area, high-grade metamorphies in nearby parts of the East Antarctic shield show a secular increase in the sedimentary component. Archaean terrains like the Vestfold Block consist mainly of granitic orthogneisses derived by partial melting of igneous protoliths (I-type), whereas Late Proterozoic terrains (such as the Prydz Bay coast) include a much higher proportion of rocks derived either directly or by partial melting (S-type granitic orthogneisses) from sedimentary protoliths. Related chemical trends include increases in K2O2, Rb, Pb, and Th, and decreases in CaO, Na2O2 and Sr with decreasing age, essentially reflecting changes in the proportions of plagioclase and K-feldspar. 相似文献
4.
Quartz was studied with respect to its silicon isotopic composition and cathodoluminescence in micro-fine disseminated gold deposits in SW Guizhou and NW Guangxi.The results showed that quartz in wall rocks.ores and that in association with hydrothermal silicification are distinctive in silicon isotopes and cathodoluminescence characters.Quartz in association with primary silicification is non-luminescent while that in wall rocks and associated with secondary silicification exhibits striking luminescence.Based on the dynamic fractionation of silicon isotopes,it is suggested that the mineralization was accompanied by rapid transport of aprimary siliceous fluid along the major deep fault system into subordinate faults before ore components deposited in favorable strata via penetration and metasomatism.Therefore,a deep origin is implicit for gold deposits of this type. 相似文献
5.
Gold mineralization in Southern Granulite Terrain (SGT) of India has close spatial relationship with the shear zones (Moyar–Bhavani) present in Cauvery Suture Zone. Gold is found to be associated with primary quartz veins, placers and laterites. The gold prospects in SGT can be broadly grouped into three provinces i) Wynad-Nilgiri, ii) Malappuram and iii) Attappadi. The auriferous quartz veins are within the deformed biotite/hornblende bearing gneisses and amphibolite. Wall rock alteration is conspicuous around the mineralized veins and gives an assemblage of muscovite–calcite–ankerite–chlorite–biotite–pyrite related to fluid–rock interaction at the time of vein formation. Fluid inclusion studies of vein quartz gives an idea of the nature of the ore forming fluids, the fluid involved in gold mineralization is of low saline and aqueous-carbonic in composition and quite similar to the orogenic lode gold deposits reported world-wide. Micro-thermometric data indicates fluid immiscibility (phase separation) during trapping of fluid inclusions and this must have played an important role in gold deposition. Geochronological studies of mineral separates from Wynad-Nilgiri province using Rb–Sr and Sm–Nd isochron methods of the auriferous quartz veins gave an age of approximately 450 Ma for the vein formation. The present studies on SGT gold mineralization indicate 1. During the Pan-African orogeny, extensive fluid influx from mantle and metamorphism extracted gold from a mafic source and were focused along major structural discontinuities of Moyar–Bhavani Shear Zone, 2. The aqueous–carbonic ore fluid interacted with rocks of the upper crust and triggered a set of metasomatic changes responsible for the dissolved components such as Ca, Si and Fe and finally precipitating in the veins and 3. The mineralizing fluid with dissolved gold in sulphide complex got destabilized due to fluid immiscibility and wall rock alteration leading to the deposition of gold with associated sulphide minerals in the vein system. 相似文献
6.
总结了召河庙地区金矿的成矿规律，指出本区所发现的具一定规模的金矿（化）点在区域上主要集 分布于青灰窑子－大井－程二沟－东柜一线，矿体均为含金石英脉。容矿岩系为新太古代变质石英闪长岩、斜长岩花岗岩。成矿物质来源主要为古老的变质中基性深成侵入岩，即所谓广义的绿岩带。矿源岩中金物质的活化受深断裂作用、韧性剪切作用、退变质作用、变质流体以及岩浆热液的多重影响，其中以构造作用和岩浆热液最为重要。金矿的形成时期较长，主成矿时期在元古代。预测程二沟－白音查干－东柜一带为今后进一步寻找金矿的优选靶区。 相似文献
7.
Ore minerals and geochemical characterization of the Dungash gold deposit,South Eastern Desert,Egypt
Islam A. Dourgham Khairiya M. Fawzy Hartwig E. Frimmel 《Arabian Journal of Geosciences》2017,10(6):145
The Dungash historic gold mine is located in the South Eastern Desert of Egypt. The gold-bearing quartz veins are hosted by the metavolcanic and metavolcaniclastic rocks along an ENE–WSW trending shear zone. Alteration types recorded in the wall rocks are sericitization, silicification, carbonatization, chloritization, sulfidization, ferruginization, and listwanitization. The ore mineral assemblage comprises arsenopyrite, pyrite, native gold, pyrrhotite, sphalerite, chalcopyrite, and galena. The primary sulfide mineral assemblage formed during a hypogene hydrothermal stage whereas anglesite and goethite occur as secondary supergene phases. Microthermometric fluid inclusion analysis revealed that the auriferous quartz precipitated from a moderately saline (5 to 11.22 wt% NaClequiv) solution at temperatures above the recorded homogenization temperatures (T h), which range from 380 to 177 °C. The minimum pressures of trapping are between 350 and 400 bars. The fluid evolution during mineralization is explained by mixing of a magmatic fluid with meteoric waters. Initially, the high temperature and moderately saline magmatic fluid dominated and progressively became diluted with meteoric waters. Highest gold content is recorded in the carbonatized zone and the quartz veins. However, gold content in the carbonatized zone of the footwall exceeds several times its content in the quartz veins and the carbonatized zone of the hanging wall. 相似文献
8.
Ore-microscopic and geochemical characteristics of gold-tellurides-sulfide mineralization in the Macassa Gold Mine,Abitibi Belt,Canada 总被引：1，自引：0，他引：1
G. Tesfaye 《Mineralium Deposita》1992,27(1):66-71
The Macassa Gold Mine is the only operational mine (Lac-Minerals Ltd., Macassa Division) of seven original gold producers in the Kirkland Lake camp of northern Ontario, Canada. The gold deposit is in Archaean volcanic and sedimentary rocks which have been intruded by a composite syenite stock. The mineralization has taken place in two stages. The first stage is not gold bearing but involves pyritization and concomitant development of titanium phase minerals (leucoxene, rutile) and hematite. It is mainly associated with carbonatization, silicification and hematitization marked by Ba, Sr and Rb enrichment. In contrast to this, the quartz vein-type mineralization is associated mainly with later silicification and enrichment with tellurium, lead, silver, gold and copper. It is relatively depleted in Sr, Ba and Rb. The ore mineralogical assemblages in the second stage include pyrite, chalcopyrite, petzite, altaite and native gold. Geochemical and petrographic evidence indicate that the reddened wall rocks (hematitized) and reddened fragments are neither related with nor contain any gold. Therefore, hematitization and the presence of barium, in this case in K-feldspars, could not be considered as the sole evidence to suggest a magmatic oxidizing fluid model for the genesis of Macassa gold deposit. Regarding the metals transport, tellurides and thiocomplexes are considered as the important carriers of gold and silver. Hence, fugacity of tellurium and sulphur controlled the precipitation of gold in the Macassa gold deposit. 相似文献
9.
Nyankanga is the largest gold deposit in the Geita Greenstone Belt of the northern Tanzania Craton. The deposit is hosted within an Archean volcano-sedimentary package dominated by ironstones and intruded by a large diorite complex, the Nyankanga Intrusive Complex. The supracrustal package is now included within the intrusive complex as roof pendants. The ironstone fragments contain evidence of multiple folding events that occurred prior to intrusion. The supracrustal package and Nyankanga Intrusive Complex are cut by a series of NE–SW trending, moderately NW dipping fault zones with a dominant reverse component of movement but showing multiple reactivation events with both oblique and normal movement components. The deposit is cut by a series of NW trending strike slip faults and ~ E–W trending late normal faults. The Nyankanga Fault Zone is a major NW dipping deformation zone developed mainly along the ironstone–diorite contacts that is mineralised over its entire length. The gold mineralization is hosted within the damage zone associated with Nyankanga Fault Zone by both diorite and ironstone with higher grades typically occurring in ironstone. Ore shoots dip more steeply than the Nyankanga Fault Zone. The mineralization is associated with sulfidation fronts and replacement textures in ironstones and is mostly contained as disseminated sulphides in diorite. The close spatial relationship between gold mineralization and the ironstone/diorite contact suggests that the reaction between the mineralising fluid and iron rich lithotypes played an important role in precipitating gold. Intense brecciation and veining, mainly in the footwall of Nyankanga Fault Zone, indicates that the fault zone increased permeability and allowed the access of mineralising fluids. The steeper dip of the ore shoots is consistent with mineralization during normal reactivation of the Nyankanga Fault Zone. 相似文献
10.
万宝源斑岩型钼矿流体包裹体及成矿物质来源研究 总被引：2，自引：0，他引：2
万宝源斑岩型钼矿位于辽东裂谷内,产于石柱子花岗闪长岩体及其后侵入的石英斑岩内。矿化类型可以分为浸染状、细脉充填状和石英脉状三种。为了解决该钼矿的成矿流体来源及矿床形成机制问题,我们从流体包裹体、REE、S、D-O同位素入手进行了研究。石英中的流体包裹体测试数据揭示:钼矿化可以分为三个阶段,高温阶段、中温阶段和低温阶段,以中温阶段为主。REE分析表明,成矿物质起源于花岗闪长岩体,后经分离结晶作用,最终与花岗闪长岩体表现出不同的REE配分模式;S同位素分析显示,S来源于岩体与地层,是一种混合硫;D-O同位素研究则说明,成矿流体是以岩浆水为主,后期有天水加入的混合流体。最后建立石柱子成矿系统,对石柱子花岗闪长岩内外接触带上的矿床成因进行了探讨。 相似文献
11.
The Aitik Cu–Au–Ag deposit is located in northern Sweden and is hosted by strongly deformed 1.9 Ga Svecofennian volcano-sedimentary rocks. The main copper mineralization, which occurs as disseminations and veinlets, is hosted by garnet–biotite schist. Subeconomic mineralization in the footwall to the ore is hosted by feldspar–biotite–amphibole gneiss and porphyritic quartz monzodiorite. The deposit has been affected by post-mineralization metamorphic and igneous activity. Fluid inclusions in six samples of copper-mineralized quartz veins record the presence of three different fluid populations. The main ore was deposited from an aqueous, highly saline (31–37 eq. wt% NaCl + CaCl2) fluid. This fluid was trapped in inclusions intimately associated with the main chalcopyrite mineralization. Later bornite deposition took place from a less saline (18–27 eq. wt% NaCl + CaCl2), aqueous fluid. A third fluid composed of almost pure CO2, interacted with the copper-rich system during a post-ore event. The Aitik Cu–Au–Ag deposit shares some features with both porphyry-type and Fe-oxide–Cu–Au deposits. A high calcium content of the ore fluids, similar to other Cu–Au deposits in northern Scandinavia, suggests a contribution to the salinity of the mainly magmatic-hydrothermal fluids from evaporitic rocks in stratigraphically lower units. 相似文献
12.
13.
上世纪90年代中期通过成矿预测发现的水银洞金矿床,通过近10年的勘查,成为特大型层控金矿床。矿体呈层状、似层状产出于灰家堡背斜轴部附近300m范围内二叠统龙潭组的大孔隙度生物碎屑灰岩中,形态与背斜形态一致。矿体严格受控于碳酸盐岩,顶板和底板皆为粘土岩或粉砂质粘土岩,界线清楚。矿化表现为“硅化、白云石化、黄铁矿化”组合。硅化与白云石化是成矿的先决条件,碳酸盐岩最终能否成矿及品位的高低,取决于是否具有黄铁矿化热液蚀变及其强度。矿床具矿体多、厚度薄、品位富的特点。单矿体即达中型矿床规模。具中—低温超高压热液成矿的特点。金赋存于沿自形黄铁矿内核生长成的含砷黄铁矿环带中。 相似文献
14.
E. J. M. Bloem N. J. McNaughton D. I. Groves J. R. Ridley 《Australian Journal of Earth Sciences》2013,60(5):447-451
The Corinthia lode‐gold deposit in amphibolite‐facies greenstone belt rocks in the Southern Cross Province of the Archaean Yilgarn Block contains a largely undeformed pegmatite dyke emplaced during the last phases of movement along the Fraser's‐Corinthia shear zone. Gold mineralization and shear zone development were synchronous, and a Pb‐Pb isochron age of 2620 ±6 Ma for pegmatite emplacement either indirectly dates mineralization, or places a minimum age constraint on the timing of mineralization. This age is in accord with a broadly synchronous dominant episode of Archaean lode‐gold mineralization throughout the Yilgarn Block. 相似文献
15.
Warda Saad Djamal Eddine Aissa Koichiro Watanabe Sachihiro Taguchi 《Arabian Journal of Geosciences》2018,11(2):26
The Tirek gold deposit hosted in the Archean shield is one of the richest sources of mined gold for Algeria. The deposit is controlled by the East Ouzzal shear zone (EOSZ), a transcurrent N–S lithospheric fault. The EOSZ is a late Pan-African dextral-ductile shear zone separating two contrasting Precambrian domains: the Archean In Ouzzal block to the west (Orthogenesis with subordinate metasediments reworked and granulitized during the ca. 2 Ga Eburnean event) and a middle Proterozoic block to the east involved in the ca. 600 Ma Pan-African event. The auriferous quartz veins are mainly oriented in two directions, N–S veins hosted in mylonitic rocks and NE–SW veins hosted in gabbroic or gneissic bands. The NE–SW veins contain the richest ore. Gold ore is found in a system of veins and lenticular quartz veinlets arranged in anastomosing networks. The hydrothermal alteration associated with these veins is characteristically a carbonate-sericite-albite-pyrite assemblage. Gold is the main metal of economic importance; it is disseminated in the quartz as grains or fibers along microcracks and as microscopic grains in the host rocks. Microthermometric results and Raman laser data from fluid inclusions demonstrate that the ore-forming fluids contained H2O-CO2±CH4 and were low salinity. Homogenization temperatures are commonly 250–310 °C. In the Tirek deposit, the role of the shear zone that hosts the mineralization was to drain the hydrothermal fluid. Interactions between the fluid and the mafic host rocks and CO2 also contributed to the formation of the hydrothermal gold deposit at Tirek. 相似文献
16.
安徽池州马头铜钼矿是长江中下游成矿带中安庆—贵池矿集区内一个典型的铜钼矿床。通过野外地质祥查和系统的岩相学、矿相学工作,对该矿床的蚀变特征及分带进行了深入研究。识别出马头铜钼矿的蚀变类型主要有硅化、绢云母化、钾长石化,其次为黏土化、绿泥石化和碳酸盐化等。矿区围岩蚀变在空间上往往重叠,但具有一定的水平及垂向分带特征,自岩体深部至浅部、自内向外总体表现为面型石英钾长石化带、线型石英钾长石化带和石英绢云母化带。矿（化）体以脉状矿化为主,其中分布较广的石英脉带矿化主要产在石英绢云母化带中,以石英细（网）脉为主,受节理和裂隙控制;而品位较富的细脉浸染状矿化则主要产在面型钾长石化带中。通过研究认为,马头铜钼矿在成矿过程的早期阶段,由于高温、富钾和高pH值的热液流体作用,形成大面积的钾长石化,伴生与面型钾长石化有关的细脉、浸染状矿化;热液演化中期阶段,随着温度持续下降、K＋活度和流体pH值的降低,形成硅化、绢云母化等蚀变类型,并伴随范围较大的细脉-网脉状矿化;热液演化晚期阶段,主要形成碳酸盐化,而相应的矿化作用不显著。通过与部分典型斑岩型铜钼矿床的对比研究认为,马头铜钼矿在蚀变类型等方面与斑岩型铜钼矿大体相同,可归至斑岩型成矿体系。 相似文献
17.
In the Dharwar Craton, southern India, gold deposits are found mostly along the six arcuate shear zones passing through late Archaean greenstone belts (2.7 Ga). One such shear zone complex extends for about 400 km within and along the Ramagiri–Hungund schist belt. The Penakacherla sector of this shear zone is excellently exposed, enabling a detailed investigation of synorogenic gold mineralisation and its relationship to associated hydrothermal alteration.Metamorphism and deformation under NE–SW compression associated with Archaean subduction processes converted mafic volcanic rocks into amphibolites and intermediate to felsic volcanic rocks into quartz mica schists. Continued compression generated a 50–100-m-wide shear zone complex consisting of mafic phyllonites. Advection of hydrothermal fluids through this shear zone and reaction between fluids and the mafic phyllonites resulted in a silicified, K-metasomatic assemblage mainly consisting of chlorite, amphibole, K-mica, plagioclase, ankerite, quartz, Fe-oxides, pyrite, chalcopyrite and arsenopyrite. Networks of quartz and carbonate veinlets, a few millimeters to a few centimeters thick, formed along the foliation planes giving rise to microscopic alteration envelope, in which individual veinlet systems are merged into one another to form a composite alteration system. Gold is found within these quartz veinlets, mafic phyllonites and at their mutual contacts.Hydrothermal fluids have modified the primary major, minor, trace and LREE compositions of host rocks such that their mutual behaviour became non-systematic. Some HFSE and HREE also show minor mobility but the overall REE pattern generally resembles that of the precursor mafic volcanic rocks. Mass and volume loss/gain by Si and Ca has made significant impact on Al, Ti and Zr abundances, which are generally immobile during hydrothermal alteration. However, element pairs such as Zr–Hf, V–Sc and Nb–Ta maintain primary inter-element ratios, although their absolute abundances are drastically diluted. Similarly, ΣREE in highly silicified and carbonatised samples are reduced, but patterns remain similar to those of relatively least altered mafic phyllonites with (LaN/Yb)N between 1 and 3. In some samples, LREE enrichment is observed elevating in (LaN/Yb)N from 3 to 11. Pathfinder elements and base metals such as As, Cd, Cu, Pb, Zn and Sb have been added along with the Au and Ag.δ13C of carbon varies from −16‰ to −21‰ suggesting a biogenic origin, whereas coexisting pyrite δ34S ranges from 1‰ to 3‰, pointing towards the involvement of magmatic or average crustal sulphur. Overall concentrations of K, Rb, Sr, Ba, Nb, Ta, Ti, Cs, Cr, Co, V, Y and Sc and many of the ratios such as K/Rb, La/Sc, La/Yb indicate that metamorphism, devolatilisation and dehydration of an oceanic subducting slab might have partially contributed the mineralising fluids and generated the alteration assemblage observed in the host rocks. Fluid sources were mantle and greenstone belt dehydration and devolatilisation generating observed compositional and alteration diversity. 相似文献
18.
赣南漂塘钨矿流体包裹体研究 总被引：24，自引：7，他引：17
赣南是我国最重要的钨矿产地,漂塘钨矿是赣南的一个重要的大型石英脉型黑钨矿床,含矿石英脉具有多阶段矿化的特征。本文采用“流体包裹体组合”（FIA）,这一国际上近年来提出的适用于多阶段流体活动的包裹体研究新方法,对漂塘钨矿主成矿阶段,即黑钨矿-锡石-硫化物-石英脉阶段的含矿石英脉中流体包裹体进行岩相学和显微测温研究,并运用显微激光拉曼光谱测试技术对不同流体包裹体组合（FIA）中单个流体包裹体成分进行测试。结果表明,主成矿阶段具有明显的两期流体活动特征,流体组分主要为水溶液,不含或只含少量的CO2。 相似文献
19.
三角顶金矿是在柴达木盆地北缘唯一发现的产出于中酸性岩体中“似玲珑式”金矿,矿床具有重要的区域找矿意义。对该矿床的地质特征、矿石类型、岩矿石原生晕特征、含金石英脉的流体包裹体特征以及区域成矿事件进行了综合分析,探讨了矿床成矿特征及其找矿意义。含金石英脉、含金硅化糜棱岩反映了三角顶矿区多期次、多流体参与的叠加复合成矿作用,其中含金石英脉呈现浅成中低温中低盐度流体的特征,与岩浆作用关系密切;含金硅化糜棱岩型矿石与动力变质作用关系更为密切;三角顶金矿成矿深度由西向东增大,西矿区石英脉型矿体代表了该期成矿的顶部,形成了石英脉型的穹顶式金矿化层。在矿区西侧的石英脉型穹顶式金矿化层和矿区东侧的含金糜棱岩化带中,找矿潜力巨大。 相似文献
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The Rämepuro gold mineralization is situated in the Hattu sub-belt of the Archaean Ilomantsi greenstone belt, Eastern Finland. It consists of gold-bearing quartz veins located mainly within the shear zone contact between felsic volcanics and sedimentary rocks. The quartz veins cutting all the types of Archaean rocks are composed mainly of quartz and tourmaline and minor amounts of pyrite, pyrrothite, chalcopyrite, sphalerite, siderite, hedleyite, native bismuth and gold. The highest amounts of gold are found in the quartz-tourmaline veins, with abundant chalcopyrite and sphalerite. Gold has its best correlation with Bi, Te, S, Zn and Cu. The minor mineralogical alterations (sericirization, saussuritizarion, chloritization) are connected with variations in some major elements. The quartz veins were emplaced under greenschist facies conditions after the peak in the lower amphibolite facies metamorphism. 相似文献