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内蒙古中部地区绿岩及绿岩型金矿成矿地质特征 总被引：6，自引：0，他引：6
内蒙古中部大青山、色尔腾山地区发现的绿岩型金矿，经数年的勘查评价、研究，近两年被逐步认识和肯定。其成矿地质条件独特，矿化体赋存于新太古界色尔腾山群柳树沟组的特定层位。矿化与变质变形作用有关，变形强（包括糜棱岩化），矿化好。地表品位一般较低，多在1g/t左右，向深部增高。矿体规模大，适于大规模堆浸。化探异常主要集中在绿岩分布区，激电异常与矿化层吻合较好，矿（化）点多，找矿标志较为明显，资源潜力巨大，运用综合方法找矿效果较好。 相似文献
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恩泽加绿岩带是坦桑尼亚重要的成矿带之一,产出了高登普莱德(Golden Pride)等多个大型金矿。通过对坦桑尼亚恩泽加绿岩带已发现的隐伏金矿床进行分析研究,结果显示恩泽加绿岩带隐伏金矿床构造控矿作用明显;高精度磁法和激电中梯测量结果显示含矿构造蚀变带具有高磁、低阻、相对高极化的特征;土壤地球化学测量结果显示成矿元素Au异常在空间分布上大于相应的含矿构造蚀变带的分布范围,其浓集方向与含矿构造蚀变带展布一致,并与指示元素As、Sb的套合性较好。根据该区域隐伏金矿床的地质、地球物理及地球化学特征,对该区隐伏金矿床的找矿标志进行了总结,明确了各找矿标志与隐伏金矿床之间的关系,并在此基础上构建了恩泽加绿岩带隐伏金矿床的综合找矿模型,该模型的应用显示了多种技术手段联合实施在寻找绿岩带型隐伏金矿床的有效性。 相似文献
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依据构造控矿为成矿主因、矿源层是物质基础,将五台山绿岩带金矿划分为3种主要类型:与次级褶皱有关的条带状铁建造型金矿床、与剪切变形有关的变质中酸性火山沉积岩型金矿床、与剪切变形有关的变质砾岩型金矿床.这些不同类型的金矿床构造控矿特征明显.五台山绿岩带的区域性倒转复式向斜构造制约了含矿带呈NEE向展布,大型紧闭褶皱转折端控制了矿床的定位,与紧闭褶皱伴生的剪切变形及次级褶皱控制着矿体的规模、形态和产状,剪切裂隙控制着金矿脉的分布和金矿化的局部富集.紧闭褶皱倒转翼部(近转折端)的剪切变形是五台山绿岩带金矿构造控矿的普遍规律.矿源层是物质基础,而经历了紧闭褶皱及伴生的剪切变形带叠加改造的矿源层才是最佳的成矿和找矿靶区.文章以构造控矿理论为指导,重点剖析了典型矿床的构造控矿特征,深入探讨了控矿构造对矿床定位、规模大小、矿体形态、富集程度的制约,认为褶皱与剪切变形不仅在于控矿,而且其本身就是一种重要的成矿作用,进而总结了五台山绿岩带金矿构造控矿的普遍规律. 相似文献
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通过对内蒙古包头公益明铁矿变基性火山岩的系统采样和测试分析 ,其常量、微量、稀土元素地球化学的特征表明该区的变基性火山岩形成于类似现代大陆裂谷的构造环境中。Sm -Nd、Rb-Sr同位素年代学的研究表明 ,色尔腾山绿岩下部的变基性火山岩形成于 2 80 0～ 2 90 0Ma的壳幔分异事件中 ,在新太古晚期 (2 5 0 0Ma± )遭受了角闪岩相 -绿片岩相变质作用的改造。而在中元古代 (16 0 0Ma± )由于受华北克拉通与西伯利亚克拉通裂解的影响 ,该区岩石的Rb -Sr体系又一次发生变化。研究表明 ,色尔腾山绿岩生成于中太古代 ,该区在古太古代可能就已存在稳定的陆壳 相似文献
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绿岩型金矿是刚果(金)重要的金矿类型之一。刚果(金)东北部的金矿床以内生金矿为主,次为外生金矿,内生金矿中主要为构造控制的脉状金矿床。典型矿床为基巴里绿岩带中的基洛矿区,矿化主要发生在发生碳酸盐化岩石的片理、剪切带和褶皱裂隙中;其次为受片理控制的浸染状金矿床,主要位于基巴里绿岩带的摩托矿区,矿化通常与围岩的片理相一致,并发育碳酸盐化等蚀变。研究认为,金矿床中的金质主要来源于绿岩带,太古宙岩浆活动形成了金的第一次富集,后期绿片岩相变质作用和强烈的蚀变造成了金的活化,并最终沉淀在构造裂隙中成矿。文章还总结了金矿床的找矿标志,并为区域金矿勘查方法提出了建议。 相似文献
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津巴布韦太古宙花岗-绿岩型金矿床受构造的控制,金矿可分为褶皱控矿型、剪切带控矿型、层控型、深成花岗岩控矿型和构造-蚀变岩型等5类。津巴布韦花岗-绿岩型金矿多产于花岗质片麻岩与绿岩带的接触带上,金以自然金或金的硫化物形式产出。金矿成矿时代大致分为(2660±50)Ma和(2410±70)Ma(米德兰德绿岩带北部白钨矿Sm-Nd测年)2个时段,分别与新太古代TTG事件和大岩墙侵入相关。津巴布韦花岗-绿岩型金矿较多,但发现的中-大型绿岩型金矿较少,具有较好的金矿找矿前景。 相似文献
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随着绿岩带金矿与浅成热液金矿研究的深入,人们认识到1)绿岩带型、浅成热液型金矿床成矿机制是相当复杂的,矿化类型是多样的,各自矿化类型间构成一成矿系列;2)绿岩带金矿受绿岩带的特点及发展演化规律的控制;3)以浅成热液金矿矿化与蚀变分带为基础建立了更接近于客观的成矿、找矿模式;4)对上述两大类金矿的具体的分析,明确和扩大了金矿的勘查找矿标志与范围.从认识矿床之间的联系入手,为认识矿床成因开拓新的思路. 相似文献
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枪口南银多金属矿位于东昆仑多金属成矿带东段,1：2.5万沟系沉积物测量在矿区圈定出以Ag、Cu、Pb、Zn、Mo为主的综合异常4处.经异常查证,圈出9条矿化带,21条矿（化）体,取得了较好的找矿效果.通过进一步异常查证,在AS1、AS2异常中Ⅶ、Ⅷ和Ⅸ号矿带内圈出银、银铅锌以及银金砷异常高值段,展示出了异常区具较好的银多金属矿的找矿远景.AS3异常内的Ⅳ号含矿花岗斑岩体深部发现多条铜多金属矿（化）体,且发育较强的围岩蚀变,显示具有较好的斑岩型铜多金属矿找矿潜力.AS4异常内Ⅰ－Ⅲ号金矿化带具较好的金多金属矿找矿潜力.本区具有优越的成矿地质条件,化探异常发育,且已发现了较好的银多金属矿找矿信息,充分展示出本区具较大的找矿潜力. 相似文献
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Shen Baofeng Peng Xiaoliang Luo Hui Mao DebaoTianjin Institute of Geology Ministry of Geology Mineral Resources Tianjin 《《地质学报》英文版》1994,68(1):15-29
Chinese Achaean greenstone belts are mainly distributed along the northern and southwestern margins of the North China platform. In terms of their geological characteristics, the greenstone belts in China are comparable to those in other countries but at the same time have unique features of their own. In view of their geochemistry, the Chinese greenstone belts may be grouped into three types: the Jiapigou type, Qingyuan type and Xiaoqinling type. The greenstone belts were formed possibly in a rift-type palaeo-tectonic setting, similar to that of the modern island are-continental margin mobile belts. 相似文献
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Deformation experiments have been carried out on a microgranodiorite under undrained conditions at a pressure of 0.448 GPa and temperatures up to 720 °C. The granodiorite contained a small amount of chlorite and amphibole minerals which decomposed at elevated temperatures, giving rise to a pore pressure. Evidence about the decomposition reaction was obtained from differential thermal analysis and optical microscopy. In some experiments small amounts of free water were enclosed with the sealed rock sample. The strength (at fracture or 2 per cent strain) fell to very low values (0.02 GPa) at 700 °C, and at temperatures of 670 °C and above there was evidence of partial melting which led to ductile behaviour. At somewhat lower temperatures the rock was relatively weak but brittle. 相似文献
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绿岩带型金矿研究的进展 总被引：1，自引：0，他引：1
丁式江 《华东地质学院学报》1996,19(3):231-236
本文介绍了近年来国外绿岩型带金矿在成矿模式，构造控制，成矿物化条件研究方向的某些进展，我国绿岩带与国外经典绿岩带有一定的差异，因而表现在成矿作用上也独树一帜，初步提出我国绿岩带型金矿研究中应注意的问题。 相似文献
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The granite-greenstone terranes nested in Archean cratonic nuclei of continents over the world are composed of variably metamorphosed igneous and sedimentary remnants of ancient ocean basins.These rocks preserve distinct geological and geochemical imprints of mantle evolution and differentiation of primordial crust,varying 相似文献
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Prof. Dr. Christoffer Oftedahl 《International Journal of Earth Sciences》1968,57(3):920-930
It seems possible to locate some of the volcanic centres of the greenstone effusions of the Caledonian geosynclinal volcanism in Norway from simple geologic features, such as greenstone thickness and character, gabbro intrusion intensity, and quartz keratophyre frequency. In the central part of the Trondheim region some six probable and four likely volcanoes are indicated. The best example may be the upturned Joma volcano further north.
Dedicated to Professor Dr. A.Rittmann on the occasion of his 75. birthday 相似文献
Zusammenfassung Es scheint möglich, einige der vulkanischen Zentren der Grünsteineffusionen im Vulkanismus der kaledonischen Geosynklinale durch einfache geologische Merkmale wie Mächtigkeit und Charakter des Grünsteins, Intensität der Gabbrointrusion und Häufigkeit der Quarzkeratophyre aufzufinden. Im Mittelteil des Trondheimgebietes werden 6 wahrscheinliche und 4 mögliche Vulkane angegeben. Das beste Beispiel wäre vielleicht der umgekehrte Joma Vulkan weiter nördlich.
Résumé Il semble probable de localiser quelques-uns des centres volcaniques des émissions de « greenstone » dans le volcanisme géosynclinal calédonien en Norvège d'après des marques géologiques comme l'épaisseur et le caractère de «greenstone», l'intensité de la gabbro intrusion, et la fréquence de quartz kératophyre. Au milieu de la Trondheim région on constate six volcans probables et quatre volcans possibles. Le meilleur exemple est peut-être le Joma volcan renversé plus au nord.
, .: , , . Trondheim .
Dedicated to Professor Dr. A.Rittmann on the occasion of his 75. birthday 相似文献
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JAHN BOR-MING; AUVRAY B.; BLAIS S.; CAPDEVILA R.; CORNICHET J.; VIDAL F.; HAMEURT J. 《Journal of Petrology》1980,21(2):201-244
Archean metavolcanic rocks from three greenstone belts (Suomussalmi,Kuhmo and Tipasjärvi) of eastern Finland have been subjectto a detailed geochemical study which leads to a discussionof their petrogenesis and the problem of compositional heterogeneityin the Archean mantle. Lithostratigraphically, the greenstonebelts are roughly divided into a lower and an upper volcanicsequence. Rocks of komatiitic and tholeiitic compositions arerestricted to the lower sequence, while andesitic tuffs, dacite-rhyodacitelavas and minor basalts of alkaline affinity occur in the uppersequence. All rocks from the greenstone belts have been subjectto regional metamorphism of the upper greenschist facies tothe lower garnet amphibolite facies. Consequently, the geochemicaldistinction of original magma types and the discussion of petrogenesishave relied heavily on the abundances of less mobile elements,such as TiO2, rare earth elements (REE), and some transitionmetals (e.g. Ni and Cr). Using all the possible discriminants of major element compositions,we have concluded that two general magmatic series that existin the lower volcanic sequence might be distinguished by theparameter of TiO2 content: the komatiitic series is characterizedby having TiO2 1.0 per cent and the tholeiitic series by 1.0per cent. The general series do not imply that a cogenetic relationshiplinked only by fractional crystallization exists in each series. Several magmatic types could be distinguished by their characteristicREE distribution patterns. In general, the komatiitic rocksshow flat HREE (heavy REE) and flat or depleted LREE (lightREE) patterns; the tholeiitic rocks show fractionated patternswith some degree of LREE enrichment, whilst the acidic rocksdemonstrate highly fractionated patterns with significant HREEdepletion. Model calculations indicate that: (1) the komatiiticand the tholeiitic series have no clear genetic relationship;(2) some basaltic komatiites (MgO < 12 per cent) could havebeen derived by crystal fractionation from a melt of peridotitickomatiite composition (MgO 30 per cent), but others requirevarious degrees of partial melting from the same or differentsource regions to account for their trace element abundances;(3) both partial melting and fractional crystallization haveinterplayed for the production of various rocks within the tholeiiticseries; (4) three different types of source materials are proposedfor all magmas from the lower volcanic sequence. All three typeshave the same initial HREE (about 2x chondrites) but differentLREE (from very depleted to 2x, flat) abundances; (5) volcanicrocks of the upper volcanic sequence must have originated atgreat depths where garnet remains in the residue after partialmelting and melt segregation. The recognition of the strongly LREE-depleted mantle sources,deduced from the REE patterns of peridotitic komatiites fromFinland, Canada and Rhodesia, may suggest that this depletionis a worldwide phenomenon, and that the Archean upper mantleis as heterogeneous in composition as the modern upper mantle.The causal effect of the depletion might be related to the generationof some contemporaneous LREE-enriched tholeiitic rocks, or morelikely, to contemporaneous or previous continental crust formingevents. 相似文献
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本文通过对胶东地区早前寒武变质地层和花岗岩的研究，提出胶东绿岩带在变质地层、同位素年龄、变质程度、韧性剪切带和矿产等方面存在的证据，与世界典型绿岩带相比，胶东绿岩带具有５个方面的显著特征：①胶东绿岩带下部层位未发现完整科马提岩地层；②胶东绿岩带变质程度较高，一般可达角闪岩相，少数达麻粒岩相；③胶东绿岩带分布面积不大；④胶东绿岩带形成时间在２８．５８～２６亿ａ；⑤胶东绿岩带主要产出Ａｕ，Ａｇ，Ｚｎ，Ｃｕ等矿产。 相似文献
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Abstract Experiments were conducted on the leaching of gold from greenstone by chloride solution under the temperature of 200-550°C and the pressure of 60 MPa. During part of the experiments, the oxygen fugacity was controlled. The results show that the leaching rate of gold is related to temperature, composition of the solution, pH and oxygen fugacity. In the experiment with oxidative acidic solution, the leaching rate was up to 50% or more. It is known that the leaching of gold is restricted by the reaction in which the gold is dissolved from the rock to form gold chloride complex. Therefore, the authors hold that the acidic chloride solution derived from granite magma has caused the remobilization-migration of gold from greenstone and its enrichment into ore. 相似文献
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Maarten J. de Wit 《Journal of Structural Geology》1982,4(2):117-136
Regional recumbent folds, inverted stratigraphy, nappes and olistostromes are described from the southern part of the 3.3–3.5 Ga Barberton Greenstone Belt. Overthrusting of thin rigid silicified slabs with minimum dimensions of 25 km2 and up to 500 m in thickness, occurred over minimum distances of 86 km. More ductile and coherent units were overfolded up to at least 2 km during their emplacement. The glide planes on which these nappes travelled were zones of high fluid pressures related to hydrothermal fluid circulation patterns, driven by heat sources from igneous intrusions. The upwelling areas of the geothermal convection cells were sites of mud-pools and hydrothermal vents which may mark the trailing edges (pull aparts) of the overthrust units. Progressive silica and carbonate precipitation due to decreasing temperatures, within the zones of fluid migration distant from the areas of high heat flow, probably acted as built-in braking systems below the travelling slabs. Active sedimentation and metasomatism during this tectonism indicates a protracted history for the evolution of the greenstone belt. The recognition of nappe and overthrust tectonics in the Barberton Belt, processes which may have been commonplace in Archaean terrains, necessitates a re-evaluation of the stratigraphy of this belt. 相似文献