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中国主要富铁矿床类型及地质特征 总被引：8，自引：2，他引：6
中国铁矿总资源量相对较多,但大部分为贫矿,富铁矿的资源量很少,只占已探明铁矿总资源储量的4.6％;其中,可直接入炉的炼钢用富矿和炼铁用富矿则更少,仅11.8亿吨,占全国探明铁矿总资源储量的2.27％.已知主要富铁矿矿床的成因类型有:①沉积变质贫铁矿(BIF)中的热液改造型;②沉积变质贫铁矿(BIF)中的风化淋滤型;③陆相火山-侵入岩型;④海相火山(-侵入)岩型;⑤矽卡岩型;⑥热液充填交代型.文章简要介绍了各类富铁矿矿床的地质特征,认为矽卡岩型和海相火山(-侵入)岩型富铁矿有一定的找矿潜力. 相似文献
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沉积变质型铁矿成矿条件及富铁矿形成机制 总被引：1，自引：0，他引：1
我国铁矿床类型有沉积变质型、岩浆型、接触交代 热液型(矽卡岩型)、火山岩型、沉积型和风化淋滤型6种,以沉积变质型最为重要。我国的沉积变质型铁矿床主要分布于华北克拉通,以鞍山式铁矿为代表,沉积时代为新太古代末,为阿尔果马型条带状铁建造 (BIF)变质而成;吕梁地区的袁家村式铁矿为苏比利尔型BIF变质而成,BIF沉积时代为2. 384~2. 210 Ga或新太古代末;舞阳、霍邱地区的沉积变质型铁矿可能为苏比利尔型BIF变质产物,BIF沉积时代分别为2. 473~2. 468 Ga、＜2. 54 Ga。BIF的形成与缺氧环境向大氧化事件初期的层化海洋环境过渡有关,海水中巨量溶解的铁质部分氧化,在初始层化海洋氧化还原界面附近的浅海环境以胶体形式沉淀。我国的BIF遭受区域变质变形作用,成为条带状磁铁石英岩,作为沉积变质型铁矿开发利用。BIF经历后期流体改造可形成富铁矿,形成机制有“去硅富铁”、“铁质活化再富集”和“去碳酸盐富铁”3种,弓长岭富铁矿的成矿年龄为1. 85 Ga左右,由BIF“去硅富铁”而成;齐大山富铁矿可能形成于2. 5 Ga,由BIF“铁质活化再富集”而成;袁家村富铁矿形成于1. 41~1. 34 Ga,可能由含碳酸盐的BIF“去碳酸盐富铁”而成。 相似文献
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福建马坑铁矿辉石的成因矿物学研究 总被引：2，自引：0，他引：2
本文研究了福建马坑铁矿床中辉石族矿物的时空分布、产状、种属及其晶体形态标型、物理标型、化学成分标型。通过不同成因的辉石(308个不同成因辉石)化学成分标型对比、图解等综合判别方法确定马坑铁矿中辉石有火山岩变质、沉积变质、接触交代和岩浆四种成因。矿体底部成矿建造为富Fe、K、Mn火山岩建造,中下部为富F、Mn硅铁质沉积建造,上部为富Ca、Mg、Mn、Fe、Si碳酸盐沉积建造。马坑矿床主矿体为海底火山沉积变质型铁矿。提出利用辉石的种属、含铁系数、化学标型判断有无矿体及其贫富的矿物学标志。 相似文献
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海南石碌铁矿是我国著名的富铁矿床。由于其复杂的地质特征,矿床的形成机制和富集机理一直存在争议。本文对石碌铁矿的碧玉和铁矿石进行了详细的矿相学和岩相学研究,特别是对肉眼无法识别的微小的碧玉进行了识别和观察。结果发现,碧玉除了在铁矿层的露头中有发育,在微观尺度上,微小的碧玉在铁矿石中也普遍发育,并和铁矿具有密切的共生关系,说明碧玉是石碌矿床重要的组成部分。由于碧玉是一种与火山-热液活动有关的化学沉积产物,因此可以明显地排除铁矿的矿浆喷溢型成因模式和矽卡岩型成因模式观点,表明原始的石碌铁矿是一套化学沉积的Si-Fe建造,从而为矿床的火山-热液沉积模式提供了直接有力的证据。由于Si-Fe质沉积过程有可能直接沉积形成富铁矿,所以石碌矿床的富铁矿是否像前人所提出的由构造去硅作用富集形成,值得进一步研究。 相似文献
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铁矿床的工业类型很多,但最重要、储量最大的,则是前寒武纪沉积变质铁矿.据报道,该类型铁矿占国外铁矿石总储量的60%以上,其中相当大的一部分是富铁矿.国外对沉积变质型的富铁矿一直都很重视,近年来在找矿和开发方面进展较大.例如,目前世界上已知最大的苏联库尔斯克铁矿区,总面积12万平方公里,断续延长600多公里,已探明的铁矿石储量426亿吨(铁品位32～62%),其中富铁矿(铁品位54～62%)储量261亿吨,占全苏富铁矿储量的70%以上.克里沃罗格是苏联的另一个重要铁矿区,面积300平方公里,绵延长达100多公里,平衡表内铁矿石储量200亿吨,其中富铁矿约20亿吨.其他如美国的上湖地区,印度的比哈尔-奥里萨邦铁矿带,巴西的米纳斯-日赖斯,加拿大的拉布拉多地槽和巴芬 相似文献
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本文提出我国铁矿主要成因类型的划分方案,并指出在我国今后富铁矿的找矿中,除对玢岩型、矽卡岩型、细碧角斑岩型、风化壳型等应继续予以大力重视外,还应对地槽型的沉积和火山沉积(铁的物质来源主要是火山的,而形成方式是沉积的)富矿(简称“沉积型富矿”)给以应有的注意.我国这一类型富矿分布广、延续时间长(从太古代到侏罗纪),并为以后的叠加—再造提供了基础.来自深部的含铁的成矿物质的上升主要受深大断裂带和海底扩张带的控制.本文还讨论了铁建造的某些形成条件及白云鄂博矿床的成因. 相似文献
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Carlos Alberto Spier Sonia Maria Barros de Oliveira Carlos Alberto Rosière José Domingos Ardisson 《Mineralium Deposita》2008,43(2):229-254
Several major iron deposits occur in the Quadrilátero Ferrífero (QF), southeastern region of Brazil, where metamorphosed and heterogeneously deformed banded iron formation (BIF) of the Cauê Formation, regionally called itabirite, was transformed into high- (Fe >64%) and low-grade (30%?2O3, with a higher amount of detrimental impurities, especially MnO, in the soft ore. Both hard and soft ores are depleted in trace elements. The high-grade ores at the Águas Claras Mine have at least a dual origin, involving hypogene and supergene processes. The occurrence of the hard, massive high-grade ore within “fresh” dolomitic itabirite is evidence of its hypogene origin. Despite the contention about the origin of the dolomitic itabirite (if this rock is a carbonate-rich facies of the Cauê Formation or a hematite–carbonate precursor of the soft high-grade ore), mineralogical and geochemical features of the soft high-grade ore indicate that it was formed by leaching of dolomite from the dolomitic itabirite by meteoric water. The comparison of the Águas Claras, Capão Xavier and Tamanduá orebodies shows that the original composition of the itabiritic protore plays a major role in the genesis of high- and low-grade soft ores in the QF. Under the same weathering and structural conditions, the dolomitic itabirite is the more favorable to form high-grade deposits than siliceous itabirite. Field relations at the Águas Claras and Capão Xavier deposits suggest that it is not possible to form huge soft high-grade supergene deposits from siliceous itabirite, unless another control, such as impermeable barriers, had played an important role. The occurrence in the Tamanduá Mine of a large, soft, high-grade orebody formed from siliceous itabirite and closely associated with hypogene hard ore suggests that large, soft, high-grade orebodies of the Quadrilátero Ferrífero, which occur within siliceous itabirite, have a hypogene contribution in their formation. 相似文献
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Abstract: The metamorphosed sedimentary type of iron deposits (BIF) is the most important type of iron deposits in the world, and super-large iron ore clusters of this type include the Quadrilatero Ferrifero district and Carajas in Brazil, Hamersley in Australia, Kursk in Russia, Central Province of India and Anshan-Benxi in China. Subordinated types of iron deposits are magmatic, volcanic-hosted and sedimentary ones. This paper briefly introduces the geological characteristics of major super-large iron ore clusters in the world. The proven reserves of iron ores in China are relatively abundant, but they are mainly low-grade ores. Moreover, a considerate part of iron ores are difficult to utilize for their difficult ore dressing, deep burial or other reasons. Iron ore deposits are relatively concentrated in 11 metallogenic provinces (belts), such as the Anshan-Benxi, eastern Hebei, Xichang-Central Yunnan Province and middle-lower reaches of Yangtze River. The main minerogenetic epoches vary widely from the Archean to Quaternary, and are mainly the Late Archean to Middle Proterozoic, Variscan, and Yanshanian periods. The main 7 genetic types of iron deposits in China are metamorphosed sedimentary type (BIF), magmatic type, volcanic-hosted type, skarn type, hydrothermal type, sedimentary type and weathered leaching type. The iron-rich ores occur predominantly in the skarn and marine volcanic-hosted iron deposits, locally in the metamorphosed sedimentary type (BIF) as hydrothermal reformation products. The theory of minerogenetic series of mineral deposits and minerogenic models has applied in investigation and prospecting of iron ore deposits. A combination of deep analyses of aeromagnetic anomalies and geomagnetic anomalies, with gravity anomalies are an effective method to seeking large and deep-buried iron deposits. China has a relatively great ore-searching potential of iron ores, especially for metamorphosed sedimentary, skarn, and marine volcanic-hosted iron deposits. For the lower guarantee degree of iron and steel industry, China should give a trading and open the foreign mining markets. 相似文献
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Economic significance of the sedimentary iron ore deposits is shown. The most important types of these deposits are characterized and their genesis is considered. Special attention is given to the formation of goethite-chlorite-siderite ooliths, which represent the main component of marine iron ore deposits. Geochemical and mineralogical features of different types of iron ores are examined. 相似文献
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辽宁弓长岭铁矿床二矿区类矽卡岩的岩石矿物学特征 总被引：3，自引：0，他引：3
辽宁弓长岭铁矿床二矿区是我国最重要的鞍山式沉积变质型富铁矿床.不同于鞍山-本溪地区其他贫铁矿床,弓长岭铁矿二矿区富铁矿体的附近分布有大量的类矽卡岩,这些类矽卡岩与富铁矿体具有密切的成因联系.本文在野外和岩相学研究的基础上,选择弓长岭二矿区类矽卡岩的岩相学、矿物学、矿物化学特征进行了研究.结果表明:类矽卡岩可分为石榴石岩、绿泥石岩、含石榴石绿泥石岩、含磁铁矿阳起石岩四种类型;类矽卡岩矿物中石榴石端员组分以铁铝榴石为主,角闪石属于钙角闪石系列中的透闪石,绿泥石属于蠕绿泥石.类矽卡岩和富铁矿是由热液交代改造磁铁贫矿形成的,二者是同一期热液活动的产物. 相似文献
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Exploitation of low-grade iron ore would be quite unique in a South African context as South Africa is well endowed with
high-grade iron ore resources. Low-grade iron ore, defined as containing between 20 and 47% iron, is thought to be the primary
iron-bearing lithology from which most high-grade ore deposits formed, through different processes of enrichment. The low-grade
iron ores in the Northern Province represent meta-banded iron formations (BIFs), with an average iron content of about 36%.
The main iron-bearing mineral is magnetite. The Northern Province ores have to be milled to sizes smaller than 150 μm in order
to liberate the iron minerals from the host rock, and beneficiation is accomplished through a series of magnetic separation
processes. Irrespective of the in situ quality of the ore, final concentrates of exceptionally good quality with more than
69% iron and very low contaminant levels can be produced. This, combined with mass yields of between 40 and 50% and iron recoveries
greater than 80%, are excellent for this type of iron ore deposit. The beneficiation products are suitable for use in iron-
and steel-making processes.
Received: 4 July 1996 / Accepted: 7 January 1997 相似文献
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华北克拉通条带状铁建造中富铁矿成因类型的研究进展、远景和存在的科学问题 总被引：2，自引：2，他引：0
本文在查阅前人大量资料的基础上,对华北克拉通条带状铁建造中富铁矿的研究历史进行了回顾和总结,将研究历史分为1949年以前,1950~1965年期间,1978~1986年期间,1987~1994年期间和2009年以来5个阶段。重点介绍了鞍本地区、冀东-吕梁地区和河南舞阳地区富铁矿的基本地质特征以及典型富铁矿的研究概况,针对鞍本地区弓长岭二矿区磁铁富矿成因的复杂性,对不同成因观点以及目前已取得的共识进行了详细阐述。目前大多数学者不支持接触交代假说和菱铁矿经变质转化为富铁矿成矿假说,近半数学者支持变质热液成矿假说,半数学者支持混合岩化热液成矿假说。作者在综合分析前人大量资料后,认为变质热液成矿说依据不足,理由有四点:(1)磁铁富矿中往往见有磁铁贫矿的残体;(2)磁铁富矿与蚀变岩紧密伴生,蚀变矿物石榴子石、部分角闪石(透闪石)和部分绿泥石均属非变质热液成因;(3)研究区遭受区域高绿片岩相至低角闪岩相变质作用的时间为2500~2450Ma,而与蚀变矿物石榴石紧密伴生的热液锆石SHRIMP U-Pb定年结果为1840±7Ma,明显小于区域变质作用年龄,据此可将热液作用时间限定于古元古代晚期,相当于大陆地壳伸展阶段;(4)部分热液成因富铁矿利用Re-Os方法定年,除一种属原生沉积成矿外,年龄范围也在古元古代晚期,可作为参考。此种热液是否为混合岩化热液尚缺乏足够证据,故本文暂将其作为古元古代晚期热液。此外,本文对华北克拉通条带状铁建造中富铁矿成因类型及其远景进行了初步总结,认为古元古代晚期形成的磁铁富矿规模属大型矿床,有较好远景;原生较富贫铁矿因褶皱构造产生磁铁矿流变而形成的富铁矿(可能尚有热液叠加)规模较大,具有一定远景;其他类型均为小型规模,不具工业意义。最后,本文指出富铁矿成因研究中尚存在的主要问题,包括早元古代晚期热液的来源;热液的形成是一期还是多期;铁建造遭受区域变质达高绿片岩相时,贫铁矿的围岩变质演化机理等,尚需进一步探讨。 相似文献
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Enrichment iron ore of the Hamersley Province, currently estimated at a resource of over 40 billion tonnes (Gt), mainly consists of BIF (banded iron-formation)-hosted bedded iron deposits (BID) and channel iron deposits (CID), with only minor detrital iron deposits (DID). The Hamersley BID comprises two major ore types: the dominant supergene martite–goethite (M-G) ores (Mesozoic–Paleocene) and the premium martite–microplaty hematite ores (M-mplH; ca 2.0 Ga) with their various subtypes. The supergene M-G ores are not common outside Australia, whereas the M-mplH ores are the principal worldwide resource. There are two current dominant genetic models for the Hamersley BID. In the earlier 1980–1985 model, supergene M-G ores formed in the Paleoproterozoic well below normal atmospheric access, driven by seasonal oxidising electrochemical reactions in the vadose zone of the parent BIF (cathode) linked through conducting magnetite horizons to the deep reacting zone (anode). Proterozoic regional metamorphism/diagenesis at ～80–100°C of these M-G ores formed mplH from the matrix goethite in the local hydrothermal environment of its own exhaled water to produce M-mplH ores with residual goethite. Following general exposure by erosion in the Cretaceous–Paleocene when a major second phase of M-G ores formed, ground water leaching of residual goethite from the metamorphosed Proterozoic ores resulted in the mainly goethite-free M-mplH ores of Mt Whaleback and Mt Tom Price. Residual goethite is common in the Paraburdoo M-mplH-goethite ores where erratic remnants of Paleoproterozoic cover indicate more recent exposure. Deep unweathered BIF alteration residuals in two small areas of the Mt Tom Price M-mplH deposits have been used since 1999 for new hypogene–supergene modelling of the M-mplH ores. These models involve a major Paleoproterozoic hydrothermal stage in which alkaline solutions from the underlying Wittenoom Formation dolomite traversed the Southern Batter Fault to leach matrix silica from the BIF, adding siderite and apatite to produce a magnetite–siderite–apatite ‘protore.’ A later heated meteoric solution stage oxidised siderite to mplH + ankerite and magnetite to martite. Weathering finally removed residual carbonates and apatite leaving the high-grade porous M-mplH ore. Further concepts for the Mt Tom Price North and the Southern Ridge Deposits involving acid solutions followed, but these have been modified to return essentially to the earlier hypogene–supergene model. Textural data from erratic ‘metasomatic BIF’ zones associated with the above deposits are unlike those of the typical martite–microplaty hematite ore bodies. The destiny of the massive volumes of dissolved silica gangue and the absence of massive silica aureoles has not been explained. Petrographic and other evidence indicate the Mt Tom Price metasomatism is a localised post-ore phenomenon. Exothermic oxidation reactions in the associated pyrite-rich black shales during post-ore removal by groundwater of remnant goethite in the ores may have resulted in this very localised and erratic hydrothermal alteration of BIF and its immediately associated pre-existing ore. 相似文献
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矽卡岩型铁矿的铁质来源与迁移富集机理探讨 总被引：4，自引：0，他引：4
矽卡岩型铁矿是我国最重要的富铁矿类型,其铁质来源及迁移富集机理是目前最核心、也最具争议的问题之一。本文在矽卡岩矿床复杂性和多成因性研究的基础上,对浅部铁质活化、迁移和富集机理进行整理归纳,建立了流程图;分别探讨了不同类矽卡岩型铁矿铁质的最大可能来源,认为与中酸性侵入体有关的该类铁矿,铁质主要源于浅部侵入岩;与酸性侵入体有关的该类铁矿,矿床附近的原始赋铁层位可能提供了大量铁质。但并非所有与酸性岩有关的此类铁床附近都存在赋铁地层,故本文对铁质深部来源的可能性进行了探讨,结合"岩浆矽卡岩-富碱侵入岩对"的概念,提出了全新的深部铁质活化、运移和富集的可能模式,即深部岩浆同化钙质岩石融离出的富铁矿浆上升并运移到浅部侵入岩与碳酸盐岩的接触带附近,与该系统中的热液相遇并反应,热液吸收矿浆中的铁质生成富铁的复合热液,后复合热液在接触带因物理化学条件的剧变而沉淀成矿。 相似文献