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辽东裂谷为古元古代拉伸环境下产生的EW向陆内裂谷,裂谷的北缘斜坡带赋存有大石桥—塔子岭超大型菱镁矿带,中央裂陷带赋存了瓦峪—青城子大型菱镁矿带。菱镁矿床的产出与成矿物质来源的位置有较大的关系,同时与沉积的环境因素、后期的各种扰动因素有关。在古元古代富含CO_2的环境中,源于太古宙地块剥蚀物中和远源火山喷发物中的镁质进入海水,在持续稳定的陆缘潮间-潟湖蒸发环境中,在藻类生物吸附吸附作用的有力辅助下,沉积了巨厚的富镁碳酸盐岩,经过成岩作用形成原生菱镁矿层。在区域变质-变形过程中,原生菱镁矿层经过褶皱变形和矿物重结晶,完成形态方面的最终定型;因此,辽东裂谷菱镁矿属于沉积-变质型矿床。 相似文献
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ZHAO Zheng CUI Xiaolin WANG Denghong CHEN Yuchuan BAI Ge LI Jiankang LIU Xinxing 《《地质学报》英文版》2015,89(5):1747-1761
China has abundant reserves of magnesite, making it the world’s leading source of this strategic mineral. Sparry magnesite is the main type of magnesite deposit, and is easy to exploit. It occurs mainly as the sedimentary-metamorphic type. Production is centred on eastern Liaoning Province, where a world-class large to super large magnesite ore processing and production facility has been developed. Hydrothermal metasomatic deposits, associated with ultramafic complexes and eluvial deposits produced by weathering, are two other important types found in China. The Western section of the Bangonghu-Nujiang metallogenic belt is an important target region for prospecting lake-sedimentary magnesite deposits. Based on a systematic analysis of material from 62 magnesite production areas, this study investigated the metallogeny of magnesite and delineated 13 magnesite metallogenic belts. Maps were produced showing metallogenic regularities in magnesite deposits, the metallogenic system of the magnesite deposits, and the distribution of the metallogenic belts of Chinese magnesite deposits. It provides a theoretical basis for forecasting the location of potential magnesite resources in China. Finally, it explores some key scientific issues, including the formation processes of ultra magnesite ore-concentrated areas, and their sources of magnesium. 相似文献
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产于内蒙古索伦山缝合带蛇绿岩中的菱镁矿,其深入研究对于菱镁矿的勘查、增加战略矿产资源以及国民经济的发展有重大意义。本文对内蒙古索伦山地区菱镁矿进行了系统的调查和研究,通过归纳索伦山地区菱镁矿矿床地质特征,探讨了索伦山地区菱镁矿矿床的成矿地质条件,在此基础上,分析和评价了索伦山地区菱镁矿的找矿潜力。索伦山地区菱镁矿产于索伦山蛇绿岩的地幔橄榄岩内,受岩体内部微小构造控制,矿体贫富受风化程度的制约,受超基性岩风化淋滤形成。菱镁矿与超基性岩硅质风化壳在成因上具有耦合关系,上部为风化淋滤残留物—超基性岩硅质风化壳,下部为风化淋滤的产物—菱镁矿。索伦山地区含菱镁矿的地幔橄榄岩岩体巨大,深部矿体众多,与国内西藏巴夏式菱镁矿在成矿条件和成矿模式方面相一致。所以,索伦山地区具有较大的菱镁矿找矿潜力。 相似文献
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奥地利东阿尔卑斯山地区Austroalpine杂砂岩带中的石炭纪Veitsch逆冲推覆体是"Veitsch型"晶质菱镁矿化的典型地区。几十年来,对其成因的解释一直是人们争论的焦点。为了解决这一长久以来的问题,本文对Veitsch推覆体的地质学、矿物学和地球化学制约条件进行了论述。菱镁矿仅仅存在于Veitsch推覆体之中,而其它推覆体中的碳酸盐岩岩层中则无菱镁矿。赋存于Veitsch推覆体中的碳酸盐岩石中的菱镁矿以不规则的岩株状、透镜状和层状产出。块状和厚层状的菱镁矿总是被白云岩包裹。在Veitsch推覆体中,沉积作用开始于晚维宪期的后造山的类磨拉石海相建造,并晚于内部基底带的变形和变质作用("Bretonic期")形成,该基底带位于现代的东阿尔卑斯山地区。沉积序列研究表明,演化从浅海大陆架开始,有时还穿插有高盐度的泻湖和透镜状生物礁,发展到海退的海岸线伴随有发育强烈的三角洲沉积的分支海湾和河流。由于成矿作用有好几个期次,所以对地球化学数据的解释相当复杂。 在Hohentauern／Sunk矿床中,石膏和硬石膏层在菱镁矿质沉积主岩中互层,其δ34S值分别为 17.6±0.2‰和 17.2±0.2‰,表现出石炭纪海水的特征。白云岩和菱镁矿的REE浓度要高于石灰质主岩。在Hohentauern／Sunk矿床中,球形白云岩中的白云岩球体和白云质基质 相似文献
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早寒武世黑色岩系中蕴藏丰富的有色金属、贵金属、稀土金属、石煤及非金属矿产。其中,位于扬子板块北缘的南秦岭褶皱带下寒武统钒矿资源潜力巨大,笔者以鄂西北为例,探讨该类钒矿床地质特征、成矿规律及成矿条件。鄂西北钒矿床产于下寒武统底部富含有机质的炭、硅、泥质黑色岩系中。矿层形态简单,产状稳定,埋藏浅,分布广,储量大。成矿受地层、岩性、古构造和古地理条件控制。钒矿床初始富集属受制于生物―化学成矿作用,后期构造改造作用对矿化分布及富集有一定的影响。认为鄂西北钒矿床具有生物成矿与海底热水沉积成矿双重特征,矿床成因类型应归属于生物化学沉积―变质改造型矿床范畴。 相似文献
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国土资源部为了基本摸清全国重要矿产资源“家底”,为矿产资源保障能力和勘查部署决策提供依据,开展了全国重要矿产资源潜力评价项目。菱镁矿是开展的25个重要矿种之一。本项目的实施,是我国矿产资源方面的一次重要的国情调查。本次工作以成矿地质理论为指导,深入开展区域成矿规律研究;充分利用地质、物探、化探、遥感和矿产勘查等综合成矿信息,建立典型矿床预测模型和区域预测模型,圈定成矿远景区和找矿靶区;充分应用现代矿产资源预测评价的理论方法和GIS评价技术,逐个评价其成矿远景区资源潜力;用地质体积等多元信息方法估算了地下2 000 m以浅的菱镁矿资源量,为科学合理地规划和部署矿产勘查工作提供依据。中国菱镁矿主要成矿时代为古元古代,成矿类型以沉积变质型为主,全国共有累计查明资源储量（矿石量）36.42亿t,主要分布于辽宁、山东和新疆。全国共圈定菱镁矿最小预测区129个,获2 000 m以浅预测资源量（矿石量）131亿t。全面总结并建立了菱镁矿典型矿床预测模型及区域预测模型,共划分菱镁矿成矿区带11个。 相似文献
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和静县哈勒哈特菱镁矿地质特征与找矿方向 总被引：1，自引：0，他引：1
新疆和静县哈勒哈特菱镁矿,产于南天山中泥盆统萨阿尔明组下段第五岩性层中,该矿床由32个矿体组成,主要赋矿岩性为厚层白云岩夹菱镁矿透镜体、矿化白云岩及少量生物碎屑灰岩.矿石矿物为菱镁矿,脉石矿物主要为白云石.哈勒哈特菱镁矿中MgO含量为41.82％-45.87％,CaO含量为1.23％～5.54％,SiO2含量为0.24％～0.85％,矿石主要为半自形粗晶结构,块状构造.矿床成因类型是与区域变质作用有关的热液矿床.经研究对比发现,可利用矿区地层、构造、地貌和矿物标志等作为矿区和区域找矿标志. 相似文献
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Hans C. Oskierski Judy G. Bailey Eric M. Kennedy Geraldine Jacobsen Paul M. Ashley Bogdan Z. Dlugogorski 《Mineralium Deposita》2013,48(4):525-541
Nodular, cryptocrystalline, weathering-derived magnesite deposits in the New England Orogen, Australia, provide a significant source of high-purity magnesite. Common textural features and related isotopic fingerprints indicate a close genetic relationship between weathering-derived magnesite deposits hosted by ultramafic rocks at Attunga and by sediments at Kunwarara while silica-carbonate rock alteration and rare hydrothermal magnesite vein deposits reflect contrasting conditions of formation. Localised weathering of carbonates in a soil environment shifts stable isotopic composition towards low δ 13C and high δ 18O typical for weathering-derived magnesites while intrusion-related fluids do not significantly change the isotopic composition of affected carbonates. At Attunga, magnesite consists of irregular, nodular veins and masses filling faults and cracks in the weathered serpentinite host rock as well as soft powdery magnesite in pervasive serpentinite alteration zones. The high-grade magnesite at Attunga can be contaminated by amorphous silica and serpentine relicts but does not contain dolomite or ferroan magnesite as observed for its hydrothermal equivalent, the Piedmont magnesite deposit, or other widespread deposits of silica-carbonate rock in the Great Serpentinite Belt. Heavy δ 18O values are compatible with a supergene formation from meteoric waters while low δ 13C suggests C3-photosynthetic plants as the predominant source of carbon for the Attunga magnesites. We infer that weathering-derived, nodular magnesite deposits hosted in ultramafic rocks like the Attunga magnesite deposit have formed in a two-step process involving the hypogene formation of a pre-cursor magnesite deposit and complete supergene overprinting by meteoric waters that acquired carbon from percolation through soil. 相似文献
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湘西黔东地区铅锌矿床与古油藏关系初探 总被引：3，自引：0，他引：3
本文以湖南花垣铅锌矿床和贵州牛角塘铅锌矿床为例,探讨了湘西黔东地区铅锌矿与古油藏的关系。二者在空间分布上关系密切,存在"共生"和"上油下矿"两种关系,下寒武统清虚洞组既是铅锌矿重要的赋矿层位也是古油藏储集层之一;铅锌矿源层可能为新元古代基底岩系或下寒武统石牌组碎屑岩,古油藏烃源岩主要为下寒武统牛蹄塘组。古油藏中的油田卤水萃取了石牌组碎屑岩中的铅锌等成矿物质,形成成矿流体并运移,在古油藏形成后,由于加里东末期的构造运动的影响,古油藏和成矿流体的平衡被打破导致铅锌矿质沉淀,在这个过程中古油藏中的油田卤水可能为铅锌矿的沉淀提供了部分硫源。铅锌矿成矿时代与加里东期形成或破坏的古油藏时间上较为一致。 相似文献
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观音梁子锰矿赋存于寒武系邱家河组中,是龙门山中段在邱家河组中新发现的工业锰矿床。通过矿区勘探工作及室内观察、测试等手段,对矿区成矿地质背景、含锰岩系、矿体及矿石矿物特征、矿床成因、找矿前景等方面进行了初步总结分析。研究发现,观音梁子锰矿为典型的沉积型锰矿床,矿体呈层状产于邱家河组三段硅质白云岩中,延伸较稳定,严格受层位的控制;矿石类型为菱锰矿型,主要由菱锰矿、硫锰矿、水锰矿等组成。早寒武世,龙门山地区由于地壳拉张裂陷形成深海盆地,在还原环境下,锰元素与碳酸根直接结合形成碳酸锰矿物,稳定的物源、深海还原环境为锰矿富集提供了有利的成矿环境。观音梁子锰矿的发现,证实了龙门山北段邱家河组含锰层位的存在,为龙门山中段的锰矿找矿提供了契机,同时显示了寒武系邱家河组具有良好的找锰远景。 相似文献
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Magnesite occurrences in the West Carpathians, a part of the Alpine Orogenic System, have been known since the second half of the 19th Century. They are hosted by Cambrian, Silurian, Devonian, Carboniferous, Permian, Lower and Upper Triassic sedimentary units.Economically most important are crystalline magnesite (Veitsch-type) and locally associated talc in the Devonian sequence of the Veporides and in the Caboniferous of the Gemerides (yearly production 2–3 million tonnes).Traditionally, the Slovak magnesite deposits had been interpreted as hydrothermal-metasomatic, related to magmatically-derived fluids. More recently, a sedimentary-diagenetic origin of the magnesite with Mg derived in full or in part from the contemporaneous submarine basaltic volcanism is considered more probable. After deposition and diagenesis, the magnesites and their host rocks were metamorphosed in greenschist (Carboniferous of the Gemerides) to amphibolite (Devonian of the Veporides) facies. 相似文献
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排庭金矿是贵州三都——丹寨锑、汞、金成矿带上,继苗龙锑-金矿、宏发厂汞-金矿后首次发现的产于中下寒武统独立型的微细浸染型金矿,其矿体受断裂构造、地层、岩性等因素控制,矿床规模为中型。对该矿床的地质特征及成因进行总结和分析,对于华南褶皱带与扬子准地台过渡带寻找寒武纪地层中的微细浸染型金矿具有重要的借鉴和指导意义。 相似文献
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