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行口铁矿位于沁阳市北部太行山山脚下,是上世纪80年代发现的一个中型贫磁铁矿床。矿体成群出现,延长900～1200m,宽度变化70～290m,厚度变化5～270m;呈似层状、透镜状,控制延深700m,有用矿物主要为磁铁矿和赤铁矿。矿体的品位在走向上和倾向上基本稳定,矿石化学成分和矿物组成简单,有害物质含量低,矿体群中夹层较多,属于火山沉积变质铁矿床。 相似文献
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霍邱铁矿田位于华北地台南缘，处于北淮阳山字型构造脊柱部位。李老庄铁矿—菱镁矿床置于霍邱铁矿田中部。该矿床主要产于上太古界霍邱群变质岩系中，矿体赋存于富镁碳酸盐中，矿石类型可以分为菱镁矿磁铁矿石和蛇纹石磁铁矿石，各占25%。成矿物质来源于这些变质岩系的多层、分散的含铁建造矿源层中。依据矿床地质特征，结合矿石同位素地质和测年结果，李老庄铁矿—菱镁矿铁矿床是晚太古代海相火山—沉积变质型矿床。 相似文献
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通过对西藏日土县材玛铁矿床的调查研究表明,南羌塘拗陷带的材玛铁矿床成矿地质条件较好.经地表槽探揭露和深部钻探工程控制,发现其矿体为似层状;矿体品位和厚度沿走向和倾向变化较小;容矿岩石主要为矽卡岩、矽卡岩化灰岩;矿石类型简单,主要为磁铁矿矿石.矿化富集与侵入于上三叠统地层的燕山晚期花岗闪长岩、二长花岗岩、花岗斑岩密切相关;矿体产出部位严格受碳酸盐岩层位及其层间破碎带的控制,属接触交代型矿床.其形成与燕山晚期岩浆活动关系密切,空间分布严格受岩浆岩和断裂的控制.花岗岩类岩体与上三叠统地层的接触带和层间破碎带是寻找铁矿的有利部位,外围地区具有寻找相同类型铁矿床的远景. 相似文献
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通过对我国西南“三江”地区嘎村与老厂两个大型海相火山岩型银矿床和我国东部及新疆天山地区陆相火山岩-次火山岩型银矿的地质地球化学研究,认为海相火山岩型银矿床主要产于岛弧、裂谷构造环境的次级火山-沉积盆地中,矿床具有明显的分带现象,下部为脉状-网脉状矿化,上部为产于热水沉积岩中的层状矿化(主矿体),从地表向深部成矿元素为As(Au)→Ag,Pb,Zn→Cu,嘎村矿床的层状矿体全岩Rb-Sr同位素等时线年龄为(204±14)Ma,主成矿期为晚三叠世。陆相火山-次火山岩(斑岩)型银矿床银矿形成时代多晚于围岩,矿石构造以浸染状、细脉浸染状、网脉状和团块状为主。并详细地研究了陆相火山岩-次火山岩型银矿床的矿床地球化学特征和银矿床或银与萤石、卤素元素、锰的关系。 相似文献
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我国与火山岩有关的大型、超大型银矿床 总被引：6，自引：0，他引：6
通过对我国西南“三江”地区嘎村与老厂两个大型海相火山岩型银矿床和我国东部及新疆天山地区陆相火山岩次火山岩型银矿的地质地球化学研究,认为海相火山岩型银矿床主要产于岛弧、裂谷构造环境的次级火山-沉积盆地中,矿床具有明显的分带现象,下部为脉状-网脉状矿化,上部为产于热水沉积岩中的层状矿化(主矿体),从地表向深部成矿元素为As(Au)→Ag,Pb,Zn→Cu,嘎村矿床的层状矿体全岩Rb-Sr同位素等时线年龄为(204±14)Ma,主成矿期为晚三叠世.陆相火山-次火山岩(斑岩)型银矿床银矿形成时代多晚于围岩,矿石构造以浸染状、细脉浸染状、网脉状和团块状为主并详细地研究了陆相火山岩-次火山岩型银矿床的矿床地球化学特征和银矿床或银与萤石、卤素元素、锰的关系. 相似文献
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东天山沙泉子铜铁矿床磁铁矿Re-Os定年初探 总被引：2，自引：0，他引：2
对东天山沙泉子铜铁矿的矿石矿物磁铁矿进行了Re-Os同位素研究,结果表明磁铁矿具有变化的Re含量(0.7~50.9 ppb)和普通Os含量(16~63 ppt),8个磁铁矿样品构建的模式3等时线年龄为(303±12)Ma(2σ),与共生的黄铁矿获得的Re-Os等时线年龄((295±7)Ma)在误差范围内是一致的.构造演化表明,阿齐山-雅满苏构造带在晚石炭世末期为弧后伸展环境,~300 Ma的年龄表明该矿床的形成可能与伸展过程中幔源岩浆活动的侵入有关.沙泉子铜铁矿床磁铁矿Re-Os同位素定年的成功使用表明,在保证磁铁矿的纯度以及Re-Os体系封闭的情况下,具有较高且变化较大的Re和Os含量的磁铁矿能够获得可靠的等时线年龄,拓展了Re-Os同位素体系的应用. 相似文献
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This paper deals with the geology and geochemistry of the Gacun and Laochang large-sized marine volcanic rock-type Ag deposits in the Sanjiang (Tri-River) area of southwestern China and of the continental volcanic-subvolcanic rock-type Ag deposits in the Tianshan area of Xinjiang, and in the East area, China. It is considered that the marine volcanic rock-type Ag deposits occur mainly in the second-ordered volcano-sedimentary basins developed in island-arc and rift tectonic environments. The Ag deposits show an obvious zonation, with vein-network mineralization in the lower parts and hot water sedimentary rock-hosted stratified mineralization in the upper parts. From the Earth's surface downwards the ore-forming elements follows the order of As(Au))→Ag, Pb, Zn→Cu. The whole rock Rb-Sr isotopic isochron age of layered orebodies in the Gacun deposit is 204±14 Ma, indicating that the main stage of mineralization is Late Triassic in age. The continental volcanic-subvolcanic (porphyry) rock-type Ag deposits were formed later than the country rocks. The ores exhibit disseminated, veinlet disseminated, network and lumped structures. In addition, this study also deals with the geochemical characteristics of the continental volcanic-subvolcanic rock-type Ag deposits and the relations between Ag deposits or silver itself and fluorite, halogen-family elements and manganese. 相似文献
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系统的等温剩磁和热退磁分析表明，松辽盆地深层早白垩世火山岩具有特征剩磁和黏滞剩磁两组剩磁分量，载磁性矿物为磁铁矿.校正后的火山岩特征剩磁方向及古磁极位置与欧亚大陆的白垩纪古磁极位置，在95%置信区间内重叠，佐证了应用黏滞剩磁定向岩芯的方法是可行的.黏滞剩磁定向研究表明，研究区火山岩裂缝主要发育有北东向、北西向、近南北向和近东西向四组，其中北东向和北西向裂缝更占优势.古地磁定向成果与成像测井成果对比，显示出良好的定向效果. 相似文献
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This paper deals with the geology and geochemistry of the Gacun and Laochang large-sized marine volcanic rock-type Ag deposits in the Sanjiang (Tri-River) area of southwestern China and of the continental volcanic-subvolcanic rock-type Ag deposits in the Tianshan area of Xinjiang, and in the East area, China. It is considered that the marine volcanic rock-type Ag deposits occur mainly in the second-ordered volcano-sedimentary basins developed in island-arc and rift tectonic environments. The Ag deposits show an obvious zonation, with vein-network mineralization in the lower parts and hot water sedimentary rock-hosted stratified mineralization in the upper parts. From the Earth’s surface downwards the ore-forming elements follows the order of As(Au)) →Ag, Pb, Zn→Cu. The whole rock Rb-Sr isotopic isochron age of layered orebodies in the Gacun deposit is 204±14 Ma, indicating that the main stage of mineralization is Late Triassic in age. The continental volcanic-subvolcanic (porphyry) rock-type Ag deposits were formed later than the country rocks. The ores exhibit disseminated, veinlet disseminated, network and lumped structures. In addition, this study also deals with the geochemical characteristics of the continental volcanic-subvolcanic rock-type Ag deposits and the relations between Ag deposits or silver itself and fluorite, halogen-family elements and manganese. 相似文献
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广丰县李家膨润土矿床赋存于白垩系上统南雄组第二岩性段酸性火山岩的顶底部。膨润土的主要矿物成分为蒙脱石,矿石结构构造与成矿原岩有关。矿石化学成分与酸性熔岩相近,矿体形态及空间分布受酸性熔岩流相带的控制。因此认为,膨润土矿床成矿原岩为酸性玻质熔岩,矿床是由酸性玻璃质熔岩经水解脱玻化而形成,其成因类型为风化淋滤蚀变岩型矿床。膨润土可自然改型,由原来的钠基膨润土改型成钙基膨润土和偏镁的钙基膨润土。对时代较新的酸性火山岩,在玻质熔岩发育处都有可能找到有利用价值的膨润土矿。由于膨润土常由珍珠岩、沸石脱玻化形成,三者常共生出现,是很好的找矿标志。 相似文献
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东溪-南关岭金矿为北淮阳东段发现的第一个原生金矿,产于磨子潭-晓天中生代火山盆地边缘,容矿围岩为安山质-英安质火山岩,矿化和蚀变受桐柏-桐城深大断裂带的次级构造带控制。该金矿发育陡倾斜的脉状矿体和缓倾斜的似层状矿体,成因类型为冰长石-绢云母型浅成低温热液金矿。火山岩盆地之下的变质基底可能起到了初始矿源层作用,桐柏-桐城断裂带及其次级构造破碎带为重要的导岩导矿构造,早白垩世强烈的岩浆活动提供了热源、动力源和部分矿源。参照国内外类似金矿的特征,认为本区成矿地质条件良好,有可能隐伏着与石英正长岩体有关的细脉浸染型矿化,晓天火山盆地具有良好的找矿前景。 相似文献
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Re-Os dating of magnetite from the Shaquanzi Fe-Cu deposit,eastern Tianshan,NW China 总被引：2，自引：0，他引：2
Magnetite separates from the Shaquanzi Fe-Cu deposit in the eastern Tianshan are used for Re-Os geochronological study.Re-Os data show that magnetite separates contain ca.0.7 to 50.9 ppb Re and ca.16 to 63 ppt Os.Eight samples yield a model 3isochron age of(303±12)Ma(2),which is within uncertainty consistent with of the Re-Os date(295±7 Ma)of associated pyrite.Tectonic evolution shows that the Late Carboniferous Aqishan-Yamansu belt was a back-arc rift.Therefore,the Re-Os age of ca.300 Ma indicates that the Shaquanzi Fe-Cu deposit may have formed in a back-arc extensional environment and was closely related to mantle-derived magmatism.The successful application of Re-Os magnetite geochronology in the Shaquanzi Fe-Cu deposit suggests that the purity of magnetite,relatively high Re and Os contents,and the closure of Re-Os systematic are base factors for a successful Re-Os geochronology.There would be a good prospect for Re-Os geochronology for magnetite. 相似文献
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Petr Schnabl Jiří K. Novák Vladimír Cajz Miloš Lang Kadosa Balogh Zoltan Pécskay Martin Chadima Stanislav Šlechta Tomáš Kohout Petr Pruner Jaromír Ulrych 《Studia Geophysica et Geodaetica》2010,54(1):77-94
This study provides new thermomagnetic and petrographic data on specific basaltic rock association from the broader vicinity of the Lou?ná-Oberwiesenthal volcanic centre, western Bohemia/Saxony. Two types of volcanic rocks were recognized there: (i) high-Ti types (3.5–5.2 wt% TiO2) represented by (mela)nephelinite s.s., and sporadically present (ii) medium-Ti types (2.5–3.5 wt% TiO2) of olivine nephelinite, nepheline basanite and phonotephrite compositions. In order to examine the rock-magnetic behaviour, they were studied for their variations in the Curie temperature (TC) and field-dependent susceptibility, spinel group minerals, chemistry and petrology. Magnetic susceptibility of ulvöspinel-rich titanomagnetite, as a dominant magnetic carrier, depends on the amplitude of measured magnetic field, whereas pure magnetite is field-independent. Field dependence parameter kHD of the studied basaltic rocks ranges from 0.8 to 18.7%, TiO2 contents in titanomagnetite range from 12.7 to 20.1 wt.%. TiO2 content in titanomagnetite does not correlate with whole-rock TiO2 content (2.8 to 5.6 wt.%). The content of substituted titanium in the sublattice of magnetite is also sensitively reflected in the Curie temperature, ranging from 200 to 580°C. The spinel group minerals are designated as titanomagnetite with the dominance of ulvöspinel, magnetite and magnesioferrite components, or titanomagnetite with the magnetite, ulvöspinel and magnesioferrite components. Only two samples are characterized by a significant presence of Cr-spinel and magnesiochromite components forming cores of titanomagnetites. The titanomagnetite-bearing rocks in the studied area, likewise the low- to medium-Ti basaltic rocks from the ?eské st?edoho?í Mts., provide similar thermomagnetic curves. 相似文献
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The rocks comprising the Kari Kari massif southeast of the city of Potosi, Bolivia, consist entirely of welded ignimbrites. It is argued that the massif constitutes the resurgent centre of a 20-m.y.-old resurgent caldera. Plutonic rocks are exposed in the south, but volcanic rocks of the caldera rim are exposed in the north, and indicate a shallower erosion level there. The volcanic rocks consist of a coarse moat deposit, consisting of angular fragments of basement material and juvenile clasts, overlain by an extensive garnet-bearing ignimbrite. A plant-fossil-bearing lacustrine deposit was laid down in a lake within the caldera. The Cerro Rico stock, noted for its silver-tin mineralisation, may be a late intrusion along the caldera ring fractures. 相似文献
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Petrogenesis of the Ulsan carbonate rocks from the south-eastern Kyongsang Basin, South Korea 总被引：1，自引：0，他引：1
Abstract The petrogenesis of the Ulsan carbonate rocks in the Mesozoic Kyongsang Basin of South Korea, which have previously been interpreted as limestone of Paleozoic age, is reconsidered in the present study. Within the Kyongsang Basin, a small volume of carbonate rocks, containing a magnetite deposit and spatially associated ultramafic rocks, is surrounded by sedimentary, volcanic and granitic rocks of the Mesozoic age. The simple cross‐cutting relationships and other outcrop features of the area indicate that the carbonate rocks are an intrusive phase and younger than the other surrounding Mesozoic rocks. The Ulsan carbonates have low concentrations of rare earth elements (REE) and trace elements with the carbon and oxygen isotope values in the range of δ13CPDB = 2.4 to 4.0‰ and δ18OSMOW = 17.0 to 19.5‰. Outcrop evidence and geochemical signatures indicate that the Ulsan carbonates were formed from crustal carbonate melts, which were generated by the melting/fluxing of crustal carbonate materials, caused by the emplacement‐related processes of alkaline A‐type granitic rocks. Compared to typical mantle‐derived carbonatites associated with silica‐undersaturated, strongly peralkaline systems, the relatively small size and geochemical characteristics of the Ulsan carbonates reflect carbonatite genesis in a silica‐saturated, weakly alkali intrusive system. Major deep‐seated tectonic fractures formed by the collapse of the cauldron or the rift system associated with the opening of the East Sea (Japan Sea) might have facilitated the ascent of the crustal carbonate melts. 相似文献