共查询到19条相似文献，搜索用时 156 毫秒
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通过桂东南混合岩区破碎带蚀变岩型金银矿典型矿床的地质地球化学特征的研究，认为该区破碎带蚀变岩金银矿床为混合岩化复合热液矿床。 相似文献
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桂东南混合岩区金银矿床地质地球化学特征 总被引：2，自引：0，他引：2
通过桂东南混合岩区破碎带蚀变岩型金银矿典型矿床的地质地球化学特征的研究，认为该区破碎带蚀变若金银矿床为混合岩化复合效液矿床。 相似文献
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通过国外碱性交代岩矿床的成矿区域背景、矿床类型、交代作用特征及矿床成因的综述，和与国内混合岩型稀有金属矿床的对比研究，认为它们不属于同一成因类型矿床。 相似文献
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各种不同类型的混合岩大都是壳型花岗岩(即S型花岗岩)在成岩过程中不同阶段的遗迹。澳大利亚学者B·W·查佩尔和A·J·R·怀特提出的S型花岗岩的成因观点已在我国广泛引用和流传,矿床学者力图把不同矿种归属于不同源岩的花岗岩所造成。笔者认为进一步认识壳型花岗岩特征与成矿的联系,将有助于问题的发展和解决,为此深入研究混合岩的岩石特征及混合岩化作用是非常重要的。本文初步总结了甘肃北山柳园、安北至北山煤窑一带混合岩的岩石特征及成因,以供研究者参考。 相似文献
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近年来,在著名的河把燕山金矿带西段发现了钾化蚀变岩型金矿床。矿床产于混合源变质-交代型的(石英)二长岩体内微斜长石交代岩的破碎带中,以及岩体附迁的变质岩内,为-新的矿床类型,它是该区深大断裂带自大古代至燕山期反复多次活动对金的活化、迁移和富集的产物,特别是海西期沿构造带的局部性混合岩化作用、期后热液沿各级构造裂隙的交代作用,促进金的富集,局部形成混合岩化中温热液矿床。本文介绍了矿床产出的大地构造条件,矿床地质特征和对成因的认识,最后指出了进一步寻找金矿的方向。 相似文献
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本文研究了西昆仑造山带南带的新疆赛力格塔什刚玉矿床,该矿床赋存于古老基底的变质 岩系中,含矿岩石为眼球状黑云母长石片麻岩,眼球部分由刚玉（中心）及钾长石（外围）组成,基体为 黑云母及钾长石。经岩石化学及微量元素等的研究表明,这是一个由贫硅富铝的沉积岩经高级变质 作用形成的矿床。 相似文献
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A corundum-bearing skarn deposit was discovered in the Bakumuna area. The geology, petrology, and geochemistry of the deposit were studied. The skarn deposit comprises three mineralogically different zones, and the corundum is chiefly mineralized in the outermost zone. The deposit formed by the reaction of late magmatic fluids with the marble which eventually enriched the fluids with Al, causing Al2O3 to precipitate as corundum. 相似文献
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湖北英山刚玉矿物学研究 总被引：1，自引：0，他引：1
湖北英山刚玉矿床是本世纪五、六十年代发现的,由于多种原因未能对其进行研究和开发利用。本文系统地研究了英山刚玉矿物学特征,测定了各种物性和参数,观测了刚玉包裹体;并利用电子探针、粉晶Ｘ射线分析、可见光谱等现代测试手段,较详细地分析了刚玉的化学成分、晶体结构及光谱特征,并进行了热处理实验研究。指出湖北英山产出的刚玉颗粒大,晶形好,颜色较浅,可用热处理的方法改成蓝色、黄色、肉红色,但由于裂隙发育,包裹体 相似文献
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苏北某地超基性岩中,首次发现了红刚玉,少量已达宝石级。通过野外地质调查、矿物分析与测试和成因分析,该处产出的红刚玉是球斑状镁铝榴石二辉橄榄岩经热液蚀变后的产物,是一种新的红刚玉成因类型,从而为在苏北和鲁南地区寻找红宝石矿床拓宽了思路。 相似文献
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Zeming Zhang Huixia Ding Xin Dong Zuolin Tian Hongchen Mu Mengmei Li Shengkai Qin Zhixiang Niu Ning Zhang 《地学前缘(英文版)》2018,9(5):1337-1354
The genesis of Liangguo corundum deposit in the southern Gangdese magmatic arc, east-central Himalaya, remains unknown. The present study shows that the corundum-bearing rocks occur as lenses with variable sizes in the Eocene gabbro that intruded into marble. These corundum-bearing rocks have highly variable mineral assemblage and mode. The corundum-rich rocks are characterized by containing abundant corundum, and minor spinel, ilmenite and magnetite, whereas the corundum-poor and corundum-free rocks have variable contents of spinel, plagioclase, sillimanite, cordierite, ilmenite and magnetite. The host gabbro shows variable degrees of hydration and carbonization. The corundum grains are mostly black, and rarely blue, and have minor Fe O and TiO_2. The spinel is hercynite, with high Fe O and low Mg O contents. The corundum-bearing rocks have variable but high Al_2O_3, FeO and TiO_2, and low SiO_2 contents. Inherited magmatic and altered zircons of the corundum-bearing rocks have similar U e Pb ages(~47 Ma) to the magmatic zircons of the host gabbro, indicating corundum-bearing rock formation immediately after the gabbro intrusion. We considered that emplacement of gabbro induced the contact metamorphism of the country-rock marble and the formation of silica-poor fluid. The channeled infiltration of generated fluid in turn resulted in the hydrothermal metasomatism of the gabbro, which characterized by considerable loss of Si from the gabbro and strong residual enrichment of Al. The metasomatic alteration probably formed under Pe T conditions of ~2.2 -2.8 kbar and ~650 -700℃. We speculate that SiO_2, CaO and Na_2O were mobile, and Al_2O_3, FeO, TiO_2 and high field strength elements remained immobile during the metasomatic process of the gabbro. The Liangguo corundum deposit, together with metamorphic corundum deposits in Central and Southeast Asia, were related to the Cenozoic Himalayan orogeny, and therefore are plate tectonic indicators. 相似文献
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元江红宝石的呈色机理和改色效果 总被引：1，自引：0，他引：1
元江红宝石属区域变质成因大理岩型，与著名的缅甸抹谷红宝石矿床的成因类型几乎完全一致。该矿红宝石的颜色中，浅红、浅玫瑰红、及无色刚玉占总量的50％，提高该矿的潜在经济价值，增加红宝石的色调饱合度和消除色调不正的现象，必须研究红宝石呈色机理。电子探针分析结果为改色工艺提供依据。通过实验表明，浅玫瑰红的红宝石改色效果明显。 相似文献
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Nguo Sylvestre KANOUO Khin ZAW Rose Fouateu YONGUE Frederick Lin SUTHERLAND Sebastien MEFFRE Emmanuel NJONFANG Changqian MA Milan Stafford TCHOUATCHA 《Resource Geology》2012,62(3):316-324
Zircons and other heavy minerals (corundum, rutile, ilmenite, magnetite, sillimanite) are identified in the Nsanaragati gem corundum placer deposit, in the western part of the Mamfe sedimentary basin, SW Cameroon. These alluvial minerals have different morphological characteristics and zircons, in particular, vary mostly in colour and shape. They are reddish, brownish, yellowish, pink or colourless. These minerals form rounded and sub‐rounded alluvial grains, prismatic, pyramidal or dipyramidal crystals. Reddish zircons retain their original crystallographic shape. Trace element and U–Pb isotopic geochemical analyses of these reddish zircons, using the LA‐ICP‐MS method give significant Hf (4576–6334 ppm), Th (46–1565 ppm) and U (66–687 ppm) contents, with Th/U ratio ranging from 0.6 to 3.0. The 206Pb/238U corrected mean age gave 12.39 ± 0.55 Ma, which characterizes an Upper Cenozoic (Serravallian) magmatic event. The zircons are probably sourced from a magmatic field in the South eastern boundary of the Cross River Formation. The Cameroon Volcanic Line of basaltic and alkaline lavas and intrusions which lie east of the Mamfe Basin mostly range in age from 37 Ma to <1 Ma. The zircons may also relate to the Mount Bambouto plateau lavas which lie northeast of the Mamfe sedimentary basin and have an eruptive age range of 21–14 Ma. The oldest Nsanaragati reddish zircon ages overlap within error with the end stages of the Bambouto eruptions. This eruptive or a related episode provides a potential source for megacrystic reddish zircons within the Nsanagarati placer deposit. 相似文献
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Granulite facies quartzites from the Ihouhaouene region, in the northern part of In Ouzzal, contain the assemblage corundum+quartz+magnetite together with hercynitic spinel+quartz+magnetite, sillimanite+quartz+magnetite and almandine-rich garnet+quartz+magnetite. Two types of corundum have been recognized: the first is primary and is found with quartz and magnetite only; the second type is found together with magnetite and chlorite rimming spinel as a fine-grained corona. The textures show that spinel-rich magnetite probably exsolved primary corundum, sillimanite, spinel and garnet during the cooling history. The secondary corundum formed later from the spinel already exsolved from magnetite. The secondary corundum is certainly metastable with respect to quartz. This may also apply for the primary corundum. However, given the high-temperature setting of this rock, it cannot be excluded that the stable contacts observed between primary corundum and quartz indicate equilibrium between the two phases. Taking into account the uncertainties in the thermodynamic data, the stability of this assemblage would imply that this part of In Ouzzal has recorded very high P–T conditions, above 1100°C at 12 kbar. 相似文献
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An Al‐rich, SiO2‐deficient sapphirine–garnet‐bearing rock occurs as a metapelitic boudin within granulite facies Proterozoic charnockitic gneisses and migmatites on the island of Hisøy, Bamble Sector, SE Norway. The boudin is made up of peraluminous sapphirine, garnet, corundum, spinel, orthopyroxene, sillimanite, cordierite, staurolite and biotite in a variety of assemblages. Thermobarometric calculations based on coexisting sapphirine–spinel, garnet–corundum–spinel–sillimanite, sapphirine–orthopyroxene, and garnet–orthopyroxene indicate peak‐metamorphic conditions near to 930 °C at 10 kbar. Corundum occurs as single 200 to 3000 micron sized skeletal crystal intergrowths in cores of optically continuous pristine garnet porphyroblasts. Quartz occurs as 5–60 micron‐sized euhedral to lobate inclusions in the corundum where it is in direct contact with the corundum with no evidence of a reaction texture. Some crystal inclusions exhibit growth zoning, which indicates that textural equilibrium was achieved. Electron Back‐Scatter Diffraction (EBSD) studies reveal that the quartz inclusions share a common c‐axis with the host corundum crystal. The origin of the quartz inclusions in corundum is enigmatic as recent experimental studies have confirmed the instability of quartz–corundum over geologically realistic P–T ranges. The combined EBSD and textural observations suggest the presence of a former silica‐bearing proto‐corundum, which underwent exsolution during post‐peak‐metamorphic uplift and cooling. Exsolution of quartz in corundum is probably confined to fluid‐absent conditions where phase transitions by coupled dissolution–precipitation mechanisms are prevented. 相似文献