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在过去的二十年里,EBSD (Electron Backscattered Diffraction),即电子背散射衍射测试技术,已广泛应用于韧性组构分析,成为变形运动学、流变学分析的常规手段。该方法主要应用于流变条件下矿物晶轴组构定向性分析,以判定流变剪切指向、对比应变强度、估算变形温度。理论上讲,EBSD法适用于所有矿物的全部晶轴定向的分析测试。然而鉴于天然变形的复杂性,笔者建议EBSD分析应以石英,特别是经历了动态重结晶的石英条带为组构分析的主要对象。长期以来,石英晶轴组构的不对称性被视作独立的剪切指向标志。然而,近年来基于天然变形和一般剪切实验的研究结果表明,塑性流变的剪切指向含义应为多重流变剪切指向标志综合判别比对的结果。尽管在提出之初,石英的轴组构开角被视作独立可靠的变形温度计(Kruhl,1998)。然而限于天然变形的复杂性,特别是对变质与变形阶段的对应、耦合的认识;尽管石英变形滑移系及石英晶轴组构开角可为动力变质温度提供重要的参考,但是石英晶轴组构开角并非独立的变形温度计。 相似文献
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辽西兴城—台里地区发育系列花岗质岩石,强烈构造变形特征均显示其具有韧性剪切带的特点。对剪切带北段进行详细宏微观构造解析,结合岩石变形强度差异性分析、有限应变测量、石英C轴EBSD测试以及古差异应力值估算等研究,结果表明剪切带内花岗质片麻岩和眼球状花岗质片麻岩具有NEE向左行剪切变形特征,变形岩石为S-L构造岩,应变类型属于平面应变,古差异应力值介于30~40 MPa之间。长石-石英矿物温度计以及石英C轴EBSD组构指示剪切带以中低温变形为主,温度在400℃~500℃,属绿片岩相变质,具中-低温韧性剪切带特征。韧性剪切带内普遍存在变形分解现象,弱变形带内岩石残斑含量较高,眼球状构造和S-C组构较为发育;强变形带岩石残斑含量较低,剪切面理较为发育,糜棱面理发育较弱或者不发育。 相似文献
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电子背散射衍射（EBSD）技术在大陆动力学研究中的应用 总被引：14，自引：10，他引：4
电子背散射衍射（Electron backscatter diffraction,简称EBSD）技术可以快捷准确地进行物相鉴定,确定矿物晶体的晶格优选定向和多相岩石中各矿物的空间分布,使其成为定量研究岩石显微构造的理想工具。将岩石组构测量、野外地质观察与矿物的变形实验研究相结合,可以判别物质运动的剪切指向和变形的温压条件,从而进行运动学和动力学机制的分析。本文首先介绍了EBSD技术的原理和主要矿物组构的实验研究进展,然后以国土资源部大陆动力学重点实验室5年来的成果为例,总结了EBSD技术在研究大陆深俯冲和折返的动力学机制和大陆造山带动力学研究中的应用。结果表明：橄榄石和绿辉石的组构揭示了板块深俯冲阶段的组构运动学特征,而石英、斜长石和夕线石的组构可以用来研究地壳内大型韧性剪切带的变形历史,如与苏鲁超高压变质岩折返相关的韧性剪切带、龙门山逆冲剪切带、西昆仑康西瓦走滑剪切带和喜马拉雅造山带的康马拆离剪切带。因此,EBSD技术的应用有助于实现显微构造与宏观构造相结合,建立变质-变形-运动学相统一的地球动力学模型。 相似文献
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内蒙古色尔腾山地区花岗绿岩带糜棱岩变形变质过程探讨 总被引：2，自引：0，他引：2
采用不同研究方法分析和解读岩石和矿物的显微构造特征，能再造结晶基底岩石复杂的变形和变质演化过程和条件。通过对色尔腾山地区花岗绿岩带中韧性剪切带的糜棱岩显微构造、石英组构、矿物化学等综合分析，发现该区糜棱岩在经历了低角闪岩相区域变质及绿帘角闪岩相退变质变形之后，发生了不均匀进变质重结晶作用及中低绿片岩相退变质变形等几个演化阶段。由不同阶段温压条件所限定的p-T演化轨迹为一个在早期顺时针的基础上叠加了一个晚期逆时针环的复杂图像。 相似文献
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石英c轴组构影响因素探讨:以郯庐断裂带糜棱岩为例 总被引：1，自引：1，他引：0
石英是自然界中最主要的造岩矿物之一,也是地壳流变过程的主要变形矿物,其c轴组构特征与变形温度、剪切指向具有密切的关系,因而常被用来获取剪切指向、估计变形温度、计算运动学涡度等。但由于受到变形分解、先存构造、流体等因素的影响,同一岩石中常会得到多个不同的石英c轴组构结果。如果天然变形岩石同时受到多种因素的影响,其石英c轴组构会表现为何种特征?与岩石变形温度、剪切旋向是否仍具有很好的对应性?基于以上问题,本次工作以大别山东缘郯庐断裂带内经历了多期变形、富含流体活动的超糜棱岩为研究对象,在同一岩石薄片中选择不同区域,利用EBSD开展石英c轴组构分析。分析结果表明,选择的超糜棱岩的石英c轴组构点极密分布形态指示岩石变形发生于非共轴变形条件下;剪切指向方面,6个分析区域中区域1表现为左旋剪切指向特征,与薄片中优势剪切指向一致,而除区域4外的其他4个区域显示出与优势剪切指向相反的右旋剪切指向特征;变形温度方面,区域4以柱面滑移为主,显示了高温变形特征,而其余5个区域均以底面滑移为主,指示了低温变形环境。根据本次石英c轴组构特征分析结果,可以得出一些认识:岩石中石英表现为完全的GBM动态重结晶,所指示的温度明显高于大量沿糜棱面理分布的绿泥石所指示的绿片岩相环境,显示流体活动促进了岩石变形;而石英c轴组构指示的变形温度为绿片岩相环境,与绿泥石存在的现象一致,表明糜棱岩化过程中流体活动对石英c轴组构的影响并不明显。在发生过多期变形事件的岩石中,岩石中早期高温变形信息有可能保留下来并记录在石英c轴组构特征中,因而通过石英c轴组构分析有可能获得早期事件的信息;虽然石英c轴组构影响因素众多,但首先开展详细的显微镜下观察,然后有选择地对剪切指向清晰区域开展石英c轴组构分析,仍然能够得到与岩石中优势剪切指向一致的石英c轴组构结果。 相似文献
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岩石电子背散射衍射（EBSD）组构分析及应用 总被引：18，自引：1，他引：17
电子背散射衍射（EBSD）技术是现代构造地质学与显微构造分析领域一项崭新的技术,它与现代高分辨率扫描电子显微镜和能谱分析设备结合,可以对块状样品中微米或纳米级尺度的颗粒进行晶体结构分析, 从而使微观结构、微区成分与结晶学数据结合起来,能够更精细地对比研究矿物和岩石显微构造,为岩石显微构造分析开辟了一个全新的领域。分析了EBSD技术的基本原理、系统构成、样品制备和工作程序。介绍了石英组构测量,极细粒物质（微角砾岩）的组构特点,二轴晶矿物（角闪石）的组构、变形机制和金属硫化物组构分析的应用实例,对于应用EBSD系统开展研究存在的一些问题进行了讨论。 相似文献
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阿尔金山喀腊大湾地区变形岩石EBSD组构分析 总被引：4，自引：0，他引：4
岩石组构是指组成岩石的矿物在岩石中分布的各向异性,EBSD(Electron Back Scattered Diffraction)岩组分析就是运用电子背散射衍射技术测定岩石结构要素——岩石中矿物分布的规律性。本文作者运用EBSD技术方法,对阿尔金山喀腊大湾地区变形岩石的组构分析显示,花岗质糜棱岩和蚀变变形花岗岩中,石英变形机制是以中温I级柱面(10-10)0001和中高温II级柱面(10-10)0001滑移为主,少量为中低温底面(0001)11-20滑移;而在变形火山岩中,石英变形机制是以中低温底面(0001)11-20滑移系为主。在区域南北向剖面分布上,接近阿尔金北缘断裂和白尖山断裂的中北部变形温度较高,向南变形温度有逐渐降低的趋势。从岩石组构特点结合宏观构造分析,可以认为本区北段属于中—中深层次(15~25km,t=350~550℃,P=0.40~0.60GPa)的韧性变形,而中南段为中浅层次(10~15km,t=250~350℃,P=0.25~0.40GPa)的韧脆性变形。结合不同变形特点花岗岩的年代学资料,确定构造变形的时代为早古生代。上述特征与区域上发育板块碰撞带,且北部发育高压榴辉岩和蓝片岩的构造部位以及该构造变形带的演化历史相吻合。 相似文献
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关于太古宙早期地壳演化构造机制的争论已经持续了数十年,其焦点主要集中于水平构造还是垂向构造两大经典构造模式的探讨.对于早期地壳构造演化方面的研究,将会有助于我们更好地理解早前寒武纪的地球动力学机制.本文对华北克拉通东北部鞍山地区花岗-绿岩带内齐大山韧性剪切带的构造变形特征进行了详细的解析,揭示了该区新太古代垂向构造作用样式.研究结果表明,齐大山韧性剪切带内花岗质岩石长英质矿物塑性拉长特征明显,条带状构造发育,面理向NWW方向陡倾,不对称组构特征和矿物拉伸线理产状指示向NWW的陡倾正滑移剪切作用.变形岩石中的长英质矿物均发育中低温显微变形特征,石英C轴电子背散射衍射（EBSD）组构分析揭示石英以菱面＜a＞和底面＜a＞滑移系为主,岩石经历了中低温非共轴变形.根据矿物的变形行为以及石英的结晶优选方位推测变形温度约为400~500℃,岩石变形特征以位错蠕变为主.有限应变分析结果表明,靠近铁矿带方向,构造岩类型由L=S构造岩过渡为LS构造岩,岩石应变强度呈明显增强趋势.运动学涡度测量结果显示齐大山韧性剪切带内大多数岩石样品的Wk值大于0.75,岩石形成于以简单剪切作用为主的一般剪切作用.对比花岗-绿岩带西侧的白家坟韧性剪切带,显示二者均具有相向的陡倾正滑移运动学特征,表明新太古代时期鞍山地区地壳构造演化模式以垂向构造作用为主. 相似文献
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湖南郴州枞树板铅锌矿X光组构分析 总被引：1，自引：0，他引：1
作者通过对湖南郴州枞树板铅锌矿围岩及含矿构造带岩石的X光岩组分析,认为在构造变形过程中,原岩粒度越细,对变形的反映越敏感。在相同的变形条件下,较细的变质砂岩石的石英定向组构比较粗的变质砂岩内明显,板岩和粉砂质板岩的定向组构最明显。枞树板地区近EW向褶皱变形组构表现强烈,近SN向褶皱变形组构较弱。矿化热液的蚀变作用破坏了岩石中早期褶皱变形组构,但铅锌矿脉内的石英没有明显的生长组构,说明在矿化和含矿石英脉成生过程中没有明显的张性充填结晶表现,而是一种以交代为主的矿化形式。这与从其它地质地球化学研究取得的关于本 相似文献
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Metamorphic evidence for an inverted crustal section, with constraints on the Main Karakorum Thrust, Baltistan, northern Pakistan 总被引：1，自引：0，他引：1
Abstract The Shyok Suture Zone separates rocks in the Asian plate from rocks in the Kohistan-Ladakh island arc. In Baltistan, this suture has been reactivated by the late 'break-back'Main Karakorum Thrust (MKT). The P-T histories of metamorphic rocks both north and south of the MKT have been determined in an effort to place constraints on the tectonic history of this zone. The terranes north and south of the MKT have different, unrelated metamorphic histories. Rocks from the Kohistan-Ladakh island arc south of the MKT have undergone a static low- P (2–4 kbar, c. 500° C) thermal metamorphism. The P-T paths and metamorphic textures of these rocks are consistent with metamorphism due to emplacement of plutonic rocks into the island arc. This metamorphism pre-dates folding and deformation of these rocks. Rocks in the Karakorum Metamorphic Complex, north of the MKT, have experienced a complex deformational and metamorphic history. Prograde metamorphic isograds have been deformed by subsequent south-verging folding and by gneiss dome emplacement. However, decompression metamorphic reactions occurred during nappe emplacement. Higher pressure rocks are associated with higher level nappes, creating an inverted pressure metamorphic sequence (8–9-kbar rocks over 5–6-kbar rocks). There is little variation in temperature with structural level (550–625° C). These two different terranes have been juxtaposed after metamorphism by the late south-directed MKT. 相似文献
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Deformation, metamorphism and imbrication of the Indian plate, south of the Main Mantle Thrust, north Pakistan 总被引：2，自引：0，他引：2
P. J. TRELOAR R. D. BROUGHTON M. P. WILLIAMS M. P. COWARD B. F. WINDLEY 《Journal of Metamorphic Geology》1989,7(1):111-125
ABSTRACT South of the Main Mantle Thrust in north Pakistan, rocks of the northern edge of the Indian plate were deformed and metamorphosed during the main southward thrusting phase of the Himalayan orogeny. In the Hazara region, between the Indus and Kaghan Valleys, metamorphic grade increases northwards from chlorite zone to sillimanite zone rocks in a typically Barrovian sequence. Metamorphism was largely synchronous with early phases of the deformation. The metamorphic rocks were subsequently imbricated by late north-dipping thrusts, each with higher grade rocks in the hanging wall than in the footwall, such that the metamorphic profile shows an overall tectonic inversion. The rocks of the Hazara region form one of a number of internally imbricated metamorphic blocks stacked, after the metamorphic peak, on top of each other during the late thrusting. This imbrication and stacking represents an early period of post-Himalayan uplift. 相似文献
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羌塘中部高压变质带的退变质作用及其构造侵位 总被引：6，自引：1，他引：5
羌塘中部的高压变质带主要由榴辉岩、石榴石白云母片岩和蓝片岩等组成,它们在遭受高压变质作用之后折返,构造侵位于晚古生代展金组地层中,二者以韧性变形带为接触边界.本文以高压变质带中的榴辉岩和韧性变形带为研究对象,讨论了高压变质带折返过程中的退变质作用特征及折返时代.研究表明,榴辉岩在高峰期变质作用之后的折返过程中经历了由榴辉岩相→蓝片岩相→绿帘角闪岩相的退变质作用演化过程;在高压变质带构造侵位过程形成的韧性变形带中,白云母石英片岩的白云母40Ar-39Ar坪年龄为219±2Ma.高压变质带在219Ma左右构造侵位于展金组地层中,并于214Ma之前最终抬升出露地表. 相似文献
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Abstract The Shangdan fault in the Qinling Orogenic Belt of China is an important boundary between the Caledonian North Qinling Fold Belt and the Hercynian South Qinling Fold Belt. In the Danfeng area, the fault zone strikes WNW–ESE and comprises four strongly deformed zones and three weakly deformed domains parallel to each other. The fault zone has a complex history of multiple deformation and each domain has a different tectonic style that was formed at different stages of the deformation.
The rocks exposed in the weakly deformed domains belong to the Qinling, Danfeng and Liuling Groups. In this paper, the mineral chemistry and mineral assemblages are used to infer the metamorphic conditions and the P–T paths of these units. The metamorphic units in and near the fault zone have different metamorphic conditions and histories that are correlated with the tectonic evolution of the fault zone. Caledonian–Hercynian uplift and southward thrusting of the Proterozoic Qinling Group, over the Danfeng and the Liuling Groups, produced the main metamorphic and tectonic features of the fault zone. Folding of both the Liuling Group and the thrust faults during the Hercynian–Indosinian was accompanied by northward thrusting. 相似文献
The rocks exposed in the weakly deformed domains belong to the Qinling, Danfeng and Liuling Groups. In this paper, the mineral chemistry and mineral assemblages are used to infer the metamorphic conditions and the P–T paths of these units. The metamorphic units in and near the fault zone have different metamorphic conditions and histories that are correlated with the tectonic evolution of the fault zone. Caledonian–Hercynian uplift and southward thrusting of the Proterozoic Qinling Group, over the Danfeng and the Liuling Groups, produced the main metamorphic and tectonic features of the fault zone. Folding of both the Liuling Group and the thrust faults during the Hercynian–Indosinian was accompanied by northward thrusting. 相似文献
15.
原划分的阿拉善群包含了时代、成因各异、构造样式有别、变质程度不同的变质地层和变形深成片麻岩体。作为一个岩石地层单元已不合适,应予解体并重新厘定。根据目前的研究,原阿拉善群可划分成3套变质地层单元和两个变形深成片麻岩杂岩。本区最古老的岩石地层单元为迭布斯格岩群,由深变质的变质表壳岩系组成,是区内的基底岩系。初步的锆石SHRIMPU-Pb年代学研究表明,它们形成于27亿年左右,属于新太古代。新建立的巴彦乌拉山岩组主要由变质火山岩组成,是区内的火山岩系。目前获得的年龄为2264Ma和2271Ma,属于古元古代。重新厘定的阿拉善岩群主要由变质碎屑岩和变质碳酸盐岩组成,是陆缘沉积岩系,形成于古元古代晚期或更晚。波罗斯坦庙英云闪长质-花岗质片麻岩杂岩,由早期的英云闪长质片麻岩和晚期的花岗质片麻岩组成。早期英云闪长质片麻岩形成于18亿年左右,晚期的花岗质片麻岩大致形成于古生代期间。毕及格台花岗闪长质片麻岩杂岩主要由角闪斜长片麻岩、黑云斜长片麻岩等组成,初步的同位素年龄测定结果显示它们的主期形成于8￣10亿年的晋宁期。 相似文献
16.
Here we discuss the post-metamorphic metasomatism of high-grade orthogneisses by studying granite-looking, pink-coloured microcline-bearing rocks exposed around Ambagaspitiya, Sri Lanka. These rocks are medium- to coarse-grained, and are more or less homogeneous, and isotropic. Textural, and petrographic analyses clearly show that these special rocks are neither deformed nor metamorphosed, and that they are not any kind of intrusive rocks. The present study shows that these rocks have formed through K-metasomatism of once intensely deformed, and metamorphosed granodiorite, tonalite, monzodiorite, and quartz monzodiorite. The modal compositions of most of these metasomatic rocks of Ambagaspitiya are very similar to those of syenite, quartz syenite, monzonite, quartz monzonite, and quartz monzodiorite.All the original metamorphic rocks — namely granitic gneiss, metagranite, metagranodiorite, metatonalite, metamonzodiorite, metaquartz monzodiorite, metadiorite, basic dikes, and metapelites — had undergone at least five ductile deformations, D1 to D5, and had been metamorphosed under upper amphibolite to granulite facies conditions prior to the metasomatism. Almost all the parent metamorphic rocks had acquired a well-developed gneissic foliation (S2), and had suffered at least two intense folding events (F3, and F5) before the metasomatism occurred. All the metamorphic, and deformational fabrics of affected metamorphic rocks have been completely or partially obliterated by the metasomatism. This indicates that the metasomatic process post-dates all ductile deformations (D1 — D5), and the regional metamorphism. Of the parent metamorphic rocks, metagranodiorite, metatonalite, metamonzodiorite, and metaquartz monzodiorite have undergone intense metasomatism. It is shown that the metasomatism has nucleated along late-stage, post-D5 shear zones, which may form an interconnected network. Potassium-bearing metasomatic fluids, derived from a deep-seated K-rich source, may have migrated along these shear zones. The fluids which entered the shear zones have pervaded the orthogneisses through foliation planes, and along grain boundaries, and microcracks in minerals, transforming the host gneisses to metasomatic rocks. The main metasomatic transformation has taken place through the replacement of metamorphic plagioclase, and plagioclase-quartz by microcline, and through formation of myrmekite. Further studies are necessary to unravel the nature, composition, and the source of these late-stage K-rich fluids in the lower crust. 相似文献
17.
The stratigraphy of the highly deformed and overthrust supracrustal rocks of the Akjoujt area consists of two sequences separated by an angular unconformity. A new stratigraphic framework has been proposed that is virtually the reverse of previously published schemes. The oldest recognisable supracrustal sequence consists of metabasalts overlain by banded iron formations and semipelitic and quartz-rich metasedimentary schists, for which the name Eizzene group has been proposed. This is overlain with angular unconformity by orthoquartzite followed by a suite of siliciclastic rocks, mafic to felsic volcaniclastic rocks, flows and banded iron formations. This well-layered sequence is overlain by poorly layered monotonous submarine metabasalts and coeval dolerites. All the rocks above the unconformity have been assigned to the newly created Oumachoueı̈ma group. The supracrustal rocks of the Akjoujt area are preserved as a complex system of overlapping thrust sheets, representing the disjointed limbs of a large-scale recumbent syncline. Igneous and metamorphic basement, with basal Oumachoueı̈ma group metasedimentary rocks attached, has been overthrust and is preserved in synformal remnants within the supracrustal domain. These are the erosional remnants of refolding by later, upright events. The main tectonic episodes consisted essentially of two periods of thrusting and recumbent folding followed by two episodes of thin-skinned upright folding above the sole thrust. Overthrusting of the suite onto the Archaean Amsaga basement to the northeast along the sole thrust is believed to be a late-stage event. The idiosyncratic Fe–Cu–Au–Mg carbonate mineralisation style of the Akjoujt area shows evidence of having been generated more than once during the evolution of the host rocks. Starting with pre to syn-early thrusting events, the carbonate-rich mineralisation recurred at least until the upright folding. There is strong field evidence for a genetic link to carbonate-rich iron formations by remobilisation, but no evidence of a synvolcanic or synsedimentary mineralising event. 相似文献
18.
P. M. Valley D. L. Whitney S. R. Paterson R. B. Miller H. Alsleben 《Journal of Metamorphic Geology》2003,21(2):203-220
The Swakane Gneiss and the overlying Napeequa Complex in the North Cascade range, Washington, were metamorphosed and deformed during development of a Cretaceous‐Paleogene continental arc, and are among the structurally deepest exposed rocks within the Cordilleran arcs of North America. Peak metamorphic conditions in both the Swakane Gneiss and Napeequa Complex were c. 640–750 °C, 9–12 kbar. Clockwise paths and widespread evidence for high‐P metamorphism in meta‐supracrustal rocks (burial to >40 km) document major vertical tectonic motion during arc construction and unroofing. These and other moderately high‐pressure rocks in the North Cascades‐Coast Mountains experienced a dramatically different tectonometamorphic history than metamorphic rocks within other Cordilleran arcs. The exhumed arc complexes of the Sierra Nevada and Peninsular Ranges are dominated by relatively low‐P metamorphic and plutonic rocks (typically <6 kbar). There is no evidence that the northern Cordillera was thickened to a greater degree than these other belts, suggesting that the greater magnitude of vertical motion in the Cascades may have been related to exhumation mechanisms: Eocene extension in the northern Cordillera vs. erosional unroofing in the central and southern Cordillera. 相似文献
19.
野外地质调查发现尾亚地区分布的主体为岛弧杂岩,被更晚的造山后花岗岩如钾长花岗岩等侵入改造。尾亚地区的岛弧杂岩受造山作用的改造,局部发生了一定程度的变质变形作用。这套变质岩分布局限,变质程度较低且主要为绿片岩相,劈理化强。2个样品YM01、YM02分别为黑云斜长变粒岩、角闪斜长变粒岩,其原岩分别为中酸性火山碎屑岩及闪长岩。2个样品的锆石年龄记录了中天山地块北侧的岛弧岩浆事件,表明古亚洲洋(北天山洋)从奥陶纪已经开始,一直持续到泥盆纪由北向南持续俯冲。俯冲过程在晚寒武世开始,暗示中天山地块北侧在当时已经发生了构造转换,作为一个微陆块由被动大陆边缘转变为主动大陆边缘。另外,岛弧杂岩体中没有前寒武纪年龄记录的特征,表明区域内的前寒武纪基底物质分布有限,而变质变形强烈的部分多为造山过程的产物,是在造山带后期改造形成的。 相似文献
20.
The Cu-Zn Obrazek ore deposit is reinterpreted as metamorphosed volcanogenic-type rather than epigenetic vein-type. Enclosed by undeformed, non-metamorphosed mafic-ultramafic rocks of the Ransko complex, the ore is a highly folded, intensely metamorphosed (Zn-rich) association of banded, massive sphalerite-barite-pyrite-pyrrhotite-chalcopyrite and (Cu-rich)pyrite-chalcopyrite-pyrrhotite. Cu-rich ores are disseminated in deformed metamorphic assemblages of quartz, sillimanite, cordierite, anthophyllite, orthopyroxene and gahnite. Textural and compositional features in the metamorphic rocks suggest that the cordierite-anthophyllite assemblage was produced by regional metamorphism of rocks associated with the ore deposit. Inclusion of the Cu-Zn deposit and associated rocks in the Ransko intrusive complex produced contact metamorphic hornfelses of quartz, cordierite, orthopyroxene and Al-spinel. The occurrence and compositions of Zn-rich chromian spinel and minor intercumulus sulfides in anorthosite, troctolite and norite of the Ransko complex near the Obrazek ore body are interpreted to result from contamination of the Ransko parent magma by the Cu-Zn deposit and associated rocks. 相似文献