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熊耳山变质核杂岩构造研究及找矿进展 总被引：5，自引：0，他引：5
豫西熊耳山区是一个在中新生代伸展构造背景中形成的拆离－变质核杂岩构造。其核部由新太古界太华群变质岩系和燕山斯重熔型花岗岩体组成,盖层主要中由元古界熊耳群火山岩系组成。脱拆离系包括位于伏华群和熊耳群之间的主滑脱拆离带和盖层中一系列次级滑脱断层,区内金银矿化在空间分布上受到变质杂岩构造的控制,成矿时代与变质核杂岩主要形成期一致,成矿过程和扩离断层的发展过程一致,拆离断空矿体系可分为６种基本控构造类型, 相似文献
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辽西医巫闾山变质核杂岩构造系统及其对金矿的控制 总被引：6，自引：0，他引：6
医巫闾山变质核杂岩形成于白垩纪，属对称型变质核杂岩，中心为晚燕山期的医巫闾山二长花岗岩体，周围是代表地壳深部变形特点的太古宇变质岩组成的变质核。变质核北面和东面以拆离断层与盖层下部中元古界相接触，西面以阜新盆地东南缘边界正断层与白垩纪脆性变形碎屑岩相邻。在横剖面上变质核杂岩构造系统中的组合较齐全，且不同的构造带、构造部位对成矿和控矿作用不同，可分为：（1）产于拆离断层中深层次韧性流变层内的矿床——排山楼金矿；（2）产于拆离断层中浅层次韧性流变层内的矿床——大板金矿；（3）产于盖层下部韧-脆性构造层中的矿床——大樱桃沟金矿；（4）产于盖层上部脆性构造层中的矿床——五家子金矿。显示了变质核杂岩构造系统对该区金矿的控制作用。 相似文献
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庐山变质核杂岩具有典型的3层结构。拆离带是核部隆升过程中盖层滑脱、剪切变形而形成的,该拆离面是在北东向褶皱基础上叠加杂岩核部隆升作用而形成的波状起伏面。拆离带在核部以西发育倾向西向、南西向、北西向的面理和矿物生长线理,显示向西滑脱形成剪切拉伸变形的特征。拆离带岩石以糜棱岩和构造片岩为主,辅以碎裂岩和构造角砾岩。岩石变形特征表明其既具有韧性变形,也具有脆-韧性变形及脆性变形的特点。核部隆升引起的拆离变形作用,不仅形成了拆离带,还影响了拆离带以上盖层岩石,形成一个由拆离带向上由强变弱的变形域。这种规律性递变现象使庐山变质核杂岩具有垂向变形分层、水平变形分带的特点。拆离带中角闪石-斜长石矿物对计算得出的变质温度为653 ℃～694 ℃,压力为0.56～0.67 GPa。 相似文献
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庐山出露的变质核杂岩的构造层次具有典型的三层结构,即最上面的未变质沉积盖层、中间韧性流变层、核部的变质基底,其间分别以上剥离断层和拆离断层为分界线。上部沉积盖层以脆性变形为主,中间韧性流变层变形程度不一,但远离拆离带变质变形逐渐减弱,而核部的变质基底以强塑性变形为特征。对变质核杂岩南北两条地质剖面的分析,得到三个构造层次的岩石变质变形及岩性变化特征。区域动力学分析反映变质核杂岩东部原拆离带在五里正断层附近。拆离带中多硅白云母压力计得出的变质压力为0.6~1.1 GPa;锆石U-Pb年龄测试得到变质核杂岩的隆升时代为早白垩世。 相似文献
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雅拉香波穹隆韧性剪切带变形特征与剪切作用类型研究 总被引：1，自引：0，他引：1
雅拉香波变质核杂岩位于北喜马拉雅穹隆带东端，其拆离断层系的糜棱岩带构成了杂岩核部的外缘，带内主要变形岩石类型为石榴石千糜岩、糜棱状片麻岩和糜棱状花岗岩．糜棱状岩石中宏、微观韧性变形组构丰富，暗示区内存在多种显微变形机制：物质扩散迁移、晶内脆性破裂、粒内滑动及粒间滑动等，3种运动学涡度统计和计算结果表明：雅拉香波变质核杂岩拆离系的剪切作用类型是以简单剪切作为主的一般剪切；剪切带厚度变化为76％左右，属于减薄型：后期纯剪切应变速率比早期的有所增强，这可能与杂岩体核部岩浆岩后期上侵增强，穹隆进一步抬升和脆性垮塌下滑作用相关． 相似文献
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河淮地幔亚热柱的隆升，使岩石圈发生强裂减薄的同时，地幔物质呈蘑菇状向外围造山带之不拆离。当幔源拆离薄层被造山带陡倾韧性剪切带切割造成减压释荷，使韧性软化岩石转变为深熔岩浆上侵。形成沿造山带轴部展布的点状或线状构造岩浆带，表现为以构造岩浆带为核部的隆升构造－幔枝构造。隆升较快的构造我段上覆盖层呈揭顶式大幅度拆离，形成典型折变质核杂岩构造。地幔亚热柱→幔枝构造→变质核杂岩演化过程控制着成矿物质的运移、 相似文献
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变质核杂岩的定义、类型及构造背景 总被引：20，自引：6，他引：20
伸展变质核杂岩（mcc）的基本特征包括：（1）缓倾至中等倾角的具有大规模位移的（几十千米）区域信至准区域性延伸的主拆离断层；（2）与断层相关的糜棱片和片麻岩下盘（包括可能出露更深层次的非糜棱化结晶岩）；（3）上盘上地壳基底岩和／或表壳岩层。关键的一点是，所有为质核杂岩是沿地壳深部（大于10－15km）大型拆离断层大规模地壳伸展和地壳切除（缺失）的产物。我们认为，地壳剖面无大规模缺失的以基底为核的穹隆状杂岩不是一般构造定义上公认的变质核杂岩。变质核杂岩形成于同缩短期和缩短期的多种构造环境中。由于前期或同期或缩短的作用，变质杂岩似乎都发育在地壳强烈增厚的区域。绝大多数（但显然并非全部）变质核杂岩都与岩浆作用有密切的时空关系。变质核杂岩起控制作用的拆离断一般生根于中地壳或直接位于石英变为晶质塑性的韧脆性转化带下的深处，但有些拆了断层切穿大部或整个地壳。大多数为质核杂岩总体上具有不对称或简单剪切的构造几何特征，但有些变质核杂岩呈现较为对称的边界拆离断层。 相似文献
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楼子店变质核杂岩韧性变形作用的40Ar/39Ar年代学约束 总被引：9，自引：1，他引：8
楼子店变质核杂岩以拆离系中韧性剪切与脆性拆离运动学不一致,有别于北美科迪勒拉变质核杂岩。构造分析表明,核杂岩两侧拆离系中韧性剪切具有统一的上盘向北东的剪切特征。采自核杂岩两侧韧性剪切带中的3个黑云母单矿物^40Ar／^39Ar年龄介于126～128Ma之间,西侧韧性剪切带中1个角闪石单矿物^40Ar／^39Ar年龄为134Ma,4个样品的坪年龄与对应的等时线年龄一致。角闪石和黑云母坪年龄记录的韧性剪切作用的时限为126～134Ma,并且显示出韧性伸展的特点。研究表明楼子店变质核杂岩两侧的韧性剪切带形成时间一致并具有相同的运动学,韧性剪切作用是核杂岩形成演化的一个重要阶段,这为核杂岩形成的韧性伸展阶段的约束提供了年代学证据。 相似文献
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Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
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Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
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The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
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Emmanuel Skourtsos Daniel Vachard Alexandra Zambetakis-Lekkas Rossana Martini Louisette Zaninetti 《Comptes Rendus Geoscience》2002,334(12):925-931
Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931. 相似文献
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正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.) 相似文献
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正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.) 相似文献
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正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.) 相似文献
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正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus., 相似文献
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正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an 相似文献