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和田玉(透闪石玉)的研究 总被引:12,自引:0,他引:12
用电子探针、X射线衍射、扫描电镜等测试方法,对新疆和田玉进行了研究,结果表明和田玉的主要矿物组成为透闪石,主要结构为毛毡状结构.本文还论述了其成因,指出了进一步找矿及考古意义. 相似文献
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运用偏光显微镜、电子探针对辽宁岫岩县桑皮峪透闪石玉的岩石学特征进行了研究,并运用二次离子质谱仪测定从桑皮峪透闪石玉中分离的锆石和榍石的年龄。结果表明:桑皮峪透闪石玉主要由透闪石组成,次要矿物包括磷灰石、方解石、绿泥石、石墨、褐铁矿、锆石、榍石等。偏光显微镜下桑皮峪透闪石玉的主要结构是毛毡状纤维交织结构、显微细晶质结构和纤维变晶结构;主要构造为块状构造。主要化学成分为SiO2、MgO和CaO,Mg2+/(Mg2++Fe2+)值为0.964~0.971。桑皮峪透闪石玉的锆石U-Pb谐和年龄为1 851±7 Ma,榍石的207Pb/206Pb年龄为1 848±17 Ma,表明桑皮峪透闪石玉矿形成于古元古代白云岩的区域变质时期。 相似文献
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论透闪石玉命名及分类 总被引:2,自引:0,他引:2
德穆尔1863年发表了对来自我国圆明园的和田玉及翡翠的矿物学分析成果,将它们分别命名为“Nephrite”和“Jadeite”。这两个词后来被译成“软玉”和“硬玉”一直沿用至今。其实,它们之间硬度并无不同,“软玉”一词在矿物学界和玉石界使用中也有一定混乱。根据玉石命名原则及和田玉的矿物成分和它在我国悠久的命名历史,建议“软玉”一词以“透闪石玉”取代。透闪石玉是由微晶透闪石组成、具毡状结构、符合工艺要求的玉石。可按地质产状、颜色、工艺等级、并考虑传统名称进一步划分品种。按产状可分为子玉、山玉、山流水等,按颜色分为白玉、黄玉、青玉、墨玉、碧玉等。 相似文献
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在滇西福贡亚五夺地区普遍发育有规模不等的透闪石玉矿(化)体,呈不规则大脉状产于片麻岩、片岩的大理岩夹层与糜棱岩化花岗岩的接触部位。本文在系统调查矿床(体)地质的基础上,采用化学分析、粉晶X衍射及能谱分析等方法,研究了区内透辉石玉的宝石学、矿物学特征,进而对其成因进行探讨。透闪石玉矿石折射率1.60,硬度5.6,密度2.9g/cm~3±,达到玉石品质的指标要求,可作为一种新类型的软玉矿床开发;其主要矿物组成(体积分数)为透闪石(45%)、透辉石(40%),并含方解石(5%)、石英(5%),以及少量的长石、石榴石、磷灰石、榍石、独居石等;透闪石的SiO_2、CaO、MgO含量(质量分数)分别54.54%、22.32%、18.62%,并有少量的Fe_2O_3、Na_2O、Al_2O_3,其晶胞参数a0、b0、c0及β分别为0.978×10~(-10) m、1.785×10~(-10) m、5.284×10~(-10) m及104.45°。结合矿床地质特征以及矿石与围岩稀土元素示踪分析,该透闪石玉矿床仍属变质热液型矿床,但其是在区域性同岩浆同变形时期的拉张阶段,变质流体混合岩浆残余热液沿裂隙充填而成的,应是一种新的矿床成因类型。其成矿时期与碧罗雪山—崇山变形带喜马拉雅中晚期大规模的走滑剪切作用相关大体时限为22~15Ma。本区域具有同等地质背景和成矿条件的地段范围巨大,具有很大的找矿前景。 相似文献
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贵州罗甸玉岩石化学特征及成因意义 总被引:4,自引:0,他引:4
以XRF、ICP-MS及常规化学分析方法为主要研究手段,对贵州罗甸玉的岩石化学特征进行研究,玉石常量化学特征表明,罗甸玉中透闪石的形成经历了Mg相对饱和及不饱和两个阶段,Mg相饱和的成矿阶段形成了白色罗甸玉中接近理想透闪石晶体化学组成的透闪石,其晶体化学通式为A0.01B2.00C5.34T8O22(OH)2;而在Mg不饱和阶段,则形成了青色系列罗甸玉中具有高Ca低Mg特点的透闪石,相应的晶体化学通式A0.01B2.35C4.13T8O22(OH)2。微量元素研究表明,罗甸玉中的白色与青色系列,由不同微量元素组合所表征的三个主因子有所差异,同时,罗甸玉中青色主要由其化学组成中微量的V,Cr引起;罗甸玉的稀土元素配分具有δCe和δEu异常的特点,稀土配分模式与围岩辉绿岩及灰岩均较为一致。在罗甸玉岩石化学特征研究的基础上,认为罗甸玉的形成是罗甸玉为岩床状辉绿岩顺层侵入时带来气液流体,与灰岩围岩发生长期的交代蚀变所形成的,灰岩提供成矿所需的Ca,Mg,而气液流体则主要提供了Si,为一种新类型的软玉矿体。 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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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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Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozach Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003). 相似文献
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正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level 相似文献
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正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7), 相似文献
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正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci- 相似文献
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正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli- 相似文献
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正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.) 相似文献
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正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861 相似文献