用户名: 密码: 验证码:
俄罗斯西萨彦岭翡翠矿区的含钠铬辉石的绿辉石岩
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
绿辉石岩是一种较为罕见的岩石,这种岩石在硬玉岩区和超高压变质带偶有出露,引起了相关学者的兴趣与重视。在硬玉岩区中,目前有报道的绿辉石岩主要在缅甸,被作为一种多期次硬玉化的标志。在研究俄罗斯西萨彦岭翡翠时,发现了绿辉石岩。该绿辉石岩主要由绿辉石、钠铬辉石组成,此外另有少量铬铁矿、金云母和镍黄铁矿,其中绿辉石的含量可达到90%以上。绿辉石岩的结构有冠状结构、亚颗粒化和锯齿状高度缝合边等。该绿辉石岩中显示出冠状结构从开始发育到形成完全形态的演化趋势,在此过程中冠状结构核心处的钠铬辉石被交代为含Cr量较少的绿辉石。绿辉石岩的成分和结构特征反映了该岩石至少有两期的硬玉化作用:(1)主期的充填交代作用,主要为硬玉质流体交代铬尖晶石类形成钠铬辉石,交代辉石类矿物形成绿辉石;(2)与变质变形同期的充填交代作用,生成新的Ae-Di-Ko固溶体系列。并且两期的硬玉化作用主导了绿辉石岩中Cr的迁移,表现为四种迁移形式:(1)铬铁矿→钠铬辉石;(2)钠铬辉石→含铬较高的绿辉石;(3)含铬较高的绿辉石→含铬较低的绿辉石;(4)含铬较低的绿辉石进一步淡化。这四个阶段的“铬的淡化”以及伴随铬的淡化的构造剪切力的作用决定了翡翠的绿色的色形、色度和均匀度,极大地影响着翡翠的质量。
     与缅甸绿辉石岩对比,西萨彦岭绿辉石岩中含有钠铬辉石,但缺少硬玉,并存在与钠铬辉石有关的冠状结构;在化学成分上Mg、Ca的含量较高,Fe的含量低了很多,并且几乎不含K。
     解决形成硬玉岩以及导致绿辉石岩形成的硬玉质流体/熔体的物质来源的问题是合理解释硬玉岩和绿辉石岩成因的重要步骤。以往的研究结果显示:硬玉岩的物质来源与俯冲洋壳上部富含Na的沉积物有关。据此推测硬玉岩是大洋板块在向下俯冲至大陆板块的过程中,随着温压的增大,其洋壳沉积物在一定条件下发生脱水或熔融,然后向上运移至超基性岩中结晶而成。绿辉石岩则可能与硬玉岩同时或之后形成,被认为是硬玉质的流体或熔体在俯冲板块带低温高压的条件下,与蛇绿岩套内含Fe和Ca较高的岩石类型如辉石岩等交代的产物。在硬玉质流体交代含Ca高的辉石类矿物形成绿辉石的同时,硬玉质流体也交代铬铁矿,形成钠铬辉石。
Omphacitite that catches lots of scholars interest and attention is a relatively rare rock that occasionally exposed in jadeitite area and UHP metamorphic zone. In the jadeitite area, Myanmar is the most important place in that the omphacitite was reported. And the omphacitite is thought to be a index of multi-stage jadeitizations. Omphacitite was found in the research of West Sayan jadeitite. The omphacitite mainly contains omphacite and kosmochlor, also contains chromite, phlogopite and a small amount of pentlandite, and the content of omphacite reaches more than 90%. There are mainly three distinct textures in the omphacitite:corona texture, subgrain. The omphacitite shows the evolution of corona texture from the development to the full formwith the containing of Cr in the kosmochlors in the core of corona texture increasing. The chemical composition and the texture show two or more stages of jadeitization in West Sayan omphacitite:(1) the main period of filling metasomatism. In this stage, The kosmochlor forms by the reaction between jadeitic fluids and chromite, and the omphacite forms by the interaction of pyroxene and jadeitic fluid; (2) the period of filling metasomatism related to metamorphism. In this stage, the series of new Ae-Di-Ko sosoloid formed. And the jadeitization controls the desalinization of chromium that is divided into four stages:(1) transformation from chromite to kosmochlor; (2) from kosmochlor to high chromium-bearing omphacite; (3) from high chromium-bearing omphacite to low chromium-bearing omphacite, and (4) from chromium-bearing omphacite to lower chromium-bearing omphacite, which is essentially the further evolution of the stage 3. Using the desalinization of chromium, the feature that green colour in jadeite jade has special shape can be interpreted, and how and what the green colour changes can be understood.
     The comparison between West Sayan omphacitite and Myanmar omphacitite shows: West Sayan omphacitite contains kosmochlor, but lack of jadeite, and there are corona textures related to kosmochlor. In chemical compositions, West Sayan omphacitite contains more Mg and Ca, less Fe and lack of k, whereas Myanmar omphacitite contains a little of K.
     To resolve the origin of jeditic fluid/melt that form the jadeitite and the omphacitite is very important for a reasonable interpretation of the genesis of jadeitite.Recent researchs shows the jadeitic fluid is more likely related to sediments of subducted slabs. According to recent researchs, the jadeitite thought to be the the production of the crystallization of jadeitic fluid.As the process of oceanic crust subducting to the continental plate, the sediments of subducted slabs dehydrate or melt with the temperature and pressure increasing, and the melt uplift,then the crystallization of the melt under certain conditions forms the jeditite. The omphacitite forms by the interaction of pyroxenite rich in Fe and Ca in ophiolite complex and jadeite fluids at HP/LT conditions during active subduction/collision. The kosmochlor forms by the reaction between jadeite fluids and chromite at the same time of the forming of omphacitite.
引文
[1]Bell P M, Roseboom E H. Melting relationships of jadeite and albite to 45 kilobars with comments on melting diagram s of binary system at high pressures. M in Soc Am Spec Pap,1969(2):151 ~ 161
    [2]Bender F. Geology of Burma. Gebruder Borntraeger, 1983,293p.
    [3]Chhibber H L. The mineral resources of Burma. Macmillan London,1934,320p.
    [4]Chihara K. Mineralogy and paragenesis of jadeites from the Omi-Kotaki area, Central Japan. Mineralogical Society of Japan, Special Paper,1971,1:147~156
    [5]Coleman R G. Jadeite deposit of the Clear Creek area, New Idridistrict, San Benito County, California. Journal of Petrology,1961,2(2):209~24
    [6]Compagnoni R, Rolfo F. First finding of jadeite in the serpentinite melange of Monviso meta-ophiolite, Western Alps. The Alice Wain Memorial Western Norway Eclogite Field Symposium,2003,37:21~28
    [7]Delvaux D, Moeys R, Stapel G, et al.. Palaeostress reconstructions and geodynamics of the Baikal region, Central Asia, Part I. Palaeozoic and Mesozoic pre-rift evolution. Tectonophysics,1995,252:61~101.
    [8]Dobretsov N L, Ponomareva L G. Comparative characteristics of jadeite and associated rocks from Polar Ural and Near-Balkhash Region. Proceedings of the Institute of Geology and Geophysics,1965,31:178~243.
    [9]Dobretsov N L. Mineralogy, petrography and genesis of ultrabasic rocks, jadeitites, and albitites from the Borus Mountain Range (the West Sayan). Proceedings of the Institute of Geology and Geophysics,1963,15:242~316.
    [10]Ermolov P V, Kotelnikov P E. Composition and origin of jadeitites of Imurundinsky Melange (northern Balkhash Area). Soviet Geology and Geophysics,1991,2:44~51
    [11]Garcia-Casco A, Vega A R, Parraga J C, et al.. A new jadeitite jade locality (Sierra del Convento, Cuba):first report and some petrological and archeo-logical implications. Contributiongs to Mineralogy and Petrology,2009, 158:1~16
    [12]Harlow G E. Jade (Nephrite and Jadeitite) and Serpentinite:Metasomatic Connections. International Geology Review,2005,47:113-146.
    [13]Harlow G E. Jadeities, albitites and related rocks from the Motagua Fault Zone, Guatemala. J Metam Geo,1994, (12):49~68
    [14]Harlow G E. Jadeitites, albitites, and related rocks from the Motagua Fault Zone, Guatemala. Journal of Metamorphic Geology,1994,12:49~68.
    [15]Hughes R W, Galibert 0, Bosshart G, et al.. Burmese jade:The inscrutable gem. Gems and Gemology,2000,36(1):2~26
    [16]Iwao S. Albitite and associated jadeite rock from Kotaki District, Japan. Reports of the Geological Survey of Japan,1953,153,26 p.
    [17]Johnson C A, Harlow G E. Guatemala jadeitites and albitites were formed by Deuterium-rich serpentinizing fluids deep with in a subduction channel. Geology,1999,27(7):629~632.
    [18]Komatsu M. Hida "Gaien" belt and Joetsu belt, in IchikawaK, Mizutani S, Hara I, Hada S, and Yagi A, et al., Pre-Cretaceous terranes of Japan, IGCP project No. 224:Osaka, Japan, Nippon Insatsu Shuppan Co., Ltd.,1987,25~40.
    [19]Morishita T. Occurrence and chemical composition of barian feldspars in a jadeitite from the Itoigawa-Ohmi district in the Renge high-P/T-type metamorphic belt, Japan. Mineralogical Magazine,2005,69:39~52
    [20]Morkovkina V F. Jadeitites in the hyperbasites of the Polar Urals. Izvestiya Akademia Nauk SSSR, seriya geologicheskaya,1960,4:78~82 (in Russian)
    [21]Orzo 1 J, Trepmann C, Stobckhard B et al. Critical shear stress for mechanical twinning of jadeite-an experimental study. Tectonophysics,2003,372(3) :135~145.
    [22]Safonova H Yu, Buslov M M, Iwata K and Kokh D A. Fragments of Vendian-Early Carboniferous Oceanic Crust of the Paleo-Asian Ocean in Foldbelts of the Altai-Sayan Region of Central Asia:Geochemistry, Biostratigraphy and Structural Setting. Gondwana Research,2004,7:771~790.
    [23]Scotese C R. Quicktime Computer Animations. PALEOMAP Project. University of Texas at Arlington,1998.(www.scotese.com).
    [24]Shi G H, Cui W Y, Cao S M, et al.. Ion microprobe zircon U-Pb age and
    geochemistry of the Myanmar jadeitite. Journal of Geological Society, London,2008,165:221~234.
    [25]Shi G H, Cui W Y, Tropper P, et al. The petrology of a complex sodic and sodic-calcic amphibole association and its implications for themetasomatic processes in the jadeitite area in northwestern Myanmar, formerly Burma. Contributions to Mineralogy and Petrology,2003,145(3):355~367
    [26]Shi G H, Cui W Y, Wang C Q, et al. The fluid inclusions in jadeitite from Pharkant area, Myanmar. Chinese Science Bulletin,2000,45(20):1896-1900.
    [27]Shi G H, Jiang N, Liu Y, et al.. Zircon Hf isotope signature of thedepleted mantle in the Myanmar jadeitite:Implications for Mesozoic intra-oceanic subduction between the Eastern Indian Plate and the Burmese Platelet. Lithos,2009, 112:342-350.
    [28]Shi G H, Stockhert B, Cui W Y. Kosmochlor and chromian jadeite aggregates from the Myanmar jadeitite area. Mineralogical Magazine,2005,69:1059-1075
    [29]Shi G H, Tropper P, Cui W Y, et al.. Methane (CH4)-bearing fluid inclusions in the Myanmar jadeitite. Geochemical Journal,2005,39:503-516.
    [30]Trepmann C, Stobckhert B. Mechanical twinning of jadeite—an indication of synseismic loading beneath the brittle lastic transition. International Journal of Earth Sciences,2001,90(1):4-14.
    [31]Zorin Yu A, Sklyarov E V, Belichenko V G, et al.. MazukabzovIsland arc-back-arc basin evolution:implications for Late Riphean-Early Paleozoic geodynamic history of the Sayan-Baikal folded area. Russian Geology and Geophysics, 2009,50:149-161.
    [32]奥岩.缅甸翡翠原生矿床成因研究.1997’全国宝石学年会论文汇编,1997:12-29.
    [33]崔文元,施光海,王长秋等.缅甸帕敢地区硬玉岩石中流体包裹体.科学通报,2000.45:1433~1437.
    [34]崔文元,施光海,林颖.钠铬辉石玉及相关闪石玉(岩石)的研究.宝石和宝石学杂志,1999,1(4):16~21.
    [35]崔文元,施光海等.一种新观点—翡翠新的岩浆成因说.宝石和宝石学杂志,2000,(3):16~22.
    [36]高媛,肖渊甫,管琪.翡翠的结构特征及其对宝石质量的影响.地质找矿论丛,2006,21(2):120~124.
    [37]黄作良杨红霞朱薇珊.翡翠的矿物组成特征及其质量.化工地质,2001,23,218-222
    [38]欧阳秋眉,曲懿华.俄罗斯西萨彦岭翡翠矿床特征.宝石和宝石学志,1999,1(2):5-11
    [39]欧阳秋眉.翡翠的矿物组成.宝石和宝石学杂志,1999(1):18-23.
    [40]欧阳秋眉.翡翠全集.香港:天地图书有限公司,2000,上册.
    [41]欧阳秋眉.紫色翡翠的特征及成色机理探讨.宝石和宝石学杂志,2003,3(1):]~7
    [42]彭卓伦,彭明生.缅甸硬玉中的包裹体.中山大学学报(自然科学版),2004,43(4):98-101.
    [43]森木信男等.辉石的命名(国际新矿物及矿物命名委员会1987年5月表决通过).陈健译,国外地质科技,1989.3
    [44]施光海,崔文元,等.缅甸翡翠中的多相包裹体的发现及其意义.中国宝石,2000(2):139~143
    [45]施光海,崔文元,刘晶,于海侠.缅甸含硬玉的蛇纹石化橄榄岩及其围岩的岩石学研究.岩石学报,2001,17(3):483-490.
    [46]施光海,崔文元.不同产地硬玉岩的共性与个性.地学前缘,2000,7(1):42
    [47]施光海,崔文元.缅甸硬玉岩的结构与显微构造:硬玉质翡翠的成因意义.宝石和宝石学杂志,2004,6(3):8~11.
    [48]施光海,崔文元.缅甸翡翠中“铬的淡化”及意义.宝石和宝石学杂志,2005,7(4):7-12
    [49]易晓,施光海,何明跃.缅甸硬玉岩区的硬玉化绿辉石岩.岩石学报,2006,22(4):971~976
    [50]于波.缅甸原生翡翠成因研究发展与思考.珠宝科技2003,15(5):31-34.
    [51]赵明开.硬玉及相关辉石化学成份与翡翠玉种研究.云南地质,2002.21(2):159-174.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700