俄罗斯极地乌拉尔Сыум-Кеу超基性岩体中的硬玉岩  

Jadeitite from Symn-Keu ultramafic complex,Polar Urals,Russia.

作　　者：孟繁聪[1] МакеевА.Б. 杨经绥[1] 白文吉[1] 

机构地区：[1]中国地质科学院地质研究所 [2]俄罗斯科学院乌拉尔分院科米科学中心地质研究所

出　　处：《岩石学报》2007年第11期2766-2774,共9页Acta Petrologica Sinica

基　　金：中国地质调查项目(1212010611811);国家自然科学基金重大国际合作项(40610098)资助。

摘　　要：俄罗斯极地乌拉尔Сыум-Кеу超基性岩体中的硬玉岩呈脉状在以叶蛇纹石为主的蛇纹岩中产出,硬玉岩由硬玉和绿辉石组成,根据硬玉岩的颜色、结构和构造可划分出三个世代,可能对应存在三期硬玉化过程。第一世代硬玉为主体,灰白色,粗粒结构,致密块状,硬玉分子(Jd)含量54%～88%;第二世代硬玉发育在灰白色硬玉中,呈浅绿色,细粒-隐晶结构,细脉状-囊状,硬玉分子(Jd)含量74%～86%;第三世代硬玉呈绿色-深绿色,半透明-透明,中-细粒结构,瘤状。第二、三世代硬玉达到珠宝首饰级,具有较高的商业价值。根据硬玉岩的产状和晶体具有韵律生长环带及流体包裹体发育等特征,认为硬玉岩是在高压低温环境中由富含Na、Al、Si的流体直接结晶形成的。Jadeitite is hosted as vein(up to 5m wide)by antigorite-dominated serpentinite bodies from Synm-Keu ultramafic complex,Polar Urals,Russia.Jadeitite is composed of Jadeite and Omphacite.It had experienced multi-stage jadeitizations indicated by color and structure of Jadeite.The Jadeite with gray-white color and coarse grain and massif structure,which has 54mol%～88mol% Jadeite,is considered to be the stage-ⅠJadeite.The stage-ⅡJadeite that has light green color and fine crystal occurring as fine vein nodular in the white Jadeite contains 74mol%～86mol% Jadeite.The last-stage Jadeite is green-emerald green color,medium-fine and nubble formed,which is translucency-lucency.Part of stage-Ⅱand stage-Ⅲjadeitite can be used as fine jewelry.Based on the occurrences of Jadeitite,crystal with growth zoning and fluid inclusions in jadeite,We consider that the jadeitite vein produced from Na-Al-Si-rich fluids at HP/LT conditions during active subduction/collisions.

关 键 词：硬玉岩 Сыум-Key超基性岩 极地乌拉尔 俄罗斯 

分 类 号：P588.125[天文地球—岩石学]