寻找超高压地幔矿物的储存库——豆荚状铬铁矿

STUDY ON A STOREHOUSE OF ULTRAHIGH PRESSURE MANTLE MINERALS──PODIFORM CHROMITE DEPOSITS

沿印度河—雅鲁藏布江缝合线出露的罗布莎蛇绿岩块位于拉萨南东 2 0 0km处 ,含有地幔矿物群。罗布莎蛇绿岩主要由地幔方辉橄榄岩、堆晶岩和蛇纹混杂岩组成。由 60～ 70种矿物组成的一个地幔矿物群出现在方辉橄榄岩相内的豆荚状铬铁矿中。这些矿物包括 :自然元素矿物 :金刚石、石墨、金、铜、铁、镍、硅、铬、铝、钨、锌、铅、锡 ;铂族矿物 :铱锇矿、锇铱矿、铱锇钌矿、含锇铱矿、含铱钌矿、Ir Os硫化物 ;合金 :FeSi,FeNi,SiC ,CrC ,NiC ,NiCrC ,Au Ag ,Ag Au ,Ag Sn ,AlFe ,IrFe ,NiFeCr,NiIrFe ,FeC ,FePtPd ;硫 (砷 )化物 :黄铁矿、毒砂、镍黄铁矿、闪锌矿、方铅矿、三方闪锌矿 ;氧化物 :铬铁矿、含硅镁尖晶石、刚玉、方镁石、金红石、方铁矿、锰方铁矿、CaO、石英 ;磷酸盐 :磷灰石 ;硅酸盐 :橄榄石、斜顽辉石、铬透辉石、锆石、榍石、硅线石、蓝晶石、角闪石、白云母、黑云母、金云母、钙铬榴石、钙铁榴石、镁铝榴石、铬绿泥石、蛇纹石、八面体假象蛇纹石、八面体假象绿泥石 ;碳酸盐 :方解石、白云石等。文中只介绍几个矿物 ,如金刚石、碳硅石、富Cr铬铁矿、富Si顽辉石、富Mg橄榄石、锆石、含硅镁尖晶石、八面体硅酸盐以及含水硅酸盐的深部爆破结构。这些矿物信息对地幔研究具有重要意义。

The Luobusha ophiolitic body containing a group of mantle minerals crops out along the Indu-Yarlunzangbu suture zone, and lies about 200km to the southeast of Lhasa. The Luobusha massif consists predominantly of mantle harzburgite, cumulate and serpentinite melange. A group of deep mantle minerals including about 60～70 kinds of minerals containing diamond has been discovered in podiform chromite deposits in the Luobusha ophiolitec mantle harzburgite. In this paper,the authors introduce several important minerals in podiform\|chromite ores, such as diamond, moissanite, Cr-rich chromite, Si-rich enstatite, Mg-rich olivine, zircon, Si-Mg spinel, octahedral silicate and micro-explosion of hydrous silicate. The information on the above minerals is of significance for study of deep mantle. About 60-70 kinds of the minerals are in the list:Native elements:diamond,graphite,gold,copper,iron,nickle,silicon,chromium,alumium,tungsten,zinc,lead,tin;PGE minerals:iridosmine,osmiridium,Ir-Os-Ru,Os-Ir,Ir-Ru,Ir-Os-sulfide;Alloys:FeSi,FeNi,SiC,CrC,NiC,NiCrC,Ag-Au,Au-Ag,Ag-Sn,AlFe,IrFe,NiFeCr,NiIrFe,FeC,Fe-Pt-Pd;Sulphides:pyrite,arsenopyrite,pentlandite,sphalerite,galena,matraite;Oxides:chromite,chrundum,rutile,periclase,wüestite,(MnFe)O,SiO 2,CaO;Phosphates:apatite;Sulfates:celestite;Silicates:olivine,enstatite,Cr-diopside,zircon,sphene,sillimantite,gehlenite,wollastonite,amphibole,muscovite,biotite,phlogopite,uvarovite,almandine,Cr-chlorite,serpentite,octehedral psuedomorph serpentine,octehedral psuedomorph chlorite;Carbonates:dolomite,calcite.