中国大陆科学钻探(CCSD)主孔石榴石橄榄岩中发现Fe_2P合金矿物  

Discovery of Fe_2P alloy in garnet peridotite from the Chinese Continental Scientific Drilling Project (CCSD) main hole.

作　　者：杨经绥 [1] 白文吉 [1] 戎合 [1] 张仲明 [1] 许志琴 [1] 方青松 [1] 颜秉刚 [1] 李天福 [1] 任玉峰 [1] 陈松永 [1] Jinzhu HU  Jinfu SU  Ho-kuang MAO  

机构地区：[1]国土资源部大陆动力学重点实验室,中国地质科学院地质研究所,北京,100037 [2]Geophysical Laboratory and Center for High Pressure Research, Carnegie Institute of Washington, USA

出　　处：《岩石学报》2005年第2期271-276,共6页Acta Petrologica Sinica

基　　金：国家重点基础研究发展规划(973)项目(2003CB716503)国家自然科学基金重大项目(40399143)中国地质调查局地质大调查项目(编号121201056606)的联合资助

摘　　要：在东海大陆超深钻(CCSD)的钻孔橄榄岩岩屑(孔深603-683米深部)中,分离出的矿物有硅酸盐、氧化物、硫化物、碳化物、自然元素、金属互化物和合金,计50-60种矿物。多种特征表明其中有一些不寻常矿物,并且有些矿物具有球状外形,如自然铁、镍纹石、铁镍合金、磁铁矿等。本文报道通过成分和结构分析鉴定出的铁磷合金矿物(Fe,P),成分中含少量Cr,Ni和Co,成分均一,分子式为(Fe1.80Ni0.05Cr0.02)P。EDXD数据表明该矿物的晶系属六方晶系;格子类型为P;空间群为P62m;晶胞参数a=b=5.877Ac=3.437A,a:c=1:0.5848。通过ICDDPDF-2x射线粉晶衍射数据库2004年公布的最新版本搜索查询,发现与人工合成的同种矿物Fe2P(ICDD83-2337,Barringerite.syn)十分接近,类似的矿物已在陨石中发现(FeNi)P,故确定本文报道的铁磷合金(Fe2P)为地球上首次发现的天然合金矿物。其成因和形成条件的研究正在进行中。Cuttings of garnet peridotite were collected between 603.2 and 683.5 in in the CCSD at Donghai. Minerals were separated by various methods and handpicked under a binocular microscope. The selected minerals were identified by SEM-EDS, microprobe, Laser Raman, and EDXD ( Synchrontron X-ray Diffraction). A number of unusual minerals have been recognized from the cuttings, e. g., moissanite, w stite, native Fe, native Cr, native Ni, native An, native Cu, native Al, taenite, kamacite, Ni-Fe-Cr alloy, Ni-Fe alloy, Fe-Cr alloy, Si-Fe alloy (Fe3Sgamma), and Co-Ni alloy. Two grains of Fe2P alloy (barringerite), have also been found. They are spheroidal in shape, with diameters of about 200 mu m, and they have identical hexagonal structures with cell parameters of a = 5.877 angstrom, c = 3.437 angstrom, and a: c = 1 :0.5848. They belong to space group P62m. This mineral, which is similar in structure and composition to artificial Fe2P (ICDD 83-2337), has previously only been found in meteorites. This is the first reported natural terrestrial occurrence of barringerite. Further study on its genesis and formational conditions is underway.

关 键 词：铁磷合金 石榴石橄榄岩 中国大陆科学钻探 苏鲁 超高压变质作用 

分 类 号：P575[天文地球—矿物学] P573[天文地球—地质学]