西藏罗布莎蛇绿岩地幔岩中首次发现超高压矿物方铁矿和自然铁  

A Discovery of Ultrahigh Pressure Minerals-Wustite and Native Ironfrom the Mantle Ophiolite, at Luobusa, Xizang

作　　者：白文吉[1] 杨经绥[1] 施倪承[2] 方青松[1] 代明泉[2] 熊明[2] 颜秉刚[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质大学,北京100083

出　　处：《地质论评》2004年第2期184-188,共5页Geological Review

摘　　要：在西藏雅鲁藏布江蛇绿岩带的东部,距拉萨市200 km 的罗布莎蛇绿岩的豆荚状铬铁岩中,发现方铁矿和自然铁。而且以自然铁为核心并包裹于方铁矿中,两者形成圆球形态。自然铁的空间群为 Fm3m,晶胞参数α=0.28663 nm。方铁矿空间群为 Fm3m,晶胞参数α=0.43070 nm。根据有关实验资料推断,高压矿物方铁矿和自然铁来自下地幔,并且可能为核幔边界化学反应生成物。Wustite and native iron have been first discovered from podiform chromitite ore bodies in the ophiolite at Luobusa, eastern part of the Yarlung Zangbo River, about 200 km southeast of Lhasa. The grains of native iron are in globular form rimmed by wustite. The two minerals have been analyzed by the X-ray diffraction and energy dispersion spectrometry methods. The space group of the native iron is Fm3m, and that of wustite is Fm3m too, with a = 0. 28663 nm and 0. 43070 nm respectively. Based on high-pressure and high-temperature experimental data, this assemblage was formed in the lower mantle as a result of the reaction between the Earth's outer core and lower mantle, and then brought up to the upper mantle by the plume.

关 键 词：方铁矿 自然铁 下地幔 超高压矿物 西藏 蛇绿岩 

分 类 号：P588.3[天文地球—岩石学]