纯橄榄岩

利用沈步明（1993）提出的分形结构因子的新方法，计算了橄榄岩包体、方辉橄榄岩、纯橄榄岩和铬铁矿等六种尖晶石的分形结构因子。

The fractal structure factors ( FSF ) of spinel from ultramafic xenolith , harzburgite , dunite and chromite have been calculated using a new method presented by Shen ( 1993 ) .

上地幔部分熔融作用不仅控制了上地幔岩石类型演化（二辉橄榄岩→方辉橄榄岩→纯橄榄岩），同时它对铬铁矿的预富集起着关键作用。

The partial melting of the upper mantle not only controlled the evolution of mantle rock types ( lherzolite → harzber-gite → dunite ) but also played a critical role for chromite preconcentration .

岩体成因类型为蛇绿岩组合中的超镁铁质单元，铬铁矿的富集部位是地幔橄榄岩和堆积杂岩带底部的纯橄榄岩。

On the basis of the genetic type , the ultramafic bodies are part of ultramafic unit of ophiolite and the positions where the chromite enriched are mantle peridotite or bottom dunite of cumulate complex zone .

山旺新生代玄武岩中的超镁铁质包体分为五类：尖晶石纯橄榄岩、尖晶石二辉橄榄岩、尖晶石方辉橄榄岩、尖晶石石榴石二辉岩和石榴石二辉橄榄岩。

The Shanwang basalts contain ultramafic inclusions and megacrysts of clinopyroxene and anorthoclase . The ultramafic inclusions can be divided into five classes : spinel dunite , spinel lherzolite , spinel harzburgite , spinel-garnet websterite and garnet lherzolite .

主要岩石类型是方辉橄榄岩和纯橄榄岩，二辉橄榄岩极少（单斜辉石含量5～7%），具有典型的变质岩结构构造特征，矿物显微塑性变形普遍发育。

Lithologic types of the massifs are mainly harzburgite and dunite , with subordinated lherzolite ( orthopyroxene : 5 ~ 7 % ) . The textures and structures are similar to those of metamorphic rocks , and micro - plastic deformation of minerals is ubiquitous .