摘要
大别苏鲁超高压变质带上的大陆科学钻探主孔(CCSD-MH)中榴辉岩中的金刚石形成于大陆深俯冲作用过程,西藏雅鲁藏布江缝合带罗布莎蛇绿岩铬铁矿中的金刚石来自深部地幔,两者的形成背景和机制可能不同。本文对两地的金刚石样品开展了傅立叶变换红外光谱(FT-IR)定性分析。结果表明,西藏罗布莎金刚石样品为ⅠaA型;而CCSD-MH金刚石为ⅠaAB型,既表明其杂质氮的聚集形式和演化路径上存在着差异。红外光谱特征不仅仅表明两者属天然金刚石常见类型,并且超高压变质带中的金刚石形成时间可能更久远。
Diamonds from eclogite in main hole of the Chinese Continental Scientific Drilling Project ( CCSD-MH) on the Sulu ultrahigh-pressure metamorphic ( UHPM) belt were formed by the deep subduction of continent crust,while diamonds from the Luobusa ophiolitic chromitites in the Yarlung Zangbo suture of Tibet were originated from the deep mantle. Thus,their formational background and mechanism are much different. A primary analysis of FT-IR show that UHPM diamonds are Ⅰ aAB type,and the ophiolitic diamonds areⅠaA type,both are different in the way of gather and evolvement for N-impurity. The FT-IRdata show that the diamonds from the two locations are natural diamonds,and the UHPM diamonds might formed earlier than the ophiolitic diamonds.