江苏六合橄榄岩包体的矿物化学,稀土元素组成及其意义

根据１块橄榄岩包体矿物化学组成，得出由Ｋｈｌｅｒ－Ｂｒｅｙ法和Ｓａｃｈｔｌｅｂｅｎ－Ｓｅｃｈｔｈ法算得的二辉橄榄岩和方辉橄榄岩的平衡温度分别为７５０℃～９５０℃和１１００℃～１２００℃，表明了岩石圈不均一的分层特征。矿物化学组成的准确定量对温度的确定至关重要。岩石中重稀土和易熔元素的不相关表明，地幔曾发生过一种富化过程，使轻稀土偏离相关性，重稀土基本不变，这一过程可能是岩石圈中原始地幔和地幔残余物质的混合。

MINERAL CHEMISTRY AND REE COMPOSITIONS OF PERIDOTITE XENOLITHS FROM LIUHE,JIANGSU AND ITS IMPLICATIONS

Based on the careful determination of mineral chemistry compositions and calculation of geothermometry for 11 peridotite xeneliths from Liuhe, Jiangsu, it is concluded that accurate chemical compositions is very important forobtaining an acceptable equlibrium temperature of xeneliths. If the results of geothermometer on K6hler-Brey and Sachtleben-Seek methods are the same or similar, the temperatures are reliable. In Liuhe area, equlibrium temperature for harzburgite is lower than that of lherzolite. It might imply that harzburite is probably locatedin shallower position of upper mantle.The abundance and distribution patterns of rare earth element in xeneliths are not simply correlated with partial melting and indicated that an enriched process in the mantle must have happened and caused the LREE enrichment, and HREE unchanging. This might be a mixing process between primitive mantle component and residue of partial melting.