作　　者： ; ;

机构地区： 中国地震局地质研究所

出　　处： 《岩石学报》 2011年第10期2833-2841,共9页

摘　　要： 大兴安岭哈拉哈河-绰尔河第四纪火山岩中含有尖晶石相和石榴石相橄榄岩捕虏体。本文报道的尖晶石相橄榄岩包括方辉橄榄岩和二辉橄榄岩两类,前者分布数量略高于后者。方辉橄榄岩多数具有较高的平衡温度(1072～1193℃),矿物化学成分变化大,含有高Mg橄榄石和高Cr#尖晶石,这些特征一致表明是古老岩石圈地幔残余的样品。而二辉橄榄岩显示相对均一的矿物化学成分和很宽的平衡温度变化范围(636～1178℃),代表了明显受到改造的岩石圈地幔,可能反映岩石圈地幔的不同深度和局部经历了软流圈与岩石圈相互作用。通过与华北克拉通的对比,发现地处兴蒙造山带的大兴安岭岩石圈地幔中仍保留有相当量的古老岩石圈地幔残余,区别于遭受强烈改造和破坏的华北克拉通东部地区的岩石圈地幔。 Mantle peridotite xenoliths,including spinel peridotites and garnet peridotites,are found entrained in the Quaternary basalts in the Halaha river and Chaoer river area,the middle of Great Xing＇an Range.This study focuses on the spinel peridotites,which could be divided into harzburgites and lherzolites.Most of the harzburgite xenoliths are characterized by generally higher equilibrium temperature（1072~1193℃）,large variation in their mineral and chemical compositions,and high-forsterite olivine and high-Cr# spinel,which indicate they are the relics of aged lithospheric mantle.In contrast,the lherzolite xenoliths are relatively homogeneous in their mineral and chemical components,with wide range of calculated equilibrium temperature,which indicate they are modified lithospheric mantle,possibly reflecting that part of the lithospheric mantle has been modified by the interaction between asthenosphere and the lithosphere at different depth.It is deduced that the Xing＇an-Mongolia orogen have a great amount of aged lithospheric mantle,which is distinguished from the intensively modified and destroyed lithospheric mantle beneath the eastern North China Craton.

关 键 词： 大兴安岭 哈拉哈河 绰尔河 橄榄岩捕虏体 矿物化学 平衡温度 岩石圈地幔特征

领　　域： [天文地球] [天文地球] [天文地球]