华北晚中生代中基性侵入岩中橄榄岩捕虏体是岩石圈地幔直接样品?  

Are the peridotitic xenoliths entrained in Late Mesozoic intermediatemafic intrusive complexes on the North China Craton the direct samples of lithospheric mantle?

作　　者：张瑾[1] 张宏福[1] 英基丰[1] 汤艳杰[1] 

机构地区：[1]中国科学院地质与地球物理研究所岩石圈演化国家重点实验室

出　　处：《岩石学报》2005年第6期1559-1568,共10页Acta Petrologica Sinica

基　　金：国家自然科学基金委杰出青年科学基金(批准号:40225009);创新研究科学基金(批准号:40421202)联合资助项目

摘　　要：华北东部晚中生代中基性侵入杂岩体(如山东莱芜地区铁铜沟岩体;山东潍坊地区金岭-湖田岩体;河北邯邢地区符山岩体)中常含有橄榄岩捕虏体。这些橄榄岩的来源和成因问题存在很大争议,主要有堆晶成因或代表古老洋壳蛇绿岩和岩石圈地幔来源两种观点。本文在对山东潍坊地区金岭-湖田岩体中橄榄岩捕虏体的研究成果和总结前人资料的基础上,通过岩石学、矿物学和地球化学研究认为这些橄榄岩捕虏体皆是堆晶成因或代表古老洋壳蛇绿岩,而非岩石圈地幔直接样品因此,不能用这些橄榄岩捕虏体的组成来反演该地区晚中生代岩石圈地幔特征。Late Mesozoic intermediate-mafic intrusive complexes on the eastern North China Craton （such as Tietonggou complex in Laiwu region of Shandong province; Jingling-Hutian complex in Weifang region of Shandong province; Fushan complex in Hanxing region of Hebei province） often contain peridotitic xenoliths. The origin and petrogenesis for these peridotites remain controversial, of which two opinions： accumulative origin/representative of old oceanic ophiolite or direct samples from lithospheric mantle are prevalent. This paper, on the basis of the resuhs from the study on the peridotitic xenoliths entrained in Jingling-Hutian intrusive complex in Weifang region of Shandong province and compilation and re-recognition of previously-published data realized that these peridotitic xenoliths were all accumulative origin or represent ancient oceanic ophiolites, rather than direct samples from the lithospheric mantle through careful petrological, mineralogical and geochemical studies. Therefore, these peridotitic xenoliths cannot be used to probe the compositional features of the Late Mesozoic lithospheric mantle beneath the North China craton.

关 键 词：华北 晚中生代 中基性侵入岩 橄榄岩捕虏体 堆晶成因 

分 类 号：P588.125[天文地球—岩石学]