河北阳原新生代玄武岩中橄榄岩捕虏体矿物化学：华北岩石圈地幔演化  

Mineral Chemistry of Peridotite Xenoliths in Yangyuan Cenozoic Basalts:Significance for Lithospheric Mantle Evolution beneath the North China Craton

作　　者：陈曦[1] 郑建平[1] 

机构地区：[1]中国地质大学地球科学学院中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2009年第1期203-219,共17页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金项目(No.90714002);国家杰出青年科学基金项目(No.40425002)

摘　　要：橄榄岩及其中矿物的组成,特别是单斜辉石的微量元素,可以很好的揭示岩石圈地幔性质.在对河北阳原新生代玄武岩中橄榄岩捕虏体详细岩相学和矿物化学研究基础上,重点分析了单斜辉石的激光原位微量元素,讨论了新生代华北内部山带岩石圈地幔特征及其演化机制.阳原地区陆下岩石圈,除个别样品的部分熔融程度为15%～20%外,多数样品<5%,显示该区的地幔演化是不均一的,并表现为饱满与难熔-过渡型地幔的交叉并存.这种共存现象可以用软流圈物质对古老地幔进行不均匀侵蚀、改造和置换作用来解释.The compositions of the minerals and peridotites, especially trace elements of clinopyroxene （Cpx） can well reflect the characteristics of the subcontinental lithospheric mantle （SCLM）. Based on the petrographical study of peridotite xenoliths in Yangyuan Cenozoic basalts and chemical study of minerals, the paper mainly analyzes the LAM-ICP-MS trace element com- positions of Cpx from the Yangyuan peridotitic xenoliths and discusses the nature and evolution of the Cenozoic SCLM beneath the center of the Trans-North China orogen. The SCLM beneath the Yangyuan area is heterogeneous, forming from the different partial melting of the primitive mantle： most melted less than 5% of the total, except a few among 15%-20%. The coex- istence of the fertile and refractory-transitional mantle was better explained by the effects of heterogeneous erosion, transformation and replacement of asthenospheric materials on the cratonic lithosphere mantle.

关 键 词：橄榄岩 矿物化学 侵蚀 置换 不均匀性 华北 

分 类 号：P588.2[天文地球—岩石学]