摘要
大兴安岭北部晚侏罗世塔木兰沟组玄武质岩石具有富碱(K2O+Na2O>5.45%),高K2O(2.15%~3.75%)、K2O/Na2O(0.48~1.12)和高的Th/Ta、Ce/Nb、Ta/Nb比值,以及强烈富集大离子亲石元素(LILE)和轻稀土元素(LREE)的特征,属于钾玄质系列。现有资料分析表明,该钾玄质岩石形成于大陆板内环境。元素地球化学特征揭示,形成钾玄质岩石的原生岩浆经过强烈的结晶分异作用,并混染了前中生代的基底物质。
Basaltic rocks of the Late Jurassic Tamulangou Formation in the northern Da Hinggan Mountains are characterized by rich alkalis (K2O+Na2O〉5.45%), high K2O (2.15%-3.75%), high ratios of K2O/Na2O (0.48-1.12), Th/Ta, Ce/Nb and Ta/Nb and strong enrichment in large-ion lithophile elements (LILE) and light rare earth elements (LREE), belonging to the shoshonitic series. Analysis of the available data indicates that these shoshoniric rocks formed in a continental intraplate setring. Geochemical characteristics suggest that the primary magma of these shoshonitic rocks underwent strong crystallization differentiation and was contaminated with pre-Mesozoic basement materials.
出处
《地质通报》
CAS
CSCD
北大核心
2005年第9期848-853,共6页
Geological Bulletin of China
基金
中国地质调查局国土资源调查项目(0100123059)资助
关键词
钾玄质岩石
地球化学
晚侏罗世
大陆板内
大兴安岭北部
shoshonite
geochemistry
Late Jurassic
continental intraplate setting
northern Da Hinggan Mountains