摘要
本文综合运用Sr、Pb同位素和微量元素对东北镜泊湖新生代玄武岩的成因及其地幔源化学特征进行了较详细的讨论。提出本区新生代玄武岩有两种成因和来源,本区地幔具有似原始地幔的化学特征,与华北、华南等邻区相比,Sr、Pb同位素特征具有区域性差异。
The Cenozoic basalts in the Jinbohu area, Northeast China have been studied systematically for Sr and Pb isotopes, trace elements and major elements. Various lines of evidence show that there are two types of basalts differing in source and genesis in this area. One is Na-alkali ba-salts ranging from Neogene to Hoiocene and formed in a shear environment. These basalts have Sr and Pb isotopic compositions similar to those of the primitive mantle except for a few samples which show a slight deviation in isotopes or/and trace elements because of fractional crystallization or AFC during magma upwelling. The other is quartz-tholeiites emplaced during the Eocene and derived from the lithospheric mantle with higher Sr but lower Pb ratios (87Sr/ 86Sr> 0.7050, 206Pb/204Pb-17.0). In addition, it is found that the isotopic characteristics of the Na-alkali basalts in the Jinbohu area are distinct from those in the Shando and other areas.
出处
《地球化学》
CAS
CSCD
北大核心
1989年第1期9-19,共11页
Geochimica
