摘要
湘南早白垩世（１３２～１３５）Ｍａ基性火山岩中含有橄榄岩类、辉长岩类、角闪麻粒岩相酸性岩包体，这三类包体的岩石学特征及地球物理参数（ｖｐ，ρ），分别与岩石圈地球物理模型中的上地幔，下地壳及中地壳相吻合。包体的岩相学、主要元素、ＲＥＥ及稀有元素地球化学特征及同位素年龄的研究结果表明，现在的岩石圈中的下地壳部分是元古代（１１４１Ｍａ±６７Ｍａ）由底板垫托垂直增生形成的；中地壳与世界范围内的中地壳和中国华北及扬子克拉通相比偏酸性，而下地壳则偏基性，以富Ａｌ２Ｏ３为其特征。这一富Ａｌ２Ｏ３的下地壳包体除了在美国亚利桑那以外，在世界范围内还未曾见过报道。
Deep-seated source xenoliths of peridotite,gabbro and intermediate acidic hornblende granulite occur in Early Cretaceous basalts,South Hunan Province.Petrologic characteristics and geophysical data ( v p, ρ ) of these xenoliths respectively accord with upper mantle,lower crust and intermediate crust.Achievement in research on petrography,petrologic major,REE and other trace elements geochemistry and isotopic age determination suggests that the lower crust of the present continental lithosphere was formed by the underplating mantle derived vertical accretion in Proterozoic (1 141 Ma±67 Ma),the intermediate crustal composition is more acidic by comparison with the world and Northern China and Yangze craton,and lower crustal composition is more basic and rich in Al 2O 3.These xenoliths of lower crust rich in Al 2O 3 have not been reported,excluding Geronino volcanic field,Southeastern Arizona U S A.
出处
《地质科技情报》
CAS
CSCD
北大核心
1997年第3期1-7,共7页
Geological Science and Technology Information
基金
国家自然科学基金
关键词
包体
岩石圈
岩石学模型
火山岩
South Hunan Province,xenoliths,lithosphere,lithosphere model
