摘要
菲尔德斯半岛出露一套第三纪岛孤火山岩,包括高铝玄武岩、玄武安山岩、及少量安山岩与英安岩,从早到晚可划分为碧玉山段、玛瑙滩段、化石山段和岩块山段四个岩性段.它们属于同一钙碱性岩浆演化系列,其中高铝玄武岩是其它火山岩的母岩.高铝玄武岩的形成过程可分两个阶段:首先是上地幔楔经过20～25％的部分熔融生成原生橄榄拉斑玄武质岩浆,然后原生岩浆再经40％的矿物分离结晶作用(其中橄榄石占30％,单斜辉石占70％)而分异形成高铝玄武岩浆.
Cenozoic volcanic rocks in Fildes Peninsula can be divided into four lithological members, i.e., Jasper Hill Member (Eb), Agate Beach Member (Em), Fossil Hill Member (Eh) and Block Hill Member (Ey). They include mainly high-alumina basalt, basaltic andesite, a few of andesite and dacite as well, belonging to calc alkaline series but somewhat tholeiitic series in the early stage. High alumina basalt has a two-stage genetic model, i.e., during the first stage the upper mantle wedge underwent partial melting and produced primary olivine tholeiitic magma, and then during the second stage the primary magma evolved high-alumina basaltic magma after extensive crystallization of olivine and clinopyroxene.
出处
《火山地质与矿产》
1992年第2期26-36,共11页
Volcanology & Mineral Resources
基金
地质行业科学技术发展基金资助项目
关键词
火山岩
岩浆
演化
岩石学
volcanic rocks, two-stage genetic model, magmatic difFerentiation, Antarctica
