北祁连西段香毛山一带早—中寒武世基性火山岩基本特征及其成因

Basic features and genesis of the early-middle Cambrian epoch volcanics in the Xiangmaoshan district of western part of northern Qilian

1.
Geological Survey of Gansu Province, Lanzhou 730000, China
2.
No.4 Institute of Geology and Mineral Exploration, Gansu Provincial Bureau of Geology and Mineral Exploration and Development, Jiuquan 735009, China

摘要: 香毛山一带早-中寒武世基性火岩以碱性玄武岩系列为主,具富钠,低钾、镁特点;稀土总量较低,属轻稀土富集型,分布模式为右倾平滑曲线,略具正铕异常;微量元素含量接近洋中脊过渡性玄武岩与板内拉斑玄武岩的丰度,岩浆来自富集的地幔源区;该火山岩系形成于强烈拉张产生的有限微洋盆构造环境,当时洋盆的扩张速率为1～2cm/a,属初始发育阶段.
- 基性火山岩 /
- 基本特征 /
- 成因 /
- 北祁连西段香毛山
Abstract: At Xiangmaoshan,alkaline basalt series with mark of rich Na and low K,Mg are the main of ∈₁-∈₂ basic volcanic rock.REE is lower and belongs to the type of enrichment LREE.Distribution pattern of REE is right dip smooth curve,and there is appreciably Eu positive anormaly.Trace element content is close to the abundance of midocean ridge intergrade basalt and intraplate tholeiite,and magma derived from the enriched source of mantle.So,this volcanic rock series was formed in rift micro-ocean basin tectonic setting of badly extension mechanism,then,the spreading velocity of ocean basin was 1-2 cm/a,belongs to the growth initial stage.
- basic volcanic rock /
- basic features /
- genesis /
- Xiangmaoshan