云南个旧印支期基性火山岩地球化学特征及其大地构造背景

Geochemical characteristics of basic volcanic rock in Indo-Chinese epoch in Gejiu,Yunnan,and its geotectonic background

通过对个旧地区印支期火山岩的地质、岩石地球化学、微量元素和稀土元素等研究表明,该期火山岩的岩石类型为杏仁状斑状纤闪石化玄武岩,属于硅不饱和、富碱、高钛,镁、铁偏高,铝偏低,具有大陆碱性橄榄玄武岩的组分特征。该玄武岩为陆内拉张环境下基性程度高、分异程度低的幔源岩浆分异的产物,形成于大陆板内裂谷环境,并与拉裂作用有关。

An approach was carried out on geology, rock geochemistry, trace elements and REE in volcanic rocks in Ladinian （Indo-Chinese） epoch in Gejiu area, Yunnan province. The result shows that the rock type of volcanic rocks in the epoch is uralitized basalt with blastoamygdaloidal and blastoporphyritic structure, being silica unsaturation and rich in alkali, high titanium, relatively high in magnesium and iron, lower in aluminiun, characterized by the composition of continent olivine alkali basalt. The basalt originated from mantle source magma differentiation of lower extent and high basicity forming in inner continent rift environment of continent plate and related with drawing breakage process.