塔里木微板块震旦-寒武系火山岩地球化学及其大地构造意义

Geochemistry and their tectonic significance of the volcanic rocks from Tarim micro-plate

塔里木微板块震旦-寒武系火山岩是反演该区震旦-寒武纪构造背景及演化过程的重要依据。本区震旦-寒武系火山岩主要有碱性玄武岩、流纹岩及少量安山岩。通过对该组岩石中玄武岩的常量、微量及稀土元素地球化学研究,结果表明,塔里木微板块在震旦-寒武纪期间曾经受到边缘活动带的明显影响,而产生陆内裂陷,形成了具有特殊的双重地球化学特征的火山岩岩石构造组合。它们为该区古构造环境的反演和古板块构造格局的重建提供了可靠的火成岩岩石学纪录。

The volcanic rock association which formed during Sinian to Cambrian period in the Tarim micro-plate can be divided into alkaline basalt, tholeiite and rhyolite. Based on the studying of trace elements and REE geochemical characteristics for the basalt, we have come to some conclusions that the volcanic rocks mainly formed in continental rift valley, but their source region were affected by the contents which derived from the subduction oceanic crust. These geochemical information is significance to discuss about the evolutionary process and the tectonic setting during Sinian to Cambrian period in Tarim area.