东准噶尔卡拉麦里蛇绿岩形成时代、地质特征及构造意义

The Kalamaili Ophiolites:Age,Geological Characteristics and Tectonic Significance

通过对卡拉麦里蛇绿岩地质特征、形成时代及就位机制研究探讨,认为卡拉麦里蛇绿岩岩石组合齐全,已被强烈肢解,形成时代为357～492 Ma。洋盆拉张时期从中志留世或更早开始,蛇绿岩被上泥盆统不整合覆盖,因此确定洋盆闭合于中泥盆世。

We have investigated the geological characteristics,formation age and emplacement mechanisms of the Kalamaili ophiolite from the East Zhungar, Xinjiang.The ophiolite contains a variety of rocks including serpentine, cumulative rocks,diabase,pillow lava,plagiogranite and radiolarian chert, and has been strongly dismembered.The formation age of the ophiolite is constrained to be between 357-492 Ma, indicating that the rifting stage of the oceanic basin represented by the Kalamaili ophiolite started at middle Silurian or earlier.The oceanic basin may be closed at middle Devonian,as the ophiolite is covered unconformably by upper Devonian rocks.This conclusion may be significant for understanding the geological evolution history of the eastern Zhungar and adjacent regions.