新疆木纳布拉克蛇绿岩地球化学特征及形成构造背景分析

木纳布拉克蛇绿岩是新疆境内最大的蛇绿混杂岩带,由超镁铁质岩、镁铁质岩、浅色分异物和变玄武岩组成,形成时代为中元古代晚蓟县世,侵位时代为新元古代早青白口世,可能代表了阿尔金山地区中元古代的板块俯冲带.蛇绿岩可能形成于孤后或孤间有限洋盆小扩张脊;最后侵位到深海沉积物中,形成了造山带中的蛇绿岩.

Geochemistry and tectonic setting of the Munabulak ophiolites in Xinjiang

The Munabulak ophiolites as the largest ophiolitic mdange zone in Xinjiang are made up of ultramafic rocks, mafic rocks, light-coloured rocks and meta-basalts which may be traced back to the Jixianian of the Mesoproterozoie for their formation and the early Qingbaikouan of the Neoproterozoie for their emplacement, and represent the subduetion zone in the Ahun region during the Mesoproterozoie. These ophiolites may be originated from the small spreading oceanic ridges of back-arc or inter-arc restricted oceanic basins, and finally emplaced into the deep-sea sediments constituting the ophiolites in orogenic zones,