五台山晚太古代碰撞造山带构造演化

TECTONIC EVOLUTION OF THE LATE ARCHEAN WUTAISHAN COLLISION OROGEN

应用构造—岩性—事件法将五台山碰撞造山带划分为３个构造片体：弧前混杂岩带、古岛弧系和弧后混杂岩带。提出该造山带构造演化５个阶段：洋盆扩张阶段（＞２６００Ｍａ）；南部洋盆向微陆块下俯冲—微陆块转化为岛弧阶段（２６００～２５００Ｍａ）；弧前碰撞—弧后消减阶段（２５５０～２５００Ｍａ）；陆—陆碰撞阶段（２５５０～２４５０Ｍａ）；伸展作用阶段（２５００～２４００Ｍａ）。

The Wutaishan collision orogen may be divided into three tectonic slices by applying the tectonic lithologic event method;from south to north they are the forearc mélange zone,paleoisland arc system and backarc mélange zone.Five stages are proposed for the tectonic evolution of the Late Archean Wutaishan collision orogen:the ocean basin spreading stage(>2 600 Ma),stage of subduction of the southern ocean basin beneath the microcontinental blok and transformation of the microcontinental block into an island arc (2 600～2 500 Ma),stage of forearc collision backarc subduction(2 550～2 500 Ma),continent continent collisison stage(2 550～2 450 Ma),and extension stage(2 500～2 400 Ma).