Abstract: Large amount of isotopic age data achieved in recent 10 years in Hengshan & Wutai Mt. show that the climax value of Hengshan complex's (2520 Ma) is 20Ma less than Wutai complex's (2540 Ma), which coincides with the opinion of Hengshan complex being the arc root of Wutai arc. Based on the comprehensive analysis of the various geological records, three evolution stages have been suggested, 2.70-2.60 Ga, the formation stage of the primary crust in Hengshan & Wutai areas, 2.60-2.52 Ga (not less than 2.45 Ga), the subduction and collision stage from the East to West Block and 2.50-1.75 Ga, the evolution stage of the early overlying strata. The last one is subvided to five periods, which are: 1) 2.50-2.30 Ga, the continental plateau basalt eruption period; 2) 2.30-2.20 Ga, the stable subsidence period; 3) 2.20-2.10 Ga, the tectonic activation and the emplacement of anorgenic granite period; 4) 2.10-1.85 Ga, the mantle plume activition period? 5) 1.86-1.75 Ga, the emplacement of large scale basic dyke swarms and the decomposition of North China Craton (NCC) period.

Key words: Hengshan complex, Wutai complex, isotopic age, geological events

摘要： 近10年在恒山和五台地区所获得的大量同位素年代学资料，统计发现恒山杂岩的同位素年龄峰值比五台杂岩大致要年轻20 Ma, 这与恒山－五台地区为岛弧根带－岛弧关系的推论相符合。综合各种不同的同位素测年结果按不同的地质体，进行了图解分析，将恒山－五台地区早前寒武纪的地质演化划分为3个大的阶段：2.70～2.60 Ga,早期演化（洋壳形成？）；2.55～2.52 Ga(?，最晚不晚于2.45 Ga),东西陆块俯冲碰撞阶段；2.50～1.75 Ga，早期盖层演化阶段。最后一个阶段有可以根据不同时段内研究区主要事件的不同，将2.50～1.75 Ga的演化分为5个时期。1）2.50～2.30 Ga表现为间歇性大陆溢流玄武岩的活动期；2）2.30～2.20 Ga华北较稳定沉降期，基本以接受沉积为主；3）2.20～2.10 Ga，构造活化期，五台地区主要有伸展非造山花岗岩（大洼梁花岗岩）的形成；4）2.10～1.85Ga阶段，地幔柱活动期？ 5）1.86～1.75 Ga，大规模基性岩墙形成期陆块裂解。

关键词: 恒山杂岩, 五台杂岩, 同位素年龄, 事件演化