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采自五台山台怀镇南8 km处滹沱群变质火山-沉积岩层中的长英质凝灰岩样品含有两组锆石,所记录的SHRIMP锆石方法207Pb/206Pb年龄分别为2180±5Ma和2087±9 Ma.在误差范围内,较老的一组年龄与五台山大洼梁花岗岩年龄相当,表明它们来自相似的地壳岩浆源;而较年轻的一组锆石年龄与相邻地区阜平杂岩湾子表壳岩中变沉积岩和变火山岩及南营花岗片麻岩年龄相当,因而被解释为滹沱群火山作用年龄.这两组年龄的存在表明:(1)滹沱群形成于早元古代而非太古宙;(2)早元古代火山-沉积作用在五台和阜平地区同时间发生.这样,早元古代沉积作用在该区是广泛的,它们代表了华北克拉通东部陆块西侧大陆边缘相沉积.滹沱群火山作用年龄的确定也表明该群所经历的变质-变形事件发生在2087±9 Ma之后,这进一步佐证我们最近根据其他方面研究结果所得出的吕梁造山事件(约1.8 Ga)是该区主要构造事件的结论:该事件导致华北克拉通东部陆块和西部陆块的最终拼合,并成为全球早-中元古代超级大陆组成部分之一.
The felsic tuff samples collected from the Yutuo Group metamorphic volcano-sedimentary rock at 8 km south of the Taihuai town of Wutai Mountain contain two groups of zircons, and the recorded 207Pb / 206Pb ages of the SHRIMP zircons are 2180 ± 5Ma and 2087 ± 9 In the error range, the older age group is similar to the age of the Wudaishan Dagangliang granite, suggesting that they are from similar crustal magmatic sources. The younger age of a group of zircons is similar to that of the adjacent Fuping Complex Bay The metamorphic sedimentary rocks in the epicanthic rocks are similar in age to the volcanic rocks and the Nanying granitic gneiss, and are therefore interpreted as the volcanism age of the Jiu Tuo Tuo Group.The existence of these two groups of ages indicates that: (1) The Hutuo Group formed in the Early Proterozoic Archean; (2) Early Proterozoic volcano-sedimentation took place simultaneously in Wutai and Fuping areas, so that the Early Proterozoic sedimentation was extensive in the area and represented the western part of the eastern block of North China Craton Edge facies.The determination of the volcanism age of the Hudutou Group also indicates that the metamorphic-deformation events experienced by this group occurred after 2087 ± 9 Ma, which further corroborates our recent Lvliang orogenic event (about 1.8 Ga )Yes Conclusion major tectonic events area: the events leading to the final split Eastern Block and the West Block of the North China craton land, and become the world early - Mesoproterozoic supercontinent one of the components.