华北克拉通南部早前寒武纪基底形成与演化

发布时间：2018-03-07 18:24

本文选题：早前寒武纪　切入点：基底　出处：《岩石学报》2017年10期 　论文类型：期刊论文

【摘要】：简要总结了华北克拉通南部鲁山地区、小秦岭地区、登封及中条山地区的早前寒武纪地质事件序列及其地质意义,并对各地区地质特征和变质演化特点进行对比。结合前人研究工作,初步探讨了华北克拉通南部早前寒武纪基底的演化特点、陆壳形成的主要时期和华北南部基底的构造区划等问题,提出几点认识:1)华北克拉通南部鲁山、中条山、小秦岭等地区均有2.7~2.9Ga岩石记录,以英云闪长质-奥长花岗质-花岗闪长质(TTG)岩石为主,它们共同构成华北南缘的古老结晶基底,并经历了新太古代晚期~2.5Ga构造-热事件,标志着华北克拉通南部在新太古代末期可能已经形成统一基底;2)华北克拉通南部主要的陆壳形成时期为中太古代晚期-新太古代,与全球其他主要克拉通一致,而古元古代早-中期则以地壳再循环为主;3)综合地质、地球化学等特点,将华北南部鲁山-小秦岭地区和中条山等地区划归为"南部古陆块",并提出该陆块呈现为一个大型的倾伏向斜构造,可能在新太古代晚期已经形成,其枢纽向南东倾斜。"南部古陆块"在新太古代末期与其它微陆块拼合,并发生了变质作用和陆壳的活化与再循环,共同指示新太古代晚期华北克拉通统一基底的形成。
[Abstract]:The sequence of early Cambrian geological events and their geological significance in Lushan region, Xiaoqinling area, Dengfeng area and Zhongtiaoshan area in the southern part of North China Craton are briefly summarized. The characteristics of the early Cambrian basement in the southern part of the North China Craton are preliminarily discussed. The main period of continental crust formation and the tectonic regionalization of the basement in the southern part of North China are discussed in this paper. It is pointed out that there are 2.7 ~ 2.9Ga rocks recorded in Lushan, Zhongtiao and Xiaoqinling regions in the southern part of North China Craton. It is mainly composed of dolomite granodiorite and granodiorite, which together form the ancient crystalline basement of the southern margin of North China, and have undergone the late NeoArchean tectonic and thermal events of 2.5 Ga. Indicating that the southern part of the North China Craton may have formed a unified basement in the late NeoArchean) the main continental crust in the southern part of the North China Craton was the late Middle Archean-NeoArchean, which was consistent with other major cratons in the world. In the early and middle period of ancient times, Gu Yuan was characterized mainly by crustal recirculation and comprehensive geology, geochemistry, etc. The Lushan-Xiaoqinling area and Zhongtiaoshan area in the south of North China are classified as "southern paleocontinent blocks", and it is suggested that the block appears as a large dipping syncline structure, which may have formed in the late NeoArchaean period. The southern paleocontinent block joined with other microcontinental blocks in the late NeoArchean, and the metamorphism, activation and recirculation of the continental crust indicated the formation of the unified basement of the North China Craton in the late NeoArchaean period.
【作者单位】：大陆动力学国家重点实验室西北大学地质学系;山西师范大学地理科学学院;
【基金】：国家“973”项目(2012CB416606) 西北大学大陆动力学国家重点实验室科技部专项联合资助
【分类号】：P534.1

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