兴蒙造山带中段上石炭统碎屑锆石年龄特征及其地质意义

发布时间：2018-04-25 19:51

本文选题：晚石炭世地层 + 年代学　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：西伯利亚板块与华北板块的最终拼合位置及拼合时间一直都是国内外地质学者争论的焦点,由此更是引出关于兴蒙造山带是一个构造旋回的产物还是两个构造旋回的探讨。晚石炭世地层在兴蒙造山带内发育分布的差异及沉积相的差异,暗示其蕴含着兴蒙造山带构造演化过程和板块拼合的关键信息,因此本文从晚石炭世沉积地层的碎屑锆石年龄特征入手,通过对其进行物源分析,来探讨晚古生代以来兴蒙造山带的构造演化。通过对上石炭统宝力高庙组和格根敖包组地层砂岩进行锆石U-Pb测年和物源分析,再结合前人研究资料。本文认为古亚洲洋被锡林浩特微陆块分隔为贺根山洋和西拉木伦洋,西拉木伦洋于晚志留世发生闭合,贺根山洋于晚泥盆世发生闭合,至此,古亚洲洋在晚泥盆世已全部闭合。由于南面索伦-西拉木伦缝合带早已闭合,所以西乌旗地区晚石炭世本巴图组、阿木山组地层中含有峰值为~1.8Ga和~2.5 Ga的华北板块基底信息,但由于贺根山洋的碰撞造山作用导致地壳抬升,因而华北板块物源不能到达二连-贺根山以北的宝力高庙组和格根敖包组地层之中。而早二叠世西拉木伦缝合带被重新拉开,直到晚二叠世-早三叠世最终闭合。综上所述,古亚洲洋在晚泥盆世已全部闭合,而早二叠世出现的是新生洋壳,二者分属不同的构造旋回。
[Abstract]:The position and time of the final assembly of the Siberian plate and the North China plate have always been the focus of debate among geologists at home and abroad, which leads to the discussion on whether the Xingmeng orogenic belt is a product of a tectonic cycle or two tectonic cycles. The difference in the distribution of late Carboniferous strata in the Xingmeng orogenic belt and the difference in sedimentary facies indicate that the late Carboniferous strata contain the key information of tectonic evolution process and plate assemblage of the Xingmeng orogenic belt. Therefore, starting with the age characteristics of detrital zircons in the late Carboniferous sedimentary strata, this paper discusses the tectonic evolution of the Xingmeng orogenic belt since the late Paleozoic by analyzing its provenance. Zircon U-Pb dating and provenance analysis were carried out on the stratigraphic sandstone of the upper Carboniferous Baoligaomiao formation and Gegen Aobo formation, and combined with previous research data. This paper holds that the Paleo-Asian Ocean was separated by the Xilinhaote microcontinental block into the Hegen Mountain Ocean and the West Lamulan Ocean. The West Lamuron Ocean was closed in the late Silurian and the Hegenshan Ocean was closed in the late Devonian. So far, the Paleo-Asian Ocean has been completely closed in the late Devonian. As the Suoren-Xilamuron suture zone in the south has long been closed, the late Carboniferous Gbatu formation and the Amushan formation in the Xiwuqi area contain the basement information of the North China plate with a peak value of 1.8Ga and 2.5Ga. However, the collision orogeny of the Hegen Mountains resulted in the uplift of the crust, so the material source of the North China plate could not reach the strata of the Baoligaomiao formation and the Gegen Obao formation north of Erlian-Hegen Mountain. The early Permian West Lamuron suture zone was reopened until the late Permian to early Triassic finally closed. To sum up, the Paleo-Asian oceans were closed in the late Devonian, while the early Permian appeared in the new oceanic crust, which belong to different tectonic cycles.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P534.45;P542

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