Evolution and time of formation of the Hohhot metamorphic core complex, North China new structural and geochronologic evidence | |
Guo, L (Guo, Lei); Wang, T (Wang, Tao); Zhang, JJ (Zhang, Jinjiang); Liu, J (Liu, Jiang); Qi, GW (Qi, Guowei); Li, JB (Li, Jianbo) | |
刊名 | INTERNATIONAL GEOLOGY REVIEW |
2012 | |
卷号 | 54期号:11页码:1309-1331 |
关键词 | late Mesozoic extension deformation temperature pre- and post-kinematic plutons U-Pb zircon dating North China craton |
ISSN号 | 0020-6814 |
英文摘要 | The Hohhot metamorphic core complex (MCC) is one of the typical MCCs in the North China craton. Its fault systems consist of the master Hohhot detachment zone (HHDZ) on the southern flank of the Daqing Shan, and the lowermost and uppermost northern detachment zones on the northern flank. Ductile deformation temperatures of three zones were estimated as 500 +/- 50 degrees C, 650 +/- 50 degrees C, and 400 +/- 50 degrees C, respectively, by analysis of microstructures of minerals and quartz [c] crystallographic axis fabrics using electron backscattered diffraction. These measurements suggest that previous Ar-40/Ar-39 ages could not represent the time of the high-temperature (>500 degrees C) ductile deformations. Therefore, we used U-Pb zircon ages of mylonitized and non-mylonitized granitic intrusions to constrain the timing of the early high-temperature shearing. Strongly mylonitized granites and weakly mylonitized granites in the lowermost northern detachment zone yielded zircon U-Pb ages of 148 +/- 1 and 140 +/- 1 million years respectively. A syn-kinematic pluton in the lower plate of the MCC gave a U-Pb age of 142 +/- 1 million years. These allow us to speculate on the possibility that SE-directed, early tangential, high-temperature ductile shearing probably was initiated during ca. 148-140 Ma (or ca. 142 Ma) at depth, with the thrust events occurring at shallow levels. A strongly mylonitized granitic dike and a non-mylonitized pluton in the master HHDZ yielded ages of 142 +/- 1 and 132 +/- 2 million years respectively. A non-mylonitized pluton intrusive into the uppermost northern detachment zone was dated at 131 +/- 1 Ma. All these suggest that major extensional ductile shearing along the detachment zones took place during ca. 140-132 Ma. Using these new U-Pb ages, combined with previously published Ar-40/Ar-39 cooling ages that range from 127 Ma to 119 million years for the master HHDZ and supradetachment basins, we discuss and derive the time of formation process of the MCC. This is one of only a few cases of detailed study of timing for the development of an MCC from earlier deep-level shearing to later thermal uplifting (doming). |
学科主题 | 变质岩岩石学 |
WOS关键词 | MESOZOIC EXTENSIONAL TECTONICS ; INNER-MONGOLIA ; CONTINENTAL EXTENSION ; DAQINGSHAN THRUST ; EASTERN CHINA ; DIFFUSION ; PROVINCE ; AGE ; DEFORMATION ; TEMPERATURE |
WOS研究方向 | Geology |
语种 | 英语 |
出版者 | TAYLOR & FRANCIS INC |
WOS记录号 | WOS:000306119300006 |
内容类型 | 期刊论文 |
源URL | [http://119.78.100.197/handle/2HKVOGP0/39623] |
专题 | 中国地质调查局 |
作者单位 | E China Inst Technol, Fuzhou 344000, Jiangxi, Peoples R China |
推荐引用方式 GB/T 7714 | Guo, L ,Wang, T ,Zhang, JJ ,et al. Evolution and time of formation of the Hohhot metamorphic core complex, North China new structural and geochronologic evidence[J]. INTERNATIONAL GEOLOGY REVIEW,2012,54(11):1309-1331. |
APA | Guo, L ,Wang, T ,Zhang, JJ ,Liu, J ,Qi, GW ,&Li, JB .(2012).Evolution and time of formation of the Hohhot metamorphic core complex, North China new structural and geochronologic evidence.INTERNATIONAL GEOLOGY REVIEW,54(11),1309-1331. |
MLA | Guo, L ,et al."Evolution and time of formation of the Hohhot metamorphic core complex, North China new structural and geochronologic evidence".INTERNATIONAL GEOLOGY REVIEW 54.11(2012):1309-1331. |
个性服务 |
查看访问统计 |
相关权益政策 |
暂无数据 |
收藏/分享 |
除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。
修改评论