| U-Pb Zircon Dating of the Granitic Conglomerates of the Hutuo Group： Affinities to the Wutai Granitoids and Significance to the Tectonic Evolution of the Trans-North China Orogen |
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| 作者姓名： | Jian ZHANG Guochun ZHAO LI Sanzhong Min SUN LIU Shuwen Xiaoping XIA and Yanhong HE |
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| 作者单位： | Jian ZHANG1，Guochun ZHAO1，LI Sanzhong2，Min SUN1，LIU Shuwen3，Xiaoping XIA1 and Yanhong HE1 1 Department of Earth Sciences，The University of Hong Kong，Pokfulam Road，Hong Kong 2 College of Marine Geosciences，Ocean University of China，Qingdao，Shandong 266003 |
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| 摘 要： | 1 Introduction The North China Craton (NCC) is considered to be the oldest and largest cratonic block in China. Recent studies to gain understanding of basement architecture of the NCC has led to its division into the Western and Eastern Blocks, separated by a N-S trending Paleoproterozoic Trans-North China Orogen (TNCO) (Fig. 1; Zhao et al., 1998, 1999a, 2000a, 2001a; Wilde et al., 2002). Although there is now abroad consensus that the final assembly of the NCC was completed by th…
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| 关 键 词： | 地质年代学 锆石 花岗岩 聚结 岩石层位学 前寒武纪 |
| 收稿时间： | 5/9/2006 12:00:00 AM |
| 修稿时间： | 2006-08-21 |
U-Pb Zircon Dating of the Granitic Conglomerates of the Hutuo Group:Affinities to the Wutai Granitoids and Significance to the Tectonic Evolution of the Trans-North China Orogen |
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| Authors: | Jian ZHANG Guochun ZHAO LI Sanzhong Min SUN LIU Shuwen Xiaoping XIA and Yanhong HE |
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| Institution: | Jian ZHANG,Guochun ZHAO,LI Sanzhong,Min SUN,LIU Shuwen,Xiaoping XIA and Yanhong HE Department of Earth Sciences,The University of Hong Kong,Pokfulam Roa,Hong Kong College of Marine Geosciences,Ocean University of Chin,Qingdao,Shandong |
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| Abstract: | Abstract: The Wutai Complex associated with the adjacent Fuping and Hengshan Complexes represents the best and classical cross‐section in the middle segment of the Trans‐North China Orogen, generally divided into Eastern and Western Blocks. Unconformably overlying the Wutai and Fuping Complexes is the Hutuo Group considered as the youngest lithostratigraphic unit in the region and important both for interpreting Precambrian history as well as the overall evolution of the Trans‐North China Orogen. Lack of knowledge about provenance of the sedimentary rocks in this group has hindered understanding of the depositional environments and tectonic significance. LA‐ICP‐MS was applied to obtain U‐Pb zircon ages for the granitic pebbles, the lowest lithostratigraphic rock of the Hutuo Group, which, combined with previous lithostratigraphic, geochronological, structural and metamorphic data, provides new constraints on the sedimentary provenance and tectonic evolution of the region. The sequence of the Hutuo Group ranges upward from lower basal conglomerates and volcaniclastic rocks (Doucun Subgroup), through clastic sediments, slates, dolomites and marbles (Dongye Subgroup), to sandstones and conglomerates at the top (Guojiazhai Subgroup). Zircons from granitic pebbles preserved in the Doucun Subgroup basal conglomerates give weighted mean 207Pb/206Pb ages between 2517 Ma and 2566 Ma, which are the same as those for the late Archean Wutai Granitoids, indicating that the pebbles were derived from the Wutai granitic intrusions (2566‐2515 Ma). Based on the new data and previous studies, combined with an igneous zircon crystallization age of 2087±9 Ma obtained for volcanics in the Hutuo Group, the Hutuo Group was deposited in a subduction‐related retro‐arc foreland basin environment that developed behind the Wutai arc during the eastward‐directed subduction of the Western Block beneath the western margin of the Eastern Block. This basin underwent long‐lived sedimentation and finally closed during the ～1850 Ma collisional event that resulted in the final amalgamation of the North China Craton. |
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| Keywords: | Trans-North China Orogen Paleoproterozoic Wutai Complex Hutuo Group conglomerates |
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