| 五台山蒋村地区四集庄组——对滹沱群时代的再限定 |
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| 关键词:Wutai Mountain Jiangcun Hutuo Group quartz porphyry zircon U-Pb ages |
| 基金项目:国家自然科学基金项目(编号: 41172171); 中国地质调查项目(编号: 12120114021501); 全国地层委员会项目(编号: 1212011120142)和国家留学基金(编号: 201409110015) |
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| The Sijizhuang Formation at Jiangcun Area of Wutai Mountains: Further Constraints on the Age of the Hutuo Group |
| The Hutuo Group is one of the classic Paleoproterozoic strata in North China, and its age is important for building the stratigraphy framework and investigating the early Precambrian evolution process in the North China Craton. In this paper, we probed into the stratigraphy of Hutuo Group at Jiangcun, Wutai Mountains area, and obtained the zircon U-Pb ages of (2166±17) Ma and (2138±17) Ma from two quartz porphyries, which are identical with the ages of quartz porphyry pebbles in conglomerates of the Hutuo Group. Therefore, we infer that the clastic rocks in Jiangcun were deposited after 2138 Ma. Considering the distribution of a large amount of conglomerates at the base of Sijizhuang Formation and the existence of 2.2~2.1 Ga magmatism in Wutai Mountains area, we further deduce that the initial deposition of Hutuo Group took place at ca. 2.2 Ga. In combination with the fact that Doucun and Dongye Subgroups underwent the similar deformation, and undeformed syenogranite vein of 1816±18Ma intruded into the Sijizhuang Formation, we hold that the deposition age of Doucun and Dongye Subgroup should be 2.2~1.82 Ga. A sample of quartz porphyry yielded the zircon 176Lu/177Hf of 0.000717~0.002239 and 176Hf/177Hf of 0.281399~0.281563. Based on the large variation of 176Hf/177Hfi and εHf(t) in zircons, we propose that the quartz porphyry mainly originated from the upper crust with the addition of the depleted mantle. |
| DU Li-lin,YANG Chong-hui,LU Zeng-long,ZHAO Lei,GENG Yuan-sheng,CAO Guang-yue,DIWU Chun-rong,GUO Chun-li,HOU Ke-jun.2015.The Sijizhuang Formation at Jiangcun Area of Wutai Mountains: Further Constraints on the Age of the Hutuo Group[J].Acta Geoscientica Sinica,36(5):599-612. |
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