| 华北吕梁地区汉高山群和小两岭组的地层时代——火山岩锆石U-Pb年龄的约束 |
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| 引用本文： | 王彦斌,宋彪,王浩,焦永艳,任留东,杨崇辉,何碧竹,彭阳,姚宇凯.华北吕梁地区汉高山群和小两岭组的地层时代——火山岩锆石U-Pb年龄的约束[J].岩石矿物学杂志,2022,41(2):195-213. |
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| 作者姓名： | 王彦斌 宋彪 王浩 焦永艳 任留东 杨崇辉 何碧竹 彭阳 姚宇凯 |
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| 作者单位： | 1. 中国地质科学院地质研究所北京离子探针中心;2. 中国地质科学院地质研究所;3. 山西省地质调查院 |
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| 基金项目： | 国家自然科学基金项目(40773042,41073014,41373052,41773049)；;中国地质调查局资助项目(DD20190448,DD20190370)~~； |
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| 摘 要： | 华北吕梁地区出露的以陆源碎屑沉积为主的汉高山群为中元古界底界界线层型的理想候选剖面,其时代的确定对认识华北前寒武纪地质演化历史及初始盖层的确定及Nuna超大陆聚散的研究具有重要的意义.目前,汉高山群的时代、划分对比及其意义还存在较大争议.本研究使用SHRIMP(二次离子质谱仪)对汉高山群安山岩中的锆石进行了 U-Pb同...
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| 关 键 词： | 汉高山群 小两岭组 火山岩 SHRIMP 锆石U-Pb年龄 中元古界底界 |
| 收稿时间： | 2021/9/8 0:00:00 |
| 修稿时间： | 2021/11/30 0:00:00 |
Timing of the Hangaoshan Group and Xiaoliangling Formation in the Lüliang area,North China:Constraints from zircon U-Pb ages of volcanic rocks |
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| WANG Yan-bin,SONG Biao,WANG Hao,JIAO Yong-yan,REN Liu-dong,YANG Chong-hui,HE Bi-zhu,PENG Yang,YAO Yu-kai.Timing of the Hangaoshan Group and Xiaoliangling Formation in the Lüliang area,North China:Constraints from zircon U-Pb ages of volcanic rocks[J].Acta Petrologica Et Mineralogica,2022,41(2):195-213. |
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| Authors: | WANG Yan-bin SONG Biao WANG Hao JIAO Yong-yan REN Liu-dong YANG Chong-hui HE Bi-zhu PENG Yang YAO Yu-kai |
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| Institution: | Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China; Shanxi Institute of Geological Survey, Taiyuan 030006, China |
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| Abstract: | Exposed in the Lüliang area, North China, the Hangaoshan Group is dominated by terrigenous clastic deposits and bear an ideal candidate section for the stratotype of the lower Mesoproterozoic or upper Paleoproterozoic sequence, especially for the boundary between them. The determination of formation age is of great significance for understanding the Precambrian geological evolution of the North China Craton, such as emergence of the initial cover sequence of the craton, assembling and breakup of the Nuna supercontinent. To date, there are still great contro- versies on the age, subdivision, correlation and geological implication of the Hangaoshan Group. In this study, zircon U-Pb isotopes of the andesites from the Hangaoshan Group have been analyzed with SHRIMP technique, giving a weighted mean 207Pb/206Pb age of 1 769±9 Ma ( 2σ) . This is the first direct measurement of the zircon U-Pb age of the Hangaoshan Group. In addition, weighted mean 207Pb/206Pb zircon ages of the volcanic rocks in three different parts of the Xiaoliangling Formation of the same stratohorizon are 1 792±18 Ma, 1 773±19 Ma and 1 778±20 Ma, respectively, which are consistent with the age of Hangaoshan Group within the error range. Therefore, the ages of the Hangaoshan Group and Xiaoliangling Formation are determined at 1 769±9 Ma and 1 792 ~ 1 773 Ma, respectively. In combination with previous research results, formation time of the Hangaoshan Group and Xiaoliangling Formation is ca. 1 780 Ma. As regards sedimentology, the section strata of the Hangaoshan Group in Lüliang Mts area are continuous, and a horizon of andesite is stably and widly distributed in the region. So the horizon is an excellent regional isochronous marker in the central and southern part of the North China Craton. Furthermore, rift deposits and volca- nic rocks in this period occur in the western Yangtze Block, the northwestern Laurentia, northern Australia, the São Francisco, Congo and Siberian cratons, and all can be well correlated, showing the global distribution of intracontinental rift sediments during initial breakup of Nuna supercontinent in the same period. We propose here that the international Mesoproterozoic bottom boundary should be moved down, from 1.6 Ga to 1.8 Ga, and the Hangaoshan section can be used as a new candidate stratigraphic type section of the international Mesoproterozoic bottom boundary. |
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| Keywords: | Hangaoshan Group Xiaoliangling Formation volcanic rocks SHRIMP zircon U-Pb age bottom boundary of the Mesoproterozoic |
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