| 摘要: |
| 为了认识奥陶纪-志留纪之交的火山活动及事件年龄,对湖南桃源郝坪剖面的斑脱岩进行了LA-ICP-MS锆石U-Pb定年。结果表明,五峰组顶部斑脱岩LA-ICP-MS锆石U-Pb年龄为442.2±8.1Ma,该年龄反映了扬子地区奥陶纪-志留纪之交火山活动的时代,与国际地层委员会公布的奥陶系-志留系界线年龄(443.7±1.5Ma)相一致,同属晚奥陶世。奥陶纪-志留纪之交的火山活动对于探讨晚奥陶世生物绝灭、沉积环境变化与年代地层对比具有重要的意义。 |
| 关键词: 郝坪 LA-ICP-MS锆石U-Pb年龄 晚奥陶世 火山活动 生物灭绝 |
| DOI： |
| 附件 |
| 投稿时间：2012-08-30修订日期：2012-10-22 |
| 基金项目:青藏高原非常规油气调查(编号:1212011221106)、国家自然科学基金项目(编号:40972087、41072088) |
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| LA-ICP-MS zircon U-Pb dating of the bentonites from the uppermost part of the Ordovician Wufeng Formation in the Haoping section, Taoyuan, Hunan |
| XIE Shang-ke, WANG Zheng-jiang, WANG Jian, ZHUO Jie-wen |
| (Chengdu Institute of Geology and Mineral Resources, Chengdu 610081, Sichuan, China) |
| Abstract: |
| The LA-ICP-MS zircon U-Pb age of 442.2±8.1 Ma is obtained for the bentonite from the uppermost part of the Ordovician Wufeng Formation in the Haoping section, Taoyuan, Hunan. This age represents that of the volcanic activities in the Yangtze area during the Ordovician-Silurian boundary, and coincides with the age of 443.7±1.5 Ma for the Ordovician-Silurian boundary published by the International Commission on Stratigraphy. The Ordovician-Silurian volcanic activities may have important implications for the insights into the Late Ordovician biotic extinction, sedimentary environmental changes and chronostratigraphic correlation in the study area. |
| Key words: Haoping LA-ICP-MS zircon U-Pb age Late Ordovician volcanic activity biotic extinction |
