| 赵亮亮.赣东北地区双桥山群碎屑锆石U-Pb年代学研究[J].地质与勘探,2021,57(3):529-543 |
| 赣东北地区双桥山群碎屑锆石U-Pb年代学研究 |
| Detrital zircon U-Pb dating of the Shuangqiaoshan Group in northeast Jiangxi Province |
| 投稿时间：2020-05-29 修订日期：2020-11-20 |
| DOI：10.12134/j.dzykt.2021.03.006 |
| 中文关键词: 物源 双桥山群 碎屑锆石年龄 赣东北地区 |
| 英文关键词: provenance, Shangqiaoshan Group, detrital zircon dating, northeast Jiangxi Province |
| 基金项目:国家自然科学基金（编号：41602216）和中国地质调查项目（编号：12120114017201）联合资助 |
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| 中文摘要: |
| 双桥山群是赣东北地区重要的岩石单元之一，其年代学研究一直备受关注。本文对赣东北地区双桥山群凝灰质板岩和粉砂质板岩中的碎屑锆石进行了LA-ICP-MS U-Pb测年分析。碎屑锆石年代学测试结果显示4个主要年龄区间：591~634 Ma（峰值601 Ma）、803~837 Ma（峰值831 Ma）、866~1019 Ma（峰值910 Ma）和＞1800 Ma。其中最年轻的碎屑锆石年龄组591~634 Ma峰期601 Ma的年龄，可能限定了双桥山群最大的沉积年龄；而803~837 Ma（峰值831 Ma）指示其物源可能源于江南造山带东段新元古代造山过程的岛弧火山岩；866~1019 Ma峰期年龄为910 Ma的年龄与皖南-赣东北地区的基性火山岩、火山碎屑岩的形成时代基本一致；＞1800 Ma的年龄组与扬子陆块1.8~1.9 Ga锆石年龄相一致。赣东北地区双桥山群碎屑锆石U-Pb测年结果中，出现828 Ma和1800 Ma的碎屑锆石特征年龄峰值，显示它们具有与扬子地块的亲缘性，同时又含有大量的～1.0 Ga碎屑锆石，这些特征年龄相似于格林威尔期的华夏地块，说明在新元古代晚期存在的沉积盆地具有来自扬子和华夏板块的双向物源。 |
| 英文摘要: |
| The Shuangqiaoshan Group is one of the important rock units in northeastern Jiangxi, and its chronological research has long received much attention. This study presents new zircon LA-ICP-MS U-Pb dating data of the tuffaceous slate and silty slate from this unit. LA-ICP-MS U-Pb dating shows four age populations: 591~634Ma with peak age at 601 Ma, 803~837 Ma with the peak age at 831Ma, 866~1019Ma with the peak age at 910Ma and ＞1800 Ma. The youngest age population of the 591~634Ma with peak age at 601Ma may limit the largest deposition age of the Shuangqiaoshan Group. The age population of the 803~837Ma with peak age at 831 Ma indicates that it was originated from the arc volcanic rocks caused by the multi arc collage and the subduction-accretion in the eastern Jiangnan Orogen during the Neoproterozoic..The age population of the 866~1019Ma with peak age at 910 Ma is comparable with those zircons in the Neoproterozoic basic volcanic rocks and volcanic clastic rocks in south Anhui Province and northeast Jiangxi Province. The age population ＞1800Ma is consistent with 1.8~1.9Ga zircons in the Yangtze Block. U-Pb dating results of detrital zircons from two meta-sedimentary rocks of Shuangqiaoshan Group, which indicate that the meta-sedimentary rock in the northeast Jiangxi Province, have 828 and 1800Ma peak ages, suggesting its affinity with the Yangtze Block, also containing abundant ~1.0Ga detrital zircons. These age features are similar to the Cathaysia Block with abundant Grenville clastic materials, implying that the sedimentary basin in the late Neoproterozoic time had provenances in the Yangtze Block and Cathaysia Block. |
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