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湘东北前寒武纪仓溪岩群变凝灰岩SHRIMP锆石U-Pb年龄

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在湘东北地区浏阳市文家市仓溪岩群底部枫梓冲岩组(长英质二云母片岩)变凝灰岩中发现近百粒锆石,锆石虽然形态不相同,但CL图像显示出典型的岩浆生长振荡环带和韵律结构.该类锆石的U、Th含量较高,Th/U值变化范围为0.32~0.87,均属于岩浆结晶的产物.获得的SHRIMP锆石U-Pb年龄为855Ma+5Ma,该年龄改变了仓溪岩群枫梓冲岩组的时代,对重新厘定江南造山带的构造格局有着重要意义.
SRHIMP zircon U-Pb dating of metamorphic tuff from the Precambrian Cangxi Complex-Group in northeastern Hunan.
This paper reports a SHRIMP U-Pb age (855 Ma ± 5 Ma) of metamorphic tuff from the Fengzichong Complex-Formation. Although zircons have different forms, their CL images show typical magmatic oscillatory zoning. The zircons have relatively high content of U and Th, with Th/U ratios vary in the range of 0.32~0.87. Therefore, they are of magmatic origin. The new data change the traditional stratigraphic correlation of the Cangxi Complex-Group in northeastern Hunan. Therefore, the SHRIMP U-Pb dating of the metamorphic tuff from the Fengzichong Complex-Formation at the bottom of the Cangxi Complex-Group is of great significance in understanding of the tectonic framework of the "Jiangnan Orogenic Belt" in Hunan.

northeastern HunanPrecambrianCangxi Complex-GroupSHRIMP zircon U-Pb dating

高林志、丁孝忠、庞维华、刘燕学、陆松年、刘耀荣、陈峻、张玉海

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中国地质科学院地质研究所,北京100037

中国地质调查局天津地质矿产研究所,天津300170

湖南省地质调查院,湖南长沙410114

北京离子探针中心,北京100037

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湘东北 前寒武纪 仓溪岩群 SHRIMP锆石U-Pb年龄

中国地质调查局地调项目科技部科技基础性工作专项项目

1212010111201312011FY120100

2011

地质通报
中国地质调查局

地质通报

CSTPCDCSCD北大核心
影响因子:1.226
ISSN:1671-2552
年,卷(期):2011.30(10)
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