| 湖北宜昌地区第四纪沉积物中锆石的U-Pb年龄特征及其物源意义 |
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| 引用本文： | 向芳,杨栋,田馨,李志宏,罗来. 湖北宜昌地区第四纪沉积物中锆石的U-Pb年龄特征及其物源意义[J]. 矿物岩石, 2011, 31(2) |
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| 作者姓名： | 向芳 杨栋 田馨 李志宏 罗来 |
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| 作者单位： | 1. 成都理工大学沉积地质研究院,四川成都,610059
2. 西安国林资源环境信息工程有限公司,陕西西安,710075 |
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| 基金项目： | 国家自然科学基金(41072083,40602011) |
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| 摘 要： | 对于长江三峡的贯通近年来基本认为是第四纪以来的事件,但在具体贯通时间的认识上仍存在差异。紧邻三峡出口、具有第四纪以来完整地层和较好出露层位的江汉盆地西缘宜昌地区的第四纪沉积物沉积特征及测年资料显示,该地区的云池组为冲积扇—扇三角洲相沉积,善溪窑组下部为扇三角洲沉积,上部为湖相沉积。对云池组、善溪窑组、长江5级和4级阶地的015,024,YC02,00B剖面等4个典型剖面砾石层中砂质填隙物的锆石进行矿物学研究和LA-ICP-MS U-Pb年龄测定,发现015,024剖面中锆石主要来源于三峡以东的黄陵穹窿、武当地块,少量来自鄂陕边境的庙川地区和湘鄂交接的华容地区,均为三峡以东的物质来源。而长江第5,4级阶地沉积物中的锆石不仅存在上述三峡以东物源区的物质,同时出现三峡以西米仓山—大巴山地区、龙门山—攀枝花地区,以及川西巴塘—德格地区岩浆岩物源的物质,也具有来自峨眉山玄武岩的特征岩浆锆石的存在,从而证实了以015,024剖面为代表的沉积并非前人认为的长江阶地产物,同时也表明三峡的贯通应在024剖面沉积结束以后,YC02剖面沉积以前,即长江三峡贯通的时间应该在0.75 Ma以后。
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| 关 键 词： | 宜昌地区 锆石LA-ICP-MSU-Pb测年 物源分析 长江三峡贯通时间 |
LA-ICP-MS U-Pb GEOCHRONOLOGY OF ZIRCONS IN THE QUATERNARY SEDIMENTS FROM THE YICHANG AREA OF HUBEI PROVINCE AND ITS PROVENANCE SIGNIFICANCE |
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| XIANG Fang,YANG Dong,TIAN Xin,LI Zhi-hong,LU Lai. LA-ICP-MS U-Pb GEOCHRONOLOGY OF ZIRCONS IN THE QUATERNARY SEDIMENTS FROM THE YICHANG AREA OF HUBEI PROVINCE AND ITS PROVENANCE SIGNIFICANCE[J]. Journal of Mineralogy and Petrology, 2011, 31(2) |
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| Authors: | XIANG Fang YANG Dong TIAN Xin LI Zhi-hong LU Lai |
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| Abstract: | The cutting through of the Three Gorges of Yangtze River recently was considered as an event occurred in Quaternary Period,but there still has some diversity in the concrete time of cutting through.Therefore,the Jianghan Basin which is close to the outlet of the Three Gorges is selected as the research target and the entire Quaternary strata and preferable outcrop are thoroughly studied for this purpose.Detailed research of the sedimentary characters of Quaternary deposits,combing with the ESR dating data,f... |
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| Keywords: | Yichang area LA-ICP-MS U-Pb dating of zircons provenance analysis cutting through time of the Yangtze Three Gorges |
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