| 火山岩样品的预处理及其对K-Ar年龄值的矫正 |
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| 引用本文： | 刘玉琳 金小鸿 雷永良 苗国均 黄宝玲. 火山岩样品的预处理及其对K-Ar年龄值的矫正[J]. 北京大学学报(自然科学版), 2004, 40(2): 189-192 |
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| 作者姓名： | 刘玉琳 金小鸿 雷永良 苗国均 黄宝玲 |
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| 作者单位： | 北京大学造山带与地壳演化教育部重点实验室和地质学系，北京, 100871；海南省地质综合勘探院，海口，570206 |
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| 基金项目： | 国家重点基础研究发展规划课题 (2 0 0 1CB4 0 980 7)资助项目 |
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| 摘 要： | K-Ar和Ar-Ar法是中、新生代火山岩最有效的测年方法之一，合适的粒度和有效的预处理程序对于提高年龄资料的质量至关重要。样品粒度选用60～80目粒级（0.28～0.18mm）既能保证样品的均匀性，又可以有效去除大气氩的污染。新鲜火山岩需要用稀硝酸浸泡，以去除可能的碳酸盐的影响；轻微蚀变的火山岩则须用6%氢氟酸浸泡5 min，对年龄值的矫正可达20%。用电磁选的方法可以在很大程度上剔除捕虏晶的影响，对年龄值的矫正可达5%～10%。
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| 关 键 词： | 火山岩 预处理 K-Ar定年 年龄值矫正 |
| 收稿时间： | 2003-01-20 |
Preprocessing of Volcanic Rocks and Its Influence to Age of K-Ar Dating |
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| LIU Yulin ) JIN Xiaohong ) LEI Yongliang ) MIAO Guojun ) HUANG Baoling ). Preprocessing of Volcanic Rocks and Its Influence to Age of K-Ar Dating[J]. Acta Scientiarum Naturalium Universitatis Pekinensis, 2004, 40(2): 189-192 |
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| Authors: | LIU Yulin ) JIN Xiaohong ) LEI Yongliang ) MIAO Guojun ) HUANG Baoling ) |
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| Affiliation: | The Key Laboratory of Orogenic Belts and Crustal Evolution, Department of Geology, Peking University, Beijing, 100871; Hainan Institute of the Geological Integrated Survey, Haikou, 570206 |
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| Abstract: | K-Ar and Ar-Ar dating is one of the best dating method to Mesozoic-Cenozoic volcanic rocks. Appropriate size and preprocessing procedure are important for the method to get good data. 60～80 mesh (0.28～0.18mm) sample size is needed for both the need of homogeneity of a sample and to remove atmospheric argon contamination. Thin nitric acid is used to remove out the carbonatization of fresh volcanic rocks. For slightly altered rocks, 6% hydrofluoric acid is needed to etch the rocks and the age would be change up to 20% comparing to original rocks. Magnetic separation can remove the influence of xenocrysts and its age could lower 5%～10%. |
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| Keywords: | volcanic rocks preprocessing K Ar dating age correction |
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