| 西藏谢通门县查布地区中新世火山岩LA-ICP-MS锆石U-Pb年龄及其地质意义 |
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| 引用本文： | 张鹏,姚胜,李泳龙,魏铭,滕霏.西藏谢通门县查布地区中新世火山岩LA-ICP-MS锆石U-Pb年龄及其地质意义[J].地质通报,2019,38(5):767-776. |
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| 作者姓名： | 张鹏 姚胜 李泳龙 魏铭 滕霏 |
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| 作者单位： | 陕西区域地质矿产研究院, 陕西 咸阳 712000;西藏地勘局第二地质大队, 西藏 拉萨 850000,陕西区域地质矿产研究院, 陕西 咸阳 712000;西藏地勘局第二地质大队, 西藏 拉萨 850000,西藏地勘局第二地质大队, 西藏 拉萨 850000,西藏地勘局第二地质大队, 西藏 拉萨 850000,陕西区域地质矿产研究院, 陕西 咸阳 712000 |
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| 基金项目： | 中国地质调查局项目《冈底斯-喜马拉雅铜矿资源基地调查》（编号：DD20160015） |
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| 摘 要： | 西藏地勘局地质二队在谢通门县查布地区1∶5万区域地质调查中新解体出一套火山岩地层,其岩性以安山岩、流纹岩、火山角砾岩及凝灰岩为主,岩层总厚度在研究区由东向西减小。用LA-ICP-MS技术对流纹岩、安山岩2件样品中的锆石进行U-Pb同位素测定,其~(206)Pb/~(238)U年龄加权平均值分别为:流纹岩中有2组年龄15.12±0.29Ma(MSWD=1.8,n=8)、45.39±0.56Ma(MSWD=0.93,n=14),安山岩中有4组年龄15.29±0.16Ma(MSWD=1.4,n=59)、51.9±2.3Ma(MSWD=3.5,n=7)、45.2±1.4Ma(MSWD=3.8,n=10)、38.5±0.93Ma(MSWD=1.08,n=5)。据此将该套火山岩喷发时限确定为15Ma左右,划归于布嘎寺组。
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| 关 键 词： | 中新世 火山岩 冈底斯带 LA-ICP-MS锆石U-Pb年龄 |
| 收稿时间： | 2018/7/1 0:00:00 |
| 修稿时间： | 2018/9/3 0:00:00 |
LA-ICP-MS zircon U-Pb age of the volcanic rocks in Chubb area, Xietongmen County, Tibet, and its geological implications |
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| ZHANG Peng,YAO Sheng,LI Yonglong,WEI Ming and TENG Fei.LA-ICP-MS zircon U-Pb age of the volcanic rocks in Chubb area, Xietongmen County, Tibet, and its geological implications[J].Geologcal Bulletin OF China,2019,38(5):767-776. |
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| Authors: | ZHANG Peng YAO Sheng LI Yonglong WEI Ming and TENG Fei |
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| Institution: | Academy of Regional Geological Survey and Mineral Resources Exploration of Shaanxi, Xianyang 712000, Shaanxi, China;No.2 Geological Party, Tibet Bureau of Geology and Exploration, Lhasa 850000, Tibet, China,Academy of Regional Geological Survey and Mineral Resources Exploration of Shaanxi, Xianyang 712000, Shaanxi, China;No.2 Geological Party, Tibet Bureau of Geology and Exploration, Lhasa 850000, Tibet, China,No.2 Geological Party, Tibet Bureau of Geology and Exploration, Lhasa 850000, Tibet, China,No.2 Geological Party, Tibet Bureau of Geology and Exploration, Lhasa 850000, Tibet, China and Academy of Regional Geological Survey and Mineral Resources Exploration of Shaanxi, Xianyang 712000, Shaanxi, China |
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| Abstract: | The No.2 Geobrigade of Tibet Geological Prospecting Bureau has disintegrated a set of volcanic rocks in the 1:50 thousand regional geological survey of the chubb area of Xietongmen county. It composed dominantly of andesite, rhyolite, volcanic breccia and tuff. The total thickness of the rock strata decreases from east to west in the study area. The U-Pb isotopes of zircons from rhyolite and andesite samples were determined by LA-ICP-MS. The weighted average ages of 206Pb/238U were 15.12±0.29Ma (MSWD=1.8, n=8), 45.39 ±0.56Ma (MSWD=0.93, n=14) in rhyolite and 15.29 ±0.16Ma (MSWD=1.4, n=59), 51.9 ±2.3Ma (MSWD=3.5, n=7), 45.2±1.4Ma (MSWD=3.8, n=10), 38.5±0.93Ma (MSWD=1.08, n=5) in andesite. Based on this, the eruption time limit of this suite of volcanic rocks is determined to be 15Ma or so, and it belongs to the Bugasi Group. |
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| Keywords: | Miocene volcanic rocks Gangdese belt LA-ICP-MS zircon U-Pb age |
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