| 腾冲火山活动的时代和岩浆来源问题 |
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| 引用本文： | 穆治国,佟伟,Garniss H.Curtis.腾冲火山活动的时代和岩浆来源问题[J].地球物理学报,1987,30(3):261-270. |
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| 作者姓名： | 穆治国 佟伟 Garniss H.Curtis |
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| 作者单位： | 1. 北京大学地质学系;
2. 美国伯克利加州大学地质学和地球物理学系 |
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| 摘 要： | 47个腾冲火山岩样品的K-Ar年龄值域在0.09和17.84Ma之间。4条火山岩的40Ar/36Ar-40K/36Ar等时线年龄分别为2.93、0.81、0.31和0.13Ma。火山喷发的时代从中新世到更新世,喷发的高潮在晚更新世。腾冲火山目前还不是死火山,而腾冲及其邻区的热事件（侵入-热变质-喷发）又是连续发生的。20个样品的Rb和Sr含量、稳定Sr同位素初始比（0.70578-0.71437）以及其它地球化学资料还表明,这些火山岩是属于板块碰撞带生成的高钾钙碱性岩浆系列。火山岩的母岩浆来源于地幔的玄武岩浆,但在上升过程中受到过富含放射性成因Sr的地壳物质的强烈渐进混染。
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| 关 键 词： | 腾冲 火山活动时代 稀释法K-Ar年龄 等时线年龄 岩浆来源 |
| 收稿时间： | 1985-09-28 |
TIMES OF VOLCANIC ACTIVITY AND ORIGIN OF MAGMA IN TENGCHONG GEOTHERMAL AREA,WEST YUNNAN PROVINCE |
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| MU ZHI-GUO TONG WEI.TIMES OF VOLCANIC ACTIVITY AND ORIGIN OF MAGMA IN TENGCHONG GEOTHERMAL AREA,WEST YUNNAN PROVINCE[J].Chinese Journal of Geophysics,1987,30(3):261-270. |
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| Authors: | MU ZHI-GUO TONG WEI |
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| Institution: | 1. Department of Geology, Peking University, Beijing, China;
2. Department of Geology & Geophysics, University of California, Berkeley, CA 94720, U. S. A. |
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| Abstract: | Dating of forty-seven samples of the Tengchong volcanic rocks gave K-Ar ages range-from about 0.09 Ma to 17.84 Ma. On the basis of 40Ar/36Ar-40K/36Ar plot 4 isochron ages were obtained as following 2.93 Ma, 0.81 Ma, 0.31 Ma and 0.13 Ma. The eruption time of volcanoes was from the Miocene to Pleistocene with the climax occurring in the late Pleistocene. The Tengchong volcanoes could not be thought to be extinguished but dormant ones only. Perhaps, the magma-geothermal events (intrusive-metamorphic-eruptive) in Tengchong and vicinity occurred consecutively. The contents of Rb and Sr, the initial 87Sr/86Sr ratios (0.70578-0.71437) and other geochemical data of 20 samples suggest that these volcanic rocks belong to the high-K calc-alkaline series of magma formed in the collision zone. The magma may originate from mantle as a basalt diapir, but the magma might have been contaminated by crustal material rich in more radiogenic Sr strongly and progressively during its rising. |
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| Keywords: | Tengchong Times of volcanic activity Conventional delation K-Ar ages Origin of magma |
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