| 攀西构造带南部地壳与上地幔结构的爆炸地震研究 |
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| 引用本文： | 熊绍柏,滕吉文,尹周勋,赖明惠,黄一平.攀西构造带南部地壳与上地幔结构的爆炸地震研究[J].地球物理学报,1986,29(3):235. |
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| 作者姓名： | 熊绍柏 滕吉文 尹周勋 赖明惠 黄一平 |
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| 作者单位： | 中国科学院地球物理研究所 |
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| 摘 要： | 根据1984年攀西地区南部爆炸地震折射剖面资料的研究结果表明,本区的地壳厚度约为55km,且可分为20km、20km和15km厚的三个主要构造层。地壳的平均P波速度为6.22km/s。在深度23-27km之下的中地壳下部有一个厚9-14km的P波低速区,这一结果与其它地球物理观测资料相当吻合。上地幔顶部的P波速度为7.62-7.90km/s,与现代大陆裂谷区或构造活动地区的P_n波速度一致。另外,位于构造带轴部地区的渡口市一带,上地壳中有一高速岩体,下地壳中有高速夹层以及有些断裂带可能延伸到上地幔顶部,均表明地壳中曾经有地幔物质侵入。通过研究,我们推断这个地区有可能是一个被后期构造运动强烈改造过的、至今仍保留有一些裂谷构造残迹的古裂谷带。
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| 关 键 词： | 爆炸地震 构造带 地壳与上地幔 记录剖面 震相 P波速度 反射界面 测线 上地壳 渡口 |
| 收稿时间： | 1985-10-07 |
EXPLOSION SEISMOLOGICAL STUDY OF THE STRUCTURE OF THE CRUST AND UPPER MANTLE AT SOUTHERN PART OF THE PANXI TECTONIC BELT |
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| XIONG SIIAO-BAI,TENG JI-WBN,YIN ZIIOU-XUN,LAI MING-HUI,HUANG YI-PING.EXPLOSION SEISMOLOGICAL STUDY OF THE STRUCTURE OF THE CRUST AND UPPER MANTLE AT SOUTHERN PART OF THE PANXI TECTONIC BELT[J].Chinese Journal of Geophysics,1986,29(3):235. |
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| Authors: | XIONG SIIAO-BAI TENG JI-WBN YIN ZIIOU-XUN LAI MING-HUI HUANG YI-PING |
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| Affiliation: | Institute of Geophysics, Academia Sinica |
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| Abstract: | The Institute of Geophysics, Academia Sinica conducted some experiments of seismic refraction profiling crossing the Panzhihua region in 1984. The Panzhihua region is located at the southern part of the Panxi tectonic belt. We have analyzed six record sections for the W-E profile which extends 350 km. The results are as follows: （1） The crust of the Panxi region can be divided into three main layers Avith thicknesses of about 20, 20, and 15km respectively. （2） The thickness and the average velocity of the whole crust is 55km and 6.22 km/s respectively. （3） There is a high-velocity rock body near the surface of the axial area of the tectonic belt, and it is probably related to the enrichment of the Panzhihua type sefstr（?）mite in this district. （4） There is a low-velocity zone with a thickness of about 9-14 km a,t the lower part of the midcrust. The top of this low-velocity zone is located at about 23-27 km deep from the surface. The consistence of this result with the distribution of earthquake foci and the depth of Curie isotherm indicates that the existence of the low-velocity zone maybe related to the thermal state of the crust medium. （5） There are several faults which reach into the upper mantle and a high-velocity interlayer at the top of the lower crust. These may signify intrusion of the mantle substance into the crust. （6） A velocity VPn of 7.62-7.90 km/s at the uppermost mantle is consistent with that of recent continental rifting zone. After comparison with other regions in the world, we infer that the Panxi region is perhaps a paleorift zone, but it was strongly transformed by later period's tec-togenesis. |
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