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| 松潘地块与西秦岭造山带下地壳的性质和关系——深地震反射剖面的揭露 |
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高锐,马永生,李秋生,朱铉,张季生,王海燕,李鹏武,卢占武,管烨
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[1]中国地质科学院地质研究所岩石圈研究中心,北京100037 [2]中国地质大学,北京100083 [3]中石化股份有限公司南方勘探开发分公司,云南昆明650021
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| 摘要: |
| 松潘地块位于青藏高原的东缘，处于中国大陆东西向构造与南北向构造的结合部位，特殊的构造环境使其长期控制并影响着中国大陆的形成与演化。探测松潘地块的岩石圈细结构，揭示其与东昆仑-西秦岭造山带的关系，既可为研究青藏高原东北缘板块碰撞的深部过程奠定基础，同时又关联着松潘地块的油气远景评价。2004年完成了第一条横过松潘地块北缘若尔盖盆地和西秦岭造山带的长约257km的深地震反射剖面，首次揭露出若尔盖盆地和西秦岭造山带岩石圈的细结构。发现若尔盖盆地和西秦岭造山带同属统一的稳定的大陆地块，并且下地壳均以北倾的强反射为主要特征。这种北倾的反射为松潘地块向西秦岭下地壳俯冲提供了地震学证据。近于平坦的Moho反射特征反映出西秦岭造山带在造山后又经历了强烈的伸展作用。 |
| 关键词: 青藏高原 松潘地块 西秦岭造山带 基底构造 深地震反射剖面 |
| DOI： |
| 分类号:P542.4 P631.425 |
| 基金项目:国家自然科学基金重点项目（编号：40334035）、教育部重点实验室开发项目（批准号：GDL0501）资助.致谢：中石化公司原副总裁牟书令先生、油田部副主任钱基先生、刘光鼎院士、张国伟院士、南方分公司原总经理杨方之先生等对本项目的实施给予了大力支持,北京派特森科技发展有限公司薛爱民先生对数据特殊处理做出了重要贡献,在此一并表示感谢. |
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| Structure of the lower crust beneath the Songpan block and West Qinling orogen and their relation as revealed by deep seismic reflection profiling |
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GAO Rui MA Yong-sheng LI Qiu-sheng ZHU Xuan ZHANG Ji-sheng WANG Hai-yan LI Peng-wu LU Zhan-wu GUAN Ye
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| Abstract: |
| Lying at the northeastern Qinghai-Tibet Plateau, the Songpan block is tectonically located at the junction between the E-W- and N-S-trending tectonics of continental China. The Songpan block has long controlled and affected the formation and evolution of continental China owing to its special tectonic environment. Understanding the fine structure of the lithosphere beneath the Songpan block and revealing its relation to the East Kunlun-West Qinling orogen not only laid a foundation for studying the deep processes of plate collision at the northeastern margin of the Qinghai-Tibet Plateau but also are concerned with petroleum prospect evaluation in the Songpan block. A -257-km-long, deep seismic reflection profile across the Zoige basin on the northern margin of the Songpan block and the West Qinling orogen were for the first time surveyed in 2004. The profile has revealed the fine lithospheric structure of the Songpan block and the West Qinling orogen and found that both the Songpan block and the West Qinling orogen belong to the same stable continental block, and that their lower crusts are both characterized by north-dipping strong reflection. The north-dipping reflection constitutes seismic evidence for the northward subduction of the lower crusts of the Songpan block and West Qinling orogen. The nearly level Moho reflections of the Zoige basin and the West Qinling orogen show that they underwent intense extension after coUisional orogeny. |
| Key words: Qinghai-Tibet Plateau Songpan block West Qinling orogen deep seismic reflection profile basement structure |