| 青藏高原渐新世晚期隆升的地质证据 |
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| 引用本文： | 吴珍汉,吴中海,胡道功,叶培盛,周春景.青藏高原渐新世晚期隆升的地质证据[J].地质学报,2007,81(5):577-587. |
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| 作者姓名： | 吴珍汉 吴中海 胡道功 叶培盛 周春景 |
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| 作者单位： | 中国地质科学院地质力学研究所,北京,100081 |
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| 基金项目： | 中国地质调查局青藏高原综合研究与INDEPTH-IV项目，科技部国际合作项目(编号2001CB711001)资助的成果 |
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| 摘 要： | 国内外学者普遍认为,地壳缩短增厚是青藏高原隆升的主要原因,青藏高原隆升对环境变迁和东亚季风具有重要影响,但对青藏高原隆升时代存在不同认识。通过统计分析青藏高原中段新生代不同时期的地层倾角,表明区域褶皱变形主要发生于古近纪,中新世湖相沉积地层产状平缓,挤压构造变形微弱,说明地壳缩短增厚主要发生于中新世前。湖相沉积地层的孢粉分析结果表明,青藏地区热带亚热带阔叶林植被自始新世中期开始逐步减少,至中新世早期濒临消亡;暗针叶林植被自渐新世早中期开始逐步增加,至中新世早中期达到繁盛程度甚至居主导地位。根据这些地质证据,结合全球气候变化、古气温及年代学资料,综合推断青藏高原渐新世晚期隆升高度达到海拔4000m左右。
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| 关 键 词： | 中新世早期湖相沉积 孢粉组合 古植被 青藏高原隆升 |
| 修稿时间： | 2007-01-23 |
Geological Evidences for the Tibetan Plateau Uplifted in Late Oligocene |
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| WU Zhenhan,WU Zhonghai,HU Daogong,YE Peisheng,ZHOU Chunjing.Geological Evidences for the Tibetan Plateau Uplifted in Late Oligocene[J].Acta Geologica Sinica,2007,81(5):577-587. |
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| Authors: | WU Zhenhan WU Zhonghai HU Daogong YE Peisheng ZHOU Chunjing |
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| Institution: | Institute of Geomechanics , Chinese Academy of Geological Sciences , Beijing , 100081 |
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| Abstract: | Most geologists believe that uplift of the Tibetan Plateau is geodynamically related to shortening and thickening of the crust,further more which cause the change in monsoon intensity and the ecological shift in Asia.However,uplift time of the Tibetan Plateau is still unsolved.Statistical analyses of dip angle of Cenozoic strata outcropped in central Tibetan Plateau indicate that major shortening and thickening of the crust occur in Paleogene,and lacustrine strata kept horizontal and gently dipping over vast areas since Early Miocene.Sporopollen assemblages contained in lacustrine strata in the region show that tropical-subtropical broad-leaved trees decrease from Middle Eocene to Late Oligocene and almost disappear since Early Miocene while dark needle-leaved trees increase in Early-Middle Oligocene and flourish or dominate in Early-Middle Miocene.These data,together with climate change and chronological dating,indicate that the central Tibetan Plateau uplifted to ~4000 m in Late Oligocene. |
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| Keywords: | lacustrine strata sporopollen assemblage vegetation change Tibetan Plateau uplift |
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