Miocene Tectonic Evolution from Dextral-Slip Thrusting to Extension in the Nyainqentanglha Region of the Tibetan Plateau |
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作者姓名: | WU Zhenhan Patrick J. BAROSH ZHAO Xun WU Zhonghai HU Daogong LIU Qisheng |
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作者单位: | [1]Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China [2]P. J. Barosh 103 Aaron Avenue, Bristol, RI 02809, USA [3]Chinese Academy of Geological Sciences, Beijing 100037, China |
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基金项目: | This study was financially supported by China Geological Survey and the Ministry of Science and Technology of China under grants DKD9901001 and 2001CB711001, respectively. P. J. Barosh gratefully acknowledges the support provided by the Chinese Academy of Geological Sciences through the Institute of Geomechanics. |
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摘 要: | Dextral-slip in the Nyainqentangiha region of Tibet resulted in oblique underthrusting and granite generation in the Early to Middle Miocene, but by the end of the epoch uplift and extensional faulting dominated. The east-west dextral-slip Gangdise fault system merges eastward into the northeast-trending, southeast-dipping Nyainqentangiha thrust system that swings eastward farther north into the dextral-slip North Damxung shear zone and Jiali faults. These faults were took shape by the Early Miocene, and the large Nyainqentangiha granitic batholith formed along the thrust system in 18.3-11.0 Ma as the western block drove under the eastern one. The dextral-slip movement ended at -11 Ma and the batholith rose, as marked by gravitational shearing at 8.6-8.3 Ma, and a new fault system developed. Northwest-trending dextral-slip faults formed to the northwest of the raisen batholith, whereas the northeast-trending South Damxung thrust faults with some sinistral-slip formed to the southeast. The latter are replaced farther to the east by the west-northwest-trending Lhunzhub thrust faults with dextral-slip. This relatively local uplift that left adjacent Eocene and Miocene deposits preserved was followed by a regional uplift and the initiation of a system of generally north-south grabens in the Late Miocene at -6.5 Ma. The regional uplift of the southern Tibetan Plateau thus appears to have occurred between 8.3 Ma and 6.5 Ma. The Gulu, Damxung-Yangbajain and Angan graben systems that pass east of the Nyainqentangiha Mountains are locally controlled by the earlier northeast-trending faults. These grabens dominate the subsequent tectonic movement and are still very active as northwest-trending dextral-slip faults northwest of the mountains. The Miocene is a time of great tectonic change that ushered in the modern tectonic regime.
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关 键 词: | 中新世 筑造学 断层 西藏 隆起地貌 |
修稿时间: | 2007-01-112007-04-01 |
Miocene Tectonic Evolution from Dextral-Slip Thrusting to Extension in the Nyainqentanglha Region of the Tibetan Plateau |
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Authors: | WU Zhenhan Patrick J BAROSH ZHAO Xun WU Zhonghai HU Daogong and LIU Qisheng Institute of Geomechanics Chinese Academy of Geological Sciences Beijing China P J Barosh Aaron Avenue Bristol RI USA Chinese Academy of Geological Sciences Beijing China |
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Abstract: | Dextral-slip in the Nyainqentanglha region of Tibet resulted in oblique underthrusting and granite generation in the Early to Middle Miocene, but by the end of the epoch uplift and extensional faulting dominated. The east-west dextral-slip Gangdise fault system merges eastward into the northeast-trending, southeast-dipping Nyainqentanglha thrust system that swings eastward farther north into the dextral-slip North Damxung shear zone and Jiali faults. These faults were took shape by the Early Miocene, and the large Nyainqentanglha granitic batholith formed along the thrust system in 18.3-11.0 Ma as the western block drove under the eastern one. The dextral-slip movement ended at -11 Ma and the batholith rose, as marked by gravitational shearing at 8.6-8.3 Ma, and a new fault system developed. Northwest-trending dextral-slip faults formed to the northwest of the raisen batholith, whereas the northeast-trending South Damxung thrust faults with some sinistral-slip formed to the southeast. The latter are replaced farther to the east by the west-northwest-trending Lhtinzhub thrust faults with dextral-slip. This relatively local uplift that left adjacent Eocene and Miocene deposits preserved was followed by a regional uplift and the initiation of a system of generally north-south grabens in the Late Miocene at -6.5 Ma. The regional uplift of the southern Tibetan Plateau thus appears to have occurred between 8.3 Ma and 6.5 Ma. The Gulu, DamxungYangbajain and Angan graben systems that pass east of the Nyainqentanglha Mountains are locally controlled by the earlier northeast-trending faults. These grabens dominate the subsequent tectonic movement and are still very active as northwest-trending dextral-slip faults northwest of the mountains. The Miocene is a time of great tectonic change that ushered in the modern tectonic regime. |
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Keywords: | Miocene tectonics strike-slip fault thrust fault extensional tectonic system uplift graniteplutonism Nyainqentanglha region Tibetan Plateau |
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