SEISMOLOGY AND GEOLOGY ›› 2021, Vol. 43 ›› Issue (3): 576-599.DOI: 10.3969/j.issn.0253-4967.2021.03.007

• Research paper • Previous Articles     Next Articles

PROGRESS AND RESEARCH OF PALEOALTITUDE RECON-STRUCTION OF CENOZOIC BASINS IN THE SOUTHEASTERN TIBET PLATEAU

TANG Mao-yun1,2), LIU-ZENG Jing3), LI Cui-ping1), WANG Wei4), ZHANG Jin-yu4), XU Qiang5)   

  1. 1)Chongqing Earthquake Agency, Chongqing 401147, China;
    2)College of Earth Sciences, Chengdu University of Technology, Chengdu 610059, China;
    3)Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China;
    4)State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    5)Division of CNPC Key Laboratory of Carbonate Reservoirs, School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, China
  • Received:2020-04-28 Revised:2020-09-08 Online:2021-06-20 Published:2021-07-20

青藏高原东南缘的新生代盆地古高度重建研究与进展

唐茂云1,2), 刘静3), 李翠平1), 王伟4), 张金玉4), 许强5)   

  1. 1)重庆市地震局, 重庆 401147;
    2)成都理工大学, 地球科学学院, 成都 610059;
    3)天津大学, 表层地球系统科学研究院, 天津 300072;
    4)中国地震局地质研究所, 地震动力学国家重点实验室, 北京 100029;
    5)西南石油大学地球科学与技术学院, 中国石油天然气集团有限公司碳酸盐岩储层重点实验室 西南石油大学分室, 成都 610500
  • 作者简介:唐茂云, 男, 1990年生, 2015年于中国地震局地质研究所获构造地质学专业硕士学位, 工程师, 主要从事构造地貌、 微地震监测研究, E-mail: tmylzy@foxmail.com。
  • 基金资助:
    震情跟踪定向任务(2020010512, 2020010131)和重庆市地震局科技创新团队项目共同资助

Abstract: The elevation evolution history of the southeastern Tibet Plateau is of great significance for examining the deformation mechanism of the plateau boundary and understanding the interior geodynamic mechanics. It provides an important window to inspect the uplift and deformation processes of the Tibet Plateau, and also an important way to test two controversial dynamic end-element models of the Plateau boundary. In recent years, some breakthroughs have been made in the study of paleoaltitudes in the southeastern Tibet Plateau, which allows us to have a clearer understanding of its evolution process and dynamic mechanism. By reviewing and recalculation of the latest achievements of paleo-altitude studies of the basins in the southeastern Tibet Plateau from north to south, including the Nangqian Basin, Gongjue Basin, Mangkang Basin, Liming-Jianchuan-Lanping Basin, Eryuan Basin, Nuhe Basin and Chake-Xiaolongtan Basin, we discuss the surface elevation evolution framework of the Cenozoic geomorphology and dynamics in the southeastern Tibet Plateau. The results show as follows:
(1)There was an early Eocene-Oligocene quasi plateau with an altitude of at least 2.5km from the north to middle of the southeastern Tibet Plateau(north of Dali), while the surface elevation in the south(south of Dali to Yunnan-Guizhou Plateau)was relatively low, even close to sea level. Until Miocene, the north to middle of the southeastern Tibet Plateau reached the present altitude, while the southern part of the Tibet Plateau showed a differential surface uplift trend, which established the present geomorphologic pattern. But it cannot be completely ruled out that this trend was probably caused by the accuracy of the calculation results.
(2)The quantitative constraints on the uplift process of the southeastern Tibet Plateau during Cenozoic provide certain constraints for the dynamic mechanism of geomorphic evolution in the southeastern Tibet Plateau. The northern and central parts of the southeastern Tibet Plateau can be well explained by the plate extrusion model. In this model, the collision and convergence between India and Eurasia plate or Qiangtang block and Songpan-Ganzi block resulted in the shortening and thickening of the upper crust in the region, and making the early stage(early Eocene)surface uplift. Subsequently, due to delamination or the continuous convergence between the Qiangtang block and the Songpan-Ganzi block resulting in the shortening and thickening of the crust, the plateau continued to grow northward and rose to its present altitude around Miocene. In the Eocene, the area from the south of the southeastern Tibetan plateau to the Yunnan-Guizhou Plateau mainly showed a low altitude. It seems that it may be in the peripheral area not affected by the shortening and thickening of the upper crust during the early stage India-Eurasia plate collision or plate extrusion and escape. In addition, as proposed by the lower crustal channel flow model, the lower crust material made the low-relief upland surface extending thousands of kilometers in the region uplift gradually towards the southeast, which seems to explain the low elevation landform of the region in the early stage, but it could not explain the whole uplift process of the southeastern Tibet Plateau. Therefore, a single dynamic model may not be able to perfectly explain the Cenozoic complex uplift process of the southeastern Tibet Plateau, and its process may be controlled by various dynamic processes.
(3)According to the paleoaltitude reconstruction results, if most areas of the ancient southeastern Tibet Plateau, especially the area to the north of Jianchuan Basin, had been uplifted in a certain scale and became part of the early plateau in the early Cenozoic, and reached to the current surface altitude around Miocene, the widely rapid surface erosion in this area since Miocene probably would be a continuous lag response to the finished surface uplift process, and the lag time may correspond to the sequential response process of surface uplift, the decline of river erosion base level and the gradual enhancement of river erosion capacity. Therefore, it is not proper to regard the rapid denudation and rapid river undercutting as the starting time of plateau uplift, as proposed in the previous thermochronological study.

Key words: southeastern Tibetan plateau, Cenozoic basins, paleoaltitude reconstruction, plateau uplift, lower crustal flow

摘要: 掌握青藏高原的高程演化历史对检验高原边界的变形机制和理解深部地球动力学具有重要意义。 文中对青藏高原东南缘的囊谦盆地、 贡觉盆地、 芒康盆地、 黎明-剑川-兰坪盆地、 洱源盆地、 怒河盆地和岔科-小龙潭盆地等不同区域的典型新生代盆地的古高度重建研究成果进行了系统梳理、 总结以及部分重新计算后, 恢复了青藏高原东南缘新生代隆升过程的时空分布历史, 讨论了青藏高原东南缘新生代期间的主要隆升阶段与幅度。 综合分析表明, 青藏高原东南缘北段—中段地区存在始新世—渐新世准高原, 而南段地区的地势相对较低。 中新世期间, 南段地区呈现出差异化的隆升趋势。 在此基础上, 文中进一步定量化约束了高原东南缘新生代的隆升过程, 为青藏高原东南缘构造、 地貌演化的动力学机制探讨提供制约。

关键词: 青藏高原东南缘, 新生代盆地, 古高度重建, 高原隆升, 下地壳流

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