地学前缘 ›› 2012, Vol. 19 ›› Issue (5): 284-292.

• 论文 • 上一篇    下一篇

有关我国新构造运动起始时间的探讨

徐杰，计凤桔，周本刚   

  1. 中国地震局 地质研究所 活动构造与火山重点实验室， 北京 100029
  • 收稿日期:2012-01-10 修回日期:2012-06-25 出版日期:2012-09-10 发布日期:2012-09-10
  • 通讯作者: 徐杰（1943—），男，博士，研究员，博士生导师，主要从事地质构造、地震构造、石油地质和工程地震等研究。E-mail:jfj09@126.com
  • 作者简介:徐杰（1943—），男，博士，研究员，博士生导师，主要从事地质构造、地震构造、石油地质和工程地震等研究。E-mail:jfj09@126.com
  • 基金资助:

    大型先进压水堆核电站国家科技重大专项“CAP1400安全审评技术及独立验证试验”项目（2011ZX0600201015）

On the lower chronological boundary of the Neotectonic period in China.

  1. Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China
  • Received:2012-01-10 Revised:2012-06-25 Online:2012-09-10 Published:2012-09-10

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摘要：

几十年来许多研究者从地貌、最新沉积和构造等方面，对中国的新构造运动进行了大量研究，但至今大家对新构造运动的含义却有着非常不同的认识。其关键问题是对新构造运动起始时间的看法差异很大，时间跨度从始新世晚期（40 Ma）到中更新世（0.73 Ma），因此严重影响了新构造运动研究的深入和发展。现拟从动力条件方面探讨中国新构造运动的起始时间。通过分析中国现今地壳水平运动和现代构造应力场压应力轴的分布特征及其形成的动力条件，得出它们具有连续性和统一性，而二者分布方向较好的一致性表明，印度板块与欧亚板块碰撞推挤是形成中国现今地壳运动和现代构造应力场的主要动力。然而在古近纪时中国东部和西部处于两种截然不同的大地构造环境，西部挤压、东部拉张。直到中新世中期青藏高原东部的川滇、巴颜喀拉—松潘等地块被侧向挤出，它们自北而南往北东—南东方向滑移并推挤中国大陆东部的地壳块体向前运动，才开始把中国西部和东部逐渐联成一个构造运动的统一体。这不仅得到中国东部一系列相应构造事件的印证，而且还从导致中国新生代地质构造发育的动力学环境变化方面进行了讨论。中国新构造运动开始于中新世中期，即距今约15～10 Ma.

关键词: 新构造运动, 起始时间, 青藏高原, 挤出构造, 中新世中期

Abstract:

 The last decades have seen a number of studies of Neotectonics in China, concerning with geomorphology, recent sediments and tectonics. The implication of Neotectonics is, however, still controversial up to now. One reason for this is that the lower chronological boundary of the Neotectonic period has been defined as greatly different epochs ranging from the Late Eocene (40 Ma) to the Middle Pleistocene (0.73 Ma). In this work we attempt to address this issue from dynamics of tectonic movements. Analysis of presentday crustal motions, distribution of compressional stress axes of the tectonic stress field and their formation conditions suggests that they are characterized by fairly good continuity and coherence as well as consistent orientations. It indicates that the IndiaEurasia collision is the primary driving force that determines the recent crustal motions and tectonic stress field in mainland China. Geological data shows, however, that in the Eogene time eastern and western mainland China was under extension and compression respectively that were completely distinct tectonic environments. This situation continued till the Middle Miocene (1520 Ma) when the blocks in the eastern Tibetan plateau, such as SichuanYunnan (ChuanDian) and Bayan HaraSongpan, were extruded laterally. These blocks slide from north to south and towards southeast to push eastern mainland China, thus linking eastern and western mainland China together as a united tectonic system. It has caused a series of tectonic events as well as changes of dynamic setting of the Cenozoic in eastern China. All these lines of evidence demonstrate that the neotectonic movements of China started from the  middle Miocene, i.e. about 1510 Ma B.P.

Key words: Neotectonics, lower chronological boundary； Tibetan Plateau； extrusion； Middle Miocene

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