机构地区: 中国地质大学地球科学学院
出 处: 《地学前缘》 2012年第5期1-17,共17页
摘 要: 根据中国学者的开合构造观点,分析了亚洲大地构造基本特征和演化规律,提出"构造集群"、"构造运动程式"等一些新的认识。(1)亚洲划分为11个大地构造旋回并归纳为大陆基底形成、泛大陆和超大陆形成与发展以及现代板块构造与陆内演化三大阶段。(2)以23条俯冲带或碰撞带为骨干,划分了以西伯利亚陆块、古中华陆块、印度陆块和太平洋板块为核心的北亚、中亚、南亚和东亚4个构造集群,以及11个二级和86个三级构造单元。构造集群系指具有成生联系的陆块、大小不同的地块和各个时期造山带的聚合体;两个构造集群间存在一个构造结合区。(3)亚洲构造变形特点为:中亚构造集群基本呈东西向展布,分别受围绕西伯利亚陆块分布的向南突出的弧形构造和围绕印度陆块分布的主体向北北东突出的弧形构造(仅内弧出现了向南突出的喜马拉雅弧)的挤压,它们同时又被北北东向展布的东亚构造集群强烈改造,从而形成了复杂的构造格局,表明古中华陆块在亚洲大地构造演化中起着"中流砥柱"的重要作用。(4)亚洲大地构造时空演化与全球同步经历了哥伦比亚古陆、罗迪尼亚古陆和潘基亚古陆形成的3次重要造陆事件。在此过程中,中亚构造集群独具特色:哥伦比亚古陆1 850Ma形成,稍早于南亚构造集群(1 800 Ma)和北亚构造集群(1 800~1 600Ma);罗迪尼亚古陆830Ma形成,晚于南北两侧的900~1 000Ma;潘基亚古陆210Ma形成,也比全球普遍于250Ma形成的时间晚。印支运动的广泛发育和强烈影响是中亚构造集群乃至亚洲最显著的特征。(5)总结出背向俯冲对接式、单向运移拼贴式和原地开合手风琴式3种构造运动程式。背向俯冲对接式的动因是地幔对流(软流圈对流或地幔柱对流);单向运移拼贴式可能与地幔上升产生的地幔层流有关;原地开合手风琴式推测是深部地幔"热点"周期活动所 The present paper aims at the studies of the major characteristics of geotectonics of Asia and their regularities of evolution on the basis of opening-closing tectonic points of view proposed by Chinese authors and aims at presenting the major results of studies listed as the following:(1)11 geotectonic cycles have been subdivided which can be deduced into 3 periods,i.e.,the formation period of continental basement,the formation and development period of Pangea and super-continent together with the period of modern plate tectonics and intra-continental evolution.(2)Taking the 23 subduction and collision zones as a key framework and assuming the Siberian continental block,the Paleo-Chinese block,the Indian block and the Pacific plate as kerns,4 tectonic assemblages,namely,the North Asia,the Mid-Asia,the South Asia and the East Asia,as well as 11 second order and 86 third order tectonic units can be subdivided.A tectonic assemblage is referred to the aggregate of the kern continental block together with its surrounding cogenetic orogenic belts and blocks.Between two tectonic assemblages there is always a tectonic connection region.(3)The Asian geotectonic deformation features can be delineated as follows: the Mid-Asian tectonic assemblage surrounding Paleo-China is trending east-west which is respectively compressed by the North Asia tectonic assemblage surrounding the Siberia continental block as an arc-tectonics protruding to the south and also by the South Asia tectonic assemblage surrounding the India continental block as an arc-tectonics protruding to the NNE(only the Himalayas in the inner arc is an arc-tectonics protruding to the south).All of them are again intensively reworked by the NNE trending East Asia tectonic assemblage forming a complicated tectonic plan.And it indicates that the Paleo-China continental block plays an important role as "a firm rock in the midstream" in the geotectonic evolution of Asia.(4)The temporal-spatial geotectonic evolution of the Asian continent i