中国西北地区各构造单元之间地层和生物古地理的亲缘关系--兼论西北地区构造格局

    Stratigraphic and paleobiogeographic affinities between different tectonic units in northwestern China-With a discussion of the tectonic framework of northwestern China

    • 摘要: 在分析近年来不同学科提出的新见解及其依据的基础上,着重从基底形成期、扬子型南华系-震旦系及其冰碛岩、早古生代地层层序特征和生物古地理特征及各构造单元间的边界性质,揭示与西北地区有关的板块、块体的亲疏关系.经分析认为,西北地区构造格局是塔里木与扬子板块为一体,与华北、西伯利亚为并立的3个不同的构造域;柴达木-祁连-阿拉善为一楔状地块,来源于塔里木-扬子板块.该楔状地块是在新生代青藏高原大规模隆升、北推高峰期时,西沿阿尔金、东沿贺兰山西缘-龙门山断裂带错移、向北楔入的一个三角形地块.

       

      Abstract: Different new views about the tectonic framework of Northwestern China have been proposed by different disciplines in recent years. According to the comparative analysis of the basement age, Yangtze-type Nanhuaan System (Sinian) and its tillite and Early Paleozoic stratigraphic sequence and paleobiogeographic characteristics, as well as the nature of boundaries between different tectonic units, the present paper deals with the affinity of tectonic units in northwestern China. The tectonic framework of northwestern China is as follows: the Tarim and Yangtze plates belong to a unified large plate once. This large plate and the North China and Siberia plates are three different tectonic domains; Qaidam-Qilian-Alxa as an integrated wedge-shaped block originated from the Tarim-Yangtze plate. This block was displaced on the west along the Altyn Tagh fault and on the east along the western Helanshan margin-Longmenshan fault and wedged into a triangular block during the large-magnitude uplift and northward pushing of the Qinghai-Tibet plateau in the Cenozoic.

       

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