中国大陆大型盆地的岩石圈结构及构造意义  

Lithospheric Structures of the Main Basins in China's Mainland and Its Tectonic Implications

作　　者：李孟奎[1] 宋晓东[1,2] 李江涛[2] 鲍学伟[3] Li Mengkui;Song Xiaodong;Li Jiangtao;Bao Xuewei(School of Geodesy and Geomatics,Wuhan University,Wuhan 430079,China;Department of Geology,University of Illinois at Urbana-Champaign,Champagne 61820,USA;School of Earth Sciences,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]武汉大学测绘学院,湖北武汉430079 [2]美国伊利诺伊大学地质系,伊利诺伊香槟61820 [3]浙江大学地球科学学院,浙江杭州310058

出　　处：《地球科学》2018年第10期3362-3372,共11页Earth Science

基　　金：国家自然科学基金项目(No.41774056);国家自然科学基金青年项目(No.41704046)

摘　　要：研究盆地内部的岩石圈结构,有助于了解盆地的形成和演化过程,以及与区域构造的耦合关系.表面波层析成像是研究地球内部速度结构和动力过程的重要手段.根据得到的东亚地区深度达300 km的S波速度结构模型,主要关注塔里木盆地、柴达木盆地、四川盆地、鄂尔多斯盆地、渤海湾盆地以及松辽盆地的深部速度结构.结果表明,东西部盆地岩石圈厚度存在很大的差异,其中塔里木盆地、四川盆地以及鄂尔多斯盆地岩石圈较厚(最大约200 km),渤海湾盆地、松辽盆地岩石圈较薄(最大约80 km),柴达木盆地则介于二者之间.盆地内部岩石圈厚度的横向差异,反映出岩石圈的不均一性及不同程度的改变和变形.对于环青藏高原分布的盆地,区域构造挤压作用造成的山系软物质下溢,侵蚀了盆地岩石圈基底,造成盆山结合部岩石圈厚度的急剧变化,区域构造挤压可能在这些盆地的形成和演化过程中起到了关键作用.鄂尔多斯盆地岩石圈厚度变化表明华北克拉通岩石圈减薄可能只发生在盆地的东部及以东的地区.The study of lithosphere structure within the basin is helpful to understand the formation and evolution of the basin and the relationship with regional tectonics.Surface-wave tomography is an important tool for investigating the S-wave velocity structure and dynamics of the Earth’s interior. In this study a new lithospheric S-wave velocity model up to 300 km depth in East Asia is obtained by combining our newly measured Rayleigh wave phase and group velocities using the earthquake-based two-station analysis with previous published dispersion measurements. We focuse on the deep velocity structures and the lithospheric thicknesses beneath six sedimentary basins（ Tarim Basin,Qaidam Basin,Sichuan Basin,Ordos Basin,Bohai Basin and Songliao Basin） in China's Mainland. The results show that the lithospheric thicknesses of the basins in eastern China vary significantly from the basins in central and western China. Tarim Basin,Sichuan Basin and Ordos have the thickest lithosphere（ up to about 200 km）,while Bohai Basin and Songliao Basin have the thinnest lithosphere. Qaidam Basin has the intermediate lithospheric thickness. The lithospheric thicknesses in each basin show significant lateral variations,suggesting the differences of the interior deformation in basins. The basin-mountain junction belts have the strongest deformation due to regional compression and material intrusion. The regional compression due to the subduction of Indian plateto the Eurasian plate may have played an important role in the formation and evolution process for the basins surrounding the Tibetan Plateau. Ordos Basin shows thick lithosphere in the western part and sharp lithosphere thinning in the eastern part,which may imply that the lithosphere thinning of the North China Craton only occurs in the eastern part.

关 键 词：中国大陆盆地 表面波层析成像 岩石圈速度结构 地球物理 

分 类 号：P315[天文地球—地震学]