High-resolution crustal structure of the Yinchuan basin revealed by deep seismic reflection profiling： implications for deep processes of basin

• Published in: Earthquake science Vol. 29; no. 2; pp. 83 - 92
• Main Authors: Huang, Xingfu, Feng, Shaoying, Gao, Rui, Li, Wenhui
• Format: Journal Article
• Language: English
• Published: Beijing Seismological Society of China 01.04.2016; Springer Nature B.V
• Subjects: Basins; Crusts; Depth profiling; Earth and Environmental Science; Earth Sciences; Fine structure; Geophysics/Geodesy; High density; Lithosphere; Magma; Plate tectonics; Research Paper; Sedimentary basins; Seismic activity; Seismic surveys; Seismology; Thinning; Travel time; 地壳结构; 大陆裂谷; 岩浆底侵作用; 深地震反射剖面; 深部过程; 鄂尔多斯地块; 银川盆地; 高分辨率; Yinchuan basin; Deep seismic reflection section; Deep process; Moho; Magma underplating
• ISSN: 1674-4519; 1867-8777
• DOI: 10.1007/s11589-016-0148-1

The Yinchuan basin, located on the western margin of the Ordos block, has the characteristics of an active continental rift. A NW-striking deep seismic reflection profile across the center of Yinchuan basin precisely revealed the fine structure of the crust. The images showed that the crust in the Yinchuan basin was characterized by vertical stratifications along a detachment located at a two-way travel time（TWT） of 8.0 s.The most outstanding feature of this seismic profile was the almost flat Mohorovicˇic′ discontinuity（Moho） and a high-reflection zone in the lower crust. This sub-horizontal Moho conflicts with the general assumption of an uplifted Moho under sedimentary basins and continental rifts, and may indicate the action of different processes at depth during the evolution of sedimentary basins or rifts.We present a possible interpretation of these deep processes and the sub-horizontal Moho. The high-reflection zone, which consists of sheets of high-density, mantlederived materials, may have compensated for crustal thinning in the Yinchuan basin, leading to the formation of a sub-horizontal Moho. These high-density materials may have been emplaced by underplating with mantlesourced magma.