%A Bai Xiangdong, Chi Baoming, Guan Chengyao, Zhang Yan, Yuan Sihua, Liang Wentian %T Ordos Block Modern Movement Patterns in Southern Ordos Margin Tectonic Belt %0 Journal Article %D 2015 %J Journal of Jilin University(Earth Science Edition) %R 10.13278/j.cnki.jjuese.201503102 %P 674-682 %V 45 %N 3 %U {http://xuebao.jlu.edu.cn/dxb/CN/abstract/article_10311.shtml} %8 %X

Southern Ordos block were divided into 11 irregular sub-groups from A to K in terms of the newly observed GPS data through converting the different GPS data into the detail relative motion between the blocks. The authors provide a new idea and model for studying the detailed movement differences based on these different GPS data. The present stress field is compressive in east and central parts of southern Ordos. The compressive stress comes from the southwest Qinling power wedge which is a compressive stress peak. The compressive stress peaks make up the Wugong-Xianyang-Kouzhen Line a stress axis, and then those shape-wedged blocks, that are standing both sides of the stress axes, are all laterally extruding and escaping in the western Weihe basin. The escaping blocks make some GPS motion vectors deviate off the main motion direction. There is a wide sinistral strike-slip in the eastern Weihe basin, which can show action of blocking and collision of western Henan uplift. The shape-wedged blocks were extruded laterally, which complicate the GPS vector data. The pattern of relative movement of these blocks complies with a "three head collision" tectonic model in southern Ordos. Based on this model, collision among Sichuan block, Ordos block, and Yuxi block resulted in stress concentration, and these blocks were then laterally extruded along the strike-slip faults developed in low stress region. The authors present a "multi-head collision" and "escape between heads" model which has a certain universality. It will be an effective way to figure out where are the "head" contact point and where are the "escape between heads" for study the focal mechanism distribution around some large or medium blocks.