Formation of Dabashan arcuate structures: Constraints from Mesozoic basement deformation in South Qinling Orogen, China

摘要: Abstract The Dabashan arcuate structures are composed of the NW-striking Northern Belt belonging to southern margin South Qinling Orogen and curved Southern located in northern Yangtze Block with Chengkou-Fangxiang Fault as their boundary. deep understanding orogenesis is indispensable unravel mechanism structures, basement preserves important clues on deformational characteristics well timing orogenic processes. Here we report integrated field investigation, structural analysis, 40Ar/39Ar thermochronological data Wudang Ankang Uplifts decipher forming processes mechanisms structures. microscopic observations reveal a dominantly top-to-south (southwest) shear sense at low medium temperatures. deformation expanded southward (southwestward) form duplex. During continued shortening, was uplifted due thrust stacking within duplex systems. According temperatures, new published data, recorded ca. 248-212 Ma for Uplift 222-161 Ma Uplift. Based tectonic evolution study area, formation composite included three stages. Firstly, master fault accompanied by series faults came into being 450-400 Ma based previous studies. Secondly, scissor-like convergence between China North reactivated extensional formed general features 250-160 Ma. Finally, toward foreland obstruction Hannan Shennongjia-Huangling front 160-100 Ma.