Structural boundary and deep contact relationship between the Yangtze and Cathaysia Blocks from crustal thickness gradients

The deep boundary and contact relationship between the Yangtze Cathaysia Blocks (the major tectonic units of Southern China Block), as well attributes Jiangnan Orogenic Belt, have remained unknown or controversial. Using data recorded by 128 portable broadband stations 96 permanent stations, we obtained high-resolution images crustal thickness Poisson’s ratio in study area. influences anisotropy inclined interface were eliminated using newly proposed receiver function H–κ–c stacking method. We then used a gradient analysis method to obtain gradients at for first time. Our results reveal that varies from >38 km Qinling–Dabie Belt <30 east Tanlu Fault Block. Areas with high ratios (>0.27) are concentrated on flanks fault zone continental margin area; those low (<0.23) Belt. Large found beneath eastern part Jiujiang–Shitai buried (>5 km/°). Combined velocity structure discontinuity characteristics different depths, these findings suggest may constitute dividing lithospheric scale. Moreover, our support Block subducted northwest-ward toward southeastern Neoproterozoic, Jiangshan–Shaoxing shallow boundaries two Blocks, respectively; is, overlaps