Crustal structure of the central Cathaysia block in South China derived from receiver functions

The Cathaysia block in Southeast China has undergone complex compression, collision and tectonic evolution processes, which have led to the formation of rich granites and polymetallic ores. However, its history of crustal evolution and metallogenic mechanisms remain unclear. To explore the deep geodynamic processes in the central Cathaysia block, we deployed a dense broadband seismic array with a station interval of ~5 km from July 2017 to August 2020. This seismic array, composed of 80 portable stations, traverses the Nanling and Wuyi metallogenic belts and crosses four deep faults. We employ the teleseismic receiver-function method to estimate the crustal thickness and v_P/v_S ratio beneath the seismic array. Our results reveal a distinct negative correlation between the crustal thickness and the v_P/v_S ratio within the crust, which might be closely associated with crustal deformation. The average crustal thickness is ~30 km, indicating that the crust was thinned under an extensional environment. However, the crust beneath the Wuyi belt is slightly thicker and has a lower v_P/v_S ratio than its adjacent areas, which may reflect thickening of the upper crust due to its ductility and lithospheric delamination.