Crustal Velocity Structure beneath the Site of Chinese Continental Scientific Drilling Site

In order to study the deep structure, spatial tectonic characteristics and the dynamic process for the Dabie-Sulu ultral-high metamorphic belt, a wide-angle reflection/refraction seismic survey was conducted in the Chinese Continental Scientific Drilling (CCSD) site. The crustal velocity structure beneath the CCSD site has been established based on wide-angle seismic reflection/refraction data acquired at the site. According to the results, the crust beneath CCSD is composed of three layers: the upper, middle and lower crust, with velocities of 6.20 km/s, 6.40 km/s, and 6.60 km/s, and a thickness of ～10 km, ～10 km, and ～12 km respectively. The crust thickness is 31 km around with an average velocity of 6.30 km/s. However, the reversed velocity in the upper crust implies an ultrahigh-pressure metamorphic (UHPM) layer (body) with a shape of uplift beneath or near the CCSD site.