The characteristic of lithospheric thermal structure and its tectonic implications in the South China Block and adjacent areas

The South China block (SCB) west of the eastern edge of the Tibetan Plateau (ETP) is both an important part of global tectonics and an area of extremely complex geological and tectonic evolution. The coupling relationship between the SCB and the ETP is currently highly controversial. The lithospheric thermal structure contains rich information on tectonic deformation, geological evolutionary processes and geodynamics, which can provide effective constraints for an in-depth understanding of the coupling relationship between the SCB and the ETP. The functional relationship between the depth of the Curie depth and the terrestrial heat flow data is used to obtain integrated terrestrial heat flow data and improve the spatial resolution of terrestrial heat flow data in the SCB. Then, the SCB’s reliable lithospheric thermal structure by the thermal steady-state conduction equation, integrated geodetic heat flow data, and the relationship between seismic S wave velocity and temperature. Analyses of crust-mantle heat flow distribution, Moho surface temperature and thermal lithospheric thickness in the lithospheric thermal structure show that the Cathaysia Block, the North China Plate, the northeastern part of the Jiangnan Orogenic Belt and the eastern part of the Yangtze Block belong to the ‘cold crust-hot mantle’ structure, whereas the Sichuan Basin and the Songpan-Ganzi Block belong to the ‘hot crust-cold mantle’ structure. The northwesterly subduction and retreat of the Palaeo-Pacific Plate to the SCB may be responsible for the northwesterly to southeasterly rise/thickening of both the temperature and thermal lithosphere thickness trends at the Moho surface. The SCB and the ETP show opposite movement. In the shallow part of the crust, rigid blocks of the upper crust of the SGB collide with the YB to form the Longmenshan Fault Zone. In the deep part of the crust, the Western YB is affected by thermal erosion (The SGB high-temperature indicated the partial melting fluids and the upwelling of deep thermal material), resulting in the progressive dissipation of low-temperature stable craton properties.