Abstract: Thermal structure of continental lithosphere can directly affect physical and rheological properties of rock, thus limiting the evolution of lithosphere. Based on tectonic setting and influencing parameters of lithospheric thermal state in the Nansha Trough Foreland, we numerically simulated lithospheric thermal structure of 94N05 seismic profile in the basin using an one-dimensional steady-state heat-conduction equation. Simulation Results show that average heat flow is about 62 mW·m^-2 in the basin, and mantle heat flow is between 37 and 44 mW·m^-2, which is up to 60%—70% of the surface heat flow. The Nansha Trough Foreland Basin is in the tectonic thermal recovering phase. Affected by compressional tectonic surroundings since the Miocene, the surface heat flow is relatively low and mainly controlled by deep mantle, and temperature of Moho varies from 500 to 600℃. Thickness of thermal lithosphere is as thin as 60—70 km. This research also reveals that key factors of few regional earthquakes may be related to high temperature and thermal stabilization of the deep lithosphere in the Nansha Islands waters.

Key words: Nansha Trough, heat flow, heat production rate, thermal conductivity, thermal structure, earthquake