Generation and distribution of global heat flow

The globle heat flow is the primary energy flow responsible for the dynamic of nature of our planet. In this study we investigate in a three dimension al spherical geometry frame, the generation and distribution characteristic s of global heat flow on the basis of exploring thermal effects of density anomaly and platedriven mantle flows. Results show that the thermal effect of plate motion-driven mantle flow and its contribution to the observed hea t flow is greater than that due to internal density anomaly (tomography bas ed). Higher values of observed heat flow in mid-ocean ridge system could be accuounted for, to a great extent, by the thermal effect generated by the plate-driven mantle flow. Furthermore, the predicted average temperature as function of depth reveals the features of an isothermal core and two therm al boundary laters at the surface and the core-mantle boundary. An approxim ate thickness of 150km for lithosphere within which the temperature rapidly varies can be obtained. A mantle viscosity model, in which viscosity in th e lower mantle is 30 times than that in the upper mantle, appears to fit da ta better.