Numerical Simulation On The Effects Of Post-perovskite Phase Change On The Morphology Of Subducted Lithosphere

As a fundimantle concept of geodynamics,'mantle convection'has played an important role in both the research in earth geodynamics process and the terrestrial planets geodynamics process.The thesis briefly introduces the basic theories of'Mantle Convection'by representing the Control function,Boussinesq approximation as well as the nondimensional method. Then introduced the numerical computing method– Finite Element Method(FEM) and the code we employ in our research- CitcomCu.After that ,the thesis summarizes several viewpoints and previous works of the problem'the effect of the PPV phase trasition on the mantle convection'Mainly focus on the work Nagakawa and Paul Tackley have done on the Clayeron Slope's value,and the research Marc Monnereau and David A. Yuen have taken on detecting the relationship between the Clayperon Slope and the temperature intercept. The PPV phase change provide us a strong constrain in the temperature field in CMB.After the numerical calculation ,we come to the conclusions:1 the subducted lithosphere could reach the CMB and the mantle convection can be still stable.2 The exothermic reaction doesn't destabilizes the thermal boundary.3 With the PPV phase change in our numerical convection model, we could get a more obvious temperature field in CMB.This study only take into account the effect of the PPV phase change into the thermal-chemical mantle convection.However,there are other different physical properties such as latent heating and elastic constants and thermal generation rate and so on.Therefore ,it would be a better research to take these properties into the numerical model.