A comparative study of parameterized and full thermal-convection models in the interpretation of heat flow from cratons and mobile belts

Abstract

SUMMARY Heat flow from Archean cratons worldwide is typically lower than from younger mobile belts surrounding them. The contrast in heat flow between cratons and mobile belts has been attributed in previous studies to the greater thermal resistance of thicker lithosphere beneath the cratons which impedes the flow of mantle heat through the cratons and forces more mantle heat to escape through thinner mobile belt lithosphere. This interpretation is based on thermal models which employ a parameterized convection algorithm to calculate heat transfer in the sublithospheric mantle. We test this interpretation by comparing thermal models constructed using the parameterized convection scheme with models developed using an algorithm for full thermal convection. We show that thermal models constructed using the two different convection algorithms yield similar surface heat flow and thermal structure to moderate depths within the lithosphere. Therefore, we conclude that the interpretation of the heat-flow observations in terms of thicker lithosphere under Archean cratons than under mobile belts is robust in the sense that surface heat flow is not sensitive to the details of heat transfer within the convecting mantle and how deep mantle heat is delivered to the base of the lithosphere.