Inferences on Australia's heat flow and thermal structure from mantle convection modelling results

Abstract

Mantle convection is important in understanding the heat flow and thermal structure of the continental lithosphere, as it produces time variability in the surface heat flow, and allows for lateral advection of heat under a continent. Many of the fundamental questions in continental heat flow depend on the magnitude and variability of the mantle contribution to continental heat flow. We summarise the current understanding of the thermal state of the Australian continent, and discuss the application of mantle-convection modelling results to continental heat-flow problems. A parficle-incell finite-element code is used to show how the continental thermal field is modulated through time, and how the calculated mantle heat flow decreases with both root thickness and crustal heat production. An increase in root thickness is shown to enhance the stability of the deep continental thermal field. These modelling results imply a modest variation in the mantle heat flow of Australia through time, and suggest that the variation in mantle heat flow over the stable Precambrlan shield will most likely be Indiscernible. The thickness and thermal structure of the Australian lithosphere is, to a degree, dependent on the history of mantle convection around this continent. Show more