Review of oceanic and global heat flow estimates

Abstract

Direct comparisons of recent estimates of oceanic and global heat flow from the earth's interior are not simple because of the diversity of assumptions and methods which have been used. Some of these estimates have been based on conceptually inappropriate or quantitatively unreasonable models of the cooling oceanic lithosphere. The cooling uniform half‐space model is the most appropriate first approximation and is presently adequate to describe the preferred selection of oceanic heat flow data. Hydrothermal transport in young oceanic crust may account for 25% of the total global heat flow. After appropriate allowances are made for this, there is general consistency between recent estimates of total heat flow. Total global heat flow is probably 4.1 ± 0.4 × 10¹³ W, which corresponds to an average flux of 80 ± 8 mW/m². The average oceanic heat flux is roughly 70% greater than the average continental flux: they are about 95 ± 10 mW/m² and 55 ± 5 mW/m², respectively. There may be significant fluctuations in total heat flow on time scales of 10⁷–10⁸ years.