title: Statistical thermodynamic model for the distribution of crustal heat sources.
abstract: The observed linear correlation of surface heat flux in continental regions with the radioactive heat release in the surface rocks is consistent with an exponential depth dependence of the concentration of the heat sources. We suggest that this depth dependence can be explained as an equilibrium distribution of the heat-producing elements in a gravitational field. The eflective mean mass range of the elemental assemblies being differentiated is predicted, and it appears that potassium, uranium, and thorium diffuse upward in ionic complexes with other elements. Similar considerations should apply to the distribution of other elements in the crust and mantle.
authors.forename: D L
authors.initials: DL
authors.lastname: Turcotte
authors.forename: E R
authors.initials: ER
authors.lastname: Oxburgh