Temperature production in the continental crust due to radioactive heat sources

Summary The purpose of this paper is to present a method for computing the temperature distribution in the continental crust as a function of depth and time. Computed results indicate that the rise of the temperature due to the decay of long half-life radioactive elements K⁴⁰, U²³⁵, U²³⁸, and Th²³² will reach its maximum 90 m.y. after heat sources and temperature are redistributed in the upper part of the earth. This suggests that the lower part of the crust and upper mantle were periodically remelted before the present stage of the crust was reached. At the present time the decay of the radioactive elements U²³⁸ and Th²³² still significantly influences the crustal temperature. The present near-surface thermal gradient due to the radioactive heat sources alone may reach 20°C/km in a high radioactive heat source province.