A heat production model of the crust and upper mantle

Abstract

Experimental evidence on the relationship between seismic velocity and radiogenic heat production has been used to estimate the vertical distribution of heat sources in the continental lithosphere. The derived differentiation rate of the radioelements with depth has been investigated to depths ≤ 100 km in various world-wide tectonic provinces. The results show that more pronounced upward differentiation (steeper heat production distribution) corresponds to regions of higher heat flow and usually higher crustal temperatures. Thus, crustal distributions of radiogenic heat may be related to tectonic age and crustal evolution. The vertical distribution of heat production can be traced even in the subcrustal lithosphere and confirms the upward concentration of a substantial part of the radioelements into the crust at the expense of the upper mantle, reflecting the early stages of crustal separation. While in the uppermost crust the distribution of the heat sources seems to be controlled by uranium and thorium, in the upper mantle it is potassium which controls it. Data obtained may be important in the geothermal modelling, deep temperature calculation, and in determinations of Moho heat flow.