Heat production in the continental crust, part I: data converted from seismic velocities and their attempted interpretation

Abstract

When using the simple exponential distribution of radiogenic heat production ( A) with depth ( z), A( z) = A o exp(− z/ D), the statistical analysis of a large number of heat production profiles, converted from the observed seismic velocity vs. depth profiles and the experimental knowledge of the relationship between seismic velocity and heat production, disclosed certain relations between the logarithmic decrement ( D-value) and heat flow, tectonic age and crustal thickness. The D-valuein this respect characterizes the depth rate of the differentiation of the heat production. In all tectonic units the D-parameter decreases with depth. As the next step, the more complicated distribution law A( z) = A o exp(− z/ D)− a was applied, where a characterizes the quantity of removed heat sources by the processes accompanying the crustal evolution (such as remelting, metamorphosis, leaching by underground waters, etc.). All parameters A o , a and D are constant within each particular tectonic province and parameter D does not depend on depth, contrary to the former law. The amount of removed heat sources a reflects the initial concentration of heat sources, and is higher in young tectonic terranes, in areas of high heat flow and in regions of thin crust.