Vertical distribution of radioactivity in the continental crust and the Moho heat flow

Experimental evidence suggests a certain relationship between seismic velocity and radiogenic heat production. The results of the explosion seismology can thus be used to estimate the distribution of crustal heat sources. The possible vertical behaviour of A(z) was studied for a number of vp(z) profiles in various tectonic units in Central and Eastern Europe. There must be a considerable difference in the radioactive structure of the upper and lower crust and in the upper part up to a depth of 10-15 km mainly U might have undergone a certain redistribution due to deep groundwater circulation. The data obtained also suggest certain dependence of the A(z) on the geological history and the estimated mantle heat flow shows considerable variability, ranging from 15-25 mW · m-2 under the Precambrian shields to more than 40 mW · m-2 in the young tectonic regions. (author) 28 refs.; 3 figs