GEOTHERMAL CONDITIONS OF THE LITHOSPHERE OF UKRAINIAN SHIELD

In the present paper the surface heat flow pattern, the distribution of the radiogenic heat sources, and the calculated temperatures within the crust of the Ukrainian Shield are discussed. In the Ukrainian Shield the heat flow varies from 25 to 55 mWm^-2. The heat flow decreases in areas of a thick crust composed of the Archean high-grade metamorphic rocks and increases in areas of a thin crust built of granitoids. It is concluded that the decrease of heat generation with depth is exponential; at the crustal bottom its value is less than 0.2 μWm^-3. The calculated Moho temperatures range from 360º to 540 ºC. The geothermal lithosphere thickness varies from 180 km to 230 km.