Temporal and spatial radiogenic heat production rate of granitic plutons from the Eastern Pontides Orogenic Belt, NE Turkey: Constraints for the geothermal resources

The evaluation of the geothermal potential of the granitic rocks is important in long-term sustainable renewable energy projects due to increasing energy demand. The Eastern Pontides Orogenic Belt in NE Turkey contains a variety of granitic plutons changing in age, size, and composition. In this paper, we discussed the temporal and spatial distribution of radiogenic heat production by using the contents of heat-producing elements (U, Th, K) of the granitic plutons. The average U, Th, and K concentrations for the granitic plutons are 2.97 & PLUSMN; 0.95 ppm, 13.48 & PLUSMN; 3.48 ppm and 2.69 & PLUSMN; 0.47 wt% for Paleozoic plutons, 1.83 & PLUSMN; 0.98 ppm, 8.58 & PLUSMN; 5.10 ppm and 1.77 & PLUSMN; 0.80 wt % for Jurassic plutons, 5.24 & PLUSMN; 1.64 ppm, 26.02 & PLUSMN; 6.43 ppm and 3.17 & PLUSMN; 0.49 wt% for Cretaceous plutons, and 3.82 & PLUSMN; 0.90 ppm, 15.79 & PLUSMN; 4.27 ppm and 2.88 & PLUSMN; 0.40 wt% for Eocene plutons, respectively. Radiogenic heat production rates are 1.43-2.73 & mu;W/m3 for Paleozoic plutons, 0.74-1.70 & mu;W/m3 for Jurassic plutons, 0.66-6.28 & mu;W/m3 for Cretaceous plutons and 1.15-5.22 & mu;W/m3 for Eocene plutons. The studied plutons were classified as low-to moderate heat-producing granitoids. However, some Cretaceous and Eocene granitic plutons with radiogenic heat production values of 5.22-6.28 & mu;W/m3 are considered as high heat-producing granitoids. The thermal indications in the region can be related to radiogenic heat generation and the neotectonic activity of the region. Considering the large volume of the Cretaceous-and Eocene-aged granitic plutons in the Eastern Pon tides Orogenic Belt, the moderate to high radiogenic heat production of the granitic plutons in some areas has a significant geothermal impact and can be considered as the potential of enhanced geothermal systems for the future energy demand of the region.