Estimation of Radioactive Heat Production from Airborne Spectral Gamma-Ray Data of Gebel Duwi Area, Egypt

By

Ahmed S. K. Salem¹, Abuelhoda M. Elsirafi², Alaa A. Aref², Atef A. Mahmoud², Keisuke Ushijima¹

(1) Kyushu University, Fukuoka, Japan (2) Nuclear Materials Authority, Cairo, Egypt

 Radioactive heat production is governed by the amount of potassium, uranium, and thorium in rocks. Airborne radiometric surveys provide a fast estimate of the surface concentrations of potassium, uranium and thorium. However, utilization of airborne gamma- ray surveys in estimating radioactive heat production has not been presented. In this paper, we attempt to estimate the radioactive heat production from airborne spectral gamma-ray data of Gebel Duwi area, Egypt. A map of radioactive heat production was constructed from airborne gamma-ray data. The validity of estimating heat production from airborne data was confirmed using ground measurements. The area possesses a range of radioactive heat production varying from 0.21 mWm-3 to 3.09 mWm-3. The sedimentary rocks of the study area show values (0.25 mWm-3 to 3.09 mWm-3) higher than those given for the crustal sedimentary rocks. Meanwhile, the igneous rocks show average value (1.48 mWm-3) below the average for the crustal granites. The high values of heat production in the sedimentary rocks are mainly related to the relative increase of uranium content in Duwi phosphate formation. The reduced heat production of igneous rocks indicates that additional components combine with the radioactive heat production to the heat sources in the Gebel Duwi area. Generally, the results indicate that the use of airborne gamma-ray data to produce heat production map is a promising technique.