Evaluation of Heat Generation by Radioactive Elements in Jurassic and Cretaceous Successions of the Zagros Belt, Northern Iraq

This study presents data on Radioactive Heat Generation (RHG) from Jurassic and Cretaceous successions in selected wells along the Zagros belt in Northern Iraq. A total of 2,600 meters of rock intervals were analyzed, encompassing all Jurassic and Cretaceous successions within the conjugated zone of the High and Low Folded zones. RHG values were obtained from Uranium, Thorium, and Potassium concentrations, measured using Gamma Ray Spectrometry and Normal Gamma Ray logs. These measurements reflect the RHG resulting from the decay of Uranium-Radium series isotopes (U238, U235, and U234), the Th232 series, and the primary decay of K40. In the Jurassic section, the heat generation rate ranges from 1.51 µW/m³ in the upper part of the Butmah Formation to 5.52 µW/m³ in the Naokelekan Formation. In the Cretaceous section, it varies from 0.77 µW/m³ in the Kometan Formation to 1.48 µW/m³ in the Sarmord Formation. The contribution of these RHG rates to the subsurface temperature is approximately 2.60 mW/m² for the Jurassic section and 1.54 mW/m² for the Cretaceous section. These findings can be applied to evaluate how lateral variations in RHG rates influence heat flux and temperature distribution within the upper crust and sedimentary basins, particularly in terms of radioactive heat flow (RHF).