Vertical distributions of uranium, thorium and potassium and of volumetric heat production rates in the sediments of the São Francisco Basin, Central Brazil

Uranium, thorium and potassium measurements and volumetric heat production rate calculations were made in Bambuí Group Neoproterozoic sedimentary rocks from the São Francisco Basin, central Brazil. The measurements were made from drilling cuttings from two deep wells drilled near the cities of Alvorada do Norte, northeast Goiás State, and Montalvânia, north of Minas Gerais State. The obtained results allowed the construction of the vertical profiles depicting the abundances of heat generating elements, of the heat production rate and of U/Th, U/K and Th/K ratios in these sediments. These profiles, which reflect both the lithology and the sediment history, are used to interpret some aspects of the Bambuí Group sedimentation sequence.