Radiogenic heat production in rocks from the Sabinas Basin (northeastern Mexico) determined by in situ gamma radiation measurements

Abstract

Abstract In situ gamma radiation measurements were performed to calculate the radiogenic heat production of sedimentary and igneous rocks from the Sabinas Basin (northeastern Mexico). The sedimentary rocks include shales, sandstones, and limestones from Cretaceous geological formations. The igneous rocks consist of basalts and granodiorites. The basalts belong to different volcanic fields, and the granodiorites are located in the Candela-Monclova magmatic belt. The analysis of all rocks yielded values of up to 13.4 ppm, 47.3 ppm, and 9.1% for uranium (U), thorium (Th), and potassium (K), respectively, and their radiogenic heat production (RHP) values ranged from 0.11 to 6.42 µWm− 3. The studied rocks were accordingly classified as having a low (< 2 µWm− 3), moderate (2–4 µWm− 3), and high (> 4 µWm− 3) RHP. Most studied rocks were characterized by a low heat production, and only 12% of the measurements indicated rocks with moderate and high heat production rates. These latter rocks are represented by clastic sedimentary rocks (shale and sandstone) and granodiorites. The sedimentary rocks, particularly shales, had the highest contents of radioelements and RHP (0.43 to 6.42 µWm− 3). These rocks belong to the Olmos Formation, and their high RHP potential are related to their organic matter and silica contents, and their relationship with deep geological structures. The sandstones of the Pátula Formation also yielded high RHP values (0.72 to 4.73 µWm− 3), linked to their silica contents, feldspar, and micas. The shales and granodiorites showed the highest RHP rates from U and sandstones from Th.