Determination of alteration zones and geological unit limits using natural radioactivity properties of Sandıklı-Suhut areas

Abstract

This study aims to determine the radioactivity properties of the geological units outcropped in the area between Sandıklı-Şuhut (Afyonkarahisar) and reveal the origin and boundary relations of geological units by taking advantage of these properties. The geologic units outcropping in the region consist of Paleozoic metamorphics, Mesozoic olistrostromal sediments and mega limestone blocks, Tertiary volcanic and volcaniclastics, and fluvial and lacustrine sediments. In the contacts of these geological units, alteration zones developed at the influence of thermal fluids due to volcanic activity. These zones exhibit different radiological characteristics depending on the lithological features of the geological units and their proximity to volcanic activity. The measured 238U, 232Th and, 40K activity concentrations, U/Th, Th/U, Th/K, and U/K values, Efimov parameter depending on these activity concentrations indicate characterizations that can estimate the boundaries of the alteration zones and geological units. The alteration zones and limits of geological units were determined using the maps generated from measured and calculated parameters. In addition, many trachyandesitic dykes and thin lava levels that could not be marked in the units signed as agglomerate, tuff, and lava in the geological map, were determined on the radioactive maps with high anomaly values.