Regional geothermal studies in the state of Tocantins, north-central region of Brazil

Abstract

The Tocantins state is located in north-central region of Brazil. Its tectonic structure comprises the northern Tocantins Province and the western edge of the Parnaíba Basin. In this geological context, new geothermal data were acquired in 38 different locations, ranging from the southern to northern part of the area in two collection periods. Measurements were based on the conventional acquisition method, where we used a thermal probe that records temperature in depth. Mapping of the values of thermal gradient allowed the identification of a significant geothermal anomaly in the central region, whose average geothermal gradient is 22.2 ± 1°C/km. This is a low value for a region, whose probable geothermal resources wouldn’t be able to be used for power generation, but geothermal resources contained in the geothermal anomaly could be developed for direct uses as tourism and spas, agribusiness, fish-farming and other. This anomalous region may be related with a directional trend of hot springs mapped in the southern region of the state and in neighboring regions with aligned structural directions along the Tocantins-Araguaia region.