Three-dimensional lithospheric-scale thermal model as supporting tool for new exploration campaigns for geothermal resources: insights from the Calabria region (Southern Italy)

This study presents the first lithosphere-scale, steady-state 3D thermal model of the Calabria region (Southern Italy), developed to support the geothermal resource assessment and exploration. By integrating geological, geophysical, and thermal datasets, a high-resolution 3D geological model was built and used as a structural framework for finite-element thermal simulations. The simulations incorporated spatially variable thermal conductivity, radiogenic heat production, and a range of basal heat flux values applied at the crust-mantle (Moho) interface. Five thermal scenarios were tested and calibrated against 254 measured temperature data points from exploration wells. The results reveal pronounced lateral thermal heterogeneity, with temperatures exceeding 90 ◦C at 3 km depth beneath the Ionian basins, driven by the local crustal structure, sedimentary blanketing, and Moho geometry. While the model delineates zones suitable for low-to-medium enthalpy geothermal exploitation (1-3 km), deeper high-enthalpy targets remain less constrained and deserve further investigation. This study establishes a geologically consistent framework that enhances the understanding of the regional thermal regime and serves as a strategic tool for guiding future geothermal exploration in Calabria.