Geothermal 3D model of the shallow crustal structure of the Alta Val d’Agri area (southern Apennines)

Abstract

A geothermal model for the area of the Val d’Agri oil fields has been obtained by an analytical procedure. The model takes into account both the temperature variation due to the re-equilibrated conductive state after thrusting and frictional heating. Input parameters include heat flow density data and a series of geologically derived constraints - thrust depth, timing of thrusting, slip rate - obtained by the integration of surface and subsurface datasets. The results of this work, representing a first attempt to reconstruct a geothermal 3D model for the Val d’Agri zone of the Basilicata region, emphasize two main regional features: (i) the isotherms relative to temperatures lower than 350 °C are roughly parallel and sub-horizontal across the whole study area, tending to deepen just along the NE-most edge of the investigated region; (ii) the isotherms relative to temperatures greater than 350 °C tend to deepen toward the center of the valley. Therefore, while the thermal structure at mid crustal depths appears to be perturbed and roughly mirroring the surface valley, the seismogenic upper crust of the study area is characterized by an unperturbed, roughly homogeneous and regular thermal structure.