This data publication provides the results of the investigations and measurements of thermal rock properties conducted on site in the Tournemire field laboratory and at the Thermal Petrophysics Lab at GFZ.

The thermal characterization of the clayey Jurassic (Upper Toarcian, ca. 180 My old) is contributing to the site characterization of the Tournemire Underground Research Lab (URL), located in Southern France. This URL is installed in a former railway tun-nel to better understand the physical processes resulting from thermal and hydrau-lic loading in a small fault zone in a highly consolidated shale formation (Bonnelye et al., 2023). At the Tournemire site, faults and fractures of different sizes extend from the surface (sedimentary cover) to the crystalline basement. At one specific gallery (Gallery East 03) installed in the former tunnel, thermally controlled in-situ fluid injection experiments are scheduled on a strike-slip fault zone outcropping at the URL (Bonnelye et al., 2023). In 2022, we visited the URL for baseline characteri-zation of thermal properties and to study the heterogeneity of the clay-dominated formation. Therefore, we took the chance to collect data and samples for a laborato-ry measurement campaign and to measure thermal conductivity in-situ in the tun-nel wall of Gallery East 03. The thermal data shall provide the baseline for the pa-rameterization of future numerical 3D models to better understand the thermal-hydraulic processes related to the experiment. This data publication provides the results of the investigations and measurements conducted on-site in the field la-boratory and at the Thermal Petrophysics Lab at GFZ.