The GeoLaB-1 well

The exploration well GeoLaB-1 will be drilled in February 2025 into the Tromm pluton in the Odenwald (SW Germany) with a maximum depth of 500 m. An only 20-30 cm thin veneer of Quaternary sediments is expected on top of a few m of weathered granite, followed by massive granites and quartz-monzonites until final depth. The drilling plan involves full coring and a comprehensive logging program of the Tromm pluton. Drilling is accompanied by 2D-seismic, gravimetric, geoelectric, and magnetic surveys. The cores will provide basic information about the compositional heterogeneities of the Tromm pluton, particularly their mineralogy, fracture network, hydrothermal alteration, and their microbiology with depth. The focus of the investigations will be on petrography and mineralogy, petrophysical properties, quantitative analysis of fracture networks, the native upper crustal microbiome, hydrochemistry, hydrotesting, and geomechanical modelling. Borehole completion includes implementation of glass fiber optic cables and geophones for later monitoring.

The results will influence the site selection and design for the construction of the GeoLaB research underground infrastructure. Furthermore, it will allow the evaluation of potential future impacts from tunnel construction and laboratory operation.