In a study performed in the crystalline rocks of the Grimsel Underground Rock Laboratory, migration pathways in water-conducting features and within the matrix rock were investigated using fluid tracers containing radionuclides (Möri et al., 2006, Möri 2009). To obtain information about spatial localization and distribution of fluid flow, a series of rock slabs were investigated by autoradiography, which revealed the localization of radionuclides along the flow paths.
Visual light photograph and autoradiography of a granodiorite from the Grimsel Underground Laboratory (Möri, 2009). The dark features in the autoradiograph are radionuclide-rich minerals such as zircons or monazites (discrete spots) and flowpaths of the radionuclide tracer fluid (elongate, continuous traces).