Reconstruction of palaeoinfiltration during the Holocene using porewater data (Laxemar, Sweden)

The ability to interpret the natural tracer profiles in accordance with independent geological, hydrological and climatic constraints indicates that matrix diffusion in crystalline rocks is effective over decametres within timescales of ∼10-14 ka. The impact of matrix diffusion on the fracture groundwater composition will become measurable over these timescales, especially in low transmissivity fractures. These data demonstrate that porewater indeed acts as an archive for palaeohydrologic variations although the resolution is still limited.