Fig. 7From: Deep hydrochemical section through the Central Alps: evolution of deep water in the continental upper crust and solute acquisition during water–rock-interaction along the Sedrun section of the Gotthard Base TunnelCa and Na concentration along the Sedrun Section: Numbers 1–6 in green circles: Strongly fractured zones with high discharge rates, high TDS and Cl (see discussion Sect. 7)Back to article page