POSEIDON POS535

Seafloor conductivity anomalies may be caused by sulfide mineralization, or also by hot saline pore fluids. In past experiments, we applied an EM coil-system to study mineralization at hydrothermally inactive sites. This year, we will study hydrothermal activity without known mineralization at the Grimsey Vent Field (GVF). For 2019, we propose two further EM experiments near Loki’s Castle, which would be the first hydrothermally active vent site with known mineralization to be investigated with our EM system. Our shallow investigations would complement previous EM experiments of our cooperation partner NTNU with deeper penetration. Additionally, we intend to continue our work at GVF, where we propose a “4D” experiment by repeating and extending this year’s survey. The increased seismicity in 2018 indicates that the GVF is currently very active. The proposed experiment in 2019 will identify if EM investigations are capable of differentiating phases of hydrothermal activity.