POSEIDON POS524

In the marine environment elevated electrical conductivities may be caused by sulfide mineralizations within the seafloor as well as hot saline pore fluids. Such conductive targets may be studied with suitable electromagnetic systems like the novel coil-system MARTEMIS1, which we previously used to investigate a known zone of sediment covered mineralization at the Palinuro Seamount (cruise POS483). The Palinuro site is hydrothermally inactive and, thus, allows for the study of the influence of mineralizations apart from the influence of heated pore fluids. The MARTEMIS system was able to detect a conductivity anomaly in the vicinity of a known mineralization as well as a second anomaly, possibly a zone of buried mineralization at greater depth, which will be further investigated during cruise POS509 (February 2017). Within this proposal we want to study the suitability of the MARTEMIS and other EM systems to characterize active hydrothermal systems in the vicinity of the Grimsey Vent Field (North of Iceland, previously studied during cruises
POS229, POS253, POS291). EM investigations will not only give insight into the hydrothermal structure, but can also reveal potential covered mineralizations at depth. EM investigations are to be accompanied by geophysical (heat probe) and geological (gravity core) measurements to aid the interpretation of EM data, for ground truthing and to gain further structural insight.