Cobalt in active seafloor massive sulfide deposits in the Norwegian Sea

Cobalt is critical for the green energy transition, yet the mineralogical distribution and the mechanisms of concentration of Co in different types of hydrothermal ore deposits remain poorly constrained. Here we document ore mineral assemblages from the active Fåvne and Loki’s Castle seafloor massive sulfide deposits located along the Mohns Ridge in the Norwegian Sea, and determine their whole-rock and mineral chemical compositions with a special emphasis on Co.