Hydrothermal Processes And Metallogenesis. New Perspectives After Drilling On Tag (ODP Leg 158), Middle Valley (ODP Leg 169) And Recent Investigations On Slow Spreading Ridges

Results of the two main drilling operations on hydrothermal fields demonstrate that the two dimensional submersible operations need to be followed by drilling expeditions to study the third dimension of hydrothermal systems and understand hydrothermal and ore forming processes. Two types of environments were drilled recently in basaltic environment on slow spreading ridge, and on a sedimented ridge. Similar work has still to be done and targets to be discussed in other environments such as back-arc basins for felsic rocks environments and slow spreading ridges for ultramafic rock environments.