The devil's in the details: Hydrogeology of Middle Valley Active Venting Areas



A scientific team aboard the R/V Maurice Ewing conducted a fine-scale examination of the hydrogeology of two areas of active venting in Middle Valley, northern Juan de Fuca Ridge. Earlier expeditions had identified moderate-to-high temperature vent activity at the two sites, as well as by-products of hydrothermal processes: sediment alteration; massive, disseminated sulfide deposits; and extensive vent faunal communities. Preliminary analyses of new data reflecting fluid, heat, and chemical fluxes suggest that the flows are complex in their distributions, have a significant hydrothermal recharge within the vent areas, and may be more vigorous than previously thought.