Sulfide Deposits From The Juan De Fuca Ridge At 47 ° 57 ́ N, 129 ° 06 ́ W

More than 140 kg of sulfide material was dredged from the Endeavour Segment of the Juan de Fuca Ridge. The Endeavour samples differ significantly from previously described seafloor sulfide deposits. They exhibit complex texture, including apparently sealed exit channels and intricate mineralogical layering. A detailed study of the largest sample (which weighs nearly 80 kg and measures cm) suggests that the sulfide deposits formed from mixtures of seawater and hydrothermal fluid. The relative proportions of seawater and hydrothermal fluid varied frequently on a time scale that is short in comparison to the time required to produce the deposits. Compositional variations among seafloor sulfides can be explained by subsurface deposition of copper and zinc sulfides.