Surface hydrothermal deposits of the shallow-water Menez Gwen vent field located in the rift zone of the Mid-Atlantic Ridge are mostly composed of nonmetalliferous minerals in contrast to sulfide deposits of deep-water fields. Here sulfide minerals occur only in dispersed form. High-temperature sulfide deposits strongly enriched in copper and zinc occur only immediately below the surface of the bottom. This is related to subsurface boiling and phase separation of initial high-temperature hydrothermal ore-bearing solution that ascends from the interior to the floor surface.

Supplement to: Bogdanov, Yury A; Lein, Alla Yu; Sagalevich, Anatoly M (2005): Chemical composition of the hydrothermal deposits of the Menez Gwen vent field (Mid-Atlantic Ridge). Translated from Okeanologiya, 2005, 45(6), 897-905, Oceanology, 45(6), 849-856