Experimental and theoretical constraints on hydrothermal alteration processes at mid- ocean ridges.

Experimental and theoretical data can be used to constrain hydrothermal alternation processes in the submarine geothermal system at mid ocean ridges. These data indicate, for example, that seawater chemistry, basalt diabase chemistry and texture and temperature and pressure dictate the direction and magnitude of chemical exchange, the chemistry and mineralogy of alteration phases, and the mechanism of H⁺ production, which is so critical to the solubility of heavy and base metals. Experimentally-derived Fe, Mn, pH and density data constrain the temperature and pressure of formation and ridge-crest hydrothermal fluids when it is assumed that these fluids are in equilibrium with quartz. -from Author