Serpentinization is the process in which the mineral olivine reacts with water and gets transformed to serpentinite. The process creates a high pH fluid enriched in electron donors and acceptors that can be used by microorganisms for food and energy source, although living in these serpentinizing fluids represent challenges to the cell. 

The mineral olivine is abundant in ultramafic rocks, rocks that are representative of the uper mantle. At Ophiolites these ultramafic rocks are uplifted and are exposed obove sea level in continents. Thus, serpentinization can ocurr at the sea floor, but also at these continental ophiolites.