Were does serpentinite form?
Serpentinite is a metamorphic rock that forms at tectonic plate boundaries deep within the Earth. In the Franciscan Complex, it formed when ocean water carried down with subducting ocean crust was heated and moved through upper mantle and basal ocean crust rocks, hydrating their magnesium- and iron-rich minerals, like olive and pyroxene, to form magnesium-rich serpentine minerals.
