Volcanic Ultramafic Rocks
Volcanic ultramafic rocks are rare outside of the Archaean and are essentially restricted to the Neoproterozoic or earlier, although some boninite lavas currently erupted within back-arc basins (Manus Trough, New Guinea) verge on being ultramafic. Subvolcanic ultramafic rocks and dykes persist longer, but are also rare. Many of the lavas being produced on Io may be ultramafic, as evidenced by their temperatures which are higher than terrestrial mafic eruptions.
Examples include komatiite and picritic basalt. Komatiites can be host to ore deposits of nickel.
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