CoachAn ophiolite is a distinctive assemblage of mafic to ultramafic rocks, a piece of oceanic lithosphere now found on land. The Penrose ophiolite sequence is the complete assemblage defined by a conference of geologists in 1972; from bottom to top:
- an ultramafic complex of harzburgite, lherzolite and dunite, usually with a deformation fabric acquired in the solid state;
- a gabbroic complex, ordinarily with cumulus textures;
- a mafic sheeted dyke complex;
- a mafic volcanic complex, commonly pillowed.
