Original: Oceanic lithosphere Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle ( peridotite ) and is denser than continental lithosphere , for which the mantle is associated with crust made of felsic rocks .
Simplified: Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle and is denser than continental lithosphere , for which the mantle is associated with crust made of felsic rocks .