A new type of oceanic crust and its dynamical significance

Conclusions There are two types of oceanic crust: the “Troodos type” with stratiform and thick oceanic crust, characterized by the development of sheeted dike swarms and thick cumulative rocks; and the “Shuanggou type” with thin oceanic crust composed of mafic plutonic and volcanic rocks, without sheeted dike swarms and ultramafic cumulates. The different types of oceanic crust represent the different dynamic processes under the mid-oceanic ridges, which relate with not only the spreading velocity of oceanic plate, but also the formation and volume of magmas under spread ridges. It is suggested that the spreading velocity of oceanic plate is most probably related with the rock assemblage, not the composition of oceanic crust.