Subduction-Zone Ophiolites and Island-Arc Ophiolites

Abstract

Although it is often said that typical ophiolites show a definite pseudostratigraphic sequence of rocks and occur in ancient subduction zones, most ophiolites showing a typical sequence occur outside subduction zones, and most ophiolites in subduction zones do not show a regular sequence. So, in this paper, large-scale mafic and ultramafic rock associations in subduction zones and other parts of orogenic belts are called ophiolites, regardless of the presence or absence of a regular sequence. Ophiolites in this sense occur not only in ancient subduction zones but also in ancient island arcs.