Some Problems on Emplacement of Ophiolitic Rocks around Plate Subduction Boundaries

Abstract

Some modes of occurrences of ophiolitic rocks from plate subduction boundaries are simply reviewed and the present problems are summarized. The occurrences indicate that most of the basaltic rocks in accretionary complexes are not of MORB origin but of hot spot origin; while those form non-accretionary type landward slopes of trenchs are mixtures of island arc, MORB and hot spot origins, although the first is dominant. Future more detailed data which make good relations between the tectonic settings and occurrences may provide some implications on the ophiolite problems.