オフィオライト研究の新展開

抄録

 This short article reviews studies on ophiolites over the last two decades. Chapter titles are; I. Introduction, II. Definition of ophiolites and differences from other mafic-ultramafic complexes, III. Classification of ophiolites and their petrologic diversity, IV. Ophiolites and the oceanic crust, V. Relationships between ophiolites and metamorphic rocks and accretionary complexes, VI. Time-space distribution of ophiolites, VII. Genetic settings of ophiolites (Miyashiro's debate and consequences), VIII. Conclusion. Special attention has been paid to recently discovered oldest and youngest ophiolites as well as the recent re-evaluation of “Troodos Debate” provoked by Miyashiro (1973), who threw a rock that stirred up the peaceful consensus among the world's geologists that correlated ophiolites to mid-ocean ridges, and stimulated extensive geochemical and geotectonic studies on both ophiolites and ocean floor. Geologists are eventually approaching a new consensus that most ophiolites formed at a subduction initiation along the edge of a new oceanic plate.