This volume follows a Specialized Symposium on "Mantle denudation in slow spreading ridges and in ophiolites," held at the XII EUG Meeting in Strasbourg, spring 1993. During the meeting it was felt that the contribu tions to the Symposium justified a volume presenting its main scientific achievements. The present title of the volume shows that the center of inter est has slightly shifted with respect to the initial objective: in order to under stand the processes involved in accretion taking place at oceanic ridges, it is crucial to study the interaction between uppermost mantle and lower...

viii debate of those earlier days has been beautifully summarized by H. H. Read in his famous "Granite Controversy" (1957). Read's formulation of the controversy occurred at the time when geochemistry was as a new and powerful tool. The new techniques opened era during which emerging an granites were considered mainly from this new viewpoint. Geochemical signatures have shown that mantle and crustal origins for granites were both possible, but the debate on how and why granites are emplaced did not progress much. Meanwhile, structural geology was essentially geometrical and mechanistic. In...

1.1. HISTORICAL DEVELOPMENT OF THE OPHIOLITE CONCEPT. Ophiolite, Greek for 'the snake stone', appears to have received its first written definition by Brongniart (1813) as a serpentine matrix containing various minerals. Later in 1821 and 1827, Brongniart determined that volcanic and gabbroic rocks were also present, associated with cherts, and he ascribed an igneous origin to the ophiolite. Amstutz (1980) gives an excellent exegesis of these early contributions and traces the further use of the term and concept of ophiolite. This concept had been forged in the western Alps and Apennines...