SAUNDERS, A. D. & NORRY, M. J. Introduction GASS,I. G. Magmatic processes at and near constructive plate margins as deduced from the Troodos (Cyprus) and Semail Nappe (N Oman) ophiolites WHITE, R. S. Asthenospheric control on magmatism in the ocean basins SPRAY, J. G. Upper mantle segregation processes: evidence from alpine-type peridotites NATLAND, J. H. Partial melting of a lithologically heterogeneous mantle: inferences from crystallization histories of magnesian abyssal tholeiites from the Siqueiros Fracture Zone DICK, H. J. B. Abyssal peridotites, very slow spreading ridges and ocean ridge magmatism BLOOMER, S. H., NATLAND, J. H. & FISHER, R. L. Mineral relationships in gabbroic rocks from fracture zones of Indian Ocean ridges: evidence for extensive fractionation, parental diversity, and boundary-layer recrystallization ELTHON, D. Pressure of origin of primary mid-ocean ridge basalts Fum, T. Genesis of mid-ocean ridge basalts PALACZ, Z. A. & WOLFF, J. A. Strontium, neodymium and lead isotope characteristics of the Granadilla Pumice, Tenerife: a study of the causes of strontium isotope disequilibrium in felsic pyroclastic deposits STOREY, M., WOLFF, J. A., NORRY, M. J. & MARRINER, G. F. Origin of hybrid lavas from Agua de Pau volcano, Sao Miguel, Azores THOMPSON, G., BRYAN, W. B. & HUMPHRIS, S. E. Axial volcanism on the East Pacific Rise, 10-120 N HELGASON, J. The Fjallgardar volcanic ridge in NE Iceland: an aborted early stage plate boundary or a volcanically dormant zone? FLOYD, P. A. Geochemical features of intraplate oceanic plateau basalts DAVIES, G. R., NORRY, M. J., GERLACH, D. C. & CLIFF, R. A. A combined chemical and Pb-Sr-Nd isotope study of the Azores and Cape Verde hotspots: the geodynamic implications CHAFFEY, D. J., CLIFF, R. A. & WILSON, B. M. Characterization of the St Helena magma source JORON, J.-L. & TREUIL, M. Hygromagmaphile element distributions in oceanic basalts as fingerprints of partial melting and mantle heterogeneities: a specific approach and proposal of an identification and modelling method FISHER, D. E. Evaluation of rare gas data in relation to oceanic magmas SUN, S.-S. & McDONOUGH, W. F. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes MURTON, B. J. Tectonic controls on boninite genesis Index