AbstractThe melting relations of a group of oceanic basalts—olivine basalts, tholeiitic to midly alkaline, and high‐alumina tholeiites are determined. The liquidi of these rocks follow closely the course of the temperature—iron enrichment relationship of Kilauean thoeliitic basalts, ranging from 1430°C for an olivine enriched tholeiite, to a tholeiite of liquidus temperature of 1190°C, the liquidus phase of the assemblages being either olivine or plag