The results of melting lavas from the continental and oceanic successions of the seaward-dipping reflectors allow the phase equilibria constraints for low-pressure crystal fractionation to be evaluated. The experimental liquid lines of descent as well as modeling of crystal fractionation indicate near-multiple saturation and modest extent of fractionation for the majority of recovered flows. The melting relations for samples from the oceanic succession (Sites 918 and 989) differ from those obtained from the continental succession (Thy et al., 1998) by the early appearance of low-Ca pyroxene. Therefore, the continental and oceanic successions are not comagmatic and related to identical low-pressure liquid lines of descent. The results of melting basaltic andesite from the Middle Series are difficult to reconcile with the compositional variation in the extruded lavas. The principal reason is that the variation in SiO₂ and FeO suggests early magnetite crystallization and that this phase was not saturated in the melting experiments. The REE modeling shows that the dacites can be produced by low degrees of melting (<20%) of hydrated gabbroic or basaltic material at middle to upper crustal levels. Such crustal melts may have been important contaminants of the Lower and Middle Series basaltic magmas. The trace-element modeling does not support leucogneiss contaminants as suggested by Fitton et al. (1998a, 1998b).