Given the recognition that the melting processes that produce the oceanic
crust are polybaric and most probably near-fractional, quantitative models
of the compositions of the mantle-derived magmas that form the oceanic
crust are directly linked to physical and chemical constraints on mantle
upwelling and melting, melt segregation, and melt transport. The past 4
years have seen substantial progress in our ability to model and
quantify these processes.