Melt Migration in Oceanic Crustal Production: A U-Series Perspective

The aim of this chapter is to review the observations of uranium series nuclide studies on mid-ocean ridge basalts (MORBs) and discuss their implications for melt transport processes. We initially recap the fundamental behavior of the naturally occurring actinide decay chains, and outline the analytical challenges of their measurement. We then evaluate the gross signatures of disequilibrium observed in MORBs and consider the co-variations of disequilibria with other geochemical and geophysical parameters. This is followed by a detailed discussion of models of melt transport that have been developed to account for these observations, allowing a synthesis of the key constraints that uranium-series measurements provide on the process of melt migration beneath mid-oceanic ridges.