Halogens and H2O in the Petrogenesis of MORB and BABB

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This is a study of halogen elements and water in basalt rocks from the mid-ocean ridge system. Several questions will be addressed. Is the elevated abundance of chlorine in some basalts the result of seawater alteration of the rocks, or does the chlorine come from the earth's mantle? If alteration is the source, is the concentration related to seafloor spreading rate, tectonic associations, or crystallization depth of the basalt? Does the observed excess in chlorine relate to commonly observed excesses in some other elements? Are there regional variations in the concentration of water relative to other elements in mid-ocean ridge basalts, and if so, does this reflect mantle heterogeneity? Despite their low abundances in mid-ocean ridge basalt, these volatiles play an important role in magmatic processes with the suboceanic mantle and crust and this study of the nature and concentration of volatiles will provide crucial information about the formation and evolution of magmas at mid-ocean ridges.