Early high-temperature metamorphism and deformation of oceanic gabbros record the evolution of the lower crust near mid-ocean ridges. Deciphering this record has proven difficult for two reasons: (1) imprecise temperature estimates for metamorphism, and (2) uncertainties about the equilibrium state of mineral assemblages. This study employs a combination of experimental, analytical, and statistical methods to address these issues. Experimental studies focus on the temperature and time dependence of secondary mineral compositions using natural metamorphosed gabbros formed at the East Pacific Rise. The petrologic and statistical component of this project will determine metamorphic mineral compositions from a suite of gabbros from ophiolites and mid ocean ridges. This study will yield a better understanding of the time scales and spreading-rate dependence of lower crustal processes near mid-ocean ridges.
