Fig. 19

The distribution of Atlantis Bank mineral compositions relative to modeled liquid and solid lines of descent modeled for 1 kb using Ghiorso and Sack (1995). Gray bars connect equilibrium melt and plagioclase compositions using the most primitive MORB glass from Dick et al. (2000) as a starting composition for 30–90% crystallization. a Atlantis Bank seafloor gabbro sample plagioclase anorthite contents (upper data array) and Ca × 100/(Ca + Na) for present day ridge segment glasses (lower array) plotted against the coexisting augite and glass Mg#. b–e The predicted solid line of descent from panel a and the plagioclase and augite compositions for the northern, eastern (top of bank), southern, and western regions, respectively