Figure F7. A. Variations in Zr/Ba vs. Ba of basaltic glass dredged from 0- to 7-Ma seafloor within and east of the Australian Antarctic Discordance (AAD) (D.G. Pyle and D.M. Christie, unpubl. data). PRT = propagating rift tip lavas; MORB = mid-ocean-ridge basalts; dashed line separates Indian- and Pacific-type zero-age Southeast Indian Ridge (SEIR) basalt glass. B. Variations in Na₂O/TiO₂ vs. MgO of basaltic glass dredged from 0- to 7-Ma seafloor within the AAD and Zone A (D.G. Pyle and D.M. Christie, unpubl. data). Dashed line separates Indian- and Pacific-type zero-age SEIR basalt glass.