Figure F25. A. Variations in Zr/Ba vs. Ba of basaltic glasses dredged from 0- to 7-Ma seafloor within and east of the Australian Antarctic Discordance (AAD) (D. Pyle and D. Christie, unpubl. data). PRT = propagating rift tip lavas; dashed line = approximate geochemical boundary between Indian- and Pacific-type zero-age Southeast Indian Ridge basalt glass. B. Variations in Na₂O/TiO₂ vs. MgO of basaltic glass dredged from 0- to 7-Ma seafloor within and east of the AAD (D. Pyle and D. Christie, unpubl. data).