Figure F12. A. Variations of Zr/Ba vs. Ba of basaltic glass from Holes 1158A, 1158B, and 1158C and whole-rock samples compared with Indian- and Pacific-type mid-ocean-ridge basalt (MORB) fields defined by zero-age Southeast Indian Ridge (SEIR) lavas dredged between 123°E and 133°E. TP = Transitional Pacific; PRT = propagating rift tip lavas. B. Variations of Na₂O/TiO₂ vs. MgO for Holes 1158A, 1158B, and 1158C basaltic glass and whole-rock samples compared with Indian- and Pacific-type MORB fields defined by zero-age SEIR lavas dredged between 123°E and 133°E. A dashed line separates Indian- and Pacific-type zero-age SEIR basalt glass.