Figure 26. Average analyses for all Leg 187 glasses in relation to the 0- to 7-Ma data fields from Figure 25. A. Zr/Ba vs. Ba. Data are color coded according to the field in which they plot. Yellow triangles lie outside the 0- to 7-Ma fields and are referred to as Transitional Pacific because they appear to extend the Pacific field in the direction of Zone A propagating rift tip lava (PRT) compositions. The red triangle is a glass from Hole 1164A that plots at the boundary between the Pacific and Indian fields. MORB = mid-ocean-ridge basalt. B. Na2O/TiO2 vs. MgO. Color coding is defined by the Ba-Zr systematics in A. Note that no Leg 187 sample plots in the 0- to 7-Ma Indian field, but, with the exception of four Pacific samples, there is a clear division between Pacific and Indian samples. These four samples plot to the left of the B5 tie line in A, a region where small analytical errors in Ba result in large shifts in plotting position. Note also that Transitional-Pacific samples plot in both fields.