Figure 8.09. Comparison of Igneous Data Sets. Data from Mauna Loa (blue) Rhodes (2015), data from a Pacific MORB suite (orange) from PetDB, and data from a Sierra Nevada batholith suite (red) from the PETROS dataset. All three data sets show linear, but different, trends on the (Na2O+K20)-FeO(T)-MgO ternary diagram. FeO(T) is all the iron in the rock represented as FeO. It was argued in Figure 8.08 that the Mauna Loa trend was due to fractional crystallization of olivine. Fractionation of what minerals might have produced the Pacific MORB and the Sierra Nevada Batholith trends?