Figure F15. Whole-rock variation diagrams of incompatible minor elements (A) MnO and TiO2 vs. Mg# and (B) P2O5 vs. Mg#. MnO and TiO2 are negatively correlated with Mg#, and most Hole 1105A nonoxide gabbroic samples are depleted with respect to basaltic compositions. Oxide-rich gabbros become more enriched than the basaltic rocks. P2O5 is also incompatible and tends to increase slowly with decreasing Mg# until apatite precipitates in oxide gabbros. P2O5 can climb to >2 wt% from low background levels.

Figure F15. Whole-rock variation diagrams of incompatible minor elements (A) MnO and TiO₂ vs. Mg# and (B) P₂O₅ vs. Mg#. MnO and TiO₂ are negatively correlated with Mg#, and most Hole 1105A nonoxide gabbroic samples are depleted with respect to basaltic compositions. Oxide-rich gabbros become more enriched than the basaltic rocks. P₂O₅ is also incompatible and tends to increase slowly with decreasing Mg# until apatite precipitates in oxide gabbros. P₂O₅ can climb to >2 wt% from low background levels.