Figure 8.
Proposed fuzzy classification of gabbroic rocks in the plagioclase-olivine-orthopyroxene-clinopyroxene (POOC) tetrahedron. All boundaries are meant to be fuzzy. The base of this tetra-hedron is the OOC triangle of Figure 7, and plagioclase-poor rocks can be named using either one (see examples). Names in the base of the tetrahedron are omitted for clarity.