Granulite is a metamorphic rock with which level of foliation?

• A. Strong foliation
• B. No foliation
• C. Weak foliation
• D. Moderate foliation

Answer: (C)

Foliation strength reflects how mineral grains align under directed pressure. In granulite facies metamorphism, rocks form at high temperatures with relatively little water. This environment promotes recrystallization of minerals into a granular, equant texture rather than stretching and aligning, so you get little to no alignment of platy minerals. The result is an approximate isotropy with only a weak fabric if any. That makes weak foliation the best description for granulite rocks. Strong foliation comes from directional pressure with minerals that can easily reorient (like micas in schists), while no foliation would require a perfectly uniform, undeformed fabric, which is less typical for granulite textures.