Final answer:
Low-grade metamorphism of shale generally leads to the formation of slate, which is a foliated metamorphic rock with planar foliation planes.
Step-by-step explanation:
The metamorphism of a shale at a low metamorphic grade typically produces slate. Slate is a foliated metamorphic rock that is formed by the low-grade metamorphism of shale. It is characterized by its fine-grained texture and ability to split into thin layers.
Slate is a foliated metamorphic rock that retains the original shale bedding and is recognized by its planar foliation planes. It forms when shale, which is a type of mudstone or claystone, undergoes low-grade metamorphism.
The process involves compaction and slight recrystallization but not enough to form the larger crystals characteristic of higher-grade metamorphic rocks like schist and gneiss.