1. Chemical Composition: The original mineral composition of the protolith directly determines the types of minerals that can form during metamorphism. For example, a limestone protolith will primarily yield metamorphic rocks composed of calcite and other calcium-rich minerals, while a sandstone protolith will predominantly form quartz-rich metamorphic rocks.
2. Physical Properties: The texture, grain size, and layering of the protolith can influence the degree and type of metamorphism that occurs. For instance, a finely-grained, thinly layered shale will exhibit more pronounced foliation (alignment of minerals) under pressure than a coarse-grained granite.
Let me know if you'd like to know more about any of these aspects!
