Final answer:
Foliated metamorphic rocks are listed in increasing order of metamorphic grade as slate, phyllite, schist, gneiss, and migmatite, with each exhibiting more complex textures and mineral compositions as the grade increases.
Step-by-step explanation:
The question pertains to foliated metamorphic rocks and their organization in terms of metamorphic grade. Foliated metamorphic rocks have a layered texture where minerals align due to pressure and temperature conditions during the metamorphic process.
Here is a list starting from the lowest to highest grade:
- Slate: Very fine-grained, results from low-grade metamorphism.
- Phyllite: Fine-grained, characterized by a slightly higher grade than slate with a glossy sheen and wavy surface.
- Schist: Medium to coarse-grained, representing a higher grade where minerals start to grow larger and become more distinct.
- Gneiss: Coarse-grained, a high-grade metamorphic rock with distinct banding due to intense metamorphism.
- Migmatite: Exhibits features of both igneous and metamorphic rocks and forms at the highest temperatures of metamorphism before melting occurs.
As the grade of metamorphism increases, the texture and mineral composition of these rocks become more complex, with higher grades of rocks generally found deeper in the Earth's crust or in regions that have been subject to greater pressures and temperatures.