Answer:
if the foliation on a rock is running north-south, the pressure might be vertical (for instance, up to down)
Explanation:
The pressure is the second most principal factor that influences metamorphic rocks. It originates from the weight of the own materials, their densities, and the deepness.
Litostatic pressure originates from the weight of materials in the interior of the crust.
Pressure generates alignment of materials (foliation and schistosity) and mineral rotation.
There are different types of metamorphism.
Dynamic metamorphism is the one where pressure is the principal factor. It generates by tectonic conditions, and it presents mainly in failure or fracture areas. It provokes trituration and recrystallization of minerals.
Classification of the metamorphic rocks according to their structure:
- Granulation
- Recrystallization
- Metasomatism
- Massive
- Foliation
Foliation refers to dynamic metamorphism, where pressures act and minerals orientate perpendicular to the pressure direction.
<em>According to this concept, if the foliation on a rock is running north-south, the pressure might be vertical (for instance, up to down) while minerals' weight helping in the process of foliation. </em>