Geothermal activity visible on the surface,acute to extreme seismographic readings. typically on the borders of tectonics plates. (Ring of fire)
Igneous Rocks
At diverging plate boundaries, convection currents bring hot magma to the surface. Sometimes, magma that gets pushed up at plate boundaries cools before it gets there. It fills in cracks and voids in the bedrock
Metamorphic Rocks
Hot magma pushes itself to the surface at both divergent plate boundaries and convergent plate boundaries. This magma comes in contact with rocks as it rises to the surface.
