This region is more than 2.5 billion years old and is composed of felsic intrusive rocks.

This is especially critical for komatiite lavas and ultramafic intrusive rocks.

Magmatic fluids coming from the intrusive rock may also take part in the metamorphic reactions.

It was descriptively named from the prevalent intrusive rock on the bluff which has the appearance in color and texture of a fruitcake.

This suggests that these intrusive and extrusive rocks are coeval and share a common source.

It is doubtful whether the variolite is an intrusive rock or a lava flow.

When erosion removes the overlying rock material, these intrusive rocks are exposed and the pressure on them is released.

Igneous intrusive rocks are generally not divided into Formations.