Blank can cause magma within earth to blank resulting in the formation of blank rock

Cooling can cause magma withing Earth to solidify resulting in the formation of igneous rocks

Explanation:

Magma consists of molten or semi-molten material that forms in the mantle and travels upward due to the presence of convective currents in the Earth's interior. As the magma travels upward, it encounters lower temperatures: as a result, its temperature cools down, and the material solidifies. The rocks that form as a result of this process are called igneous rocks. There are over 700 types of igneous rocks beneath the Earth's surface, and they are known to form (together with metamorphic rock) up to 90% of all rocks to a depth of 10-15 km from the surface.

the part of the wave he is travelling on is the crest