Final answer:
Yes, contact metamorphism can occur beside a lava flow, as the heat generated by the lava can lead to the recrystallization of surrounding rocks without causing them to melt, creating a contact metamorphic zone.
Step-by-step explanation:
Yes, contact metamorphism can indeed take place beside a lava flow. When lava flows onto the surface, it can provide a source of heat that leads to the metamorphism of surrounding rock material. This process involves the alteration of pre-existing rocks (the protolith) via changes in temperature, and/or pressure, or by contact with chemically reactive fluids.
In the case of a lava flow, the intense heat can cause the adjacent rock to undergo recrystallization processes resulting in a contact metamorphic zone, typically under subsolidus conditions, meaning that the rock does not melt but instead recrystallizes to form new metamorphic minerals and textures.
During this process, new minerals can form and the texture of the rock can change, but without reaching the melting point. This can lead to a banded arrangement of minerals known as foliation, or in the case of non-foliated metamorphic rocks, changes may be more textural rather than compositional. The heat from the lava flow is a critical factor, as it allows for the migration of ions within the crystal structures and facilitates the realignment of minerals under pressure without the rocks breaking.
The proximity to the heat source determines the intensity of the metamorphic process. Clay-rich rocks can be altered into hard slates and phyllites, while more intense heat might transform rocks into schist or gneiss. As indicated in the contact metamorphic zone, this change in rocks occurs within the region that is directly affected by the heat from the igneous intrusion, which could be a lava flow or other related geothermal phenomenon.