Where do pillow lavas form? Why do they form and from what type of magma?

Pillow lavas are geological features formed when a certain type of magma extrudes into a water environment, such as an ocean or a lake. They are called "pillow" lavas because of their characteristic shape - they usually resemble elongated, interconnected pillow-like structures.

Pillow lavas typically form in underwater environments. This can include the deep ocean floor, shallow seabeds, and even subglacial lakes. The extrusion of magma into water leads to a rapid cooling process, which creates the unique pillow-like structures.

Pillow lavas mainly form from basaltic magma, which is rich in iron and magnesium. Basaltic magma has a relatively low viscosity, meaning it flows more easily compared to other types of magma. This characteristic allows the magma to extrude underwater and form pillow lavas.

Pillow lavas form due to the rapid cooling of magma when it comes into contact with water. As basaltic magma extrudes into the water, the outer layer of the lava solidifies almost instantly, forming a thin crust. The pressure from the still-liquid magma inside forces the crust to expand, creating a pillow-like structure. As more magma extrudes and encounters the water, additional pillow-like structures form and connect to the existing ones. In conclusion, pillow lavas form in underwater environments due to the rapid cooling of basaltic magma when it comes into contact with water, resulting in distinctive pillow-like structures. This unique geological phenomenon provides valuable insights into the interactions between lava and water environments, as well as the geological history of our planet.