At a constructive plate margin magma rises between two tectonic plates. The plates move away from each other due to ridge push and slab pull. The magma cools to form a new plate. On land rift valleys form such as the East African rift valley. Where two oceanic plates move apart new islands can be formed e.g. Iceland.

• Less dense than oceanic crust
• Thicker than oceanic crust
• Lighter than oceanic crust
• Forms the Earth’s continents
• Older than oceanic crust