At constructive plate boundaries, the tectonic plates are moving away from one another. The Earth's crust is pulled apart to create a new pathway for rising hot magma to flow on to the surface. ... As the plates pull apart, molten rock (magma) rises up and erupts as lava, creating new ocean crust.

What happens at destructive and constructive plate boundaries?

Explanation: Constructive plate boundaries are when there are two plates moving apart from each other. ... Destructive plate boundaries are when oceanic and continental plates move together. In these places, the oceanic plate is forced, or subducted, under the continental plate.

What type of volcanoes form at constructive plate boundaries?

Shield volcanoes are found on constructive plate margins , where two plates move away from one another. Shield volcanoes have the following characteristics: basic lava, which is non-acidic and very runny. gentle sides as the lava flows for long distances before it solidifies.