Plate Movements - Earth Sciences Flashcards
What happens when tectonic plates move apart?
As plates move apart, magma from the mantle rises to fill the gap, and forms underwater volcanoes and creates new oceanic crust as it cools and solidifies. As the plates continue to move, the gap reopens and more magma rises.
What landform is created when tectonic plates move apart?
An underwater mountain range (a ridge).
What happens when two neighbouring plates slide past each other?
It causes an earthquake. If the plates move past each other smoothly, it only causes a tremor. If the plates get stuck, pressure builds up until the plates are able to continue moving, and the energy is released, causing an earthquake.
What is an example of a boundary between sliding plates?
The San Andreas Fault.
What are the two possible things that can happen when plates push against each other?
They can either form a mountain, or create a subduction zone.
What happens when plates form a Mountain? Which types of plates are involved?
When two continental crusts push against each other, they crumple upwards, forming mountain ranges.
What happens when an oceanic crust and a continental crust push against each other?
The oceanic crust, which is more dense, sinks below the continental crust, and goes into the mantle. Here it melts, and is “recycled”. Areas where this process happen are called subduction zones.
What two things make the oceanic crust go beneath the continental crust?
- The oceanic crust is denser than the continental crust.
2. Once the oceanic crust has gone under the continental crust, it’s own weight pulls it further down into the mantle.
Explain why volcanoes often form near subduction zones.
When the oceanic crust melts in the mantle, it releases gases and other volatile substances. These substances built up just under the continental crust, and the pressure accumulates until it is strong enough to shoot out of the continental crust in the form of a volcanic eruption.
