Plate Boundaries

There are three main types of plate boundaries:

• Conservative / transform
• Convergent
• Divergent

Conservative plate boundary

A conservative plate boundary is also known as a 'transform' boundary.

• When two plates are attempting to slide across / opposite each other
• Movement is not always smooth
• Friction and pressure builds up
• When the pressure is released as energy, earthquakes are caused
• No crust is created or destroyed
• *No volcanoes are made, no change in crust, no new landforms*

Example: San Andreas fault - North American plate and Pacific plate

Convergent plate boundary

There are two main types of convergent plate boundaries:

• Destructive
• Collision

The difference in between the two is basically relating to the different types of crust.

As you can see, there are 3 different combinations of crust:

• Oceanic to oceanic
• Continental to continental
• Oceanic to continental

Oceanic to oceanic and continental to oceanic are called destructive plate boundaries because a crust is subducted under the other.

• Oceanic to oceanic - faster moving crust is subducted
• Oceanic to continental - oceanic crust is subducted

*oceanic crust is denser than continental crust that just floats on magma*

1. Oceanic crust subducts
2. Crust melts and forms molten rock - magma
3. Magma escapes in the form of lava from volcanoes

Continental to continental are called collision plate boundaries because they are of the same density and the two crusts can collide with each other to form fold mountains.

*plates are of same density, cannot be destroyed nor created, plates buckle and form fold mountains*

But these two types are go under the big title of convergent plate boundaries

In a convergent plate boundary, the plates move towards each other.