Geography test

Continental Crust

Continental crusts are thicker older and lighter than Oceanic crusts. They are mainly made of granite.

Oceanic Crust

Oceanic crusts are younger and heavier than Continental crusts mainly made of basalt and gabbro.

Convergent/Destructive boundaries

An area on earth in which two or more lithospheric plates collide. Eventually, one plate slides under the other in a process called subduction.

Collision boundaries

If two continental plates collide, neither can sink and so the land buckles up to form mountains.

Transform/Conservative boundaries

They occur when plates slide past each other in opposite directions but without creating or destroying litosphere.

Constructive/Divergent boundaries

The plates are moving apart from one another. When this happens, the magma from the mantle rises up to make a new crust.

Hotspots

A hotspot is a large plume of hot mantle rising from deep within the Earth. A line of volcanoes develops as a plate moves over a hotspot.

What are the 4 Primary hazards?

Lava Flow, Pyroclastic Flow, Ash Fall, Gas Erruption