Topic 1 - Hazardous Earth Flashcards
The Crust
The crust forms the Earth’s surface. It’s a rock layer forming the upper part of the lithosphere.
Lithosphere
Split into tectonic plates. The uppermost layer of the Earth, cool and brittle. Includes the top of the mantle and the crust.
Continental Crust
Forms the land. Made of mostly granite, on average 30-50km thick
Oceanic Crust
Under the oceans. Much thinner at 6-8km thick. Denser and made of Basalt.
Asthenosphere
Partly molten rock and partly solid rock, under the lithosphere. Found in the top layer of the mantle.
Mantle
Largest layer by volume, mostly solid rock. In the layers Asthenosphere and Lower Mantle.
Geothermal
‘Earth-heat’ heat produced by radioactive decay of elements uranium and thorium in the Core and Mantle
Radioactive Decay
Atoms of elements that are naturally unstable and radioactive release particles from their nuclei and give off heat
Convection Currents
Transfer heat from one part of a liquid or gas to another. The currents that rise from the Earth’s core are strong enough to move the tectonic plates
Plumes
Parts of convection cells where heat moves towards the surface. Concentrated zones of heat. Bring magma to the surface. The mantle is less dense in a plume.
Aurora Borealis
The northern lights. An example of when radiation from space hits the magnetosphere and lights up the sky.
Magnetic Field
The magnetosphere. Protects the Earth from harmful radiation from space and the sun. Made by the outer core. As liquid iron in the outer core flows, works like an electrical dynamo and produces the magnetic field
Pangea
The supercontinent. Started to split apart 200M years ago. All continents were joined together. Identical fossils found in Africa and South America prove this.
Plate Boundary
Where tectonic plates meet. There are three types (Divergent, Convergent and Conservative)
Divergent a Plate Boundaries
Formed when two plates move apart
Example: Iceland
