Leaving Cert Geography: Plate Tectonics

Aesthenosphere

a layer of softer, weaker rock beneath Earth's lithosphere, which can flow slowly

Lithosphere

the upper part of the mantle fused to the earth

rift valley

A deep valley that forms where two plates move apart

Mantle

The layer of hot, solid material between Earth's crust and core.

Convection Currents

Circular currents in the mantle caused by the magma being heated by the core off the Earth.

Core

The central part of the earth below the mantle

Continental Drift

As the plates move, the continents move with them

Sea Floor Spreading

stated that the plates carried sections of the ocean floor

Destructive Plate Boundary

where the plates collide into each other resulting in an earthquake

Transform Plate Boundary

where the plates slide past each other resulting in an earthquake

Constructive Plate Boundary

where the plates move apart resulting in fold mountains or a mid ocean ridge

Plate Boundary

where two plates meet

Theory of Continental Drift

suggests that the continents have moved great distances and continue to move

Pangaea

one supercontinent which split up 200 million years ago

Panthalassa

single ocean surrounding Pangaea

Godwanaland & Laurasia

the names given to the two continents after Pangaea broke up

Jig Saw Theory

the coastline of Africa & South America fit together indicating that they once were together

subduction zone

The region where oceanic plates sink down into the asthenosphere.

Exogenic Forces

External forces on the surface of the earth such as weathering and erosion

Endogenic Forces

Internal forces within the earth such as folding and faulting

Moho discontinuity

the boundary between Earth's crust and mantle

Plate Tectonics

shows us the mechanisms which produces volcanoes and earthquakes

Mid Ocean Ridge

these are underwater mountains formed at a constructive plate boundary

volcano

a crater or fissure through which lava ash rock fragments and hot vapour are or have been erupted from the earths crust

Pacific Ring of Fire

ring around the pacific ocean where the worlds major plates meet and where 2/3 of the worlds volcanoes are located