First 137 words of the document:
Basalt a dark volcanic rock.
Convection currents - circulating movement of a heated fluid
caused by different densities.
Core the centre part of the Earth.
Crust the outer layer of the Earth.
Lithosphere the crust and the uppermost layer of the mantle.
Magma rock between the crust and the core of the Earth.
Mantle a thick layer of dense semi-liquid rock below the Earth's
Subduction dipping of one plate below another at a destructive
Tectonic plates very large plates of rock which float and move
very slowly on the mantle of the Earth.
Volcano a tube from inside the Earth to its surface through
which lava can escape un an eruption.