Tectonics

Question 1

Define Paleomagneticism

Answer 1

The alternating polarisation of new land created. As Magma cools, magnetic elements will align with the Earths magnetic field, which can alternate over thousands of years.

Question 2

Define Oceanic Crust

Answer 2

Crust, thinner than than continental crust, that forms the sea floor, typically 6-10km thick

Question 3

Define Slab Pull

Answer 3

The force contributing to the movement of tectonic plates.

Question 4

Define Subduction

Answer 4

Oceanic plate is forced below continental plate, due to the oceanic plate being denser than continental.

Question 5

Lithosphere

Answer 5

The upper crust of the Earth (average thickness = 100km)

Question 6

Define epicentre

Answer 6

The point on the surface, directly above the earthquakes origin

Question 7

Define Focus

Answer 7

The place in the crust where the pressure/seismic energy is released

Question 8

Define Hot Spot

Answer 8

Volcanoes found away from the plate boundary, due to a magma plume closer to the surface.

Question 9

Define Convection Currents

Answer 9

The circulation of magma within the mantle (asthenosphere)

Question 10

Define Asthenosphere

Answer 10

The upper mantle layer of the earth. Semi molten and approximately 2,000km wide.

Question 11

Define accretionary wedge

Answer 11

The accumulation of material at the point of subduction.