1.4 - Earth's Conveyor Belt

Question 1

Earth’s internal structure

Answer 1

Inner core - solid iron/nickel
Outer core - liquid iron/nickel
Mantel - rock/peridotite 
Asthenosphere - liquid upper mantle
Lithosphere - rock crust

Question 2

Mantle convection

Answer 2

Hotter rock near core rises
Reaches near surface and cools
Spreads outwards and falls

Question 3

Pressure in the Earth

Answer 3

Further away from core means lower pressure - lower melting point
Asthenosphere has lower pressure so lower melting point - minerals in peridotite melt and form sticky magma in magma chamber
Magma oozes our onto crust - volcano/ridge (constrictive plate boundary)

Question 4

Mid ocean ridge

Answer 4

Ridge with cooled magma coming out of the middle

Question 5

Palaeomagnetism

Answer 5

New land (magma) forms in middle of constructive plate boundary and spreads out on either side
As magma cools, rocks aligns to polarity (N)
Every 200000 yrs, polarity reversed - rock now aligned to S
Either side of ridge, alternating N/S aligned rock

Question 6

Sea floor spreading

Answer 6

Idea that land moves apart at constructive plate boundary

Proved by palaeomagnetism

Question 7

Ridge push

Answer 7

Land formed at middle of constructive plate boundary pushes outwards on either side because of gravity

Question 8

Slab pull

Answer 8

During subduction, one plate goes under

Weight of the plate pulls the rest of it further down