Plate tectonic theory

Question 1

Jigsaw fit

Answer 1

Alfred Wegner, 1000m below sea level edges of continental shelf fit, gaps due to landslides and overlaps from sediment e.g. Niger Delta

Question 2

Tectonic fit

Answer 2

Alfred Wegner, parts of 400m old Caledonian mountains found in Canada, Ireland etc. and reassemble to a linear structure

Question 3

Geological fit

Answer 3

Alfred Wegner. Ancient rock outcrops over 2000m old continuous in type

Question 4

Glacial deposits

Answer 4

Alfred Wegner. In Gondwana continents (Southern) continuous striation and deposits show movement from Permo-Carboniferous glaciation

Question 5

Fossil evidence

Answer 5

Alfred Wegner. Terrestrial Glossopteris fern in Gondwana

Question 6

War sonar

Answer 6

Hammond-Hess. Suggested material pushed up at and sank further from ridges as shallower and trenches where destroyed as deeper but not enough geophysical evidence

Question 7

Paleomagnetism

Answer 7

Vine and Matthews. Stripes of magnetic material either side of a ridge, when Earth’s magnetic field switches so does material polarity and cools in stripes of similar ages

Question 8

Hotspots

Answer 8

Wilson. Proposed mantle hotspots from radioactive decay plates move over, forming volcanic island chains e.g. Hawaii

Question 9

Transform faults

Answer 9

Wilson. What connects divergent and convergent boundaries e.g. San Andreas Fault between North American and Pacific plates

Question 10

Lithosphere, asthenosphere and convection currents

Answer 10

McKenzie. Explains plate movement and helps understand factors controlling partial melt and magma composition changes