Plate Tectonic Theories

Question 1

Lithosphere

Answer 1

Surface layer of the earth which is rigid and composed of the crust and upper mantle. 100km deep on average. The lithosphere is always moving (but slowly)

Question 2

Oceanic crust

Answer 2

Thin, underlies ocean basins, made mainly of basalt. High density

Question 3

Continental crust

Answer 3

Thick, underlies continents, made mainly of granite, lower density

Question 4

What was wegeners evidence

Answer 4

Jigsaw fit
Geological fit
Tectonic fit
Glacial deposits
Fossil evidence

Question 5

What was wegeners published work?

Answer 5

Theory of continental drift

Question 6

What did wegener do?

Answer 6

Named the supercontinent Pangea and later it had split into two continents Laurasia (north) and Gondwanaland (south)

Question 7

What was wegeners theory

Answer 7

A single continental existed 300 million years ago

Question 8

When was wegeners theory

Answer 8

1912

Question 9

Geological evidence that supports this

Answer 9

The coastlines of eastern South America and Western Africa line up well
The African and Arabian plates can be fitted together if the Red Sea is closed
Cratons fit across continents suggests that Africa and sought America were part of the same land mass 2 billion years ago
Tectonic fit of mountain belts across former oceans
The mid Atlantic ridge is proof that the Atlantic floor was spreading outwards from the centre

Question 10

Biological evidence that supports this

Answer 10

Plant and animal fossils found on coastlines of different continents
Mesosaurus fossils found only in Southern Africa and Eastern South America. Suggests that they were joined together
Fossils in South Africa, India and Antarctica suggests that they were closer before