Continental Drift Flashcards Preview

A2 Geography Hazardous Earth > Continental Drift > Flashcards

Flashcards in Continental Drift Deck (14):
1

What are the three primary concentric layers of the Earth

Core, Mantle and Crust

2

What is the crust/mantle boundary known as

Mohorovicic discontinuity

3

What is the core and mantle boundary known as

Gutenberg discontinuity

4

Facts on upper mantle: Asthenosphere

Consists of two layers
Semi molten, viscous layer which flows slowly
Above this is the lithosphere

5

Facts on the Lithophere

Sits above the asthenosphere
Rigid layer sandwiched between crust and asthenospehre

6

Movement within the asthenosphere

With in are convection currents
Caused by vast amounts of heat generated
As a result the semi molten asthenosphere flows carrying with it the lithosphere and crust

7

Theory of plate techtonics

Apparent fit hypothesis between South America and West coast Africa

8

What is Alfred Wegeners theory

Suggested that 250 million years ago there was a single land mass (Pangea)
Broke apart into 2 masses Gondwanaland and Laurasia
Then continued to spread until current

9

Describe fit of the continents

They appear to fit together from across the world

10

Why dont the continents fit together exactly

Sea level changes
Deposition and erosion change the coastline

11

Describe same rock types on different continents

Same age and distinctive characteristics on different continents

12

Mountain chains

Fold mountain chains are linear features hundreds of km long

13

Fossils for evidence for continental drift

Shallow water fossil who couldn't of made the journey

14

Palaeomagnetism

Without moving continents it suggests multiple poles