Continental Drift Flashcards
What are the three primary concentric layers of the Earth
Core, Mantle and Crust
What is the crust/mantle boundary known as
Mohorovicic discontinuity
What is the core and mantle boundary known as
Gutenberg discontinuity
Facts on upper mantle: Asthenosphere
Consists of two layers
Semi molten, viscous layer which flows slowly
Above this is the lithosphere
Facts on the Lithophere
Sits above the asthenosphere
Rigid layer sandwiched between crust and asthenospehre
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
Theory of plate techtonics
Apparent fit hypothesis between South America and West coast Africa
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
Describe fit of the continents
They appear to fit together from across the world
Why dont the continents fit together exactly
Sea level changes
Deposition and erosion change the coastline
Describe same rock types on different continents
Same age and distinctive characteristics on different continents
Mountain chains
Fold mountain chains are linear features hundreds of km long
Fossils for evidence for continental drift
Shallow water fossil who couldn’t of made the journey
Palaeomagnetism
Without moving continents it suggests multiple poles
