Evidence For Continental Drift Flashcards
What is continental drift theory?
Continents move over time and were once 1 land mass - Pangea
What is plate tectonic theory?
That the earths lithosphere is split into plates
Why do these plates move?
Due to convection currents (and slab pull and ridge push)
Name 5 types of continental evidence:
Fossils
Rocks
Erosion scars - glaciers
Jigsaw
Mountains
Where is an example for fossil theory?
Mesosaurus in South America and Africa
What is the explanation of the rocks theory?
Rocks of the same age are found at each side of an ocean
Name an example of rocks
Granite in Africa and South America
Where do erosion scars match?
Antarctica and Australia
What continents ‘fit’ like a jigsaw?
Africa and South America
How are mountains evidence?
Mountain belts on either side of an ocean
Name 3 oceanic evidence
Topography
Rock age
Paleomagnetism
Explain topography evidence
Centre of ocean isn’t the deepest as would be expected - new rock is less dense and sits higher
Explain rock age:
New rock pushes old rock sideways, creating a SYMMETRICAL pattern each side of the ridge
Explain paleomagnetism:
Iron particles orientate themselves to the earths magnetic poles, these poles flip - SYMMETRICAL bands of alternating polarity
What is the example for oceanic evidence?
Mid-Atlantic Ridge
