Tectonic Plates Flashcards
Theory of Continental drift
First proposed by German scientist, Alfred Wegener in 1912
Wegener’s theory was not accepted by the scientific community until after 1960!
Wegener thought all the continents were once joined together in an “Urkontinent” before breaking up and drifting to their current positions.
What evidence did Wegener have to prove his theory
Fossil evidence
Fossils of the same tropical organisms on multiple continents.
Rock Clues
Large mountain ranges composed of the same rock were found on two different continents, as well as the puzzle shape of the continents.
Climate Clues
Similar to fossil evidence, finding tropical fossils in arctic zones.
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What was the evidence Wegener did not have to prove his theory?
How the continents move.
How far do continents move each year?
About an inch. (They don’t all move at the same pace)
How do plates move?
Convection Currents
What are convection currents?
Convection currents take place in the mantle
The constant heating and cooling of magma causes the plates to move
How many main plates are there
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Convergent boundaries
When two plates are moving towards each other
Divergent boundaries
When two plates are moving away from each other
Transform boundary
When two plates are sliding past each other
Convergent boundary impact
Creates mountains or volcanoes
Divergent boundary impacts
Creates ridges, trenches, or volcanoes
Transform boundary impacts
Causes earthquakes when two or more plates become “stuck” on each other and then rip past each other suddenly
also fault lines
What are the two types of crust found on Earth’s surface?
The two types of crust found on Earth’s surface are the continental crust and the oceanic crust.
What is the name for the layer of the earth that is made up of the crust and upper mantle?
The lithosphere
