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transform boundaries
plate boundaries where plates slide past each other; example: San Andreas Fault
continental crust
crust that contains granite, is less dense, and is about 25 miles thick
tectonic plates
sections of the Earth's crust and mantle that move due to convection.
Alfred Wegener
A German scientist who proposed the theory of continental drift
asthenosphere
plastic-like layer of Earth on which the lithospheric plates float and move around
lithosphere
a rigid layer made up of the uppermost part of the mantle and the crust.
ocean crust
crust that is dense, young, about 5 miles thick, and made of basalt
Pangaea
large, ancient landmass that was composed of all the continents joined together
continental drift
The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations
convection in the mantle
the movement of magma within the mantle where hot magma rises and cooler magma sinks
evidence for continental drift
same fossils and rock types in various locations on Earth, the continents have a puzzle-like fit, marks from glaciers in areas where glaciers can no l...
How Wegener's theory was perceived in his life time
others did not believe his theory because he couldn't explain how it happened
convergent (continent - continent) surface features
mountains are made; example: Himalayas
divergent (ocean from ocean) surface features
mid-ocean ridges (new crust); example: Mid-Atlantic Ridge
convergent (ocean - continent) surface features
volcanic mountains (volcanoes); example: Andes Mountains
divergent (continent from continent) surface features
rift valley; example: East African Rift Valley
