Plate Boundaries
fault
A break in the Earth's crust where masses of rock slip past each other.
Great African Rift
A deep valley eastern Africa which is an example of a divergent boundary.
rift valley
A deep valley that forms where two plates move apart. Can be found underwater, along the large ridges that run throughout the ocean or in continental crust.
San Andreas Fault
A major geological fault in California and is an example of a transform boundary.
convergent boundary
A plate boundary where two plates move toward each other.
transform boundary
A plate boundary where two plates slip past each other in opposite directions.
plate
A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust.
scientific theory
A well-tested concept that explains a wide range of observations.
J. Tuzo Wilson
Canadian scientist who combined what geologists know about sea floor spreading, Earth's plates, and continental drift into a single theory; plate tectonics (1965).
plate tectonics
The theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle.
earthquakes
Usually occur at transform boundaries.
density
What determines which plate comes out on top when plates collide.
divergent boundary
Where two plates are moving apart, magma comes up to create new crust.
The Himalayan Mountains
World's highest mountains forming a boundry between South and East Asia. Example of a convergent boundary.
