Plate Tectonics Notes Ch. 1-5
What is a plate?
What is the theory of
Plate Tectonics?
J. Tuzo Wilson proposed that the lithosphere is broken into separate sections called
plates. His idea lead to the current theory of Plate tectonics.
The Theory of Plate Tectonics states that pieces of Earth’s lithosphere are in constant,
slow motion, driven by convection currents in the mantle. The theory explains the
formation, movement, and subduction of Earth’s Plates.
Three Kinds of Plate Boundaries:
Describe and draw the
three types of plate
boundaries.
1) Transform Boundaries
Two plates slip past each other, moving in opposite directions. Earthquakes often
happen at this kind of boundary.
2) Divergent Boundaries
Two plates move apart. Most happen at the mid-ocean ridge. Rift valleys are a kind of
divergent boundary that forms on land.
3)
Convergent Boundaries
Two plates come together. When two plates converge, or come together, a collision
happens.
Draw and describe the
three types of
Convergent boundaries.
Three types of convergent boundaries
A.) Oceanic crust – Ocean crust
The plate more dense dives under the other plate.
B) Oceanic Crust – Continental Crust
The less dense continental crust can’t sink under the denser O.C., so the O.C. plunges
beneath the C.C.
C) Continental Crust – Continental Crust
Subduction doesn’t happen. Instead the plates crash head-on and form mountain Ranges.