1. Geology Notes
Part 6

2. What is continental drift?
The theory that states that all the continents were once joined together but over time have split and drifted apart

3. What is Pangea?
The single super-continent formed 245 million years ago by the present continents

4. What is sea-floor spreading?
The process by which new ocean floor forms as magma rises to the surface and solidifies
As the tectonic plates move away from each other, the sea-floor spreads and magma fills in the gap

5. What is a mid-ocean ridge?
A undersea mountain chain that forms as magma rises from the asthenosphere and creates new sea floor as tectonic plates move apart
Forms at divergent plate boundaries

6. What is the Theory of Plate Tectonics?
The theory that states that the Earth’s crust is made up of rigid plates that move

7. What is the Theory of Plate Tectonics?
The motion of the plates causes continental drift

8. How does the Plate Tectonic theory account for features and processes that occur on or near the Earth’s surface?
As plates move apart at divergent boundaries mid-ocean ridges form.
As oceanic plates collide with continental plates, trenches form as the oceanic plate is subducted.
When two continental plates collide mountain ranges form.
Earthquakes and volcanoes occur along most plate boundaries.

9. What is the relationship between the rock cycle and the Plate Tectonic Theory?
Metamorphic rocks form at convergent boundaries where the rocks are put under intense pressure from the colliding plates. As plates diverge, igneous rock forms as the rising magma cools. As plates are forced upward, the
rocks are exposed to
weathering and erosion
and can form
sedimentary rocks

11. Geology Notes
Part 7

12. Describe the three types of tectonic plate boundaries and the geographic features associated with them.
Convergent boundaries - Plates collide, causing trenches when oceanic plates subduct under continental plates; mountains form when two continental plates collide; volcanoes and island arcs form when two ocean plates collide.
Divergent boundaries - Plates move apart, causing mid-ocean ridges and continental rifts
Transform boundaries - Plates slide past each other

13. Describe the three types of tectonic plate boundaries.

14. What causes tectonic plates to move?
Convection within the mantle; when the warmer rock rises, cooler rock near the surface sinks

15. How do rocks bend, fold, and break to create faults?
when plates move together and put stress on them
land features that start as folds and faults can eventually become mountains