1. 10.3 – Plate Tectonics and Igneous Activity

2. Do Now
How are the locations of volcanoes related to plate boundaries?

3. Do Now How are the locations of volcanoes related to plate boundaries?
Plate motion provide the mechanisms by which mantle rocks melt to generate magma.

4. Key Words
Magma Plume

5. Vocab Words
Intraplate Volcanism

6. Plate Tectonics and Igneous Activity
More than 800 active volcanoes have been identified worldwide.
Most of them located in the Ring of Fire.
The circum-Pacific belt
A second group of them are found in deep-ocean basins.
Hawaii and Iceland
A third group are irregularly distributed in the interiors of continents.
Erta Ale for example.

7. Ring of Fire

8. Converging Plate Boundaries
The basic connection between plate tectonics and volcanism is that plate motions provide the mechanisms by which mantle rocks melt to generate magma.
Ocean-Ocean
Rising magma can form volcanic island arcs in an ocean (Aleutian Islands).
Ocean-Continent
Rising magma can form continental volcanic arcs (Andes Mountains).

9. Convergent Plate Boundaries

10. Convergent Plate Boundaries

11. Convergent Plate Boundaries

12. Divergent Plate Boundaries
The greatest volume of volcanic rock is produced along the oceanic ridge system.
Lithosphere falls apart
Less pressure on underlying rocks
Partial melting occurs
Large quantities of fluid basaltic magma are produced

13. Divergent Plate Boundaries

14. Intraplate Igneous Activity
Intraplate volcanism is igneous activity that occurs within a tectonic plate away from plate boundaries.
Most intraplate volcanism occurs where a mass of hotter than normal mantle material called a mantle plume rises toward the surface.
The activity forms localized volcanic regions called hot spots.
Examples include the Hawaiian Islands and the Columbia Plateau.

15. Intraplate Igneous Activity

16. Group Challenge Question
Describe the Ring of Fire