1. 3-1 Notes
Mountains

2. How can a solid (like rock) fold?
Think About…
How can a solid (like rock) fold?

3. Mountains Form Along Plate Boundaries
The top of Mt. Everest contain rocks and fossils from the ocean. How is this possible?

4. Mountains Form Along Plate Boundaries
A sea once covered the area that is now Mount Everest

5. Mountains Form Along Plate Boundaries
When an oceanic plate collides with a continental plate, it sinks.

6. Mountains Form Along Plate Boundaries
As the oceanic plate sinks, some sea-floor material can scrape off onto the continental plate.

7. Mountains Form Along Plate Boundaries
This happened as the Indian Plate converged with the Eurasian Plate.

8. Mountains Form Along Plate Boundaries
Eventually, the oceanic crust of the Indian Plate was completely destroyed by subduction, and continental- continental collision began.

9. Mountains Form Along Plate Boundaries
As the mountains formed, the material that was once on the sea floor is now on top of a mountain.

10. Mountain Ranges and Belts
Mountain- an area of land that rises steeply from the land around it.

11. Kilimanjaro, Tanzania (Africa)

12. Mt. Fuji, Japan

13. Denali, Alaska (United States)

14. Matterhorn, Switzerland (Europe)

15. Annapurna, Nepal 10th tallest in the world- 8,091 m

16. K2, Pakistan 2nd tallest in the world- 8,611 m

17. Mt. Everest, Nepal 1st tallest in the world- 8,848 m

18. Mountain Ranges and Belts
A single mountain is rare.
Most mountains belong to ranges.

19. Mountain Ranges and Belts
Range- a long line of mountains that were formed at the same time by the same process.

20. Mountain Ranges and Belts
Mountain ranges that are close together are called mountain belts.

21. Mountain Ranges and Belts
Example: The Rocky Mountain belt contains about 100 different ranges.

22. Mountain Ranges and Belts
Most of the world’s mountain belts are located along tectonic plate boundaries.

23. Mountains, Rocks, and Sediment
Remember that while mountains are being built up, they are also being worn away by erosion!

24. Mountains, Rocks, and Sediment
As long as mountains are being pushed up faster than they are being worn away, they will continue to grow bigger.

25. Mountains, Rocks, and Sediment
Young mountains tend to be tall and steep.

26. Mountains, Rocks, and Sediment
Older mountains are more rounded and worn away.

27. Mountains, Rocks, and Sediment
If the tectonic plates stopped moving, eventually all the land on Earth would be flat due to erosion.

28. Folded Mountains
Rocks can bend when stress is applied slowly over a long period of time.

29. Heat also helps rocks bend.
Folded Mountains
Heat also helps rocks bend.

30. Folded Mountains
Folded Mountain-a mountain that forms as continental crust crumples and bends into folds.

31. Folded Mountains
Folded mountains can form at Oceanic-Continental Subduction zones OR Continental- Continental Collision zones.

32. Example: Himalayas

33. The formation of the Himalayas can be described in 3 steps:
Folded Mountains
The formation of the Himalayas can be described in 3 steps:

34. Folded Mountains
1. Convergent Boundary Develops
Oceanic crust sinks under continental crust
The edge of the continental crust begins to crumple.

35. Folded Mountains 2. Continental Collision Begins
Eventually, all the oceanic crust is destroyed and continental collision begins.
Volcanoes eventually stop erupting and the mountains continue to be pushed up higher.

36. Folded Mountains
3. Collision Continues
The two continents continue to push the rocks up into mountains that are growing taller year after year.

37. Earthquakes in these areas can also push mountains up higher.
Folded Mountains
Earthquakes in these areas can also push mountains up higher.

38. Fault-Block Mountains
Fault-Block Mountains- mountains that form as blocks of rock move up or down along normal faults.

39. Fault-Block Mountains
In the Southwest U.S., hundreds of fault block mountain ranges line up in parallel rows along normal faults.

41. Fault-Block Mountains
There are 2 steps in the formation of fault block mountains:

42. Fault-Block Mountains
1. Lithosphere bends upward and breaks into blocks separated by faults as it is heated by the mantle.

43. Fault-Block Mountainns
2. As the lithosphere stretches, blocks of rock tilt or drop down between the faults to form mountains and valleys.

44. Fault-Block Mountains
Fault-block mountains form as stress is released through earthquakes over and over.

45. Fault-Block Mountains
Even the most powerful earthquakes only move rocks a small number of meters.

46. Fault-Block Mountains
It takes millions of years and earthquakes to build up large fault-block mountain ranges, like the Sierra Nevada range in California.

48. Fault-Block Mountains
All mountains take millions of years to erode.

49. Review
1. A folded mountain belt is located far from the edge of a present-day tectonic plate boundary. This mountain belt likely formed
E. when two oceanic plates collided.
F. as the result of volcanic activity
G. when two continental plates collided.
H. when blocks of crust moved along faults

50. Review
2. Folded mountains form at tectonic boundaries where E. new ocean crust is formed. F. plates move toward each other G. plates move away from each other H. plates move horizontally past each other

51. Review
3. Blocks of rock that have tilted along faults are common
E. where two oceanic plates collide
F. along subduction zones
G. where two continental plates collide
H. along ocean spreading centers