4.7: Review- Examples of Plate Boundaries
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| Convergent boundaries | Divergent boundaries | Transform boundaries |
When continents collide mountains belts form. Examples:
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When plates diverge, spreading centers form creating new oceanic crust. Examples:
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When plates slide past each other creating fault systems along plate margins. Examples:
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| Figure 4.20. Himalayan Mountains are a convergent plate boundary | Figure 4.21. Mid Ocean Ridge in Iceland is a divergent plate boundary | Fig 4-22. San Andreas Fault system is a transform plate boundary |
| When continents collide with ocean crust trenches with subduction zones and volcanic arcs form - examples:
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Spreading centers occur where continents are pulling apart. Examples:
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Transform faults also occur within plates, but are related to movements that shape the seafloor. Examples:
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| Figure 4.23. Convergent boundary along the west coast of South America | Figure 4.24. A divergent boundary forming in the Red Sea area | Figure 4.25. Transform fracture zones offshore of California are within the Pacific Plate |
Important! Continental margins may or may not be plate boundaries! For example, the East Coast is in the middle of the North American Plate. Why? When North America first split away from Africa and Europe, there was first a continental rift valley; it became a plate boundary between the three expanding lithospheric plates. As new crust formed along the Mid Ocean Ridge spreading center, it became attached to the plates on either side. Today the North American Continent is part of the larger North American Plate! (See Figure 7.29.)