1 / 34

Theory of Plate Tectonics

Theory of Plate Tectonics. Plate Tectonics Plate Boundaries Causes of Plate Tectonics. Plate Tectonics. Questions. What is the theory of plate tectonics? What is the lithosphere? What is the asthenosphere? What are the two types of plates?. What is the Theory of Plate Tectonics?.

tamma
Download Presentation

Theory of Plate Tectonics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Theory of Plate Tectonics Plate Tectonics Plate Boundaries Causes of Plate Tectonics

  2. Plate Tectonics

  3. Questions... • What is the theory of plate tectonics? • What is the lithosphere? • What is the asthenosphere? • What are the two types of plates?

  4. What is the Theory of Plate Tectonics? • The Earth’s crust and upper mantle are broken into sections called plates • Plates move around on top of the mantle like rafts

  5. What is the Lithosphere? • The crust and part of the upper mantle = lithosphere • 100 km thick • Less dense than the material below it so it “floats” on molten rock.

  6. What is the Asthenoshere? • The plastic like layer below the lithosphere = asthenosphere • The plates of the lithosphere float on the asthenosphere

  7. 2 Types of Plates • Ocean plates - plates below the oceans (Basalt) • Continental plates - plates below the continents (Granite)

  8. Plate Boundaries

  9. Questions... • What are the three types of boundaries? • What direction do plates go for each? • Which boundary has a subduction zone…what occurs at a subduction zone?

  10. (1) Divergent Boundaries • Boundary between two plates that are moving apart   • RIFTINGcausesSEAFLOOR SPREADING - Samples collected by the Glomar Challenger showed that the youngest rocks on the ocean floor are found in the center of mid ocean ridges.

  11. Features of Divergent Boundaries • Mid-ocean ridges • rift valleys • fissure (narrow opening) volcanoes

  12. (2) Convergent Boundaries • Boundaries between two plates that arecolliding   • There are 3 types…

  13. Type 1 • Ocean platecollides with a less dense continental plate • Subduction Zone: where the more dense plate slides under the less dense plate • VOLCANOES occur at subduction zones

  14. Andes Mountains, South America

  15. Type 2 • Ocean platecollides with another ocean plate • The more dense plate slides under the more less dense plate creating a subduction zone called a TRENCH

  16. Aleutian Islands, Alaska

  17. Type 3 • A continental platecollides with another continental plate • Have Collision Zones: • a place where folded and thrust faulted MOUNTAINS form.

  18. (3) Transform Fault Boundaries • Boundary between two plates that are sliding past each other • EARTHQUAKES along faults • Earthquakes produce seismic waves that travel through Earth.

  19. San Andreas Fault, CA

  20. Causes of Plate Tectonics

  21. Questions... • What causes plates to move? • How is a convection current formed?

  22. Convection Currents • Hot magma in the Earth moves toward the surface, cools, then sinks again. • Creates convectioncurrents beneath the plates that cause the plates to move.

  23. Continental Drift • The hypothesis of Continental drift was that all the continents once were joined as a single super continent and have since drifted apart. To support his hypothesis, Alfred Wegener provided evidence from fossils to support the theory of continental drift.

More Related