1 / 30

WORLD GEOGRAPHY 3202 INTRODUCTION

WORLD GEOGRAPHY 3202 INTRODUCTION. The Size of the World. The Earth’s Interior. Crust (Lithosphere) Mantle Outer Core Inner Core. Inner Core. The deepest part of the earth (1512 miles deep) is a solid that contains both iron and nickel.

wauna
Télécharger la présentation

WORLD GEOGRAPHY 3202 INTRODUCTION

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. WORLD GEOGRAPHY 3202 INTRODUCTION The Size of the World

  2. The Earth’s Interior • Crust (Lithosphere) • Mantle • Outer Core • Inner Core

  3. Inner Core • The deepest part of the earth (1512 miles deep) is a solid that contains both iron and nickel. • It is because of this that the center of the earth is a magnet, a compass. • It generates a magnetic field that protects the earth from flying out of orbit.

  4. Outer Core • Outside of the inner core lays the outer core (1419 miles deep). • This is much like the inner core with the exception that it is a liquid that contains sulphur and oxygen (which lowers the melting point).

  5. Mantle • Occupying 1789 miles of the earth is the magma (iron and magnesium) that makes up the mantle. • Upper and lower • It is extremely hot!! • goopy; very plastic-like.(upper mantle) • Mostly solid (lower mantle)

  6. Crust • Also called lithosphere • This is the top layer of the earth, which is basically hardened mantle (magma). • It contains two segments, the oceanic and continental crusts. • Note: this is the same crust, it just depends how thick it is to determine if it is part of the Oceanic or Continental Crust.

  7. Read About Earth’s interior • Our Text p. 4-6

  8. Theory Of Continental Drift • Alfred Wegener • It is this German man to whom we credit with the proposal of the theory of Continental Drift.

  9. While pondering the similarities between the coastlines of South America and Africa, Wegener came up with an idea: • What if the continents were once all connected and just drifted over the years?

  10. Wegener’s Proof

  11. Wegener’s Proof

  12. Wegener’s Proof

  13. The Flaw in Wegner’s Theory • He thought that each of the continents were a separate plate--they were just drifting on a never-changing ocean. • Like styro-foam floating on a pool of water!!

  14. Missing Proof • Wegener could not explain what mechanism was powerful enough to move huge continents • Scientist’s never believed him

  15. Canadian Correction • J. Tuzo Wilson • the 1960’s Canadian scientist who resurrected Wegner’s theory after years of disbelief by the science community. • Today, we know that that's false, thanks to the discovery of crustal plates. • The plates of the earth are not composed of just land; they're composed of ocean too.

  16. Canadian Correction – cont’d • In some cases, the plates are just land, in others they're just ocean, and, in still other cases, they consist of land and ocean. • They each have different boundaries and move in all different directions.

  17. Plates of the earth p. 12

  18. Continental Drift Animation

  19. Continental Drift • refers to the movement of the more than 20 plates (9 major) due to convergent, divergent, and transform boundaries. • The continents drift at a rate of 2 inches a year. • Started 200 million years ago • Pangea (land) & Panthalasa (sea)

  20. Plate Tectonics • Tectonic plates move or float on top of the upper mantle. • However they do not float freely. • The plates are forced in specific directions by the flow of magma beneath.

  21. Plate Tectonics – cont’d • Plates move with the flow of magma. • The magma closer to the core heats and then rises towards the surface as its density decreases. • Once the rising magma reaches the lithosphere it moves in opposite directions. • The magma forms convectional currents.

  22. Convection Currents

  23. Plate Tectonics – Convection Currents

  24. Divergent Boundaries • Tensional Forces occur where two tectonic plates are pushed apart. The tension is created as the plates move away from each other. • Ridge Zones sometimes occur where two plates move apart. The magma rises between the plates and forms a ridge. • Again caused byconvectional currents in the magma

  25. Tensional Forces – Ridge Zones This diagram above shows “Sea Floor Spreading”

  26. Where’s the TENSION?

  27. Convergent Boundaries • Compressional Forces occur where two tectonic plates come together. They compress against each other. • Subduction Zones sometimes occur where compressional forces result from two plates colliding and one plate slips under the other. • Again caused byconvectional currents in the magma

  28. Compressional Forces – Subduction

  29. Where’s the Subduction / Compression?

More Related