1 / 29

Core Unit 1: Patterns and Processes in the Physical Environment

Core Unit 1: Patterns and Processes in the Physical Environment. - 5 th Year Mr.McMahon-. Unit 1.1 Earth’s Structure and the Tectonic Cycle. Statement

dorian-chan
Download Presentation

Core Unit 1: Patterns and Processes in the Physical Environment

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. Core Unit 1: Patterns and Processes in the Physical Environment -5th Year Mr.McMahon-

  2. Unit 1.1 Earth’s Structure and the Tectonic Cycle • Statement • The mobility of the earth’s crust produces endogenic forces, which give rise to geological structures within it. Crustal structures are created, modified and destroyed as part of the tectonic cycle.

  3. The Earth’s Structure • Learning Objectives • To understand the internal structure of the Earth. • To understand the make up of the planet. • Knowledge and understanding of key concepts

  4. Earth’s Crust • Composed of two main layers, • Lithosphere Surface. Hard, rigid and solid. • Asthenosphere : Semi- solid. Viscous material capable of flowing.

  5. The Continental Crust or Sial • Also called Sial due to the large amounts of silica and aluminium present. • 5-10 Km Thick • Lies on top of the Lithosphere.

  6. The Oceanic Crust • Made up of older, ancient rock like basalt. • Referred to as Sima due to the presence of silica and magnesium. • Covers a larger area of earth’s surface.

  7. Plate Tectonics Learning Objectives • Be able to describe the theory of plate tectonics. • Understand how plates move • Explain what happens at the margins of plates. • Understand the position of Ireland in relation to plate boundaries.

  8. The World’s Ocean Floor

  9. Plate Tectonics Theory • There are several major plates and several smaller ones. • Plates move as passengers on the semi molten asthenosphere. • As plates move they slide, diverge and collide. • This movement gives rise to earthquakes, volcanic activity, sea floor spreading and the creation of ocean ridges.

  10. How do the Plate’s Move ? • Ans: Convection Currents ! • Warm magma rises from the interior of the earth. • As it rises it cools and falls again. • This process is repeated and results in convection currents that travel in circular motions. • Consequently the plates are moved causing continental drift. http://www.youtube.com/watch?v=xEYLx_bhtoA

  11. Continental Drift • The theory that the continents moved was first proposed by a German Mathematician Alfred Wegner in 1912. • Wegner proposed that 200 Million years ago all the continents formed one supercontinent called Pangaea (Gk all the land) http://www.youtube.com/watch?v=cQVoSyVu9rk

  12. Pangaea

  13. Evidence for Continental Drift • Continental Fit • Fossil Records • Matching rock records • Matching Fossils • Matching glacial deposits

  14. Sea Floor Spreading • The theory of sea floor spreading is that the oceanic crust is widened as new crust is created along plate margins. • Evidence: Rocks at the centre of the ocean floors have proven to be younger than rock at the plate margins.

  15. Plate Margins

  16. Plate Boundary Types Locate on Map ! http://www.youtube.com/watch?v=hqp_TbIZU64

  17. Convergent Boundaries • Where Plates Collide. • E.g. South American and Nazca Plate. • Associated Landform- Fold Mountains –The Andes, Volcanic Activity. • Rock is changed and destroyed along these destructive boundaries in subduction zones.

  18. Divergent Plate Boundaries • Plates Move apart • New rock is formed. • These are therefor constructive boundaries. • E.g. The American plates and the African Plates Creating the Mid-Atlantic Ridge.

  19. Conservative Boundaries • Known as Transform boundaries. • Plates slip or slide past each other. • E.g San Andreas Fault line. North American and Pacific Plates. • Major Earthquake Zone, Cascadia

  20. Subduction • Continental-Oceanic • Oceanic –Oceanic • Continental-Continental

  21. Oceanic –Oceanic • Eurasian – Pacific Plate. • The older heavier plate is subducted underneath the younger, lighter plate. • As the older plate descends it is heated by magma and friction and is recycled into the mantle. • Island arcs, e.g Japan rise from the ocean floor as magma is released resulting in volcanic activity

  22. Oceanic -Oceanic

  23. Oceanic –Continental Convergence • The heavier oceanic plate is forced into the lighter continental plate. • The oceanic plate is subducted into the asthenosphere where it is melted back into the mantle. • This melting releases upwelling magma resulting in Volcanic Activity. • The lighter continental plate is buckled upward to create fold mountains . • Nazca and South American Plates.

  24. Oceanic – Continental Convergence

  25. Continental-Continental • When continental plates collide the lithosphere subducts. • Both plate remain afloat but continue to push into each other. • As a result a wide plateau of mountains is created. • E.g. The Himalayas where the Indian and Eurasian Plates collide. http://www.youtube.com/watch?v=7gXixxYKM80

  26. Continental-Continental

  27. The formation of Ireland • P 14 • You Tube • http://www.youtube.com/watch?v=BE5nLCOih7I

  28. Key Concepts • Lithosphere • Asthenosphere • Endogenic • Convection Currents • Continental Drift • Sea floor Spreading • Conservative Boundary • Divergent Boundary • Transform Boundary • Subduction • Plateau • Pangaea

More Related