Plate Tectonics - The Lithospheric Recycling System

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Pangea - the world's most famous supercontinent - how does it connect to theory of plate tectonics? When we examine the origins of the earth, it is clear that there is no exact science or explanation because no one was there to witness what was occurring. However, the theory of continental drift - proposed by A. Wegener in the 1960's/1970's - has gained a lot of notoriety because there is a substantial amount of proof to back up his claims.

Wegener proposed that the world is divided up into continental and oceanic plates that cover the earth's surface, and are in constant motion due to the force of the convection currents in the mantle. He theorizes that the world's continents used to be joined together in a supercontinent called Pangea - and used the similar rock types of Appalachian mountains/European range and the Triple Junction (Africa/S.A./NA) as proof of these ideas. He also believed that these plates will continue to move, and that the location of the continents will look very different in the future. Today in class, Nick wondered aloud whether the Earth would eventually explode if the continents continued to move. I have attached a photograph of the "Future World" 250 million years from now at the top of this post, to reassure Nick that the Earth will still be intact.

These continental and oceanic plates meet each along 4 different types of plate boundaries:


  • Divergent Plate Boundaries - ex. Mid-Atlantic Ridge, Iceland, East African Rift Valley
  • Collision (Convergent) Boundaries - Continental plate. vs. Continental plate. Ex. Himalayas
  • Subduction (Convergent) Boundaries - Oceanic vs. Continental Ex. Indonesia, N.A., S.A.
  • Transform/Tear Fault - Side by side friction, Ex. San Andreas Fault, California.

As part of this unit, you should understand what these plate boundaries look like, what tectonic processes occur there, and where they can be located on a world map.

HW: Report on Tectonic Current Events Issue is due next day. Headings of report should include: CAUSES, HAZARDS/DANGERS, RESPONSE TO CRISIS, ETC. DIAGRAMS ARE WELCOME. See post below for special links.

BREAKING NEWS! Almost 126 years to the day that Krakatoa exploded in one of history's greatest volcanic explosions, it seems to be bubbling again... Check out these links below for more information, and please feel free to choose this option for your report, even though it hasn't exploded yet....

Daily Mail News Article - UK Volcano World - Hot News


Comments

  1. aateka.October 13, 2009 at 10:32 AM

    hey ms sawatsky! when you test us on plate tectonics, will we be expected to know how to draw diagrams as well? what if we're not good at drawing at all?

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  2. Alana SawatskyOctober 13, 2009 at 2:49 PM

    You are expected to be able to draw diagrams as a geographer - however you are marked on clarity and detail, not artistic ability. Just make sure your diagrams have arrows, labels, etc and you'll do fine.

    Most important though, is your ability to recognize the diagrams that match with specific tectonic features and boundaries.

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