5The Tectonic PlatesTectonic plates are large pieces of the lithosphere2 different types of plate: Oceanic and Continental
6How the plates move Convergent - Plates are moving towards each other Divergent - Plates are moving away from each otherTransverse - Plates are moving past each other
7Convergent Plate Boundaries 3 different types of convergent boundariesOceanic – Oceanic Convergence (2 oceanic plates convergeOceanic – Continental Convergence (1 oceanic plate and 1 continental plate)Continental – Continental Convergence (2 Continental platesConvergent – when two objects move towards one anotherThe two objects are two tectonic plates
9Oceanic – Oceanic Boundaries The slower moving plate SUBDUCTS the faster moving plateSubducted plate – the plate that is forced into the mantle (the slower plate)Forms trenches and volcanoes.Hawaii is the result of underwater mountain ranges reaching above water.
13Continental – Continental Boundaries Two continental plates collidingNeither plate subducts the otherOne plate will crumble and break apartForms mountain ranges and a higher plateauEx. Himalayan Mountains and Tibetan Plateau
17Transform Plate Boundaries Form FaultsBreaks in the lithosphereRocks move past each otherEx. San Andreas Fault
18Evidence for Plate Tectonics In the middle of the oceans – The N and S are magnetic PolesMagnets have a certain arrangement that makes them magnetic. Every 200,000 years the earth’s magnetic poles switch and S becomes North and North become SouthThe magnetic rocks on earth reflect the direction of magnetic North and magnetic South
19Evidence Cont’dAs magma comes out of the floor at a divergent boundary, the material aligns itself the current magnetic poles. After the magma cools, this become permanent.Once the poles switch, the new magma will have a new arrangementPROOF!! – We see bands on the sea floor that reflect changes in magnetic N and S. IF the sea floor was not spreading, we wouldn’t
20Other EvidenceFit of the Continents - Noted the similarity in the coastlines of North and South America and Europe and Africa. Today the fit is done at the continental shelf and it is nearly a perfect match.Rock SimilaritiesRocks of same age match across ocean basins.Termination of mountain chains.
21References and Pictures US Geological Survey Western Earth Surface Processes Team and the National Park Service,