Major Geological Events Caused by Plate Tectonics

Types of Boundaries Divergent   Plates move apart Convergent  Plates come together Transform Plates slide horizontally past each other

Divergent Structures New crust is formed as plates pull apart Land features include: Mid-Ocean Ridges Ex. - Mid-Atlantic Ridge Rift Valleys Ex. - African Rift Valley Earthquakes

Mid–Ocean Ridge (Location of Sea Floor Spreading) http://commons.wikimedia.org/wiki/File:World_Distribution_of_Mid-Oceanic_Ridges.gif

Sea Floor Spreading (Mid-Ocean Ridge) Younger Older Older http://upload.wikimedia.org/wikipedia/commons/c/c0/Mid-ocean_ridge_topography.gif Divergent Structure

Rift Valley Divergent Structure http://commons.wikimedia.org/wiki/File:Iceland_Mid-Atlantic_Ridge_Fig16.gif http://commons.wikimedia.org/wiki/File:Rift_Valley.JPG Divergent Structure

Convergent Boundaries Crust is destroyed and recycled back into the mantle Three types of convergent collisions Features include: Trenches – Mariana Trench Volcanic Arc (Volcanic Mountains) – Andes mountains Mountain Ranges – Himalayan Mountains Earthquakes

Subduction Result of convergent boundary A more dense plate slides under a less dense plate and sinks into the mantle. Features include: Oceanic-Oceanic = Trenches Oceanic-Continental = Mountain Ranges

Subduction Examples

Oceanic-Oceanic convergence Convergent Boundary Oceanic-Oceanic Land Features – Trench and Island Arc Oceanic-Oceanic convergence http://commons.wikimedia.org/wiki/File:Oceanic-oceanic_convergence_Fig21oceanocean.gif

Oceanic-Continental convergence Convergent Boundary Oceanic-Continental Land Features – Trench and Volcanic Arc (Volcanic Mountains) Oceanic-Continental convergence http://commons.wikimedia.org/wiki/File:Oceanic-continental_convergence_Fig21oceancont.gif

Continental-Continental convergence Convergent Boundary Continental-Continental Land Features – Folded Mountains Continental-Continental convergence http://commons.wikimedia.org/wiki/File:Continental-continental_convergence_Fig21contcont.gif

Mountain Ranges http://commons.wikimedia.org/wiki/File:Physical_world_map_3200px.jpg

Transform Fault Structures Crust is neither destroyed nor created Can occur between two oceanic plates or oceanic-continental plates Features include: Earthquakes Fault line – San Andreas Fault

Transform Boundary Oceanic-Oceanic Land Feature – Fault Line

Transform Boundary San Andreas Fault Line http://pubs.usgs.gov/gip/dynamic/understanding.html

Transform Boundary Continental-Continental Land Features – Fault Line Aerial view of San Andreas Fault in the Carrizo Plain, self-made, Nov 16, 2007, I. Kluft, http://ian.kluft.com/pics/mojave/20071116/img_0327.jpg

Earthquakes – All Boundaries http://commons.wikimedia.org/wiki/File:Quake_epicenters_1963-98.png

Volcanoes http://commons.wikimedia.org/wiki/File:Spreading_ridges_volcanoes_map-en.svg

Mountain Ranges http://commons.wikimedia.org/wiki/File:Physical_world_map_3200px.jpg

Putting It All Together http://commons.wikimedia.org/wiki/File:Tectonic_plate_boundaries.png

Plate Boundaries http://commons.wikimedia.org/wiki/File:Tectonic_plates_boundaries_detailed-en.svg

Plate Movement http://en.wikipedia.org/wiki/File:Plates_tect2_en.svg