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 {PLATE} BOUNDARY What are DIVERGENT plates? They are plates that move in the opposite direction of each. How do DIVERGENT plate boundaries work? They pull apart allowing magma to ooze through the cracks to the surface of the sea floors What do DIVERGENT plate boundaries form? New Crust Form mountain ranges on the sea floor.

CONVERGENT {PLATE} BOUNDARY What are CONVERGENT plates? They are plates that COLLIDE with each other How do CONVERGENT plate boundaries work? The continental crust {what we live on} and the oceanic crust {under the sea} collide. The oceanic crust {more dense} sinks below the continental crust {less dense}. What do CONVERGENT plate boundaries form? Major Earthquakes Volcanic Mountains Deep sea trenches

TRANSFORM {PLATE} BOUNDARY What are TRANSFORM plates? The action of two plates that are sliding past each other How do TRANSFORM plate boundaries work? These plates sliding past each other horizontally cause large amounts of energy to build up. What do TRANSFORM plate boundaries form? Tsunami Major Earthquakes Faults

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

PLATE TECTONICS A theory that explains the movement of continents Massive Slab of rock Irregularly shaped Located and Float on the Lithosphere Move around Earth by circulating CONVECTION CURRENTS {hot liquid rises and cold liquid sinks, moves in a circular motion, the energy gets transferred} Move only a few centimeters each year Most of the events happen near the boundaries

Trench - a depression in the ground that is generally deeper than it is wide

Fault Lines – break in the Earth’s crust

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

Rift Valley – lowland between several highlands or mountain ranges caused by a fault

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

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

Transform Boundary Oceanic-Oceanic Land Feature – Fault Line

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

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

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 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

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

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