Major Geological Events Caused by Plate Tectonics

Take out Plate Tectonics Map Plate Boundary Notes Today we will be discussing and recording the following in your Science Journals: Type of Boundary Direction of plate movement Types of plates involved Land features formed Take out Plate Tectonics Map

Draw table (landscape/sideways) in Science Journal Type of Boundary Direction of plate movement Types of plates involved Land features formed Divergent Convergent Transform

Types of Boundaries (Direction of Plate Movement) Divergent   Plates move apart Convergent  Plates come together Transform Plates slide horizontally past each other

Divergent Structures (Land Features Formed) 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-Atlantic Ridge

Mid–Ocean Ridge (Location of Sea Floor Spreading) http://commons.wikimedia.org/wiki/File:World_Distribution_of_Mid-Oceanic_Ridges.gif The mid-ocean ridge (shown in red) winds its way between the continents much like the seam on a baseball.

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

Rift Valley Divergent Structure Types of Plates Involved: Continental http://commons.wikimedia.org/wiki/File:Iceland_Mid-Atlantic_Ridge_Fig16.gif http://commons.wikimedia.org/wiki/File:Rift_Valley.JPG Mid-Ocean Ridge when on oceanic crust Rift Valley when on land Types of Plates Involved: Continental Divergent Structure

African Rift Valley

Convergent Boundaries (Land Features Formed) 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 – (Folded Mountains)-Himalayan Mountains Earthquakes

Mariana Trench The Mariana Trench is part of a global network of deep troughs that cut across the ocean floor. They form when two oceanic tectonic plates collide. At the collision point, one of the plates dives beneath the other into the Earth’s mantle, creating an ocean trench.

Types of Plates Involved: Oceanic to Continental

Types of Plates Involved: Continental - Continental

Convergent Boundary: Andes Mountains

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 = Volcanic Mountain Ranges Continental-Continental – Folded 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 Land Features Crust is neither destroyed nor created Features include: Earthquakes Fault line – San Andreas Fault Types of Plates Can occur between: Oceanic -Oceanic plates Oceanic-Continental plates

Transform Boundary 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 Compare map to your Plate Tectonics Map. What do you notice? Are earthquakes random around the Earth? Do you think record keeping of earthquakes has helped scientists develop the Plate Tectonics Theory?!

Volcanoes http://commons.wikimedia.org/wiki/File:Spreading_ridges_volcanoes_map-en.svg Compare to your Plate Tectonics Map. Do volcanoes occur in random places? Are volcanoes found on all plate boundaries?

The Ring of Fire About 90% of the world's earthquakes and 80% of the world's largest earthquakes occur along the Ring of Fire.

Mountain Ranges http://commons.wikimedia.org/wiki/File:Physical_world_map_3200px.jpg What do mountains tell you about the location of plate boundaries? What type of plate boundary do the Himalayan Mountains have? The Andes Mountains? What land feature do you see at the Andes and not at the Himalayas?

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

The upper cookie is the lithosphere, the creamy filling the asthenosphere, and the lower cookie the lower mantle. Carefully remove the upper cookie with a “twisting” motion. Slide the upper cookie over the creamy filling to simulate motion of a rigid lithospheric plate over the softer asthenosphere. Next, break the upper cookie in half. As you do so, listen to the sound it makes. What does that sound represent? An earthquake. It takes cold, brittle lithosphere to make earthquakes – earthquakes do not occur in the soft, flowing asthenosphere.