Transcript Plate Boundaries

Plate Boundaries--The location were two plates meet.
Divergent boundaries -- where new crust is generated as the plates pull away
from each other.
Convergent boundaries -- where crust is destroyed as one plate dives under
another.
Transform boundaries -- where crust is neither produced nor destroyed as the
plates slide horizontally past each other.
Plate-Boundary zones--broad belts in which boundaries are not well defined
and the effects of plate interaction are unclear.
Experience different plate boundaries
Oceanic-continental
convergence--Where the
plate that is covered by
water and the plate that is
covered by land meet.
Oceanic-Oceanic
Convergence--when two
oceanic plates converge,
one is usually sub ducted
under the other, and in the
process a trench is formed.
Continental-Continental
convergence-- When two
continents meet head-on,
neither is sub ducted
because the continental
rocks are relatively light
and, like two colliding
icebergs, resist downward
motion. Instead, the crust
tends to buckle and be
pushed upward or sideways.
Transform Boundaries
-The zone between two plates sliding horizontally past one another.
-A transform boundary is said to occur when tectonic plates slide and
grind against each other along a transform fault.
-Concept originated by Canadian geophysicist J. Tuzo Wilson
-Offset the active spreading ridges and produce zig-zag plate
margins defined by shallow earthquakes.
-Example is the San Andres Fault in California
-Cause a lot of Earth Quakes
-The Great San Francisco Earthquake of 1906
Convergent Boundaries
-the location where sinking of a plate occurs is called a
subduction zone
-Convergence is a very slow collision of plates
-There is three types of convergent boundaries
Oceanic-Continental Convergence
-Trenches are created by subduction
-One plate is being subducted under another
-One example is when the Naza Plate bumps into the South
American Plate and is being subducted under. The Andes
Mountains were created as the S.A. Plate rises. This causes major
earthquakes
Oceanic- Oceanic Convergence
-A trench is formed when one plate is subducted and two
oceanic plates converge.
-One example is Marianas Trench
-Formed where fast Pacific Plate converges against the
slower Philippine Plate
-This convergence results in volcanoes.
-Many volcanoes (like Hawaii) are situated on island arcs
that are really trenches that was created by convergences!
Continental-Continental Convergences
- Himalayan Mountain is formed by the Eurasian Plate overriding the
Indian Plate 50 million years ago!
-Mountain ranges like the Alps and the Rockies were formed this way.
-Powerful collision
-Because the density of the plates is lower than the mantle, subduction
is prevented. A mountain is formed because subduction is difficult
Divergent boundaries -- where
new crust is generated as the
plates pull away from each other.
Occurs along spreading centers
were plates are moving across and
new crust is being created when
magna pushes up from the mantle.
Example is the Mid-Atlantic Ridge-this is a mostly underwater mountain
range that runs through the Arctic and
Atlantic Oceans.
An example of the effects of
divergent boundaries is Iceland
which is split in half by the MidAtlantic Ridge and will eventually
split in half as the Ridge expands.
HISTOICAL INFORMATION ON
PLATE BOUNDARIES
The scientist who began the research on Plate
boundaries was Alfred Wegener. He came up with the
theory that at one point in time all the continents were
one. He arrived at this theory when he red a report
talking about how some of the same types of plant and
animal fossils were being found on opposite sided of
the Atlantic ocean. He began to study the continents
and noticed how they looked as if at one time they
could have all fit together. Many scientists thought
this was not at all a logical theory and rejected the
idea all together, but eventually the idea gained more
support as time went on.
REAL LIFE APPLICATIONS

Plate movement cause a lot of natural disasters

Plate movement can cause large cracks in the surface, earthquakes, and fissures

Plate also create mountains by pushing up on each other.

Volcanoes can erupt from plate movement

Geodesy is the study of the size and shape of earth

People study plate boundaries with geodesy

Scientist can study plate boundaries on the ground but the best way is through a
satellite.
Bibliographical Information
Watson, Jim. "Understanding Plate Motions." USGS. 05.05.99.USGS. 1 Oct 2007
<http://pubs.usgs.gov/gip/dynamic/understanding.html>. Loomis,
Jennifer. "Observe animations of processes that occur along plate boundaries." Exploring
Earth. Exploring Earth . 1 Oct
2007<http://www.classzone.com/books/earth_science/terc/content/visualizations/es0804/es0804pa
ge01.cfm?chapter_no=visualization>.

"Understanding Plate Motions." Usga:Science for changing the world. 5/5/99. Usga.
<http://pubs.usgs.gov/gip>.

King, Hobart. "Teaching Plate Tectonics with." Geology.com. Geoglogy. 2 Oct 2007
<http://geology.com/nsta/transform-boundary.gif>.

"Wikipedia." Transform Boundary. 9/11/07. Wikipedia. 2 Oct 2007
<http://en.wikipedia.org/wiki/Transform_boundary>.

King, Hobart. "Convergent Plate Boundaries." Geology.com. 2005-2007. Geology. 2 Oct 2007
<http://geology.com/nsta/convergent-plate-boundaries.shtml>.

King , Hobart. "Convergent Plate Boundaries." Geoglogy.com. Geology.com. 2 Oct 2007
<http://geology.com/nsta/convergent-plateboundary-oceanic-continental.gif>.

Glasscoe, Maggie. "Education Module." Glossary of Terms. 8/13/98. Maggi Glasscoe. 2 Oct
2007 <http://scign.jpl.nasa.gov/learn/glossary.htu#twentyone>.

Glasscoe, Maggi. "Plate Boundaries." The Southern California Intergrated GPS Network
Education Module. 9/8/98. Scign Education Module. 2 Oct 2007
<http://scign.jpl.nasa.gov/learn/plate4.htm>.

Glasscoe, Maggi. "Plate Boundaries." The Southern California Intergrated GPS Network
Education Module. 9/8/98. Scign Education Module. 2 Oct 2007
<http://scign.jpl.nasa.gov/learn/plate4.htm>.
"How Volcanoes Form." Volcanoe Word. 8/4/07. University of North Dakota. 2 Oct 2007
<http://volcanoe.und.edu>.
Waggoner, Ben. "Alfred Wagner 1880-1930." Berkely . 06/09/96. Berkely.edu. 2 Oct 2007
<http://www.ucmp.berkeley.edu/history/Wagener.html>.
"Plate Tectonis." Wikipedia. 9/28/07. Wikipedia. 2 Oct 2007
<http://en.wikipedia.org/wiki/Plate_boundaries>.
"Understanding Plate Motions." USGS. 05/05/99. Usgs. 2 Oct 2007
<http://pubs.usgs.gov/gib/dyhomic/understanding.html>.
Viau , Elizabeth Anne . "Tectonic Plates." World Builders. 2003. world Builders. 2 Oct 2007
<http://curriculum.calstatela.edu/courses/builders/lessons/less/les2/tectonic.html>. .
"Plate Tectonics." Indiana . 2 Oct 2007
<http://www.indiana.edu/~geol116/week7/week7.htm>.
"Shifting and Sliding." The Tech. The Tech. 2 Oct 2007
<http://www.thetech.org/exhibits/online/quakes/plates/tectonics.html>.
"Divergent Plate Boundaries." USGS. 1/14/1999. USGS National Park Service. 2 Oct 2007
<http://www2.nature.nps.gov/geology/usgsnps/pltec/diverge.html>
Divergent Boundary Exercise
-You can simulate divergent plate motion by placing your
palms down with your index fingers touch. Now pull your hands
apart.
Convergent Boundary Exercise
-You can simulate convergent plate motion by placing your
hands together in front of you with your palms down. Now gently
slide your bottom hand downward and your top hand upward,
while keeping them in contact.
Transform Boundary Exercise
-You can simulate transformational plate motion by placing
your hands together in front of you with your palms down. Now
slide your left hand away from you and your right hand toward
you.