Transcript Plate Tectonics - NagelBeelmanScience

By: Anthony Perkins
The Pangaea Theory
 Pangaea was a supposed
 supercontinent made up of all our
 current continents.
 Alfred Wegener
- In 1912 he came up with the theory
 Of Pangaea. The name means “all lands.”
 -He said Pangaea was probably intact
 Until late Carboniferous period.
http://www.ucmp.berkeley.edu/geology/tec
hist.html
- other than geology he was accomplished in
Astronomy, Meteorology and Climatology. These all
helped him to come up with his theory/discovery.
When Wegener first proposed the idea it was
dismissed.
- He could not provide an adequate explanation of
the forces responsible for continental drift or
disprove the theory that Earth was solid and
immovable. http://www.ucmp.berkeley.edu/geology/tec
hist.html
 Arthur Holmes

- His ideas later assisted in the recognition of
Wegener’s theory.
 - He elaborated on Wegener’s hypothesis. He
said that thermal convection affects the mantle. It
causes it to heat and cool. Heating and cooling
over a period of time can cause a continent to split
up and move.
 - This received little attention at the time it was
proposed.
http://www.ucmp.berkeley.edu/geology/tec
hist.html
The theory being discussed at this time was
the Contraction theory.

- This said that the Earth was once a molten ball
and the act of cooling caused some parts of the
Earth to fold in on itself.
http://www.ucmp.berkeley.edu/geology/tec
hist.html
Convergent Boundaries
 Convergent Boundary: A boundary were one
plate overrides another one and forces it
under. The one pushed under becomes part
of the mantle again.
Convergent Boundary
Plate: A piece of the broken up lithosphere that
floats on the asthenosphere. (top part of Earth.)
Boundary: Where two plates meet.
http://scign.jpl.nasa.gov/learn/plate4.htm
What it causes:
 Mountains
 Earthquakes
 Volcanoes
 Trenches
Mariana Trench
Mountain
Mountain: A raised spot on the Earth that comes to a
Point.( a big hill.)
Earthquake: A big shaking of the Earth from the motion of
The plates moving.
Trench: A dip in the ground formed by the two plates that meet.
Volcano: An opening in the ground that magma come out of the Earth.
 One example of a Convergent Boundary is
the Ring of Fire.

- A ring of volcanoes around the edges of the
Pacific Plate.
 - due precisely to there being a lot of convergent
zones around there.
Volcano
http://scign.jpl.nasa.gov/learn/plate4.htm
Divergent Boundaries
 Divergent Boundary: At a Divergent Boundary two
plates move away from each other. As the plates
move away from each other mid- ocean ridges are
formed because magma forces itself up through
the cracks and cools.
Mid-Ocean ridge
 What it causes:

- Mid-Ocean Ridges
http://scign.jpl.nasa.gov/learn/plate4.htm
One example of a Divergent Boundary is the
Mid-Atlantic range.
- This helps to move North America and Europe
farther apart.
- The two plates involved in this are the North
American plate and the
Mid-Atlantic Ridge
Eurasian plate.
http://scign.jpl.nasa.gov/learn/plate4.htm
Transform Boundaries
 Transform Boundary: A boundary were two plates
slide past each other. Material is neither created
nor destroyed. The plates just move past each
other.
http://scign.jpl.nasa.gov/learn/plate2.htm
Transform Boundary
Earthquake
What it causes:
- Earthquakes
- Mudslides
- Landslides
Mudslide
Landslide
Mudslide: The rapid downward
movement of earth caused by
shaking
Landslide: the falling or sliding of
rock, soil, moss etc.
http://scign.jpl.nasa.gov/learn/plate2.htm
 One example of a Transform Boundary is the San
Andreas Fault.

- Fault that is in California.
 - The North American and Pacific plates are moving past
each other and it is the site of many earthquakes.
San Andreas Fault
http://scign.jpl.nasa.gov/learn/plate2.htm
Real World Connections
 The United States

- we live on the North American Plate.
 - Most of the U.S. is on the North American Plate with
the exception of Hawaii and some of California which are
on the Pacific Plate.
The United States
 - the U.S. is bordered by the
Pacific Plate and the Juan de Fuca
Plate.
http://geology.com/plate-tectonics.shtml
 Ohio is at risk of an Earthquake only if it is a very
serious one. We feel them in Ohio but usually they are
not very severe.
Ohio
 If the ancient Volcano in
Yosemite were to blow again
it would be disastrous.
http://www.dnr.state.oh.us/OhioGeological
Survey/GeologyTopics/GeologicHazards/tab
id/7902/Default.aspx
 In the very distant future California may
break away from the United states. This is
because of the San Andreas Fault. The
Pacific Plate and the North American Plate
could work it off just like Pangaea got
California
worked apart.
https://geohazards.usgs.gov/