Plate Tectonics Brigitte Steinmetz John Adams Middle School.
-
Upload
johnathan-clark -
Category
Documents
-
view
218 -
download
0
Transcript of Plate Tectonics Brigitte Steinmetz John Adams Middle School.
Plate TectonicsPlate Tectonics
Brigitte SteinmetzBrigitte Steinmetz
John Adams Middle SchoolJohn Adams Middle School
DisclaimerDisclaimer
The images, maps and diagrams in this presentation were taken from the public
domain on the world wide web. Permissions were granted where possible. Any privately owned images not available
for this non-commercial, educational project will gladly be removed.
E-mail: [email protected]
Earth’s InteriorEarth’s Interior
Oceanic CrustA.
B.
C.D.
E.
Outer Core
Inner Core
Lithosphere
Continental Crust
OceanicCrust
AsthenosphereMantle
The MantleThe Mantle• Upper part = hot &
rigid (hard)– part of the
lithosphere.
• Middle part = hotter & soft (asthenosphere)
• Lower part = hottest & solid http://pubs.usgs.gov/publications/text/inside.html - 12/7/2004
The Earth is HOTThe Earth is HOT
• Review Heat Transfer– Radiation =
• Energy transferred through an empty space (i.e. sun energy).
– Conduction = • Energy transferred directly from one object to
another (i.e. burning feet at the beach).
– Convection = • Energy transferred through the movement of a
heated fluid.
Convection inside EarthConvection inside Earth
http://pubs.usgs.gov/publications/text/unanswered.html - 12/7/2004
Convection inside EarthConvection inside Earth
• Convection in the mantle causes the crust’s plates to move!
http://www2.nature.nps.gov/geology/usgsnps/animate/A08.gif - 12/7/2004
Continental DriftContinental Drift
• Alfred Wegener:– Hypothesis:
• About 300 MYA all continents were once joined together forming a SUPER continent!
– He named it PANGEA!
Continental Drift TheoryContinental Drift Theory• Pangaea begins to break apart and
continents move to present day locations
• Occured tens of millions of years ago
http
://w
ww
.mpm
.edu
/ree
f/pt
-gif.
htm
l - 1
2/7/
2004
Evidence of DriftEvidence of Drift• Continents fit together like a puzzle
• Land forms similar on different continents (like mountain ranges)
Evidence of Drift ContinuedEvidence of Drift Continued• Fossils found in
unlikely places– For example:
• Reptiles were found in Antarctica.
• Tropical plants found in ice covered places. http://www.soc.soton.ac.uk/CHD/classroom@sea/carlsberg/
images/fossil_correlation_lge.jpg - November 27, 2005.
What about the FUTURE?
Plates on the MovePlates on the Move
• Plates move 1-10cm/year.• Moving apart.• Moving plates
cause:–Earthquakes–Volcanoes
http://pubs.usgs.gov/publications/text/Krafla.html - December 13, 2004.
Plate BoundariesPlate Boundaries
• Place where two plates meet and interact.
• Three Types:–Transform –Divergent –Convergent
http://pubs.usgs.gov/publications/text/ridge.html - December 13, 2004.
Convergent BoundariesConvergent Boundaries
• Occurs when two plates collide (run into each other).
• Two types:
Continental Oceanic
http://pubs.usgs.gov/publications/text/understanding.html - December 13, 2004.
Continental ConvergenceContinental Convergence
• Two plates collide and buckle upwards forming mountains and cause earthquakes!
Oceanic ConvergenceOceanic Convergence• When two plates collide, one goes under
the other called subduction!
• Causes volcanoes.
Divergent Plate BoundariesDivergent Plate Boundaries
• When two plates move apart.
• Occurs at two places:
Mid-Oceanic Ridge Land – Rift Valley
http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0006339.html - December 13, 2004
Sea Floor SpreadingSea Floor Spreading
• Magma comes up forming new rock and pushes old rock to sides.
http://www.uwsp.edu/geo/faculty/ritter/glossary/S_U/sea_flr_spread.html - December 13, 2004.
Which Rock is Older?Which Rock is Older?
• The older rock is closer to the continents.
• New rock is at the mid-oceanic ridge.
http://www.soc.soton.ac.uk/CHD/classroom@sea/carlsberg/science/oceanic_constr.html
- December 13, 2004.
Pacific vs. Atlantic OceansPacific vs. Atlantic Oceans
Atlantic Ocean is getting
bigger – USA and Europe are moving
apart!
Pacific Ocean is getting smaller – continents are
coming together. Oceanic crust is
moving under them.
http://www.soc.soton.ac.uk/CHD/classroom@sea/carlsberg/science/oceanic_constr.html - December 13, 2004.