Transcript Plate Tectonics

Objective
Warm-Up:
 You will use the theory of
 What do you know
plate tectonics and the
changes in the earth’s
surface in order to
explain the evidence for
continental drift theory.
about the theory of
plate tectonics?
 How do plates move?
The theory that the Earth’s Crust and
upper mantle (Lithosphere is broken up
into 20 MOVING sections called plates.
 Greek – “tektonikos” of a builder
 Pieces of the lithosphere that move
around
 Each plate has a name
 Fit together like jigsaw puzzles
 Plates Float on top of the
asthenosphere similar to ice cubes in a
bowl of water
http://pubs.usgs.gov/gip/dynamic/unanswered.html
 “Plates” of lithosphere are moved around by
the underlying hot mantle convection current
 Hot material rises
while, cooler
material sinks
 Created by the
uneven heating
of the
asthenosphere
“It is only by combing the information furnished by all the
earth sciences that we can hope to determine “truth” here.”
-Alfred Wegener (1880-1930)
Alfred Wegener 1915
Continents were once a
single land mass that
drifted apart.
Fossils of the same plants
and animals are found on
different continents
Called this supercontinent
Pangea, Greek for “all Land”
Split again – Laurasia &
Gondwanaland 180 million
years ago
http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml
Puzzle Fit
Fossil Evidence
Geological
Evidence
Climate evidence
Some thing to think about:
 What did Wegener propose as a method of explaining
the close fit of the continents on either side of the
Atlantic Ocean?
 What was so unusual about the fossil remains of
Mesosaurus?
 How did clues found in South Africa and Arctic islands
support Wegener's theory of continental drift?
 Why wasn't Wegener's theory accepted at the time?
 Is the Hypothesis that states that the continents once
formed a single land mass, broke up and drifted to
their present locations.
 Wegener Evidence:
 There are 4 pieces:
 1.
 2.
 3.
 4.
 What evidence did Wegner have that that
the continents use to be one large land mass
called Pangaea?
 How does the movement from Pangaea
impact the location of some of the resources
we use today? (think of coal and the
conditions necessary for it to form)
• Mid-Ocean Ridge :
underwater mountain
chains that run through
the Earth’s Basins
• Magma rises to the
surface cools and new
crust forms (Basalt)
• Older Crust is pushed
farther away from the
ridge
http://pubs.usgs.gov/gip/dynamic/understanding.html
http://pubs.usgs.gov/gip/dynamic/understanding.html
http://www.geology.com
http://www.geology.com
http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com
http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com
http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com
www.geology.com
 Name the 3 main layers of the Earth
 What is a tectonic plate?
 What was Pangea?
 What is Sea-Floor spreading?
 Name the three different types of plate boundaries and
one location on Earth for each one