Download Pacific Ring of Fire Plate Tectonics

Plate Tectonics
Global Earthquake Locations
Pacific Ring of Fire
Global Volcano Locations
Continental Drift Hypothesis
- The concept of continental movement
was first suggested when it was noticed
that Africa and South America had
coastlines which appeared to be
counterparts of one another
Alfred
Wegener
(1912)
- This suggested they may once have been
joined and drifted apart
- He postulated that all landmasses were
originally united into a supercontinent
named Pangaea.
- Pangaea consisted of a northern
landmass called Laurasia and a southern
landmass called Gondwana
- As Pangaea broke up, the various
continents moved to their present-day
locations.
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What is the Evidence for Continental Drift?
1. Similarity of Rock Sequences and
Mountain Ranges
–  Marine, nonmarine, and
glacial rock sequences
of Pennsylvanian to
Jurassic age are nearly
identical on all the
Gondwana continents
What is the Evidence for Continental Drift?
2. Glacial Evidence
–  Glacial tills and striations
on the bedrock beneath
the till provide evidence
of glaciation at the same
time on all the
Gondwana continents,
with South Africa located
at the South Pole.
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What is the Evidence for Continental Drift?
3. Fossil Evidence
–  Some of the most
compelling evidence
comes from fossils like
the Glossopteris fern.
–  One of the strongest
examples is the
Mesosaurus, a fresh
water reptile.
What is the Evidence for Continental Drift?
4. Paleomagnetic studies
–  Paleomagnetismis the
remnant magnetism in
ancient rocks recording the
direction and intensity of
Earth’s magnetic field at
the time of the rock’s
formation.
–  The continents had moved
over time. If the continents
were moved into different
positions relative to each
other, the separate poles
could be resolved into one.
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Plate
Tectonics
Theory
Lithosphere
= Tect. Plates
(Solid)
Crust
Mantle
Asthenosphere
(liquid)
Plate Tectonics Theory
- According to plate
tectonic theory, the rigid
lithosphere (crust +
upper most mantle), is
divided into differentsized plates (tectonic
plates) that drive on top
of the liquid
asthenosphere (mantle)
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Plate Tectonics Theory
Plate Tectonics Theory
- A convective cell heat system is the basic process
responsible for plate motion.
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Plate Boundaries
Plate 3
Plate 4
Plate 5
Plate 6
Plate 2
Plate 1
1.  Divergent
2.  Convergent
3.  Transform
Divergent Plate Boundaries
-Plates move away from one
another.
-Most divergent boundaries occur
along the crests of oceanic ridges
- New oceanic lithosphere is
formed at the opening rift.
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Convergent Plate Boundaries
2
1
3
- Convergent boundaries are
places where two plates
collide
- Lithosphere is molted and
destroyed
- Cause the strongest
earthquakes
Transform Plate Boundary
These are boundaries along
which plates slide laterally past
each other along transform
faults
strike-slip
faulting
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