Transcript No Slide Title

Evidence of Crustal Motion
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Tilted sedimentary beds- (strata)
Changes after an earthquake
Changes in Bench Mark elevations
Marine fossils high above the
oceans (uplift- the rising of crust)
• Shallow water fossils at great depth
(subsidence- the sinking of crust)
Sedimentary layers are deposited?
Tilted Sedimentary Layers Show
Changes after
an
earthquake.
Changes in
Benchmark
Elevations
What is the temperature in the
earth’s core?
What is the pressure at the outer core
inner mantle interface(boundary)?
What is the pressure at the
asthenosphere?
Scientists once believed that
continents fit into the crust and
drifted from place to place.
German Scientist Alfred Wegener
proposed in 1912 that all of the
continents were together at one
time.
If you put the continents together
they fit like a jigsaw puzzle.
He called this_________________.
Scientists disagreed with the theory
that the continents plowed through
the crust.
Common sense would prove that
the continents would have to be
part of the crust.
Evidence from the ocean floors
led to the modern theory of…..
The Earth is composed of about a
dozen rigid plates that are moving
with several smaller plates.
The plates contain areas of light
continental rock (felsic) as well as
dense oceanic bottoms(mafic)
The Earth’s outer layer is called the
lithosphere.
It is made of the rigid upper mantle
and the crust.
The lithosphere moves on the
asthenosphere, part of the mantle that
flows.
Convection occurs
due to density
differences.
Hot liquid is less
dense and rises when
more dense liquid is
pulled down by
gravity.
Forces in the Earth come from
the heat being released from
deep inside.
•The heat is left over from the
formation of the earth and the
radioactive elements in the earth.
•The heat is passed by
conduction in solids and
convection in liquids.
Convection in the Earth
Evidence of Plate Tectonics
1. Newer Crust at Mid Oceanic
Ridges
2. Warmer Crust at MOR
3. Earthquakes and Volcanos found in
belts around the world.
4. Earthquakes are deeper as you
move inland at a subduction zone.
5. Magnetic Sea Floor Banding
Seafloor Spreading Video
http://www.youtube.com/watch?v=6CsTTmvX6mc&safe=active
Convection in the Earth
Magnetic Seafloor Banding:
Iron bearing minerals in
molten material will orient in a
north south direction.
Paleomagnetism