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Geologists: Scientists
that study the forces that
make and shape planet
Earth. They study the
chemical and physical
characteristics of rock.
Geologists study the
processes that create
Earth’s features and
search for clues about
Earth’s history.
Geology is the study of
the planet Earth.
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Paleontologists: These
scientists study the forms of
life existing in former
geologic periods.
The science of
Paleontology helps us learn
about the history of
different species that have
inhabited Earth.
Information we have
regarding dinosaurs, wooly
mammoths, trilobites, and
other extinct species come
from fossil formations
found and studied by
paleontologists.
Constructive Forces:
Shape the surface by
building up mountains
and landmasses.
(Example Surtsey-2
Miles)
 Destructive Forces:
Slowly wear away
mountains and
eventually every other
feature on the surface.
(Example:
Weathering)
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 Any
ideas???? (Hint it
is not because we
sent Brendan Frasier
down there)
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We know about the
composition of the interior of
the Earth because of Seismic
Waves. (Earthquake Waves)
The speed of these seismic
waves and the paths they take
reveal how the planet is put
together.
P (primary) waves can travel
through every layer of the
earth. In solids, these waves
generally travel almost twice
as fast as S waves and can
travel through any type of
material.
S (secondary) waves can only
travel through solids.
The arrival of the
P and S waves
differs as shown
the seismograph
reading to the
right.
 The difference in
arrival times of
these two types of
waves can help
scientists locate
the epicenter of
earthquakes.
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 There
are 4 main
layers to the Earth.
 Crust, Mantle, Outer
Core, and Inner Core.
 As you go towards the
center of the Earth
the temperature and
pressure increases
greatly.
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The crust includes rocks,
mountains, soil and
water.
The crust is the smallest
layer of the earth. (Apple
Example)
There are two types of
crust oceanic crust
(Basalt which is an
igneous rock) and
continental crust (rocks
like Granite which is an
igneous rock)
The mantle is a layer of
hot rocks
 The mantle is solid but
has liquid like
characteristics. (It’s
kind of like Silly Putty)
 The mantle is the
largest of the layers of
the earth
 It is mainly composed
of silicon, oxygen, iron,
and magnesium.
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The outer core is a layer of
molten metal that surrounds the
inner core.
In spite of enormous pressure
the outer core behaves like a
thick liquid.
Currents in the liquid outer core
force the solid inner core to
spin at a slightly faster rate than
the rest of the planet. These
currents in the outer core create
the Earth’s magnetic field. This
is why you can use a compass
and the Earth is protected from
some of the harmful rays of the
sun.
Composed of mostly Iron and
Nickel
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The inner core is a dense
ball of solid metal.
It is also mainly
composed of iron and
nickel.
Temperature range is
probably between 2,0005,000 degrees Celsius.
The center of the inner
core is thought to be as
hot as the surface of the
sun.
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On average for every
40km you dig deeper
into the earth the
temperature increases by
1 degree (Celsius).
Mantle varies in
temperature from 8702000 degrees Celsius.
Cores vary in
temperature from 2,0005,000 degrees Celsius.
If it is 100 degrees
Fahrenheit then it is 37
degrees Celsius.
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The deeper you go into the
various layers of the earth
the greater the pressure in
the surrounding rock.
Pressure is the force
pushing on a surface or
area. Because of the weight
of the rock above, pressure
inside Earth increases as
you go deeper.
The density which is the
mass divided by volume
also increases as you go
further into the earth.
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Plate Tectonics is the
geological theory that states
that pieces of Earth’s crust are
in constant, slow motion, drive
by convection currents in the
Earth’s mantle.
No plate can budge without
affecting the other plates
surrounding it.
As the plates move, they
collide, pull apart, or grind
past each other.
Discussion of Convection
Currents. (on the board)
Short Convection Current
Video
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Plate movements cause
volcanoes to erupt,
mountain ranges to be
formed, and earthquakes
to occur.
Plate Tectonics are
responsible for the
deformation of Pangaea.
Plate Tectonics
Introduction
Plate Tectonics Evidence
Movement of Earth's
Tectonic Plates
The Man Behind Plate
Tectonics
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The earth is divided up into 16 plates.
Along these plate boundaries is where much of the
geological interactions such as earthquakes, mountain
formation, and volcanoes occur.
Mountain ranges and
sea floor basins line up
between continents.
 Certain ancient fossils
(Mesosaurus and
Lystrosaurus) are found
in places now
separated by oceans.
 Coal deposits in arctic
areas.
 Glacier scratches on
rocks in deserts.
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Along transform
boundaries, crust is not
created nor is it
destroyed.
A transform boundary is
where two plates slip
past each other, moving
in opposite directions.
Earthquakes occur
frequently along these
boundaries.
San Andreas Fault is an
example of a transform
plate boundary.
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The place where two plates
move apart or diverge, is
called a divergent boundary.
Most divergent boundaries
occur at the mid-ocean
ridge such as the one found
in the Atlantic Ocean. The
Atlantic Ocean is currently
growing an average of 3cm a
year.
This is about the rate at
which your fingernails grow.
Volcanoes can occur at
divergent plate boundaries
because the weak crust can
have magma from the mantle
seep upwards.
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Some divergent plate
boundaries occur across
continents. When
divergent plate
boundaries occur across
continents they are
called rifts.
There is a giant rift
across Africa called the
Great Rift Valley which
may someday split the
eastern part of Africa
away from the rest of the
continent.
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The place where two plates come
together, or converge, is called a
convergent boundary.
When two plates collide the density of
the plates determines which one
comes out on top. Oceanic crust
which is made of basalt is more dense
than continental crust which is made
mostly of granite.
When 2 plates carrying continental
crust collide, neither is dense enough
to force the other plate on top of itself.
This is how giant mountains are
created as giant plates collide with
neither of them going under or over
the other plate.
Volcanoes often times occur under
plate boundaries when a process
called subduction occurs. This occurs
when an oceanic plate is more dense
then the continental plate it is hitting
into.
 When
an oceanic
plate and a
continental plate
converge. The
oceanic plate
subducts under the
continental plate.
 This action causes
deep sea ocean
trenches as well as
volcanic activity
Mariana Trench is the
deepest trench in the
world.
 It is about 1580 miles
long and 43 miles wide.
 It’s deepest point is
about 7 miles down.
 This is why even though
the Atlantic ocean is
growing every year that
same land is being
recycled in the Pacific
Ocean.
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A tsunami is a series of
water waves caused by
the displacement of a
large volume of a body
of water, typically an
ocean.
 This is generally caused
by earthquakes,
volcanoes, or
underwater explosions.
 Hollywood Tsunami
Video
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The earth is
approximately 4.6 billion
years old.
It is broken up into
different Era’s and
Period’s that are
generally ended by mass
extinction events.
For example the
Cretaceous Period
ended 65 million years
ago (mya). This period
marked the end of the
age of the dinosaurs.
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Pre-Cambrian is an era that
covered from 4.6bya to 570mya.
There is a very limited fossil
record from this period of time.
Most of the organisms found are
stromatolites.
Stromatolites were ancient
archaebacteria that built up small
rock masses.
From 4.6bya to 2.5bya there was
very little from oxygen in the
atmosphere. The only organisms
that existed were anaerobic
organisms.
Around 530mya an event called
the “Cambrian Explosion”
occurred where the fossil record
shows a large amount of diversity
in the fossil record with a great
variety of organisms.
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The Paleozoic Era covers
from 570mya-225mya. It
includes the Cambrian,
Ordovician, Silurian,
Devonian, Carboniferous,
and Permian Periods of
Geological Time.
During this Era some of
the most abundant
organisms were trilobites
(arthropod-similar to
crustaceans),
echinoderms, sharks,
early reptiles, and ferns.
The Mesozoic Era
spanned from 225mya65mya and included
the Triassic, Jurassic,
and Cretaceous
Periods of time.
 These periods of time
are well known for all
species of dinosaurs,
early birds
(archaeopteryx),
mammals, and
flowering plants.
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The Cenozoic Era
which spans from
65mya ago to present
time. It includes the
Tertiary and
Quaternary Periods.
 This period includes
such organisms such as
large carnivores,
mammals (us), grass
lands, mammoths, and
saber toothed tigers.
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