Layers
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Glendale Community College *
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Course
101
Subject
Geology
Date
Dec 6, 2023
Type
Pages
7
Uploaded by DrSharkPerson373
Please write your answers in blue.
Part 1:
Layers of the Earth
Video
1.
Where does most of our knowledge of the Earth’s interior come from?
Much of our knowledge of Earth's insides comes from monitoring the thousands
of earthquakes that occur every year.
1.
What was the most accepted theory of the Earth’s interior around 1500?
Five centuries ago the world had mostly accepted that the Earth was not only a
sphere, but was thought to be of uniform rock throughout.
2.
What significant change did Sir Issic Newton add to the theory of Earth's interior?
Two hundred years later Sir Isaac Newton, studying our planetary system,
calculated that the interior of the earth must be made of far-denser material than the
surface rock. Newton's estimate of the overall density of the Earth remains essentially
unchanged today.
3.
What data scientists use in the early 1900’s that added to the Earth’s interior
theory?
In the early 1900 scientists discovered they could use data from earthquakes as
a method for looking deep beneath the surface.
Explain two facts that were added to the theory from this data.
a.
b.
4.
What are the three basic layers of the Earth?
The earth is made up of three different layers:
the crust, the
mantle and the core
5.
How thick is the Earth’s crust?
A.
Continental crust:
a.
up to 75 kilometers
B. B.Oceanic crust:from 5-10 kilometers
6.
Describe three important differences for each of the three earth layers.
a.
Crust:
i.
The lithosphere ranges from as much as 100 kilometers thick in the
oceanic plate to 200 kilometers thick in the continental plates. It is
in this brittle zone that earthquakes occur,
due to compression, extension, & shearing.
ii.
Over billions of years the cooled surface of Earth has been broken
up into the moving planes that are called lithospheric plates
(commonly "tectonic plates") Because they are mostly more
buoyant than the asthenosphere, they float above it.
iii.
the crust is merely the top of the tectonic plate.
This uppermost brittle mantle behaves much like the overlying crust.
Together they form a rigid layer rock called the lithosphere that moves in
unison .The lithosphere ranges from as much as a 100 kilometers thick in
the oceanic plate to 200 kilometers thick in the continental plates.
b.
Mantel:
i.
The chemical composition of the 2,900-km-thick mantle varies little
from top to bottom, but there are distinct physical variations due to
temperature & pressure differences.
ii.
The uppermost mantle is relatively cool & brittle
and ranges from 50 to 120 kilometers thick.
iii.
Below this zone the upper mantle becomes notably more plastic &
malleable
due to the right combination of heat & pressure.
That ductile zone is known as the asthenosphere varies up to 400
kilometers deep depending mainly on temperature.The lower mantle is
55% of the planet by volume. It is denser and hotter than the upper
mantle.
c.
Core:
i.
At the center the Earth is the core, nearly twice as dense as the
mantle because it's metallic iron alloy rather than rock.
ii.
Earth's core is made up of two distinct parts:
the liquid outer core & a solid inner core. Although the inner core is hotter
than the outer core, there is also greater pressure squeezing the atoms,
changing the material from liquid to solid.
iii.
The liquid outer core is convecting vigorously & generates Earth's
magnetic field.
7. What is the asthenosphere?
Structure of Earth
The
asthenosphere is
the layer below the lithosphere.
Astheno-
means lacking strength,
and the most distinctive property of the asthenosphere is movement. Because it is
mechanically weak, this layer moves and flows due to convection currents created by
heat coming from the earth’s core cause. Unlike the lithosphere which consists of
multiple
plates
, the asthenosphere is relatively unbroken.
Part 2: Earth’s Structure
. Use the following link
https://www.learner.org/series/interactive-dynamic-earth
- then
click on Earth’s Structure
at the top
1.
Label the layers of Earth in the diagram
below.
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a.
Crust_____________________
b.
Inner core_____________________
c.
Outer core _____________________
d. Mantle
_____________________
e.
_____________________
2.
The lithosphere is made up of the crust and a tiny bit of the upper mantle.
3. The plates of the lithosphere move (or float) on this hot, malleable solid rock
zone in the upper
mantle, directly underneath the lithosphere. This is known as
the asthenosphere.
4. The layer of Earth that is the only liquid layer is the outer core.
Part IIl. Plate Tectonics
. Use the following link to find these answers:
https://www.learner.org/series/interactive-dynamic-earth
then
Click on Plate Tectonics
at top
A
B
1.
What does the
Earth look like today?
b_____________
2.
What did Earth look like 250 million years ago? The continents of Earth were clustered
together in formation by a scientist named Pangaea. The scientist named “Pangaea”
was a German scientist by the name of Alfred Wegner . He theorized that “Pangaea"
split apart and the different landmasses, or continents, drifted to their current locations
on the globe. Wegener’s theories of plate movement became the basis for the
development of the theory of plate tectonics.
3.
Order the images of Earth’s plates in order from oldest or earliest .
5
3.
2.
4.
1
Part IV. Plates and Boundaries.
Use the following link to find these answers:
https://www.learner.org/series/interactive-dynamic-earth/
then
Click on Plate and
Bounderies
1.
Name the tectonic plates in the blanks on the image below.
a
Pacific plate
b
North American plate
c
South American plate
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d
African plate
e
Antarctic plate
f
Eurasian plate
g
Australian plate
2.
What is the driving force for plate tectonics?
The forces that drive Plate Tectonics include: Convection in the Mantle (heat driven)
Ridge push (gravitational force at the spreading ridges) Slab pull (gravitational force in
subduction zones)
3.
Label and describe the 3 different types of plate boundaries.
●
Divergent boundaries -- where new crust is generated as the plates pull away
from each other.
●
Convergent boundaries -- where crust is destroyed as one plate dives under
another.
●
Transform boundaries -- where crust is neither produced nor destroyed as the
plates slide horizontally past each other.
4.
Where on the earth’s crust are convergent boundaries found?
Convergent boundaries, also called destructive boundaries, are places where two or
more plates move toward each other.
5.
Where on the earth’s crust are divergent boundaries found?
Most divergent boundaries are located along mid-ocean oceanic ridges (although some
are on land).
6.
Where on the earth’s crust are transformed boundaries found?
Most transform faults are found on the ocean floor. They commonly offset the active
spreading ridges, producing zig-zag plate margins, and are generally defined by shallow
earthquakes
.