Lesson 13.
The Crust
determine the layers of Earth
Objectives 1 based on chemical
At the end of composition; and
the lesson,
you should be describe the layers of Earth
able to: 2 based on physical properties.
Learn about It!
The Crust
• The crust is the outermost
layer of Earth and is the only
layer where organisms are
found.
• This rigid layer is in the
constant process of destruction
and renewal.
Compositional Layers of the Earth
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Tectonic Plates
• Tectonic plates are
slabs of the brittle
lithosphere, which can
able to move due to the
plasticity of the
underlying
asthenosphere.
Major Plates of the Earth
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Tectonic Plates
• Most of the seismic
activities including
earthquakes happen in
between plates.
Major Plates of the Earth
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Continental Crust
• The continental crust makes
up the land surface of Earth
which is about 32 km thick.
• The composition is more
variable than oceanic crust
but can be generalized as
mostly granites.
Types of Crust
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Structure on the Continental Crust
• Mountain belts are
uplifted regions of
deformed rocks.
Mountain belts and stable interior
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Structure on the Continental Crust
• The stable interiors are
older than mountain
belts. Within these areas
are expansive and flat
regions which are
composed of deformed
crystalline rocks called
shields.
Mountain belts and stable interior
Learn about It!
Oceanic Crust
• The oceanic crust is a thin
layer averaging from 5 to 7
km thick.
• It is consists of mafic
rocks, which are made up
of silicates, magnesium and
iron.
Types of Crust
Learn about It!
Structure on the Oceanic Crust
• Continental margins are the areas which separate continental and
oceanic crust. It include: continental shelf; continental slope; and
continental rise.
Parts of the Continental Margin
Key Points
The crust is the outermost rocky layer of Earth which is mainly
1 composed of granitic and basaltic igneous rocks.
The types of crust includes continental and the oceanic crust.
2
Lithosphere makes up the tectonic plates which is composed of the
3 crust and the uppermost mantle.
Check Your Understanding
Write the word true if the statement is correct,
otherwise, write the word false.
1. Continental crust is composed of dark-colored igneous rocks known
as granite.
2. Lithosphere is composed of the crust and the lower mantle.
3. Earthquakes occur at the boundaries of the lithosphere.
4. The collision of Indonesian plate and Eurasian plate results to the
formation of Himalayas.
5. The age of mountain belts are younger than the stable interiors.
Challenge Yourself
What are the differences
between continental crust
and oceanic crust in terms of
parameters, composition,
density, average thickness,
age of oldest known crust,
and features or parts? Make
a summary table.
Bibliography
Carlson, Diane H. and Charles C. Plummer. 2009. Physical Geology: Earth Revealed, 8th Edition. New York:
McGraw-Hill Companies, Inc.
Hefferan, Kevin and John O’Brien. 2010. Earth Materials. United Kingdom: Wiley-Blackwell Publishing.
King, Hobart. “Transform Plate Boundary.” Geology.com. Accessed May 11, 2017. http://
geology.com/nsta/transform-plate-boundaries.shtml
Levin, Harold L. 2013. The Earth Through Time. United States of America: John Wiley & Sons Inc.
Marshak, Stephen. 2009. Essentials of Geology 3rd Edition. New York: W.W. Norton & Company.
Stephen J. Reynolds, et al. 2013. Exploring Geology, 3rd Edition. United States: McGraw-Hill Companies, Inc.
Bibliography
Tarbuck, Edward J. and Frederick J. Lutgens. 2015. Earth Science. New Jersey: Pearson Prentice Hall.
United States Geological Survey. 1999. “J. Tuzo Wilson: Discovering transforms and hotspots” Accessed May 11, 2017.
https://pubs.usgs.gov/gip/dynamic/Wilson.html
United States Geological Survey. 2014. “Understanding Plate Motions” Accessed May 1, 2017.
https://pubs.usgs.gov/gip/dynamic/understanding.html
