Constructive and Destructive Processes 6th Period

1
Constructive and Destructive Processes 6th Period

• a. Weathering and Erosion
• b. Crustal Deformation, Volcanic Eruptions, and
  Deposition

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Vocabulary

• Land forms- one of the features that make up
  Earth's surface
• Weathering- the various mechanical and chemical
  process that causes exposed rock to decompose.
• Erosion- the process by which the surface of the
  Earth is worn away by the action of water,
  glaciers, winds, etc.
• Crustal Deformation- a change in shape of the
  Earth's crust.
• Decomposition- the state of being decomposed
  decay.
• Deposition- the removal of an object being
  deposited.

3
Weathering

• Two types of weathering -
• Physical
• Chemical
• Types of physical weathering-
• thermal expansion
• freeze thaw weathering
• pressure release
• hydraulic action
• salt crystal growth weathering
• Types of chemical weathering-
• dissolution
• hydration
• hydrolysis
• oxidation
• biological weathering

4
Erosion

• The four main contributors to erosion are-
• water
• wind
• ice
• wave
• Water is erosional in all its forms.
• It is most erosional in streams
• Wind erosion is most powerful with rocks and
  sand
• Ice erosion occurs mostly from glaciers.
• Wave erosion occurs when waves from large bodies
  of water erode the coastline.

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Crustal Deformation

• Deformation in rock involves
• changes in shape
• changes volume
• Changes in shape and volume occur when stress
  causes rock to fracture or crumple into bends in
  the rock.
• More complex bends in rock types can develop in
  situations where lateral pressures become greater.

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H I S T O R I C A L I N F O
Volcanic Eruptions - Caused by pressure build-up
and plate tectonics - Largest volcanic
eruption - eruption of Toba - occurred about
71,000 years ago - produced 2800 cubic
kilometres of ash and may have reduced the
world's human population to only 10,000
Weathering and Erosion - Arches National Park
(See left photo) was created by weathering and
erosion - Over 2,000 natural arches were formed
over many years - This park exposed millions of
years of geologic history
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Real Life Application

• Weathering, erosion, and volcanic eruption impact
  humans in negative and positive ways. These are
  some of the impacts.
• Weathering and erosion makes a positive impact
  because it can cause fractures of rocks to erode
  into cool land formations such as arches. People
  are able to visit these sites and learn about how
  they are formed. Arches have different textures
  and can be found at national parks.
• Volcanic eruption can impact people in both a
  negative and positive way. It is negative
  because gases from volcanoes are dangerous and
  harmful. Also, a volcano will wipe out
  everything in its path when it erupts. It is
  positive because volcanoes have created great
  things like the Hawaiian Islands.
• Geologists study volcanic eruptions, erosion, and
  weathering, Seismologists and volcanologists
  study and help predict volcanic eruptions and
  earthquakes. Sedimentologists study erosion and
  deposition of rock particles by wind, water, or
  ice.

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Bibliography
"References." Dictionary.com. Lexico Publishing
Group, LLC. 1 Oct 2007 lthttp//dictionary.referenc
e.comgt. "Erosion - Information on Erosion."
About.com. 2007. The New York Times Company. 1
Oct 2007 lthttp//geography.about.com/od/physicalge
ography/erosion.htmgt. "What Causes Volcanic
Eruptions?." Thinquest. Oracle Education
Foundation. 1 Oct 2007 lthttp//library.thinkquest.
org/J001393/volcanoes/causes.htmgt. "Geology -
What was the Biggest Volcanic Eruption in
History?." Answers. The New York Times Company. 1
Oct 2007 lt http//geology.about.com/cs/basics_haza
rd/f/faq6bigeruption.htm gt. "Arches." National
Park Service . 23 Aug 2007. U.S. Department of
the Interior. 1 Oct 2007 lthttp//nps.gov/arch/gt.
"Arches Nature and Science / History."
National Park Service. 02 Oct 2007. U.S.
Department of the Interior. 1 Oct 2007
lthttp//www.nps.gov/arch/historyculture/index.htmgt
.
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Graphics (Bibliography)
This is a well known arch called Delicate
Arch. http//www.nps.gov/arch This is a picture
of a volcanic eruption of Mount
Pinatubo. http//pubs.usgs.gov/of/1997/of97-262.ht
ml This is a photo of the Toba
Caldera, http//volcano.und.edu/vwdocs/vw_hyperexc
hange/toba.html This is a photo of the Double
Arch. http//www.nps.gov/arch/photosmultimedia/upl
oad/arches1.jpg This is a photo of volcanic lava
making new layers in the earth. http//volcanoes.u
sgs.gov/lavaonsurface This is a photo of
weathering on the island of Paros,
Greece. http//www.geosci.unc.edu/faculty/glazner/
Images/Weathering/weathering.html
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Demonstration

• For our project we did a demonstration using a
  home-made volcano. We used frosting, and spread
  it over the volcano to show constructive
  processes like a volcanic eruption. Then we
  scraped the frosting off to show erosion, which
  occurs because of things like landslides, earth
  quakes, heavy rain and flooding.