Download stress that occurs when an object is squeezed

Chapter 4 Section
3, 4
Deforming the Earth’s Crust
Deformation
The process by which the shape of a rock changes because of stress
Stress
The amount of force per unit area on a given material
Compression
stress that occurs when an object is squeezed
Compression
stress that occurs when an object is squeezed
Shear
Stress that occurs when forces act parallel to the
surface, pushing in opposite directions,
Shear
Stress that occurs when forces act parallel to the
surface, pushing in opposite directions
Tension
stress that occurs when an object is stretched
Tension
stress that occurs when an object is stretched
Deforming the Earth’s Crust
Rock layers bend and break when stress is placed on them!
REVIEW
Stress that
occurs when
forces act to
squeeze an
object
Look at he
arrows.
Which type
of stress is
being
illustrated?
Stress that occurs
when forces act to
stretch an object
Stress that occurs when
forces act parallel to the
surface, pushing in
opposite directions,
producing cutting
instead of compression
or tension
REVIEW
Stress that
occurs when
forces act to
squeeze an
object
Look at he
arrows.
Which type
of stress is
being
illustrated?
Stress that occurs
when forces act to
stretch an object
Stress that occurs when
forces act parallel to the
surface, pushing in
opposite directions,
producing cutting
instead of compression
or tension
Folding
bending of rock layers because of stress in Earth’s crust
http://www.indiana.edu/~g103/G103/week9/buck.jpg
COMPREHENSION CHECK!
Q:
How do the forces of plate tectonics
cause rock to deform?
A:
Compression can cause rocks to be pushed into mountain ranges as
tectonic plates collide at convergent boundaries. Tension can pull
rocks apart as tectonic plates separate at divergent boundaries.
CONCEPT REVIEW!
Q:
What is plate tectonics?
A:
Plate tectonics is the theory that explains how large pieces of the
Earth’s outermost layer, called tectonic plates, move and change
shape.
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http://www.redthreadmagazine.com/culture/kiddush-club/when-life-offers-lemons-spike-%E2%80%99em/attachment/sqeezing-lemons
http://www.brokenmindset.org/stretching-your-christianity/
http://www.bonappetempt.com/2009/01/bon-appetits-devils-food-layer-cake.html
Boundary
A place where tectonic plates touch
Convergent Boundary
The boundary formed by the collision of two lithospheric
plates – Two plates come together
Hyperlink to Convergent
Boundary Animation
Convergent Boundary
The boundary formed by the collision of two lithospheric
plates
Continental-Continental Boundaries
Convergent Boundary
The boundary formed by the collision of two lithospheric
plates
Oceanic-Oceanic Boundaries
Convergent Boundary
The boundary formed by the collision of two lithospheric
plates
Continental-Oceanic Boundaries
Subduction Zone
Where two plates meet and one slides under the other
Transform Boundary
The boundary between tectonic plates that are sliding
past each other horizontally
Hyperlink to Transform Boundary Animation
Transform Boundary
The boundary between tectonic plates that are sliding
past each other horizontally
Hyperlink to Video 3:03
San Andreas Fault
California, USA
Divergent Boundary
The boundary between two tectonic plates that are
moving away from each other, or separate
Hyperlink to Divergent Boundary Animation
Divergent Boundary
The boundary between two tectonic plates that are
moving away from each other
Hyperlink to Divergent Boundary 0:11
Mid-Ocean Ridge
A long, undersea mountain chain that forms
along the floor of the major oceans
Mid-Ocean Ridge
A long, undersea mountain chain that forms
along the floor of the major oceans
http://www.platetectonics.com/book/page_8.asp
http://en.wikipedia.org/wiki/Mid-ocean_ridge
Fault
A break in a body of rock along which one block
slides relative to another
Fault
A break in a body of rock along which one block
slides relative to another
The blocks of crust on each side of a fault
are called “fault blocks”.
The blocks of crust on each side of a fault
are called “fault blocks”.
Hanging Wall
Footwall
Reverse Fault
Reverse Fault
Reverse Fault
The hanging wall moves up relative to the footwall.
These normally occur
when tectonic
forces cause
compression
that pushes rocks
together.
Hyperlink to Animation of Reverse Fault
Strike-Slip Fault
Strike-Slip Fault
Strike-Slip Fault
These faults form when opposing forces cause
rock to break and move horizontally.
Hyperlink to Animation of Strike-Slip Fault
Normal Fault
Normal Fault
Normal Fault
The hanging wall moves down relative to the footwall.
Hyperlink to Animation of Normal Fault
Rift
Zone
A set of deep cracks that forms between two plates
that are pulling away from each other
The East African Rift is an active continental rift zone in eastern Africa. The rift is a narrow zone
in which the African Plate is in the process of splitting into two new tectonic plates called the
Somali Plate and the Nubian Plate, which are sub plates or protoplates.
http://ajs-geo-blog.blogspot.com/2012/03/rift-valley.html
Rift
Zone
A set of deep cracks that forms between two plates
that are pulling away from each other
The actual rift between the North American tectonic plate and the Eurasian plate. Iceland
is the only place where this is visible above water.
Rift
Zone
A set of deep cracks that forms between two plates
that are pulling away from each other
Southwest Rift, Hawaii
The rift was formed over time during eruption of
Kilauea. Hot magma moved underground from
the summit reservoir in to the rift zone and tore
the crust apart.
http://www.uwec.edu/jolhm/hawaii2005/day3/hiwebsite/fs11.htm
Rift
Zone
A set of deep cracks that forms between two plates
that are pulling away from each other
Southwest Rift
Hawaii
http://www.uwec.edu/jolhm/hawaii2005/day3/hiwebsite/fs11.htm
http://www.hp1039.jishin.go.jp/eqchreng/figures/af1-2.jpg
Name each type of Fault
http://media.tiscali.co.uk/images/feeds/hutchinson/ency/c00948.jpg
What type of fault is this?
COMPREHENSION CHECK!
Q:
How does the hanging wall in a normal fault
move in relation to a reverse fault?
A:
In a normal fault, the hanging wall moves DOWN.
In a reverse fault, the hanging wall moves UP.
When Plates Collide
Land features that start as folds and faults can
eventually become large mountain ranges.
Mountains exist because tectonic plates are
continually moving around and colliding with one
another.
Uplift
rising of regions of Earth’s crust to higher elevations
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Subsidence
the sinking of Earth’s crust to lower elevations
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Subsidence
the sinking of
Earth’s crust to
lower elevations
http://ga.water.usgs.gov/edu/gwsubside.html
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http://www.earthscienceworld.org/images/search/results.html?Keyword=Subsidence
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http://www.windows2universe.org/earth/clim
ate/geosphere_plate_tectonics.html
COMPREHENSION CHECK!
Q:
A:
How do uplift and subsidence differ?
Uplift is the rising of the Earth’s crust to
higher elevations. Subsidence is the sinking of
the Earth’s crust to lower elevations.
COMPREHENSION CHECK!
Q:
A:
What are rift zones? How do they form?
Rift zones are cracks that form where
two plates are pulling away from each other. As
they pull apart, stress builds and faults form
along the rift zone.