Deformation Whether a material bends or breaks depends on h ow much stress is applied to the material Deformation Process by which the shape of a rock changes because of stress Objectives Describe ID: 259026
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Slide1
Deforming the Earth’s CrustSlide2
Deformation
Whether a material bends or breaks depends on
h
ow much stress is applied to the material.
Deformation
Process by which the shape of a rock changes because of stress.Slide3
Objectives:
Describe
two types of stress that deform rocks.
Describe
three major types of folds.
Explain
the differences between the three major types of faults
.
Identify
the most common types of mountains.
Explain
the difference between uplift and subsidence.Slide4
Compression
The type of stress that occurs when an object is squeezed, such as when two tectonic plates collide
.
When compression occurs at a convergent boundary, large
mountain ranges
can form.
Rocky Mountains
Appalachian MountainsSlide5
Tension
stress that occurs when forces act to stretch an object.
Occurs at divergent plate boundaries, such as mid-ocean ridges, when two tectonic plates pull away from each other.Slide6Slide7
Activity
How can a Mars Bar can be representative on the outer layers of the Earth?
How can we show tension using a Mars Bar?
How can we show compression?Slide8
FOLDING: Rock layers
bend
when stress is placed on them.
FAULTING:
When enough stress is placed on rocks, they can reach their elastic limit and
break
. Slide9
Folding
The major types of folds are
Anticline
Synclines
Monoclines
.
Draw a sketch of each.Slide10
Anticlines
are upward-arching folds.
Synclines
are downward,
troughlike
folds.
In a monocline,
rock layers are folded so that both ends of the fold are horizontal.Slide11
Faulting
Fault blocks
The blocks of crust on each side of the fault.
When a fault is
not vertical
, its two sides are either a
hanging wall
or a
footwall.Slide12
When a
normal fault
moves, it causes the hanging wall to move down relative to the footwall.Slide13
When a
reverse fault
moves, it causes the hanging wall to move up relative to the footwall.Slide14
A third major type of fault is a
transform fault
.
These faults form when opposing forces cause rock to break and move horizontally.Slide15Slide16
Plate Tectonics and Mountain Building
When tectonic plates collide, land features that start as folds and faults can eventually become large
mountain ranges
.
When tectonic plates undergo compressions or tension, they can form mountains in several ways.
Folded Mountains
form when rock layers are
squeezed together and
pushed upward.Slide17
Fault-Block Mountains
Form when large blocks of the Earth’s crust drop down relative to other blocks.
Volcanic Mountains
Form when magma rises to the Earth’s surface and erupts.Slide18
Activity
Use the equipment provided to form layers of sand and flour – these represent the layers of rock that form a mountain.
Take a picture using your
iPad
.
Use the card provided to apply stress to your “mountain”
Take a picture with your
iPad.Add the following labels to your picture if appropriate:
Anticline/syncline/monocline, layers of rock, tension/compressionSlide19
Uplift and Subsidence
Vertical movements in the crust are divided into two types—
uplift
and
subsidence
.
Uplift
The rising of regions of the Earth’s crust to higher elevations.
Subsidence
The sinking of regions of the Earth’s crust to lower elevations.Slide20
Uplifting of Depressed Rocks
Uplift can occur when large areas of land rise without deforming.Slide21
Tectonic Letdown
Subsidence can occur when the lithosphere becomes stretched in rift zones.
As tectonic plates pull apart, stress between the plates causes a series of faults to form along the rift zone.Slide22
Were you listening?
Describe
two types of stress that deform rocks.
Describe
three major types of folds.
Explain
the differences between the three major types of faults
.
Identify the most common types of mountains.
Explain
the difference between uplift and subsidence.Slide23
Two types of stress?
Tension
CompressionSlide24
T
hree
major types of folds.
Anticlines
Synclines
MonoclinesSlide25
Explain
the differences between the three major types of faults
.
Folded
Volcanic
Fault BlockSlide26
Identify
the most common types of mountains
.
Normal
Reverse
Strike- slipSlide27
Explain
the difference between uplift and subsidence
.
Uplift – large areas of land rise without deformation
Subsidence – land becomes stretched and is “let down”Slide28
Vocabulary words
Compression:
stress that occurs when forces act to squeeze an object
Tension:
stress that occurs when forces act to stretch an object
Folding:
the bending of rock layers due to stress
Uplift: the rising of regions of the earths crust to higher elevationsSubsidence:
the sinking of regions of the earths crust to lower elevations