Transcript Layer Earth:Stress - Jamestown School District

Earth Science
The Dynamic Earth
Introduction to Geology
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The Earth Composition
• There are 4 layers
of the Earth
–
–
–
–
Inner core
Outer Core
Mantle
Crust
The Earth’s Crust
• The Earth’s crust is
subjected to stress
• A stress is a push or pull
on the crust that causes
it to change form
• There are 3 main types
of stress on the Earth’s
crust
Earth’s Structure
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3 Types of Stress
• Compression - rock
layers get squeezed
together
• Tension - rock layers get
pulled apart like taffy
• Shearing - rock layers
get pushed in different
directions causing the
rock to twist and tear
Two Types of Crust
• There are 2 types of
Earth’s crust
– Oceanic - thin ( 8-10
km thick) very dense
– Continental - thicker
(30-70 km thick) less
dense than oceanic
Rock Deformation
• Deformation is the term used
to describe rock that has been
broken, tilted, or folded
• Fracture - break in rock layers
• Faulting- movement of rock
layers along an area of
fracture
• Folding - occurs when rocks
are bent upward or downward
Types of Folding
• Anticline - rocks are
bent upward (looks
like an “A”)
• Syncline - rocks are
bent downward (looks
like a “U”)
Plateaus and Domes
• Plateaus - a large flat
area of land that is raised
above sea level
• Domes - an uplifted area
created by rising magma
(looks like a half of
sphere)
The Floating Crust
• The Earth’s crust
floats on the mantle
• The mantle is made
of liquid rock
• Isostasy - a balance
between the upward
force of the mantle
and the downward
force of the crust