Transcript Deforming the Earth`s Crust

Science
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Do Now: 12-2
HW: STUDY TODAY’S NOTES – QUIZ THURSDAY
WORK ON PLATE TECTONIC PROJECT
1. LIST THE THREE TYPES OF PLATE
BOUNDARIES AND SHOW THEIR MOVEMENT
WITH ARROWS.
Today
~ Power Point w/notes: Deformation of the Earth’s
Crust
Deforming the Earth’s
Crust
Types of Stress
•
Deformation: When the shape of
a rock changes due to stress
1. Compression = squeezing or
pushing together (convergent
boundaries)
2. Tension = forces stretch an object
(divergent boundaries)
3. Shearing = slicing motion back and
forth (transform boundaries)
Types of Folding
•
Folding: rock layers bending because of
stress
1. Anticline = upward bend
2. Syncline = downward bend
3. Monocline = bend with horizontal ends
Types of Faulting
• Fault: the surface along which rocks break
and slide past each other
• Hanging wall: the layers of rock ABOVE
the fault line (…above the diagonal)
• Footwall: the layers of rock BELOW the
fault line (…below the diagonal)
FOOTWALL
HANGING
WALL
Hanging Wall and Footwall
How can I remember which is which???
Types of Faults
• Normal Faults = the hanging wall
slides down the foot wall
• Reverse Fault = the hanging wall
slides up the foot wall
• Strike slip Fault = the rocks on
either side of the fault line slide
past each other
“It’s Normal to Hang Down.”
Folded Mountains
• COMPRESSION…mountains formed at
continental/continental convergent
boundaries.
• Ex. Appalachian Mountains
Appalachian Mtns.
COMPRESSION
Fault Block Mountains
• TENSION…causes large blocks of the
Earth’s crust to drop down compared to
the rocks around it.
• Ex. Tetons (Wyoming)
TENSION
Volcanic Mountains
• Formed at Ocean/Continental and
Ocean/Ocean Convergent boundaries.
• Ex. Ring of Fire
Ring of Fire
Mount Saint Helens
You’ve seen this before!...
NORMAL
FAULT
ANTICLINE
SYNCLINE