Chapter 4: Lesson 4 Deforming the Earth’s Crust
I can describe the major types of folds
I can explain how the three major types of faults differ
I can explain how various types of mountains form
Name ______________________________________ #___________
Date _____________________ Due Date ___________________
Rocks Get Stressed
Folding
Deformation: When a rock
changes its shape due to stress
Stress: Is the amount of force
per unit area that is put on a
given material.
Compression – is the type of
stress when 2 tectonic plates
collide. When compression
happens Mts. and Mt. ranges are
formed.
Tension: is stress that occurs
when forces ac to stretch an
object. These occur at divergent
pate boundaries when 2 tectonic
plates pull away from each other.
These two forces bend and break
rocks to form some common
landforms
Folding: Occurs when rock layers bend
due to stress in the Earth’s crust.
Syncline: Forms when horizontal stress
acts on a rock.
Faulting
Fault: is the surface along which rocks
break when they slide past each other.
The blocks of crust on each side of the
fault are called fault blocks.
Hanging wall - is the block on the top
of the fault surface
Footwall- is the block beneath the
hanging wall.
Anticline: Forms when horizontal
stress acts on a rock.
Normal Fault: The movement of a
normal fault causes the hanging wall
to move down relative to the footwall.
Usually happen when tectonic forces
cause tension that pulls rocks apart.
Monocline: This folding forms when
vertical stress acts on rock. Rock layers
are folded so that both ends of the fold
are still horizontal.
Reversal Fault: The movement of a
reversal fault causes the hanging wall
to move up relative to the footwall –
the reverse of a normal fault.
Usually happen when tectonic forces
cause compression that pushes
Telling The Difference
You can tell what type of fault your
looking at by looking at the sequence of
sedimentary rock layers.
Chapter 4: Lesson 4 Deforming the Earth’s Crust
I can describe the major types of folds
I can explain how the three major types of faults differ
I can explain how various types of mountains form
Telling The Difference
Strike-Slip Faults
Strike Slip Faults - These faults occur
when opposing forces cause rock to
break and move horizontally.
The earth would look like it was
moving left or right.
Name ______________________________________ #___________
Date _____________________ Due Date ___________________
Strike-Slip
Plate Tectonics
Faultsand Mountain
Building
Folded Mountains & Volcanic
Mountains
The Earth’s crust changes due to the
forces of plate tectonics. When
tectonic plates collide small folds in
the Earth can change into great
mountain ranges.
Folded Mountains – form when rock
layers are squeezed together and are
pushed upwards. Formed at a
convergent boundary
Most major mountain ranges form at
the edges of tectonic plates.
Fault –Block Mountains: Where
tectonic forces put enough tension
on the Earth’s crust a large number
of fault’s can result.
Large blocks of the Earth’s crust
drop down relative to other blocks.
Volcanic mountains: Most of the
world’s volcanic mountains are
located at convergent boundaries.
They form when molten rock erupts
onto Earth’s surface.
These are fomed from new material
being added to the Earth’s surface.