Chapter 11
Mountain Building
Vocabulary:
Mountain: A large mass of rock that rises a great distance above its base
Continental Margin: The underwater part of the continental crust, which
includes the continental shelf and the continental slope.
Key Idea: Events at plate boundaries and at continental margins result in the
formation of mountains.
The process of mountain creation and erosion is cyclical (cycle).
1. Mountains form at an active continental margin
↓
2. The active continental margin becomes a passive continental margin
↓
3. Mountains begin to erode
↓
4. Sediments carried by rivers to oceans
↓
5. Sediments accumulate in the oceans
↓
6. Passive continental margins becomes active continental margin
↓
7. Sediments from oceans are deposited on continental crust
↓
The cycle begins again!
The top picture is an ACTIVE Margin, the bottom picture is a PASSIVE
Margin. Notice that the Active Margin has volcanic activity!
11.2 – How Mountains Form
Vocabulary:
Anticline: An upfold in rock layers
Syncline: A download in rock layers
Normal fault: A fault where the hanging wall moves down with respect to
the footwall.
Reverse fault: A fault where the hanging wall moves up with respect to
the footwall.
Thrust fault: A reverse fault in which the fault plane dips 45° or less from
the horizontal
Strike-slip fault: A fault where the rocks on opposite sides of the fault
plane move horizontally.
Joint: A crack or break in the bedrock along which no movement has
occurred.
Key Idea: Rocks at converging plate boundaries are under stress, and
this stress may lead to deformation.
1. Types of stress, including:
 Compression
 Tension
 Shear
2. Folds
Lead to
3. Faults classified as
a. Normal
b. Reverse
c. Thrust
d. Strike-slip
4. Joints
Folded rock layers tend to occur along continental margins.
Folded rock layers to occur deep beneath Earth’s surface.
Folded mountains can be found in New Zealand and the Appalachians.
Sidling Hill in Maryland is an example of syncline
Anticline
ic.ucsc.edu/.../Lectures/Joints/joints.htm
Fault photo
www.dukelabs.com/.../19Primer.htm
11.3 – Types of Mountains
Vocabulary:
Folded mountain: Mountains formed when two plates carrying continental
crust collide, folding the rocks and earth with great force.
Dome mountain: A nearly circular folded mountain.
Fault-block mountain: Mountains formed from blocks of crust that have
been faulted and tilted at the same time.
Key Idea: Mountains can be classified by features that result from forces
involved in plate interactions.
The process by which each type of mountain is created:
1. Folded Mountains
Two continental plates move toward
each other
The plates collide and subduction
stops
Rocks at the edges of the plates
crumple up into folded mountains
Examples: Appalachians, Alps,
northern Rocky Mountains, Urals,
Himalayans
3. Dome Mountains
Uplifting forces or igneous intrusions
push rock layers up into a dome
Examples: mountains on the border
of the Colorado Plateau or the Rocky
Mountains.
2. Volcanic Mountains
Volcanic activity tends to form
mountains
Examples: the Cascades, some
Himalayan mountains
4. Fault-block Mountains
Tension due to uplifting forces
stretches the Earth’s crust
Faults form along the surface
Blocks of crust are thrust upward
Examples: Sierra Nevada, Wasatch
Range, Teton Range
Ongoing examples of changes in the Earth’s surface include:
1. The Indian plate is pushing into the Eurasian plate
2. In some parts of the western United States, the crust is being uplifted
3. In the Great Rift Valley, rising magma is forcing the crust upward.
Indian plate into
Eurasian plate
Crustal Uplift
Great Rift Valley
FOLDED MOUNTAIN
Folded Mountain and diagram
Folded mountain diagram with anticline and syncline
Fault Block Mountains
Fault Block Mountain diagram
http://pirate.shu.edu/~schoenma/mountains.htm
Dome Mountains
Dome mountains are the result of a great amount of melted
rock pushing its way up under the earth without folding or
faulting resulting in a rounded dome. As the dome is raised
above its surroundings erosion occurs, and as a result of
erosion, peaks and valleys are formed.