Transcript Chapter-11 Mountain Building

Chapter-11 Mountain
Building
Notes
Objective – 1: Explain how some of earth’s major mountain
belts formed.

Section 11.1 “Where Mountains Form”
– Mountain – A large mass of rock that rises a
great distance above its base
– Mountain Belts:
 Mountain
ranges that follow convergent plate
boundaries
 NA Cordillera – mountain belt that runs down the
western side of NA from Alaska to Mexico
 Appalachian Mountains do not lie along a plate
boundary
Objective – 1: Explain how some of earth’s major
mountain belts formed.
 Section
Form”
11.1 “Where Mountains
– Some mountain belts are formed along
active continental margins by the
subducted plate pushing up the
overriding plate
– Therefore most mountain ranges are
located along plate boundaries
Objective – 2: Compare and contrast active and passive
continental margins.
 Define:
– Continental margin: is a boundary
between continental crust and oceanic
crust
– Passive continental margin: stable areas
that are not located near plate
boundaries
Objective – 2: Compare and contrast active and
passive continental margins.
 Compare
and contrast Active and
Passive Continental Margins:
– Active – located along plate boundaries;
both lie along continental margins;
– Passive – Not located along any plate
boundaries; consists of mainly marine
sediments; weathered rock;
Objective – 2: Compare and contrast active and
passive continental margins.

Looking at the Plate Boundary Map on
pages 712 – 713, there are a number of
Active and Passive continental margins:
– Active continental margins include west coast
of South America; west coast of North
America; east coast of Japan; west coast of
Indonesia;
– Passive continental margins include east coast
of N America; east coast of S America; west
coast of Africa; south east coast of Africa; etc.
Active continental margins:
Passive margins:
Active continental margins are along continental/ocean boundaries located
at plate boundaries.
Chapter 11 Section 2
 How
Mountains Form:
Objective – 3: Explain how compression, tension, and
shear stress deform rocks.
 Types
of Stress:
– Forces involved in plate interactions
produce features such as folds and
faults.
– Folded Mountains:
 Two
plates collide, can cause folding of rock
 Before two continents can collide the ocean
basin between them must close: Subduction
 Himalayas formed by the ocean basin
between India and Tibet closed due to
Subduction.
Objective – 3: Explain how compression, tension,
and shear stress deform rocks.
– Dome Mountains:
 Nearly
circular folded mountain
 Individual isolated structures
 Plutonic dome Mountain:
– Formed by overlaying crustal rock pushed up by
an igneous intrusion such as a laccolith.
– Center rocks (igneous) are younger than the
outer rocks
 Tectonic
Dome Mountains:
– Result of uplifting forces that arch rock layers
upward
– All the rocks were present before the uplift
occurred
Objective – 3: Explain how compression, tension,
and shear stress deform rocks.
 Fault-block
Mountains
– The crust is stretched (tensional forces) and
normal faults are created
– Whole blocks are pushed up
 Horst
and Grabens
– Tensional stress and normal faulting cause these
– Between tensional faulting, grabens (large blocks)
have dropped
– When large blocks are thrust upward, between
normal faults, it is called a Horst
Objective – 3: Explain how compression, tension, and
shear stress deform rocks.
 Define:



Anticline – an up-fold in rock layers
Syncline – down-fold in rock layers
Stress Types:
– Compression – rock layers are being squeezed together
– Tension – rock layers are being stretched or pulled apart
– Shear – rock layers are being pushed in two different,
opposite directions.
Objective – 3: Explain how compression, tension,
and shear stress deform rocks.

Objective – 3: Explain how compression, tension, and
shear stress deform rocks.
Draw a sketch of a compression, tension and
shear stress:
Objective – 4: Compare and Contrast Anticlines and
Synclines
– An anticline is an up-fold of the rock
layers
– A Syncline is a is a down-fold of the
rock layers
– Both are usually caused by
compressional forces
Objective – 4: Compare and Contrast Anticlines
and Synclines
Syncline
Objective – 4: Compare and Contrast Anticlines
and Synclines
Anticline
Objective – 5: Distinguish among the three major types of
faults – normal, reverse, and strike-slip.
Objective – 5: Distinguish among the three major
types of faults – normal, reverse, and strike-slip.
Objective – 5: Distinguish among the three major
types of faults – normal, reverse, and strike-slip.
Objective – 5: Distinguish among the three major
types of faults – normal, reverse, and strike-slip.

The difference between a normal fault and
a reverse fault are the stresses that cause
them:
– Reverse fault is caused by compressional
forces
– Normal fault is caused by tensional forces

A strike-slip fault moves horizontally
along a fault line.
Chapter 11 Section 3
 Types
of Mountains
Objective – 6: Classify mountain ranges by their most
prominent features.
– Folded Mountains:
 Two
plates collide, can cause folding of rock
through compressional stress
 Before two continents can collide the ocean
basin between them must close: Subduction
 Himalayas formed by the ocean basin
between India and Tibet closed due to
Subduction.
Objective – 6: Classify mountain ranges by their most
prominent features.
– Dome Mountains:
 Nearly
circular folded mountain
 Individual isolated structures
 Plutonic dome Mountain:
– Formed by overlaying crustal rock pushed up by
an igneous intrusion such as a laccolith.
– Center rocks (igneous) are younger than the
outer rocks
 Tectonic
Dome Mountains:
– Result of uplifting forces that arch rock layers
upward
– All the rocks were present before the uplift
occurred
Objective – 6: Classify mountain ranges by their
most prominent features.
– Fault-block Mountains
– The crust is stretched (tensional forces) and
normal faults are created
– Whole blocks are pushed up
Objective – 6: Classify mountain ranges by their
most prominent features.
– Horst and Grabens
– Tensional stress and normal faulting cause these
– Between tensional faulting, Grabens (large
blocks) have dropped
– When large blocks are thrust upward, between
normal faults, it is called a Horst
Objective – 6: Classify mountain ranges by their
most prominent features.

When two land masses collide, they usually
crumple and form folded mountains.
– Volcanic mountains tend to form on the overriding plate
at a Subduction zone.

Fault Block Mountains form when the earth’s
crust is slowly up-lifted.
– The uplift has caused the crust to stretch and crack,
forming normal faults along the surface. As uplift
continues, whole blocks of crust have been pushed up.
Objective – 7: Compare and contrast folded mountains,
dome mountains, volcanic mountains, and fault-block
mountains.
Type of Crust
Where are they
found
Uplift Mechanism
Examples of
Plutonic Dome
Mountain:
Crustal and
igneous rock
inland
Isolated structures in
flat lying
sedimentary rocks
Igneous intrusion
Border of the
Colorado
Rockies
Tectonic Dome
Mountain
Crustal rock inland
Isolated structures in
flat lying
sedimentary rocks
Uplift force
Adirondack Mtns.
Folded
Mountain
Continental Crust
Continental –
continental plate
boundaries
Continued plate
movement
Alps, Appalachians
Volcanic
Mountain
Continental, near
Subduction
boundary
Subduction boundary
Volcanic material
(magma, ash, etc.)
Cascades
Fault-block
Mountain
Continental
Western US
Uplift forces
Sierra Nevada
Mountains
Mountains
End