Transcript Physical Geology

Physical Geology
Chapter 11
Part 2 – Mountain Building
Definition
• A mountain is the most extreme type of
deformation
• Relatively small “wrinkles” in the earth’s
crust may soar from 1 to 8 km above sea
level
• A mountain is a piece of land that is higher
than a hill and stands much higher than
the land around it. Mountains have steep
sides and a pointed or rounded top. The
top of a mountain is very cold. Mountains
are created over long periods of time by
tremendous forces of the earth.
Range – a group of adjacent mountains
related by shape and structure
System – a group of adjacent ranges
Belts – the two major mountainous
regions of the world; EurasianMelanesian & Circum-Pacific belts
How do
mountains
form? It’s
all plate
tectonics!
Types of Mountains
• Folded
and
Plateaus
• Faulted
• Domes
• Volcanic
Blossom Peak, Post Falls, Idaho
Folded Mountains
• Compression stress squeezes up
accordion-like folds
• May also result in formation of uplifted,
broad, flat plateaus
• Himalayas, Rockies, Appalachians,
Urals, parts of the Alps
Types of Folds
Plateau
Faulted Mountains
•
•
•
•
Vertical movement at fracture zones
Tilted blocks, lift or drop at single faults
Uplift at double faults
Sierra Nevada, Tien Shan, western
foothills of the Rockies (Basin/Range
region)
Typical Fault Block Mountains
Fault block valley
Fault block ridge
Death Valley
Basin and Range
Domes and Basins
• Gentle upwarping or downwarping of
crustal rock produce domes and basins
• Erosion of these structures results in an
outcrop pattern that is roughly circular or
elongated
• Black Hills, Adirondacks, Stone Mountain
Domes and Basins
sandstone
Crystalline
Metamorphic
core
limestone
Volcanic Mountains
• Eruptions of gases, magma, cinder/ash
and pulverized surface material
• Piles of expelled material form cones that
may stand out from surrounding terrain as
mountains
– Shield cones
– Cinder cones
– Composite cones