Transcript Geomorphology - Cloudfront.net

Geomorphology
Changing Landforms
Chapter 2
Changing landforms

What external
forces alter the
landscape?
 What internal
forces change
the landscape?
 Mt. Hood and
Columbia
Gorge: Erosion
and Vulcanism
Degradation
(Wearing Down)

Weathering-the
process that breaks
up rocks into smaller
particles
– Chemicals
– Heat
– Physical
• Falling Rocks
• Roots
• Ice
Water

Water-water can
move these
smaller particles
to different
locations and
create valleys
and canyons
Degradation
(Wearing Down)

Glaciers: Ice sheets and
mountain glaciers
– Scrape and push matter
downhill slowly
– They can move rocks
bigger than houses
– In mountains, they can
form steep U-shaped
valley
Wind

Wind-in
deserts, on
beaches and
other places
devoid of
plants
– Sand dunes
– Loess
Mountain Building

Fault-block
 Develop where the
earth’s crust breaks
and land is pushed
up by underground
force
Fault-block
Folded

Look like a huge
corrugated roof
 Squeezing together
of rocks into a series
of rounded waves.
Folded
Dome mountains

Molten rock pushes
up the earth’s
surface
 Softer stone is worn
away
Dome Mountains
Volcanoes

Formed from
volcanic eruptions
 Heat from the
earth’s core, travels
slowly to the earth’s
surface in the form
of liquid rock
(magma or lava)
exiting out of
volcanoes.
Volcanoes
Landforms:

Hills
 Valleys
 Plains
 Plateaus,
etc.
Plate Tectonics

The theory that the
Earths’ surface
consists of huge
“plates” that float on
the molten layer
bumping into each
other and causing all
landforms.
Plate Change

Overtime, the plates
drifted away from
one another which
leads to the current
land setup of today.
 Plate Tectonicsshifting of the earth’s
plates.
Plate Movement

3 types of plate boundaries:
– Plates pushing against each other
• Trenches (Challenger Deep)
• Volcanoes and other mountains (Cascades, Andes,
Himalayas)
– Plates moving away from each other.
• Mid-oceanic ranges
• Abyssal plains
– Plates sliding past each other.
• San Andreas Fault
Plate Creations
Trenches form when heavier plates
collide with other plates heading
downward, creating a deep abyss.
These abysses are generally the
deepest parts of the oceans’ floor.
 Other times, plates will collide and form
mountains (such as the Andes of South
America).

Earthquakes
 When
plates
slide past each
other, low
mountains or
faults may
result (e.g. San
Andreas fault).