Weathering
and
Erosion
• Weathering – processes by which
environmental agents at or near the
earth’s surface
cause rocks
and minerals
to break
down
SedimentSmall pieces of rock. Mud, sand, or
silt are very fine pieces of rock.
Weathering Processes
Mechanical weathering –
breaks a mineral or rock into
smaller pieces (physical changes)
Chemical weathering –
changes the chemical composition
of minerals and rocks
Mechanical
weatheringWind
weathering
in Monument
Valley,
Arizona
Chemical Weathering- Rusting
can completely eat away iron.
Erosion –
process by
which gravity,
moving water,
wind, or ice
transports
pieces of rock
and deposits
them
elsewhere
Devil’s Tower- volcanic plug
Water
Erosion
Deer Creek
Falls
Thunder
River in the
Grand
Canyon
Water
erosion in
a field
Wavecut pattern, a geological feature
caused by the sea's erosion of cliffs, seen at
Southerndown near Bridgend, South Wales.
Loess is a deposit of silt or
material which is usually yellowish
or brown in color and consisting of
clay or dust brought by wind
Glaciationchanging of
landforms by
slowly moving
glaciers
In the Swiss AlpsThe Upper
Grindelwald Glacier
and the
Schreckhorn
Glacial Erosion
A glaciated
valley in the
Mount Hood
Wilderness
showing the
characteristic
U-shape and
flat bottom.
• Moraine is rock debris, fallen or plucked from a
mountain and transported by glaciers or ice
sheets. The moraine may be lying on the
glacier's surface or have been deposited as piles
or sheets of debris, where the glacier has melted
Soil Factors
• Parent material – chemical composition
of the original rock from which soil
develops
• Relief-physical features of a landscape
• Organisms- plants, worms, ants that
decompose material
• Climate – amount of precipitation and
prevailing temperature
• Time – longer period develops thicker
more well-developed soil(2.5 cc per 100 years)
Building Soil
• Weathering and erosion are a part
of the process of building soil
• Soil is a loose mix of:
–Weathered rock
–Organic matter
–Air
–Water
Soil Fertility
Soil Fertility depends on the texture
of the soil and the amount of:
•
humus- the amount of organic
material
•
air and water
Works cited
• scidiv.bcc.ctc.edu/barmin/geo101/6.html
• Wikipedia, the free encyclopedia
• http://www.edu.pe.ca/southernkings/loesss
p.htm