Download Section 1.3- Incremental Changes: Wind, Water, and Ice

Section 1.3- Incremental
Changes: Wind, Water, and
Ice
Incremental Changes: Shaping and
Sculpting
 Shaping and Sculpting of Earth’s Surface is
accomplished by a combination of slow, step-by-step
changes called weathering and erosion.
Incremental Changes: Weathering,
Erosion, and Deposition
 Weathering: refers to the mechanical and chemical process that
breaks down rocks by means of water, glacial ice, wind, and waves.
 Erosion: occurs when the products of weathering are transported to
another place.
 Deposition: is the process of eroded materials being laid down or
deposited by wind, water, or ice.
Throughout the weathering/deposition process material is mot gained
or lost! It simply changes form!
NEVER PRODUCES NEW MATERIAL!
Weathering: Mechanical, Chemical,
and Biological
Mechanical Weathering
 Mechanical weathering: when rock is broken down by
physical forces, such as water or wind.
 Ex. Water freezing in cracks eventually causing the rock to
break apart.
Chemical Weathering
 Chemical Weathering: when water in the air combines with
chemical substance in the air. ( water combines with these
chemical substances to form an ACID)
 Ex. Acid Rain
Biological Weathering
 Biological Weathering: the wearing away of rocks by living
things.
The Effects of Moving Water
 Have you ever seen a river that looks really “muddy”?
 Rivers flowing through soil, not rock, pick up fine grains and
carry them along, giving the water a muddy appearance.
Rivers and streams are probably the most powerful forces of
erosion that alter landscapes.
The Effects of Moving Water
As rivers flow they pick up sediment.
 Sediment: Sediment is silt, sand, mud, and gravel carried by
flowing rivers
 Sedimentation: process of sediments being deposited on
surface features.
 Fluvial landforms: landforms created by running water.
Eroding Away
 The powerful forces of erosion caused by moving water
gradually away rock and soil, transporting them to other
locations.
 HOWEVER…. Sometimes erosion can change a landslide
quickly. Example: Landslides are sudden fast movements
or rocks and soil down a slope.
Glaciers- Rivers of Ice
 Glacier: a moving mass of ice and snow.
 For over two million years this force of erosion has visited North
America at least four times. In fact, ice once covered areas
of Alberta to heights of 600-1000m and has greatly shaped its
landscape.
Glaciers- Rivers of Ice
 As glaciers flow, they pick up large
rock fragments that act as grinding
tools to carve and scrape the
landscape beneath them.
 Erosion occurs when this advancing
ice mass scoops up rock fragments
and drags them along its base. This
process grinds the bedrock producing
a polished but often scratched or
furrowed surface.
 Bedrock: the layer of solid rock
beneath the loose rocks fragments.
Glaciers- Rivers of Ice
 When the glacier melts (or retreats), it leaves its eroded
rock fragments in the form of small hills called drumlins and
moraines and snake-like hills called eskers.
Glaciers- Rivers of Ice
 Erratic- rocks left behind by glaciers
Concept Check: Section Review
 Please turn to page 367
 Answer questions 1-10 in the “assess your learning
section)