Download Weathering and Erosion

Weathering and Erosion
1. Compare and contrast the following terms:
a) Weathering and Erosion:
Weathering is the breaking down of rocks while erosion is the movement of those rocks to other locations.
b) Erosion and Deposition:
Erosion is the movement of rocks to other locations, while deposition is the dropping or depositing of those materials.
c) Physical Weathering and Chemical Weathering:
Physical weathering is a change in the shape or form of the rock while chemical weathering changes the composition
of the rock.
d) Rill erosion and Gully erosion
Rills are small channels caused by water erosion while gullies are larger channels.
e) Residual and Transported soil
Residual soil stays where it was formed while transported is moved to another location after being formed.
f) Erosion and Mass movement
While both indicate movement of material, mass movements always happen on slopes, tend to be quick and involve
large amounts of material.
g) Continental and valley glaciers
Continental glaciers form across large, flat areas while valley glaciers form in mountainous areas.
2. Identify whether the following are examples of physical weathering, chemical weathering, erosion or deposition:
a) Wind blowing sand from one location to another
Erosion
b) Flood water wearing down a canyon wall
physical weathering
c) Flood water carrying canyon wall sediment downstream
erosion
d) Glaciers moving rocks to the bottom of a valley
erosion
e) A car rusting in an abandoned parking lot
chemical weathering
f) Deltas forming at the end of the Mississippi River
deposition
3. Describe the following characteristics about physical weathering:
a) Two specific types or examples
frost wedging
exfoliation
b) Three factors that affect its rate
rock type/composition
topography (steepness)
surface area
c) Climate with highest rates
cold and wet
4. Describe the following characteristics about chemical weathering:
a) Two specific types or examples
oxidation (rusting)
carbonic acid (acid rain)
b) Three factors that affect its rate
temperature
water
acidity (how strong of an acid)
c) Climate with highest rates
warm and wet
5. What are the five main causes or methods of erosion? Describe each one briefly.
Gravity – moves rocks down slope
Water – moves rocks with its flow
Glaciers – moves with its ice
Wind – moves small, dry particles
Living things – excavating, gardening, etc.
Soils
6. Outline the process of soil formation.
-Weathering of rock into smaller pieces
-Introduction of organic material and small organisms
-Inclusion of water and nutrients
7. Which of the following soils is the most developed? Which is the least developed? How can you tell?
Most – B, Least –A, determined by the amount of organic material and differentiation of soil horizons
8. In the diagram label each of the four soil horizons and briefly compare and contrast each horizon:
O – horizon:
top layer, contains organic material called humus. Usually dark brown or
black in color
A – horizon:
Second layer, contains some organic material and some weathered rocks
Usually light gray-brown in color
B – horizon:
Third layer, contains mostly weathered rocks and usually brown to light
red in color
C – horizon:
Bottom layer, is mostly solid rock considered bed rock
9. Explain how the following affect soil development:
Time:
As more time passes, more nutrients can penetrate the soil and rocks
continue to weather leading to more developed soil
Climate:
Soils develop better in warm and wet environments where there is more access to water and organic material
Topography:
Soils develop better on flat areas where erosion is less likely to move materials
Biological Factors:
If there is more organic material and small organisms, then the soil is more likely to develop a more rich O-horizon
Parent material:
Certain materials weather quicker and allow for quicker development
10. Briefly describe how soils are classified.
Soils are classified by grain size.
Mass Movements
11. What are the four factors that influence mass movement?
Material Weight
Ability to slide
Trigger
Water
12. For each type of mass movement, briefly describe it and the factors that increase their chance of occurring:
a) Creep
The slow movement of material down slope causes a slight leaning of trees and power poles.
Can be increased by the saturation of water into the surface layer of material.
b) Mudflows
Swiftly moving mixtures of mud and water
Can be triggered by earthquakes or in volcanic regions with significant snow melt
c) Landslides
A rapid, downslope movement of a thin layer of material after separating from underlying layer.
Common on steeper slopes with high saturation of water
d) Slump
A rapid, downslope movement of a thin layer of material on a curved surface.
Common on thick soils with moderate slopes and more so after it rains.
e) Avalanches
Landslides in mountainous areas with thick accumulations of snow.
More common in early winter when snow accumulates on warm ground or due to refreezing of snow into ice.
f) Rock falls
The loosening of rocks by physical weathering and the falling downward.
Occurs in steep cut roads and in dry conditions where there is less soil and vegetation to hold rocks in place.
13. What are some ways that people can reduce the risk of mass movements?
Reduce slopes to less than 25o
Digging trenches to divert water flow
Build retaining walls
Glaciers
14. What specifically is a glacier?
A large, moving mass of ice.
15. Compare and contrast the following types of glacial erosion. Also identify each one on the diagram below.
Cirques:
Scooped out depressions caused by valley glaciers
A
Arête:
The meeting of two cirques causing a steep ridge
D
Horns:
The carving by three or more glaciers to produce a
pyramid shaped peak.
E
Hanging valleys:
Formed where glaciers meet and form valleys where
waterfalls often occur
F
16. Compare and contrast terminal and lateral moraines.
Moraines are formed when till (the unsorted rock, gravel, sand and clay that glaciers carry) is deposited in unsorted
ridges. Terminal are found along the edge of a retreating glacier and lateral are located parallel to the direction of the
glacier’s flow.
17. Compare and contrast the following types of glacial deposition.
Drumlins:
Elongated moraines that continental glaciers moved over
Eskers:
Winding ridges of sediment formed by
streams underneath the glacier
Kames:
A mound of layered sediment, usually
conical in shape
18. Identify the glacial features labeled
on the diagram to the right.
Kettles – small puddles, bottom right
Kames – small mounds, bottom middle
Eskers – winding sediment, middle
Drumlins – thin sediment, top