MIDTERM 1 - A

Question 1

1. What is Geomorphology

Answer 1

The study of the features on the Earth’s dynamic surface, their history and the processes that create them.

Question 2

2. Processes acting on the surface of the Earth (4)

Answer 2

MOVING WATER

MOVING AIR

MOVING ICE

GRAVITY

Question 3

3. What is the most important geomorphological processes for Canadian geomorphology and why?

Answer 3

Glacation. Much of Canada’s landscape was molded by glaciers over millions of years.

Valleys were widened, moraines were sculpted and bedrock was smoothed.

Glaciation also left behind many sediments that provide us with a record of geomorphic history.

Question 4

4. Importance of sediment.

Answer 4

Provides us with a record of previous environments because:

1. FOUND in almost all environments on the Earth’s surface
2. RECORDS information about the environment in which it is found. (through weathering, transport, erosion, deposition)
3. CONTAINS evidence of life forms in the form of living and dead organisms (fossils)
4. sediment (and sedimentary rock) is found throughout the rock record)

Question 5

5. Weathering

Answer 5

The disintegration of rocks and other minerals by physical and/or chemical means.

Question 6

6. Erosion

Answer 6

How sediment is set in motion.

Question 7

7. Transport

Answer 7

How sediment moves once it is set in motion.

Question 8

8. Deposition

Answer 8

How sediment stops moving. In a river, the sediment stops moving when the velocity drops. (However, sediment in solution is deposited when precipitation occurs)

Question 9

9. Precipitation

Answer 9

The formation of new mineral crystals from elements in solution

Question 10

10. Sediment texture

Answer 10

Refers to the physical characteristics of individual sediment grains.

Question 11

11. Threshold (or critical) velocity

Answer 11

The water velocity necessary to set in motion (erode) a grain of a certain size

Question 12

12. Roundness

Answer 12

A measure of how smooth or rough the surface of a grain is.

Question 13

13. Sphericity

Answer 13

A measure of how spherical a grain is. It is a measure of the shape of a grain.

Question 14

14. Sorting

Answer 14

The range of grain sizes in a sediment deposit.

Question 15

15. Why are very small grain sizes (<0.002mm) harder to erode? (CLAY MINERALS)

Answer 15

Because they often contain clay minerals. Clay minerals are flat, sheet-like grains.

Clay minerals are flat, sheet-like grains that have an electric charge on their surface. This means that clay minerals stick together and are hard to erode.

Question 16

16. Different grain compositions and why they are so important ?

Answer 16

MAFIC: Black (dark), Higher Density

FELSIC: White (light), Lower Density

Minerals will separate (move differently) because of differences in density.

Question 17

17. Sedimentary structure

Answer 17

A physical feature in sediment present because of a preferred arrangement of grains.

Question 18

18. Why is sedimentary structure is so important

Answer 18

Sedimentary structure can give you and idea of the depositional environment of that area.

Question 19

19. How do the forces of friction and gravity differ between a hillside and a river channel?

Answer 19

Gravity pulls an object down a hill or water down a river channel from a high to low gradient. Friction acts as the cause for the object or moving water to slow down or stop.

In a river, the force of friction

Question 20

20. The relationship between five vegetation zones and landform development

Answer 20

1. Grassland
2. Temperate Forests
3. Tropical Forest
4. Desert/Arid
5. Polar

Question 21

Vegetation zones

Answer 21

1. Grassland
2. Temperate Forests
3. Tropical Forest
4. Desert/Arid
5. Polar

Question 22

Geological characteristics of a GRASSLAND

Answer 22

• Most of the biomass is underground.

- Dense root mass binds the sediment and soil together.

Question 23

Geological characteristics of a TEMPERATE FOREST

Answer 23

• Large amounts of biomass are found above and below ground.
• While sediment and soil are bound together the biomass
  above ground adds a significant amount of weight and possibly organic sediment.

Question 24

Geological characteristics of a TROPICAL FOREST

Answer 24

• Most of the biomass is above ground.
• There tends to be a shallower root zone.
• Soil and sediment is less cohesive and more prone to erosion once vegetation is removed and the ground is exposed.

Question 25

Geological characteristics of a DESERT/ARID ZONE

Answer 25

- Vegetation is often minimal (small and sparse) | - In this case even a small, isolated obstacle such as a plant can significantly affect sedimentary processes.

Question 26

Geological characteristics of a DESERT/ARID ZONE

Answer 26

- Vegetation is often minimal (small and sparse) - In this case even a small, isolated obstacle such as a plant can significantly affect sedimentary processes. - Even a small plant will change how sediment is distributed. Deposition on the the downwind side, erosion on the upwind side as flow and velocity changes around the plant

Question 27

All vegetation will act to trap ______

Answer 27

sediment

Question 28

The two forces that help control the formation of landforms on the Earth's Surface are:

Answer 28

gravity and friction.

Question 29

Why is glacation important for Canadian geomorphology?

Answer 29

Much of Canada’s landscape was molded by glaciers over thousands of years. Valleys were widened, moraines were sculpted and bedrock was smoothed. Glaciation also left behind many sediments, and sedimentary structures which can be studied today.

Question 30

Glacation

Answer 30

The formation, movement and recession of glaciers.

Question 31

Clay minerals

Answer 31

Flat, sheet-like grains that have an electric charge on their surface.

Question 32

Polar zone Conditions

Answer 32

In northern Canada this includes freezing and thawing conditions.

Question 33

Polar conditions in the winter

Answer 33

Snow moves across the surface because of wind. In the presence of vegetation. In the presence of vegetation snow will accumulate on the ground. Snow on the surface acts as an insulator preventing the ground from freezing or at least not freezing as much.

Question 34

Polar conditions in the summer

Answer 34

In summer the ground that was covered with snow undergoes more thawing while the area not covered in snow during winter is less thawed. Therefore the area originally covered by snow in winter - because there was more vegetation - is more prone to erosion in the summer.

Question 35

Active Layer

Answer 35

the layer on permafrost that is subject to thawing.