Physical Geography: Natural Landscapes
Lab VI
Chapter 17 & 18
(55 points)
Instructions
- Read the information provided and answer the following questions in this document.
- All your answers should be submitted in red. The lab is due Sunday, October 11th, at 11:59 pm, in the dropbox folder “Lab 6”, in pdf format.
- The grading of all your answers will be based on how much detail you provide. This does not mean length. Go in depth and use the appropriate punctuation.
- Do not use the expressions “I think”, or “I believe”. Base your answers on the information you learned from your textbook.
- Do not paraphrase the textbook, use your own words to provide value to the answer.
- Add a reference page for your sources.
- Always read all the instructions carefully.
- Grading: the questions are worth 52 points, and 3 points are earned by following the instructions provided above.
Part I
Chapter 17: Glacial Landscapes and the Cryosphere
Section 17.1: Human impact in oceans and coastal processes
Questions
Section 1: Glacial Geomorphology and Distribution
Instructions/Questions
- Mention and describe the different types of glaciers (1 point)
- Where is each kind located? (1 point)
Section 17.2: Alpine Glacial Hazards
Glaciers act like giant conveyor belts, carrying the sediment that they erode, as well as the sediment that falls onto their surfaces, “down glacier” to the glacier terminus, where it is
deposited. In the case of alpine glaciers, glacial sediment is deposited on the ice margins as lateral and frontal/end moraines, which are often a continuous body at the time of deposition.
“In recent decades, retreat of mountain glaciers from their Little Ice Age maxima has resulted in the formation of lakes in the basins between the glacier margin and frontal and lateral moraines.” “The largest proglacial moraine-dammed lakes form in front of debris-covered glaciers, because high rates of sediment delivery at their margins can rapidly build up moraine dams, which can be well over 100 m high,” (Source: Glaciers and Glaciation by Benn and Evans)
Glacial Hazards in the Himalayans and Andes
As glaciers in mountain areas recede in response to climatic warming, a number of different glacier hazards can develop. Richardson and Reynolds (2000) have identified two main types of glacial hazard (Table 1). Direct glacial hazards involve the direct action of snow and ice and include events such as snow and ice avalanches, glacier outburst floods, and glacial advances. Indirect glacial hazards arise as a secondary consequence of a glacial feature or process and may include catastrophic breaching of moraine-dammed lakes or water resource problems associated with wasting glaciers and climate change. One of the principal glacier hazards is the threat posed by catastrophic drainage of hazardous moraine-dammed lakes, often known as glacial lake outburst floods (GLOFs). The number and volume of potentially hazardous moraine-dammed lakes is increasing in both the Himalaya and the Andes. These lakes develop behind unstable ice-cored moraines, and have the potential to burst catastrophically, producing devastating floods. Discharge rates of 30,000 m3/s and run-out distances in excess of 200 km have been recorded from Himalayan GLOFs. Glacial hazards have attracted attention recently for two main reasons:
(i) the risk of loss of life; and (ii) the serious threat to costly infrastructures such as hydropower installations, roads, and communications. Carey (2005) has discussed the impacts of these glacier hazards on people living with these risks in Peru. The image below shows the aftermath of a glacial lake outburst flood (GLOF) in the Nepalese Himalaya showing a large breach through a moraine and spread of gravel deposited during the GLOF. (Source: Glacial Geology: Ice Sheets and Landforms by Bennett and Glasser).
| Types of glacier and glacial related hazards | |||
| Category | Hazard Event | Description | Time Scale of Event |
| Direct | Avalanche | Slide or fall of large mass of snow, ice, and rock | Minutes |
| Glacier outburst flood | Catastrophic discharge of water under pressure from a glacier | Hours | |
| Jökulhlaup | Glacier outburst flood often associated with subglacial volcanic activity | Hours to days | |
| Glacier surge | Rapid increase in rate of glacier flow | Months to years | |
| Glacier fluctuations | Variations in ice-front positions | Years to decades | |
| Indirect | Glacial lake outburst floods (GLOFs) | Catastrophic outburst, typically from a moraine-dammed proglacial lake | Hours |
| Débâcle | French term for an outburst from a proglacial lake | Hours | |
| Aluvión | Spanish term for a catastrophic flood of liquid mud | Hours | |
| Lahars | Catastrophic debris flow associated with rapid melt during volcanic activity | Hours | |
| Water resource problems | Water supply shortages, particularly during low flow conditions, associated with wasting glaciers and climate change, etc. | Decades | |
(Source: Glacial Geology: Ice Sheets and Landforms by Bennett and Glasser).
Section 17.3: Case Study and Application
“One of the most destructive GLOFs in recent times occurred in the Cordillera Blanca, Peru, in 1941. The flood was initiated when an ice avalanche crashed into Lake Palcacocha, triggering giant waves that overtopped and eroded the moraine dam. Flood volume was increased when it flowed into a second moraine-dammed lake further down valley, causing it to burst as well. By the time the flood reached the town of Huaraz, 23 km downstream from Lake Palcacocha, it contained 8 million m3 of water and debris. The rapidly flowing slurry destroyed one third of the town, killing an estimated 5000 people. During the twentieth century, GLOFs in the Cordillera Blanca have resulted in considerable loss of life, due to the presence of large population centers in glacierized catchments,” (Source: Glaciers and Glaciation by Benn and Evans).
- Mark Carey reports that glacial lake outburst floods flow at speeds ranging from 40 to 50 km per hour. If the people of Huaraz had some sort of warning system back in 1941, how much time would they have had to evacuate? (Use the average velocity of 45 km/hr.) (3 points)
v= dt
Instructions/Questions
- Open Google Earth. Enter 9 23 39 S, 77 22 40 W into the search box and hit search. That is Lake Palcacocha. Zoom out and find Huaraz (Look to the southwest.)
- Do you think Huaraz is still at risk from Lake Palcacocha? Why or why not?(2 points)
- If Lake Palcacocha were to experience another glacial lake outburst flood, what other named place(s) would be at risk?(2 points)
- Search the region. What level of risk do you think the region is at for glacial lake outburst floods? (1.5 points)
- What are some things that places like Huaraz could do to reduce their risk to glacial lake outburst floods? (Hint: Visit http://glaciers.uoregon.edu/hazards.html for more information) (2 points)
Section 17.4: Glacial Retreat
The Seward area represents an excellent example of active alpine glaciation. Alpine glaciers are also referred to as mountain or valley glaciers and covered much of the mountain terrain in the middle and high latitudes during the past glacial periods.
Instructions/Questions
- This area is an excellent example of a fiordedWhat is a fiord (fjord)?(1 point)
- For this activity you must have Google Earth installed in your device. Otherwise you will not be able to download and open the kmz file provided.
- Open the document kmz from the D2L content in Google Earth.
- What differences do you notice between the photographs in Figure 8.3 taken in 1984, and the image in Google Earth in 2011? Hint: The photograph orientation is not the same as the Google Earth image. To change the image orientation use 3D Viewer Navigation (2 points).
- What type of stream is draining Portage Lake? (2 points)
- Where did the sediment load associated with the stream draining Portage Lake originate? (2 points)
Section 17.5: Northwestern Glacier: Google Earth Measurements
Instructions
- Open Google Earth, navigate to Latitude: 59°45’55.58″N, Longitude: 150°13’2.35″W.
- Enter: 59°45’55.58″N, 150°13’2.35″W in the search box.
- Use the historical imagery function (clock icon) on the toolbar to see how the landscape looked several years ago. Set the historical imagery to 1996.
- Select the Add Path icon on the toolbar. Draw a straight line roughly outlining the glacier’s edge in 1996. Do the same for the year 2011.
- Use the ruler at the top to measure the distance between the two lines to determine the extent of glacial retreat.
Questions
- How far did the glacier retreat between 1996 and 2011? (1 point) Answer with metric system (this may require you to change the settings to obtain units in metric)
- Suppose the glacier is an average of 0.5 kilometers thick (H). Assume that the glacier is a rectangle (W = glacier retreat distance).What is the volume of ice that has melted between 1996 and 2011? (H, W and L have to be in the same unit to calculate the volume. Volume= L*W*H) (2 points) Answer with metric system (this may require you to change the settings to obtain units in metric)
- Disregarding thermal expansion, how many glaciers of this volume would it take to raise local mean sea level one millimeter? (Hint: 360 km³ of water will raise the oceans 1 mm.) (2 points).
- Why do you think this glacier has retreated? (1 point)
- What are some risks associated with glacial retreat? (Hint: you may only use the information provided in this lab) (2 points).
Section 17.6: Glacier National Park – Glacial Retreat
Glacier National Park is named for the glaciers that sculpted the beautiful terrain that exists there today. Even after the glaciers have melted, the park will retain its name. In 1994, Myrna Hall created an animation of Glacier National Park showing shifts in the glacier and vegetation from 1850 to the present by decade. Visit the site to watch the animation and then answer the following questions. Note: the term “mesic” refers to a moderate moisture level.
(Hint: Go to the D2L link under Course Material > Week 8 labeled “Glacier Animation”. Use this animation to help you answer the next question.)
- What is the general trend in vegetation range conversion? (Hint: How is the pattern changing and why?) (1 point)
Section 17.7: Climate Change and Critical Thinking
For questions 18-21 you do not need to do extra research. You can base your answers on the material provided by your textbook chapter.
- Explain how glacial environments impact humans, and how humans impact glacial environments (2 points)
- What is happening in Greenland and Antarctica? (2 points)
- What is the problem with ice sheet darkening? (2 points)
- Explain the relationship between global rising temperatures, glacial melting, and sea level rise. Do not define these terms separately, but rather engage them as part of a process. (3 points)
Part II
Chapter 18: The Geography of Soils
Section 18.1: Soil formation
- Based on the information on your book, name the four natural factors of soil formation. (1 point)
Section 18.2: Importance of Soils and Climate Change
For questions 38-43 you do not need to do extra research. You can base your answers on the material provided by your textbook chapter.
- Discuss the human impact on soils and the soil impact on humans (2 point).
- Explain the importance of soil by discussing the critical zone (2 points).
- What has happened to overall soil productivity in the world? (2 points).
- Explain soil erosion (1 point).
- Watch this short video by the United Nations and explain how soils are an ally to combat climate change (3 points).
- What do you think is causing the excess of CO2 in the atmosphere? (2 points)
- Name three purposes for which soil is important in the future. You can also relate problems studied in previous chapters, related to desertification, for instance (3 points).
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