LAB 07: GLACIAL LANDSCAPES

INTRODUCTION

This module examines glacial processes and features. Topics includecontinental and alpine glaciation, ablation and accumulation, cirques, drumlins, kettles, kames and moraine. While these topics may appear to be disparate, you will learn how they are inherently related.The modules start with five opening topics, or vignettes, which are found in the accompanying Google Earth file. These vignettes introduce basic concepts of the glacial processes and landforms. Some of the vignettes have animations, videos, or short articles that will provide another perspective or visual explanation for the topic at hand.  After reading the vignette and associated links, answer the following questions. Please note that some links might take a while to download based on your Internet speed.

 

Expandthe INTRODUCTION folder and then check Topic 1: Introduction.

ReadTopic 1: Introduction.

Question 1: What are some uses of freshwater from glaciers?

A.   Agriculture

B.   Industry

C.   Tourism

D.   All of the above

Read Topic 2: Types of Glaciers.

Question 2: What is the semi-circular feature at the far left of the image?

A.   Drumlin

B.   Lateral moraine

C.   Terminal moraine

D.   Medial moraine

 Read Topic 3: History within Glacial Ice.

Question 3: Within the snow, do colder temperatures result in higher or lower concentrations of light oxygen (16O)?

A.   Higher, because there is more energy to lift 18O out of the ocean

B.   Lower, because there is more energy to lift 18O out of the ocean

C.   Higher, because there is less energy to lift 18O out of the ocean

D.   Lower, because there is less energy to lift 18O out of the ocean

 Read Topic 4: The Global Retreat and Advance of Glaciers.

Question 4: What happened to the Peterman Glacier on Aug 5, 2010?

A.   Satellite imagery notice the glacier was actually advancing

B.   A large mass of the glacier broke off the main glacier

C.   Icebergs were spotted calving

D.   An ice dam created by icebergs broke unleashing 3 million cfs of water

 Read Topic 5: Human Reliance on Glaciers for Water.

Question 5: What was the peak discharge on August 14, 2002?

A.   97 cfs

B.   3.9 million cfs

C.   1.9 million cfs

D.   145,000 cfs

Collapse and uncheck INTRODUCTION.


GLOBAL PERSPECTIVE

 Expand GLOBAL PERSPECTIVE and then double-click and select Major World Glaciers.

This map shows the location of major glaciers (in blue) throughout the world. At present, glaciers cover approximately 10 to 11 percent of the surface of the Earth. Many cities depend on glaciers as their source of water.

Double‑click Question 6. When you arrive at your destination, find the information to fill in the blanks below. Repeat this for Questions 7 and 8:

Question 6:        

City:

A.   Lima

B.   Buenos Aires

C.   Santiago

D.   Bogotá

Population:

A.   7.2 million

B.   2.7 million

C.   3.6 million

D.   4.5 million

Glacier(s) located which direction from city:

A.   North

B.   East

C.   West

D.   South

 

Question 7:

City:

A. Bhutan

B. Lhasa

C. Katmandu

D. Tibet

Population:

A.2.7 million

B. 4.3 million

C. 1.9 million

D. 4.5 million

Glacier(s)located which direction from city:

A.   North

B.   West

C.   East

D.   South

Question 8:

Glacier: Atetsch

Latitude and Longitude (degrees only):

A.   Latitude 46 °N, Longitude 8° E

B.   Latitude 46 °N, Longitude 8° W

C.   Latitude 46 °S, Longitude 8° E

D.   Latitude 46 °S, Longitude 8° W

 

Collapse and uncheck GLOBAL PERSPECTIVE
ALPINE GLACIATION

Figure 1.Glacier mass budget.(Arbogast 2nd Ed.).

Alpine glaciers are found in many of the world’s major mountain ranges. These glaciers are dynamic and flow downhill under the force of gravity. In many places, alpine glaciers are retreating as the snowpack decreases in winter months and mean temperatures increase during the spring and summer months.

Expand the ALPINE GLACIATION folder.Double-click and select Mass Balance.

This is the Klinaklini glacier in British Columbia, Canada. Along an alpine glacier there are two major zones, accumulation and ablation. The zone of accumulation(Figure 1) is located at higher elevations where temperatures remain cold enough such that snowfall exceeds melting over the course of a year. Conversely, the zone of ablation is located at lower elevations where melting exceeds snowfall. The red line in the middle represents the equilibrium line, where snowfall and melting are equal over the course of a year. Farther down in the zone of ablation, and loss of ice by meltwater is evident.

Question 9: Where do we find the deep fissures in the glacier known as crevasses– in the zone of accumulation or the zone of ablation?

A.   Zone of accumulation

B.   Both zone of accumulation and ablation

C.   Zone of ablation

D.   Neither zone of accumulation now ablation.

 KeepMass Balance selected, and then double‑click Direction of Flow.

Question 10:Explain the direction of flow of glacial ice, from the zone of accumulation to the loss of ice by meltwater.

A.   The glacier flows downward from the zone of accumulation under the influence of gravity.

B.   The glacier flows uphill as it melts

C.   The glacier flows in a southern direction towards the equator

D.   Direction depends on the amount of snowfall.

 

Erosional Features

Figure 2.Glaciation (17.16 Arbogast 2nd Ed.)

 

A cirque (or corrie) is a bowl‑shaped erosional feature created by complex glacial ice flow that that plucks material from a hollow on a slope and promotes the creation of a depression. Cirque glaciers are typically the head of U shaped valley glaciers. After glaciation, many cirques contain tarn lakes (Figure 2) while in the glacial valleys, chains of paternoster lakes are formed, commonly connected by a single stream system.

 

Expand Erosional Features and then double‑click and select Mt. Rainier.

Figure 3. Geographic Features line item

 

Mount Rainier, with its 25 glaciers covering 90 square km (35 square mile), has more glaciers than any other peak in the continental US.

 

Mt. Rainier is located south of Seattle, Washington. Google has a function that enables you to see more information about the mountain such as the elevation and the elevation profile, and to fly on a tour. Open the Layers pane, expand Borders and Labels, expand Labels and then check Geographic Features (Figure 3).        

 

 Double‑click Mount Rainier Tour.

 

 Double‑click and select A and B.

Question 11: The ridgeline is what type of glacial feature?

A.           Cirque

B.           Tarn

C.           Horn

D.           Arete

 Double‑clickForbidden Peak Tourto get a closer look.

Question 12:What glacial feature (there are nearly 20 of them) is found on both sides of the ridgeline between A and B?

A.           Cirque

B.           Tarn

C.           Horn

D.           Arete

Question 13: Look at the lake below this ridgeline. This lake is what type of glacial feature?

A.           Cirque

B.           Tarn

C.           Horn

D.           Arete

 Double‑click and select .

Question 14:What type of glacial feature is this lake?

A.           Cirque

B.           Tarn

C.           Horn

D.           Arete

 Double-click select the Dfolder.

When 3 or more cirques back into each other they create a particular landform feature.However, this feature is somewhat difficult to see in the 2D perspective.

 Double‑click. Double‑click and selectMountain Tour.

Question 15: What is the name of this glacial feature, to which the mountain is named (Hint: You can determine the name of the major summit by enabling Geographic Features)?

A. Cirque

B. Tarn

C. Horn

D. Arete

 

Close the simulation control panel:

 Double-click and selectValley. Click animation in the window.

This valley was originally created by a river system and substantially modified by a glacier that has since retreated.

Question 16:What type of valley is found at D?

A. River valley

B. Glacial valley

C. Hanging valley

D. V – shaped valley

 

Collapse and uncheck Erosional Features


Transportation and Depositional Features

 Double-click Transportation and Depositional Features.

This is the glacier d'Otemma in Switzerland. Within this alpine glacier, several depositional features are evident. Most notable are the various moraines found along (lateral), among or between (medial) and at the end (terminal) of the glacier. Morainesconsist of unsorted till (diamicton or sediment) that is deposited with glaciers; the location of the moraine determines the type. Three of the most well-known moraines are:

Double‑click and select letters F, G, and H individually to identify the following features:

Question 17:Feature :

A.   Medial moraine

B.   Terminal moraine

C.   Lateral moraine

D.   Recessional moraine

Question 18:Feature :

A.   Medial moraine

B.   Terminal moraine

C.   Lateral moraine

D.   Recessional moraine

Question 19:Feature

A.   Medial moraine

B.   Terminal moraine

C.   Lateral moraine

D.   Recessional moraine

Collapse and uncheck ALPINE GLACIATION.


Continental Glaciation

During glacial periods in the past, large portions of North America were cover by continental glaciers. Today, these glaciers are found predominantly in Greenland and the Antarctica. But remnants of continental glacier activity can be found across much of Canada,the northern continental US, northern Europe and Russia.

Expand and clickCONTINENTAL GLACIATION. Click continental glaciation video in the window. This animation depicts marginal landforms of continental glaciers.

As you can see, it is the depositional features of continental glaciations that remain on the landscape.These features include those that formed under or as a result of glacial lobes while other features are a result of glacial meltwater.

 ExpandDepositional Features.

Drumlins are created by continental glaciers that reshape previous deposited glacier material as they move over it (Figure 4).They tend to be elongated and orient in the direction of ice movement. The blunt end of a drumlin faces the direction from which the glacier was moving when it created the drumlin.

 

Figure 4.Topographic representation of a drumlin and its direction of glacial ice flow.

 Double-click Drumlin.

This is a landscape with several drumlins. From the air it is difficult to see them; however, it becomes more obvious when contour lines are added to show elevation changes.

 Set the elevation exaggeration to 3.

Select Drumlin Contour.

Look for a series of contour lines forming an elongated shape similar to Figure 4. This feature is a drumlin.

Double-click and select Drumlin Oblique View to see an oblique view of the feature.

Question 20: According to the shapes of the drumlins, what (compass) direction do you think the ice was moving when it formed the drumlins?

A. NE

B. NW

C. SE

D. SW

 

Double-click and select Kettle Lake.

This large circular body of water is a kettle lake formed by a block of ice a retreating glacier falling off. Over time the block of ice is partially buried and then melts to create a depression.When filled with water, this depression is termed a kettle lake. Use the ruler tool and measure the distance across the lake from point H to point I.

Question 21: How wide, in miles, is the lake (from H to I)?

A. 1.6 miles

B. 2.6 miles

C. 3.6 miles

D. 4.6 miles

 

Question 22: Assuming the lake is circular, calculate the area of this lake (A=πr2)in square miles, where A is area, pi is 3.14, and r2 is the radius of the circle squared.

Area is __________________mi2

A. Π(0.8)2 = 2.00  square miles

B. Π(1.6)2 = 8.04 square miles

C. Π(3.6)2 = 40.72 square miles

D. Π(4.6)2 = 66.48 square miles

 

ExpandEskers. Select Ripley Esker.

Eskers are long snake like ridges created by the deposition of sediment frommelt water streams that flowed within or under glaciers. Gravel pits often mine eskers for sand and gravel.

This is the Ripley Esker in Minnesota. Notice how the trees delineate the esker.

 Select Belle Prairie.

You can use the following Google Earth tools to make the esker easier to see on the topographic maps:

·         Use the Adjust Opacity tool to see how the topographic map compares to the aerial photograph.

·         Use the Ruler tool to compute the length of the esker.

Question 23: What is the approximate length of the esker in miles?

A.   1.5 miles

B.   2 miles

C.   5 miles

D.   10 miles

Question 24: What are the two dominant economic activities found around the esker?

A.   Farming and ranching

B.   Ranching and quarrying

C.   Tourism and farming

D.   Quarrying and farming

 

Double-click Moraine.

This landscape in Minnesota is dotted with a terminal moraine and kettle lakes. While the lakes are easy to see, the moraine is not.

Double-click Moraine Perspective to view the landscape from a 3-D perspective.

The moraine appears as a series of hills.

SelectInspiration Peak to view a topographic map of the landscape.

Question 25: What is the high point (in feet) of the moraine in the red outline?The high point is located near the central eastern part of the Inspiration Peak map marked by the red number 1.

A.   1550

B.   1650

C.   1705

 

D.   1555

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    • LAB 07: GLACIAL LANDSCAPES

      Note: Please refer to the GETTING STARTEDmodule to learn how to maneuver through, and how to answer the lab questions, in the Google Earth() component.

      KEY TERMS

    • LAB 07: GLACIAL LANDSCAPES

      Note: Please refer to the GETTING STARTEDmodule to learn how to maneuver through, and how to answer the lab questions, in the Google Earth() component.

      KEY TERMS