Topo Features of Alpine Glaciers LAB

Name: _______________________________
Period: _____ Date: ____________________
LAB: Topographic Features and Advance/Retreat of Alpine Glaciers
Background:
The map in this lab shows
three glaciers in the Juneau Ice
Field in Alaska. It shows the
Taku Glacier, one of the
largest glaciers in the ice field
as well as the smaller Norris,
and Hole-in-the-Wall Glaciers.
The topographic map includes
land contours, glacial
contours, and the positions of
the margin of each glacier at
different times since 1890.
Glaciers gain and lose snow
and ice each year. The amount
of snow and ice added to a
glacier is called accumulation and amount lost due to melting is called ablation. This relationship is
called the glacial budget.
In this lab, you are going to analyze the topographic map to determine glacial features, such as U-shaped
valleys, sharp mountain peaks, and moraines, as well as the dimensions of the glaciers. The map was
made in 1980, and includes positions of the terminus (ice margin) during different times since 1890.
Where are the glaciers now, in 2013? By determining the rate of advance or retreat, we can predict
where the glacier will be in the future. Of course, this may depend on the rate not changing over time.
Make a prediction as to where you think the glaciers are now, and then write a conclusion after you
analyze your data and review Google map images of the Taku Glacier Region.
Hypothesis: ____________________________________________________________
PART 1: Topographic Map Analysis
Directions: Answer the following questions based upon the map of Alpine Glaciers in the
Juneau Icefield, Alaska.
1. Lightly shade the areas of ice, land and water on the map.
Lowland = brown Highland - Green Water = blue Glaciers = white
Copyright: Gary R. Vorwald, Paul J. Gelinas jHS, Setuaket, NY 2013
(May be used for educational purposes; please credit author)

2. What is the contour interval of the land on this map? _________________________
3. a. What is the highest elevation on the map? ________________
b. Where is this located? ________________________________________________
4. What is the approximate elevation of the Taku River? _______________
5. What is the contour interval of the glacier on this map? _______________________
6. Using the scale, measure the north-south distance covered by the map in miles and kilometers.
_________________ mi
_________________km
7. Measure the east-west distance covered by the map in miles and kilometers.
_________________ mi
________________ km
8. What is the approximate latitude and longitude of the Taku Glacier along it’s 1980 front at point X?
(Your answer should be stated to the nearest degree and minute)
_____________________________________________________
9. State the width of the Taku Glacier at the terminus (end). _____________________
10. State the width of the Taku glacier at the 1000 ft. contour. _____________________
11. Calculate the gradient of the Taku Glacier from point Y along the 1000ft contour to point Z (at the
Taku River, elevation 0 ft.). (Rate should be expressed in feet per mile)
a. State the
Equation for
Gradient
b. Substitute Values
into the Equation
c. Solve the
equation and state
your Final Answer
Gradient = _________________________
Gradient = _________________________
Gradient = _________________________
Copyright: Gary R. Vorwald, Paul J. Gelinas jHS, Setuaket, NY 2013
(May be used for educational purposes; please credit author)

Draw a topographic profile across the Taku Glacier, from point A to point B. Plot each elevation value
using a point and then connect the points with a smooth line. Draw a dashed line to show your
interpretation of the depth of the glacier and Taku River.
12. Based on your profile, how thick is the Taku Glacier? ____________________
13. What is the name of the glacial landform at A? _____________________
14. Describe or give the name of the glacial landform directly east of the 1000 ft contour on
the Taku Glacier? ________________________________________________________
15. When the Taku Glacier completely melts, what shape will the valley be? ____________
16. Describe the topography of this region. _____________________________________
________________________________________________________________________
17. The dark lines on the glacier indicate the position of the glaciers terminus (glaciers front) at
various dates in the past. Use this information to state if the glaciers appear to be advancing or
retreating.
Taku Glacier = ________________________ Norris Glacier = ______________________
Hole-in-the-Wall Glacier = __________________________
Copyright: Gary R. Vorwald, Paul J. Gelinas jHS, Setuaket, NY 2013
(May be used for educational purposes; please credit author)

PART 2: Prediction of Position of Glaciers
1. Calculate the rate of movement of the Taku Glacier for the following periods of time:
1890-1929; 1929-1948; 1948 – 1980.
Use the kilometer scale. Calculate rate in both km/yr and meters/year. 1 km = 1000 meters.
a. 1890 – 1929
Distance (km)
Distance
(meters) Time (years) Rate (km/yr) Rate (m/yr)
b. 1929 – 1948
Distance (km)
Distance
(meters) Time (years) Rate (km/yr) Rate (m/yr)
c. 1948 – 1980
Distance (km)
Distance
(meters) Time (years) Rate (km/yr) Rate (m/yr)
2. Based on your calculations, describe your observations of the rate from 1890 – 1980.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Copyright: Gary R. Vorwald, Paul J. Gelinas jHS, Setuaket, NY 2013
(May be used for educational purposes; please credit author)

3. Use your calculations of rate to predict where the Taku Glacier is now (2013). You decide which
interval to use.
Convert the rate formula to solve for the predicted distance.
Rate = Distance/Time Distance =
Rate (km/yr) Time (years) Predicted Distance
(km)
4. Indicate on the map where you think the Taku Glacier is today, based on your calculations.
5. Predict the location of the Norris Glacier in 2010. Use a red marker or pencil.
Distance (km)
Distance
(meters) Time (years) Rate (km/yr) Rate (m/yr)
Rate (km/yr) Time (years) Predicted Distance
(km)
Indicate the location of the Norris Glacier on the map. Use a red marker or pencil.
Copyright: Gary R. Vorwald, Paul J. Gelinas jHS, Setuaket, NY 2013
(May be used for educational purposes; please credit author)

Discussion Questions:
1. What is the length, width, and approximate thickness of an Alpine (Valley) Glacier?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
2. What are some topographic characteristics of a region that has been affected by alpine glaciers?
Describe some landforms observed on your map of the Taku Glacier. Include the shape of the
valley being carved by the glaciers.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
3. What conditions cause a glacier to advance or retreat? (Relate to annual snowfall accumulation
and melting/ablation)
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
4. The Taku Glacier currently appears have been in a state of Dynamic Equilibrium since 1980 .
Explain what the relationship between accumulation and melting is and describe where the
glacier is now compared to the river.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Copyright: Gary R. Vorwald, Paul J. Gelinas jHS, Setuaket, NY 2013
(May be used for educational purposes; please credit author)

___________________________________________________________________
Conclusion: Write a conclusion about what you learned about glaciers from this lab. Include
information about your rate calculations and how you can predict future positions of a glacier.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Evaluation:
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Copyright: Gary R. Vorwald, Paul J. Gelinas jHS, Setuaket, NY 2013
(May be used for educational purposes; please credit author)

Copyright: Gary R. Vorwald, Paul J. Gelinas jHS, Setuaket, NY 2013
(May be used for educational purposes; please credit author)