Glacial Geology 19. Depositional Landform Identification

K.A. Lemke – UWSP 107

19. DEPOSITIONAL LANDFORM IDENTIFICATION

28 Points

You should be able to: • Identify different types of glacial depositional landforms in photos and on topographic maps; • Correlate lateral and end moraines using their position on the landscape to determine their relative ages.

Read: • Bennett & Glasser (2009) Chapter 9 pp. 247-248; 262-288.

Questions 1-13: Identify the depositional landform(s) in each numbered image along with a brief justification. [18]

1. [1]

2. [1]

3. [1]

[1]

4. [1]

5. [1]

6. [1]

[1]

7. [1]

8. [1]

[1]

9. [1]

10. [1]

11. [1]

[1]

12. [1]

[1]

13. [1]

19. Depositional Landform Identification Glacial Geology

108 K.A. Lemke – UWSP

The image in Figure 19.1 shows Walker Lake/Bloody Canyon in California and contains numerous lateral moraines. Go to Google Earth and search for “Lee Vining, CA.” The river that runs through Lee Vining drains a canyon to the southwest of Lee Vining. Multiple moraines are visible at the outlet to this canyon. The next major canyon to the south contains Walker Lake. To help locate Walker Lake, turn on the Labels in Google Earth and check Water Bodies. Once you find Walker Lake, rotate and tilt the image in Google Earth so you can examine the topography from different directions and perspectives.

14. Mark the features listed below on the attached topographic map. Use Google Earth in conjunction with the topographic map to help you visualize the features. Use colored pencils or different line styles to differentiate the features. Indicate your coding below. [5]

• The back of the cirque (the headwall) at the head of the valley containing Walker Lake • The rock basin at the bottom of the cirque. • Two giant stair steps. • One hanging valley. • The edges of the glacial trough containing Walker Lake. Mark the trough edges up to but not beyond Walker Lake

so your lines do not interfere with your lines identifying lateral moraines.

15. On the attached topographic map, draw a line along the crest of all the lateral and end moraines in the region of Bloody Canyon. Some of the lateral moraines have truncated other lateral moraines. Walker Creek has eroded through the end moraines that would have originally connected lateral moraines of the same age on opposite sides of the valley (remember, lateral moraines often grade into end moraines). You need to figure out which lateral moraines on opposite sides of the canyon are the same age. Use colored pencils or different line styles (e.g. dashed, dotted) to show the moraines on opposite sides of the canyon that correlate to one another (i.e. are the same age). Some of the lateral moraines are quite close together so your lines need to be thin. Use the Google Earth image and the shape of the contour lines to draw the moraine crests accurately.

Once you have identified the moraines, number them from youngest (1) to oldest, using their position on the landscape and the law of superposition to determine their relative ages. [10]

Figure 19.1 Walker Lake and Bloody Canyon, CA

Glacial Geology 19. Depositional Landform Identification

K.A. Lemke – UWSP 109

19. DEPOSITIONAL LANDFORM IDENTIFICATION: PHOTOS

4

2 1

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Glacier

Glacier remnant

19. Depositional Landform Identification Glacial Geology

110 K.A. Lemke – UWSP

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11