Laboratory Manual for Introductory Geology 4e

EXERCISE 15.3
Erosional Features of Continental Glaciation
Name:
Course:
Section:
Date:
(a) Describe the topography in the DEM below in your own words, paying particular attention to the shapes of the
bedrock hills. When features in a glacial landscape display a strong alignment, geologists say that the landscape has
a “topographic grain” related to the direction in which ice moved. Describe the topographic grain in Figure 15.5 and
the direction in which the ice probably moved.
(b) Construct a topographic profile, using the graph paper provided at the end of this chapter, from St. John’s Church
to Lake Rippowam (line A–B in Fig. 15.5), using 103 vertical exaggeration. Are the hills symmetric or asymmetric?
(c) Are the steep and gentle slopes of hills distributed randomly or systematically? Describe their distribution.
(d) What is controlling the steep slopes of the hills?
(e) Based on your description and observations, draw arrows on the DEM below and on Figure 15.5 showing the
direction in which the continental glacier moved across the map area. Explain your reasoning.
(f) Fill in the blanks to complete the
following sentence that describes how
sculptured bedrock records glacial
movement: The direction of ice flow
indicated by sculptured bedrock is from
the
side of the hill
toward the
side.
DEM of the Peach Lake
quadrangle in New York (area in
rectangle is shown in Fig. 15.5).
N
15.3 LANDSCAPES PRODUCED BY CONTINENTAL GLACIATION
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