Glaciation of Wisconsin

[Sunsettommy]

Wisconsin Geological and Natural History Survey

Lee Clayton, John W. Attig, David M. Mickelson,
Mark D. Johnson, and Kent M. Syverson
Educational Series 36
2006
Third edition

EXCERPT:

Figure 1. Phases of glaciation. A phase is a geologic event rather than a period of time. Most phases represent at least a minor advance of the edge of the Laurentide Ice Sheet. Each line marks the southern edge of the ice sheet during a phase of glaciation. For example, during the Johnstown Phase of the Wisconsin Glaciation, the southern edge of the Green Bay Lobe (see fi g. 4 for lobe locations) of the Laurentide Ice Sheet advanced to the
line marked “Johnstown” in south-central Wisconsin; figure 3 shows that this occurred approximately 16,000 years before present. Only the most recent phase is shown at any location.

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