MELTWATER, MAPPING AND MORAINES: ADVENTURES IN THE SAGINAW LOBE TERRAIN OF SOUTHWEST MICHIGAN AND BEYOND

An integral process of glaciation is the production of large volumes of meltwater. Meltwater maybe stored or temporarily accumulate in proglacial or subglacial environments until the volume exceeds a topographic, glacial, or erosional threshold condition. Sustained or often sudden, release of meltwater creates a unique series of channelized landforms and deposits that can be used to deduce or hypothesize glacial events and former conditions along glacial margins.

In southwest Michigan the Saginaw Lobe of the Laurentide Ice Sheet produced a series of channelized forms in the process of deglaciation. Many of these channels are oriented northeast to southwest parallel to the flow axis of the Saginaw Lobe and intersect moraines produced at former ice margins and likely formed as subglacial tunnel channels. In other locations, such as the Grand River and central Kalamazoo Valley channel forms appear as meltwater spillways carved by catastrophic meltwater flows across terrains previously occupied by the Saginaw Lobe. Over thirty years Dr. Alan Kehew and his students studied, mapped and explored the glacial terrain, landforms and deposits in southwestern Michigan. His scientific contributions were only surpassed by his mentorship for his graduate students. Much of this work was funded by the United States Geological Survey National Cooperative Geological Mapping Program. Using innovative techniques such as rotosonic drilling, and downhole geophysics Alan and his students began mapping the 3D subsurface geologic framework in a parallel effort with the Great Lakes Geological Mapping Coalition. His legacy lives on with ongoing studies, maps and achievements being completed by his former students throughout the Great Lakes Region and beyond.