The Geology and Geomorphology of the Lake Michigan Coast
Hansen, Edward C., Michigan Academician
It is an often repeated statistic that Michigan's 2,288 miles of Great Lakes coasts give it the second longest coastline in the United States. No one in Michigan lives more than a few hours' drive from one of the Great Lakes, and few people in the state have not been affected by them in some way. They played key roles in the history and economic development of the state and continue to be one of its major recreational and aesthetic resources. The Great Lakes have also been the subject of much intellectual curiosity. A large amount of this focus has been on the geology and geomorphology of the lakes and their shores. In the state of Michigan this tradition goes back at least as far as the first State Geologist, Douglas Houghton (1809-1845), who included material on the Great Lakes in both the second and third annual reports of the State Geologist (Houghton 1928a; 1928b). Active scientific investigations of the Great Lakes have continued through today. One indication of this interest is the existence of the International Association of Great Lakes Research with a scientific journal, Journal of Great Lakes Research, dedicated to scientific studies of the Great Lakes.
In light of the long tradition of scientific studies of the Lakes, it appeared appropriate to hold a special session on the Geology and Geomorphology of the Lake Michigan coast in conjunction with the Michigan Academy of Science, Arts, and Letters 2003 annual meeting at Hope College, less than six miles from Lake Michigan. The session was held on Friday, March 21, 2003, and included 14 presentations by scientists representing 10 academic institutions, governmental agencies, and private companies from Michigan, Indiana, and Wisconsin. It was followed on Saturday by a field trip to examine coastal dunes and lake front erosion along a stretch of coast ranging from just south of Holland to north of Muskegon. In doing so we were returning to an old tradition of the Michigan Academy, which in the 1930s and 1940s sponsored annual geologic field trips. Anecdotal evidence (Fowler 2004) suggests that these trips once played an important role in the life of the geologic community in the state, among other things helping to launch the Michigan Basin Geological Society.
This volume is a result of the special session. Nine of the thirteen authors of the six papers in this issue presented at either the Friday session or the Saturday field trip. The papers in this volume are all outgrowths of the papers they presented. Each of the papers touches on one or more of the major themes brought out in the special session.
Changes in water levels have always been of particular concern to people studying the coastal geomorphology of the Great Lakes. As early as 1839, Houghton published an account of lake level changes in the early 1800s, and in 1840, he published observations of former shorelines high above the modern coasts (Houghton 1928a; 1928b). By the early twentieth century, a lake level history for the Great Lakes and their proglacial ancestors had been worked out by a succession of geologists, culminating in the work of Leverett and Taylor (1915). This history has continued to be refined up until today. Probably the most significant recent work has been done by Todd Thompson of the Indiana Geological Survey and coworkers who have developed a detailed, high-resolution lake level history for Lakes Michigan and Superior during the last 4,500 years (Baedke and Thompson 2000; Johnston et al. in press). In their paper for this issue, Todd Thompson, Steve Baedke, and John Johnston ("Geomorphic Expression of Late Holocene Lake Levels and Paleowinds in the Upper Great Lakes") explore some of the consequences of this lake level history for coastal geomorphology. In this paper they are able to link major events evident in their hydrographs with patterns in the late Holocene landforms evident throughout the coasts of the western Great Lakes. …