Great Lakes Geologic Mapping Coalition Meets at ISGS to Plan Future 3-D Mapping in the Great Lakes Region

Clear Creek Section in Marshall County

Clear Creek Section in Marshall County showing thick glacial sediments. (Photograph by Ramona Cornea.) 

On April 20, glacial geologists and mappers from geological surveys of the eight Great Lakes states, Kentucky, Ontario, and the U.S. Geological Survey (USGS) gathered at the Illinois State Geological Survey (ISGS) for their annual meeting of the Great Lakes Geologic Mapping Coalition. The goal of the meeting was to discuss future directions in three-dimensional (3-D) geologic mapping, share new science in the region, and explore state-of-the-art technologies that will facilitate their 3-D mapping efforts. Each year, Coalition members gather to discuss progress and discoveries from the previous year, their proposed mapping plans, and the societal issues that they will be addressing in the upcoming year.

The Coalition was formed in 1997 out of a need for more detailed geologic information in the glaciated midcontinent, where glaciers have deposited a thick cover of very complex sediments. Coalition members need to have an understanding of the distribution and properties of the glacial units to provide policy makers with needed knowledge about the most appropriate, sustainable uses of the land. “There are considerable complexities in glacial sediments that really don’t exist with other kinds of geology,” said ISGS Director Richard Berg, “so there’s a specific way of mapping them, a specific way of just understanding how those deposits got there.”

When the Coalition began, less than 10 percent of the subsurface in the region had been mapped. The individual surveys had a critical need to identify water resources within aquifers, but they lacked the necessary financial and personnel resources to conduct such a massive geologic mapping effort. When the Coalition was formed, the members were fully aware that by combining survey resources, they could share science, solve problems, and develop innovative technologies and mapping tools that would benefit them all. “By a group of people with common interests getting together to share their experiences, we have learned by other people’s successes and not having to reinvent the wheel,” said Berg.

As a Coalition, a common mission was framed to (1) develop a dynamic database of comprehensive geologic information and (2) create updatable 3-D geologic maps and map products. From this mission, a strategy and long-term goals were developed to generate financial and stakeholder support for 3-D mapping, pool physical and personnel resources, and share their mapping and technological expertise. “If you look at the Foreword of the USGS publication [USGS Open File Report 99-349] that dealt with the coalition concept, it talked about this as the way that the USGS would prefer doing business,” said Berg. “And we’ve suggested that other coalitions like this form, for example, on the Atlantic coast, the desert states, but it’s very difficult because it’s just difficult to get started and then maintain the momentum.”

Coalition outputs directly support decision makers in formulating critical policies on economic development, natural resources, hazards, and environmental management of the Great Lakes region. Through the Coalition’s mapping efforts, stakeholders in the region, including municipalities, federal, state, and county agencies, and private landowners, are provided with unbiased, scientifically defensible geologic information on the shallow subsurface on which to base their policy decisions. As successes, Berg notes the “remarkable advancements” the Coalition has made in portraying this information in three dimensions, and therefore increasing understandability of the relationship, thickness, and distribution, for example of aquifers and non-aquifers. “The portrayal of the information into 3-D blocks allows users to understand the importance of this for land and water use and economic development, and this situation exists throughout the Great Lakes region,” he said.

For example, in Will County, Illinois, where urban, suburban, and rural environments exist side by side, 3-D geologic maps are being developed to guide planners and decision makers in setting policy related to sustainable economic development and environmental protection, including water supply management, storm water management, wetland preservation, shallow groundwater recharge, and sand and gravel/bedrock pit and quarry development. Coalition members at the ISGS have initiated interaction with county and local agencies to determine their primary natural resource and environmental issues and then begin producing maps and reports to address their concerns, including documents and maps that would delineate and characterize specific aquifers. During and after mapping, ISGS staff plan to continue working with county representatives to explore the development of additional interpretive 3-D geologic maps, thereby providing a context for developing aquifer yield evaluations, recharge estimations, and groundwater flow models. “Through detailed 3-D mapping, we’re producing a ‘planning tool’ to prevent potential hazards and disasters from happening by having knowledge of what’s there, so land use can then reflect the vulnerability of aquifers and the situation that exists,” said Berg.

People at GLMC conference

Glacial geologists and 3-D mappers at the annual Great Lakes Geologic Mapping Coalition meeting in April. (Photograph by Michael Knapp.)

More information on the Great Lakes Geologic Mapping Coalition can be found at and (Berg et al., Geological Society of America Special Paper 520, posted April 1, 2016).

Source: Berg, R.C., S.E. Brown, J.F. Thomason, N.R. Hasenmueller, S.L. Letsinger, K.A. Kincare, J.M. Esch, A.E. Kehew, L.H. Thorleifson, A.L. Kozlowski, B.C. Bird, R.R. Pavey, A.F. Bajc, A.K. Burt, G.M. Fleeger, and E.C. Carson, 2016, A multiagency and multijurisdictional approach to mapping the glacial deposits of the Great Lakes region in three dimensions, in G.R. Wessel and J.K. Greenberg, eds., Geoscience for the Public Good and Global Development: Toward a Sustainable Future: Geological Society of America, Special Paper 520,