Geologic Mapping Effort Contributes to Local Community Education
Geologists and hydrogeologists working on the Central Great Lakes Geologic Mapping Coalition project have completed mapping of about 80% of the surficial geology and 40% of the subsurface geology of Lake County, Illinois, as part of a project to map in three dimensions the geology from land surface to top of bedrock. To accomplish this, an extensive program of drilling is being used to acquire continuous high-quality core samples of the sediment. At each borehole location where significant deposits of sand and gravel are encountered, a water-level observation well is installed to monitor long-term water levels in the aquifer. Several dozen wells are now emplaced throughout the county. One such borehole well was installed at the Deer Park village hall site near a historic barn that has been restored to serve as a facility for village hall meetings and community events and as a museum and education center.
Following discussions with the ISGS project leader, staff from the education center invited the ISGS to provide material for a display at the site. In response, several ISGS staff members prepared a multi panel poster for permanent display that illustrates the glacial history, sediments, and hydrogeology at county scale and also of the local Vehe Farm area. Specific parts of the display discuss the depositional history of the geologic materials as interpreted from the sediment sequence encountered in the borehole. Also discussed is the installation of the observation well and how it will be used to better understand the behavior of the aquifers in the area. An aerial photographic history of the Vehe Farm area from 1939 to present is shown. The local and regional geology and hydrogeology are discussed in separate panels, which include graphics illustrating groundwater flow, the hydrologic cycle, types of aquifers, and terminology commonly used in discussions concerning groundwater.
The exhibit is intended to provide a basic understanding of geological issues for the layperson. Additionally, two types of drill bits used during the borehole drilling are displayed on a shelf specially constructed for our exhibit. Samples of the sediment encountered during the drilling are shown as well. Samples of the modern soil, diamicton, sand, silt, and bedrock—cut from the original core—are on display and their core position is described. Finally, a 4 minute video of the drilling, sediment retrieval, and well installation is available for play in a kiosk in the visitor welcome area. This video was recorded during the drilling in late 2006 by the ISGS staff photographer. Additional materials suitable for community teachers are being prepared. Already, local schools have expressed interest in water sampling from the well and information about groundwater resources and glacial history.