Geological mapping projects undertaken in the Chicago metropolitan areas of northeastern Illinois are providing critical scientific information requested by government officials and public agencies to direct future land use, groundwater extraction, and environmental mitigation. Specifically, in Lake County, the Illinois State Geological Survey is undertaking a program to map glacial and nonglacial sediments from the land surface to the top of bedrock (the upper 200 to 400 feet; 61 to 122 m) in three dimensions. This mapping was completed by incorporating available datasets including historic and recent digital aerial photography, ground surface elevations acquired using Laser Imaging Detection and Ranging (LiDAR) technology, and United States Department of Agriculture soils data. By combining these data to construct oblique perspective images of the land surface, the accuracy of mapping the geologic materials could be evaluated. This study found that in some cases, geological and geomorphic data compiled from these composite images and limited field-testing supported different interpretations than indicated by the soil-parent materials map, ultimately requiring geologists to modify unit boundaries on the final map. Combining available subsurface geological information with these perspective images further enhanced the utility of this map product by enabling the user to view the geology in two- and three-dimensions. Cross sections and three-dimensional models provided visual representations of the horizontal and vertical distribution of geologic materials.
ASJC Scopus subject areas
- Geography, Planning and Development
- Earth and Planetary Sciences (miscellaneous)