Pages authored by Robin F. Rupp:

1. Data Sets / Clay Thickness
   A variety of fine-grained unconsolidated sediments are found beneath the surface of Marion County. They are commonly, but somewhat misleadingly, called “clay” in water-well records and engineering reports, even though the actual clay content seldom exceeds 20 or 25 percent.
2. Data Sets / DEM Terrain
   A representation of the elevation of the land surface of Marion County can be viewed in a digital elevation model (DEM) such as the one displayed in the interactive map portion of this website (fig. 1). A DEM is a raster data set containing elevation data in a closely spaced grid pattern.
3. Data Sets / iLITH Database
   iLITH is an Indiana Geological and Water Survey (IGWS) database containing information from water-well records provided by the Indiana Department of Natural Resources (IDNR), Division of Water. These records contain both locational and lithologic data edited by the IGWS (Brown and others, 2000).
4. Geology / Glacial Geology
   The central Indiana landscape is primarily a product of the Pleistocene Epoch of the Quaternary Period, or Ice Age, a period of widespread continental glaciation in which the temperate northern latitudes were repeatedly invaded by large ice sheets.
5. Geology / Hydrogeologic Framework
   Hydrogeology is the study of groundwater and its interaction with the geologic framework, landscape, surface-water bodies, and the human environment. It is both a qualitative and quantitative science having many applications to the modern environment.
6. Geology / Surficial Geology
   Northern Indiana was repeatedly covered by continental ice sheets during the past one million years or so, which produced a thick section of unconsolidated sediments that mantle the bedrock to depths as great as 500 ft.
7. Geology / Water-Table Elevation
   Residents of Allen County rely heavily on groundwater in the underlying strata for drinking water, irrigation, and industrial uses.
8. Data Sets / DEM Terrain
   A representation of the elevation of the land surface within Allen County, Indiana, can be viewed in great detail in a digital elevation model (DEM) such as the one displayed in the interactive map portion of this website and in fig. 1. A digital elevation model is raster data containing individual elevations in a closely spaced grid pattern.