GEOLOGIC MAPPING IN LINN COUNTY: THE IOWA EXPERIENCE IN THE NATIONAL STATEMAP PROGRAM

by
G.A. Ludvigson, E.A. Bettis III, J.D. Giglierano, M.R. Howes, and R.R. Anderson

Iowa Academy of Science
108th Session
April 26-27, 1996, Simpson College, Indianola, IA
1996 Program Abstracts, p. 21

ABSTRACT


The Iowa Department of Natural Resources - Geological Survey Bureau is engaged in the second year of a three-year program to map the near-surface geology of Linn County, Iowa, as part of the national STATEMAP Program administered by the U.S. Geological Survey. As required by national program directives, Linn County was selected by a statewide mapping advisory panel as the first priority for undertaking new geologic mapping aimed at resolving environmental and natural resource issues in expanding metropolitan areas. The mapping effort has also received funding support from county and municipal agencies responsible for decisions on local natural resource issues. Completed maps include the surficial geology of the Cedar Rapids North (OFM-95-1) and Marion (OFM-95-2) 7.5 minute quadrangles (1:24,000 scale) and the bedrock geology of Linn County (OFM-95-3; 1:100,000 scale). These areas were initially selected to address concerns about (1) the impacts of metropolitan expansion into a karst drainage area near Robins, Iowa; (2) well-head protection of the Cedar Rapids municipal well field in the Cedar River alluvial aquifer; and (3) to aid in development of long-range plans for sanitary landfill facilities north of Marion. Geologic mapping is in progress in the Cedar Rapids South and Central City 7.5 minute quadrangles, due for completion in the summer of 1996. Proposed mapping for the third and final year of the project has been recommended for funding by the national review panel, pending passage of appropriations for the U.S. Department of Interior. This will include geologic mapping of the Bertram 7.5 minute quadrangle, and compilation of surficial geology of the entire county at 1:100,000 scale.