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August 15, 2011—The Ohio Geological Survey is pleased to announce that it has just received $111,798 from the USGS National Cooperative Geologic Mapping STATEMAP program to continue mapping glacial and surficial geology in Ohio. The Survey recently completed mapping the Lima 30 x 60-minute (1:100,000-scale) quadrangle and preparing for mapping the Defiance 30 x 60-minute quadrangle in northwestern Ohio.
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Till exposure along the Auglaize River in Defiance County. The brown unit (top) is made of silty, sandy glacial lacustrine materials; the light gray material (middle) is a clayey glacial till; and the base unit (bottom) is a silty, loamy till. This pattern of glacial sediments occurs frequently in northwestern Ohio.
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Surficial geology maps have a wide variety of purposes. Water well drillers can use these maps to determine the possibility of unconsolidated aquifers and how much drill casing they need to provide for a site. Developers can look for potentially detrimental materials, such as organic (peat-muck type) soils close to the ground surface. And engineers can use these maps to determine the nature and thickness of materials and how close bedrock is to the ground surface. For example, data from surficial maps was recently used to help site suitable locations for wind turbine farms in northwest Ohio.
Robert Andrews, a well field coordinator with the City of Columbus, supports the Survey’s surficial geology mapping program because of its benefit to ground- and surface-water utilities. “The surficial geology maps,” he notes, “have enhanced the City’s understanding of the geology and hydrogeology of the [Columbus] area.”
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Geologist Mike Angle uses a hand auger to take soil samples.
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Recently, Survey geologists have been using the surficial geology maps to create a new series of maps, referred to as “derivative maps,” which have been derived from the original surficial maps and targeted for specific uses. Derivative maps are especially useful to the mineral industries. Examples include:
- Sand-and-gravel availability maps used by the aggregate industry to determine thickness and proximity to the surface of sand-and-gravel units.
- Maps showing where the drift over bedrock is thin enough to allow for quarrying the rock.
- Waste suitability maps that show areas where the materials are suitable for disposing waste materials.
The surficial mapping program for Ohio began in 1997 with mapping in the Cincinnati area. Mapping was first conducted for glaciated areas underlying Ohio’s major urban centers and has since systematically spread westward from a corridor running from the Cincinnati-Dayton area northeast through Columbus to the Cleveland-Akron-Youngstown area. (See the Glacial Map of Ohio for the glacial boundary in Ohio.)
Since 1997, the Survey has mapped nearly 27,000 square miles of the state, more than 65 percent, utilizing nearly $1.5 million from the USGS STATEMAP program to conduct this mapping. Explore the links below to learn more about surficial geology in Ohio and the Survey’s mapping program.
Further Information
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