23 research outputs found

    GIS Tools for 3-D Surficial Mapping in Ohio

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    This poster was presented at the 2007 meeting of the Digital Mapping Techniques Conference in Columbia, South Carolina, May 20-23, 2007.The Ohio Department of Natural Resources, Division of Geological Survey is currently mapping the surficial geology of Ohio in three dimensions (3-D) using a modified version of the stack-mapping technique of Kempton (1981). The stack-mapping technique depicts the geology for an area in 3-D by listing the unconsolidated (mostly glacial) geologic units from the surface to bedrock, the thickness of each unit, and the underlying bedrock unit. The new mapping of the surficial geology is intended to replace the older and smaller-scale mapping that was based upon generalized, two-dimensional mapping techniques. Three ArcMap-based software applications were developed to assist with the stack-unit mapping program. The first software application used the lithologies from water wells to create on-screen graphics representing the stratigraphic columns for each well record. These stratigraphic columns are interpreted by the geologist to assign a generalized stack unit for each polygon. The second software application consists of two tools used to attribute and label the stack-map polygons, which will capture the information in the GIS and for cartographic display. The first tool attributes a one-to-many relationship between a surficial-geology polygon and the lithology table. The second tool labels the surficial-geology polygons with the stack text for use in map publishing. The third application performs custom queries against the lithology table that can be used to create derivative mapping products, such as location and thickness of sand and gravel resources. These three applications allow the efficient creation of 3-D surficial-geology polygons and labels within a GIS database, and provide analysis tool to facilitate the use of the 3-D surficial geology maps for specific applications.Great Lakes Geologic Mapping Coalition, U.S. Geological Surve

    Potential for Mineable Bedrock in the Findlay 30 x 60 minute quadrangle

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    The Ohio Department of Natural Resources (ODNR), Division of Geological Survey has completed a reconnaissance map showing areas of mineable bedrock, including shale, limestone, and dolomite, likely covered by thin surficial materials (glacial drift) in the Findlay, Ohio, 30 x 50-minute (1:1,100,000-scale) quadrangle. The main purpose of this map was to create a reconnaissance-level map that shows the potential for mining carbonate and shale bedrock in this quadrangle. We sought to create this map from as many existing ODNR Division of Geological Survey maps and GIS datasets as possible. The map shows areas of surficial materials in increments of 10 ft and totaling less than 40 ft overlying Silurian- and Devonian-age dolomite and limestone, and it also shows a limited area in the southeastern most portion of the quadrangle where surficial materials (totaling less than 20 ft) overlay potential Devonian-age shale resources.United States Geological Survey: National Cooperative Geologic Mapping Program, Great Lakes Geologic Mapping Coalitio

    Potential for Mineable Bedrock in the Marion 30 X 60 minute quadrangle

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    The Ohio Department of Natural Resources (ODNR), Division of Geological Survey has completed a reconnaissance map showing areas of mineable bedrock, including shale, limestone, and dolomite, likely covered by thin surficial materials (glacial drift) in the Marion, Ohio, 30 x 50-minute (1:1,100,000-scale) quadrangle. The main purpose of this map was to create a reconnaissance-level map that shows the potential for mining carbonate and shale bedrock in this quadrangle. We sought to create this map from as many existing ODNR Division of Geological Survey maps and GIS datasets as possible. The map shows areas of surficial materials in increments of 10 ft and totaling less than 40 ft overlying Silurian- and Devonian-age dolomite and limestone, and it also shows a limited area in the easternmost portion of the quadrangle where surficial materials (totaling less than 20 ft) overlay potential Devonian-age shale resources.United States Geological Survey: National Cooperative Geologic Mapping Program, Great Lakes Geologic Mapping Coalitio

    Geologic maps are essential tools for fish management

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    Semiannual, 2003, no. 1-; Quarterly, fall 1990-2002, no. 3/4; Began with Fall 1990.; Ended with 2010, no. 2.; Some numbers combined

    Cost-effective mapping of benthic habitats in inland reservoirs through split-beam sonar, indicator kriging, and historical geologic data.

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    Because bottom substrate composition is an important control on the temporal and spatial location of the aquatic community, accurate maps of benthic habitats of inland lakes and reservoirs provide valuable information to managers, recreational users, and scientists. Therefore, we collected vertical, split-beam sonar data (roughness [E1], hardness [E2], and bathymetry) and sediment samples to make such maps. Statistical calibration between sonar parameters and sediment classes was problematic because the E1:E2 ratios for soft (muck and clay) sediments overlapped a lower and narrower range for hard (gravel) substrates. Thus, we used indicator kriging (IK) to map the probability that unsampled locations did not contain coarse sediments. To overcome the calibration issue we tested proxies for the natural processes and anthropogenic history of the reservoir as potential predictive variables. Of these, a geologic map proved to be the most useful. The central alluvial valley and mudflats contained mainly muck and organic-rich clays. The surrounding glacial till and shale bedrock uplands contained mainly poorly sorted gravels. Anomalies in the sonar data suggested that the organic-rich sediments also contained trapped gases, presenting additional interpretive issues for the mapping. We extended the capability of inexpensive split-beam sonar units through the incorporation of historic geologic maps and other records as well as validation with dredge samples. Through the integration of information from multiple data sets, were able to objectively identify bottom substrate and provide reservoir users with an accurate map of available benthic habitat

    Map showing elevation contours from the United States Geological Survey and the difference between the bathymetry from sonar and the bathymetry from the pre-flood topography map of Hoover Reservoir.

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    <p>Map showing elevation contours from the United States Geological Survey and the difference between the bathymetry from sonar and the bathymetry from the pre-flood topography map of Hoover Reservoir.</p

    Plot showing roughness versus hardness for muck and organic-rich clay sediments in Hoover Reservoir.

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    <p>Symbols colored blue are organic-rich clays, and those colored red are muck. The symbols are assigned by geologic unit, with squares representing upland units—T, Sh, Mf(a)—and plus symbols representing bottom land units—a, Mf(b).</p
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