Open-File Reports
Persistent link for this collectionhttps://hdl.handle.net/11299/92918
Browse
Browsing Open-File Reports by Author "Bauer, E.J."
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
Item Digitization of geologic data from 1985-1993 COGEOMAP program area, Minnesota(Minnesota Geological Survey, 1994) Miller, James D., Jr.; Wahl, T.E.; Bauer, E.J.Item A Hydrogeologic and Mapping Investigation of the St. Lawrence Formation in the Twin Cities Metropolitan Area(University of Minnesota, 2006) Runkel, A.C.; Mossler, J.H.; Tipping, R.G.; Bauer, E.J.This report summarizes the results of a two year project conducted by the Minnesota Geological Survey to map the Upper Cambrian St. Lawrence Formation and investigate its hydrologic properties in the Twin Cities Metropolitan area (TCMA). Funding was provided by the Minnesota Department of Health. Final products are a map delivered in electronic format that can be used with Arcview 3.2 GIS software, and this informal report. Our hydrogeologic study indicates that the St. Lawrence Formation commonly has a moderate to high horizontal hydraulic conductivity across all of the study area. In conditions of shallow burial beneath younger bedrock it is most similar in the development of secondary pores and measured hydraulic properties to fractured carbonate rock aquifers. Discrete intervals with secondary pores have a high horizontal hydraulic conductivity whereas rock between these intervals are orders of magnitude lower in conductivity. The properties of the St. Lawrence Formation in a vertical direction are not as wellunderstood, but available data are consistent with the traditional classification of the formation as an aquitard. However, the integrity of the formation as an aquitard in a vertical direction, particularly under conditions of shallow burial such as where it is uppermost bedrock, has not been rigorously tested, and may be markedly variable across the TCMA. This is chiefly because vertical fractures play an important role in determining aquitard integrity, and the distribution of such fractures is poorly understood. Suggestions for additional research that might lead to a better understanding of aquitard integrity are made at the end of this report.Item OFR06-02, Maps of Gridded Bedrock Elevation and Depth to Bedrock in Minnesota(University of Minnesota, 2006) Lively, R.S.; Bauer, E.J.; Chandler, V.W.Item OFR10-02, Preliminary Bedrock Geologic Map of Minnesota(Minnesota Geological Survey, 2010) Jirsa, M.A.; Bauer, E.J.; Boerboom, T.J.; Chandler, V.W.; Lively, R.S.; Mossler, J.H.; Runkel, A.C.; Setterholm, D.R.The geologic map and some associated digital map files that are part of this Open File Report have been superseded by the map and digital data that comprise S-21 in the State Map Series.