Karst conduit flow in the Cambrian St. Lawrence Confining Unit, southeast Minnesota, USA

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• 作者：Jeffrey A. Green (1) jeff.green@state.mn.us
  Anthony C. Runkel (2) runke001@umn.edu
  E. Calvin Alexander Jr. (3) alexa001@umn.edu
• 关键词：Dye tracing – ; Karst – ; Confining unit – ; Aquitard – ; Cambrian St. Lawrence
• 刊名：Carbonates and Evaporites
• 出版年：2012
• 出版时间：June 2012
• 年：2012
• 卷：27
• 期：2
• 页码：167-172
• 全文大小：526.9 KB
• 参考文献：1. Alexander SC (2005) Spectral deconvolution and quantification of natural organic material and fluorescent tracer dyes. In: Beck BF (ed) Tenth multidisciplinary conference on sinkholes and the engineering and environmental impacts of karst, San Antonio, TX, September 24–28, proceedings, Reston, VA, American Society of Civil Engineers, ASCE Geotechnical Special Publication 144, pp 441–448
  2. Green JA, Luhmann AJ, Peters AJ, Runkel, AC, Alexander, EC Jr, Alexander SC (2008) Dye tracing within the St. Lawrence confining unit in southeastern Minnesota. In: Yuhr L, Alexander EC Jr, Beck BF (eds) Eleventh multidisciplinary conference on sinkholes and the engineering and environmental impacts of karst, Tallahassee, FL, September 22–26, proceedings, Reston, VA. American Society of Civil Engineers, ASCE Geotechnical Special Publication 183, pp 477–484
  3. Jacobson W, Cowan C, Runkel AC (2009) Subtle evidence for paleoseismicity in the cratonic interior, USA: EOS, Transactions of the American Geophysical Union, vol 90, no. 52, Abstract T53D-1611
  4. Mossler JH (2008) Paleozoic stratigraphic nomenclature for Minnesota: St. Paul, MN, Minnesota Geological Survey, Report of Investigations 65, 1 pl
  5. Paylor RL, Currens JC (2001) Mapping karst ground-water basins in the inner bluegrass as a nonpoint-source management tool. In: Beck BF, Herring JG (eds) Eighth multidisciplinary conference on sinkholes and the engineering and environmental impacts of karst, Louisville, KY, April 1–4, proceedings, Lisse, A.A. Balkema, pp 209–216
  6. Runkel AC, Tipping RG, Alexander EC Jr, Green JA, Mossler JH, Alexander SC (2003) Hydrogeology of the Paleozoic bedrock in southeastern Minnesota, St. Paul, MN, Minnesota Geological Survey, Report of Investigations 61, 1 map in pocket
  7. Runkel AC, Tipping RG, Alexander EC Jr, Alexander SC (2006a) Hydrostratigraphic characterization of intergranular and secondary porosity in part of the Cambrian sandstone aquifer systems of the cratonic interior of North America—improving predictability of hydrogeologic properties. Sediment Geol 184:281–304
  8. Runkel AC, Tipping RG, Mossler JH, Bauer EJ (2006) Hydrogeology and mapping investigation of the St Lawrence Formation in the Twin Cities Metropolitan area, St. Paul, MN, Minnesota Geological Survey Open File Report, OFR 06-04
  9. Swanson SK (2007) Lithostratigraphic controls on bedding-plane fractures and the potential for discrete groundwater flow through a siliciclastic sandstone aquifer, southern Wisconsin. Sediment Geol 197(1–2):65–78
  10. Trout Unlimited (2008) The economic impact of trout angling in the Driftless Area, flyer produced by: North Star Economics Inc. http://www.tu.org/conservation/watershed-restoration-home-rivers-initiative/driftless-wi-mn-ia-il
• 作者单位：1. Division of Ecological and Water Resources, Minnesota Department of Natural Resources, 2300 Silver Creek Road NE, Rochester, MN 55906, USA2. Minnesota Geological Survey, 2642 University Avenue West, St. Paul, MN 55114, USA3. Geology and Geophysics Department, University of Minnesota, 108 Pillsbury Hall, 310 Pillsbury Drive SE, Minneapolis, MN 55455, USA
• ISSN：1878-5212

文摘

Southeastern Minnesota’s karst lands support numerous trout streams created by Paleozoic bedrock springs. Several of the Paleozoic bedrock units are recognized as karst aquifers. Recent field investigations have discovered sinking, and one losing, streams in the Cambrian St. Lawrence Formation. The siliciclastic-dominated St. Lawrence Formation has historically been viewed as a confining unit and is designated as such in the Minnesota Water Well Code. Stream sinks in the St. Lawrence Formation have been identified in five different streams, and there are numerous other streams crossing the St. Lawrence that have yet to be investigated. Dye traces have been conducted on the five streams. At all of the sites, dye was recovered at springs emanating from the base of the St. Lawrence Formation. The initial dye breakthrough occurs quickly, but the breakthrough curves have tails that continue for months to over a year. Breakthrough travel velocities from the sinks to the springs are 35–750 m/day. The five dye tracing sites are geographically separated by 65 km. The subcrop of the St. Lawrence Formation is found throughout southeastern Minnesota and southwestern Wisconsin. The St. Lawrence Formation has well-developed macroporosity; most of the formation is moderately to well cemented with dolomite and contains abundant horizontal and vertical fractures in outcrop and subcrop conditions. Volumetrically minor dolomite beds with centimeter-scale solution cavities are common in the lowermost part of the formation. These attributes, combined with rapid groundwater flow as determined by dye tracing, supports the conclusion that this purported confining unit has karst conduit flow properties in subcrop conditions.