- Abstract: In order to support science-based water resource management, a systematic effort was undertaken to characterize the nature and function of the hydrogeology in Jo Daviess County, Illinois. Jo Daviess County is a karst area. Karst is a geologically and hydrologically integrated or interconnected and self-organizing network of landforms and subsurface large-scale, secondary porosity created by a combination of fractured carbonate bedrock, the movement of water into and through the rock body as part of the hydrologic cycle, and physical and chemical weathering (Panno, S.V. et al, 2017). Springs, cover-collapse sinkholes, crevices, and caves are among the defining features of a karst terrain; each of these features is found in Jo Daviess County. Examples of these features have been located in the field and characterized by scientists from the Illinois State Geological and Water Surveys (Prairie Research Institute, University of Illinois at Urbana-Champaign). The lead-zinc ore deposits of the Driftless Area, which includes Jo Daviess County, were emplaced within the Galena Dolomite 270 million years ago (Brannon et al. 1992). Ore-forming and associated solutions (hot brines) migrated through carbonate rocks along existing fractures and were responsible for enlarging many of these fractures into crevices. The crevices and infilling sulfide ore deposits created by these solutions have the same distribution and orientation as those identified as crop lines by Panno, Luman and Kolata (2015) using remote sensing techniques. Consequently, maps of mines and mining activities reflect the fracture and crevice orientations and provide additional information about the physical characteristics of the bedrock and aquifers of the Driftless Area. This dataset was developed from the original IMDA documents by the Illinois State Geological Survey (ISGS) in fulfillment a grant from the United States Geological Survey (USGS) National Geological and Geophysical Data Preservation Program (NGGDPP). The IMDA is a detailed set of paper records for the Lead-Zinc District in Jo Daviess County in northwestern Illinois for the period 1949-1970. The IMDA consists of large-scale (1"=200') 36"x30" sheet section maps depicting mining digs and borehole locations, and a set of 8-1/2"x11" datasheets containing borehole logs and mineral analyses (assays and/or visual estimates at various depths).Information extracted from original borehole logs and map sheets allowed for the point digitizing of 4,871 borehole locations in Jo Daviess County. Currently, 2,663 of these boreholes have each been assigned an API (American Petroleum Institute) number by the Illinois State Geological Survey; an API number is a unique, permanent, numeric identifier assigned to each well (borehole) drilled in the United States. In addition, the original driller’s log sheets for all 4,871 boreholes have been scanned and are available online as pdf formatted documents. The lead, zinc, and iron mineralization data by depth for the 2,663 boreholes with API numbers have been input into the Illinois State Geological Survey's Oracle Database and these information are provided in the Boreholes GIS dataset as a related table. The following document is directly related to this dataset:Klass, R. and Z. Lasemi. Preservation of Geologic Data and Collections in Illinois: Compilation, Documentation and Planning. Technical Report, Illinois State Geological Survey, Prairie Research Institute, University of Illinois Urbana-Champaign, 2014-15.The following documents are pertinent references providing background information: Brannon, J.C., F.A. Podosek, and R.K. McLimans, 1992, Alleghenian age of the Upper Mississippi Valley zinc-lead deposits determined by Rb-Sr dating of sphalerite: Nature, v. 356, p. 509–511.Mansberger, F., T. Townsend, and C. Stratton. The People Must be Crazy: The Lead and Zinc Mining Resources of Jo Daviess County, Illinois; Fever River Research, Springfield, Illinois, 1997 (revised July, 2020). http://illinoisarchaeology.com/Lead%20Mine%20Report%20Revised.pdf
- Purpose: This dataset contains GIS points depicting mining boreholes digitized from the U.S. Bureau of Mines (USBM) Illinois Mineral Development Atlas (IMDA) for Jo Daviess County, Illinois. Each point includes a link to a corresponding log (if available). This is one of several datasets compiled for the Karst Feature Database of Jo Daviess County, IL and hosted by the U.S. Fish & Wildlife Service.