OFR 97-492: Duluth Quadrangle NURE HSSR Study
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[See History of NURE HSSR Program for a summary of the entire program.]
ORGDP: Duluth Quadrangle
The Oak Ridge Gaseous Diffusion Plant (ORGDP) was assigned the responsibility for a Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) survey of the Duluth quadrangle. In 1975, the Department of Energy (DOE) ranked quadrangles based upon the potential of the area to contain uranium resources. The Duluth quadrangle was placed in the lowest priority group. The ORGDP sampled the highest priority quadrangles first and had not sampled the Duluth quadrangle by the time that NURE funding ended in the early 1980's. Therefore no NURE HSSR study exists for this quadrangle.
East-Central Minnesota Detailed Survey
The Minnesota Geological Survey, under subcontract to the ORGDP, undertook a detailed geochemical study of parts of Aitkin, Carlton, Kanabec, and Pine Counties in east-central Minnesota. The objective of the study was to study some areas of anomalous radioactivity which had become attractive exploration targets after the recognition of a major unconformity in the Precambrian terrane. The Minnesota Geological Survey collected 883 ground-water and 200 rock samples between April and June of 1979 from parts of the Duluth and Stillwater quadrangles. (Of these samples, 800 ground waters were collected within the Duluth quadrangle.) All samples were analyzed for uranium and additional elements by the Oak Ridge Gaseous Diffusion Plant (ORGDP) and the analytical data were released as the Detailed Geochemical Survey for East-Central Minnesota GJBX-60(80) report.
Summary Tables
The following is a listing of the NURE ground water sample types collected within Duluth quadrangle.
| Sediment Sample Type | Number of Samples | Water Sample Type | Number of Samples |
|---|---|---|---|
| Wells | 800 | ||
| Total Sediments | 0 | Total Waters | 800 |
These Duluth quadrangle samples were analyzed by one or more of the following methods:
Water Samples
The Duluth quadrangle water data consist of reformatted records from the Detailed Geochemical Survey for East-Central Minnesota GJBX-60(80) report. The following problems were found and addressed during the comparison and reformatting stages for these data:
Water Records
The NURE HSSR data are now available online in two databases: The sediment database (also includes data for soils and some rocks) at http://tin.er.usgs.gov/nure/sediment/ and the water database at http://tin.er.usgs.gov/nure/water/. From these two web sites, NURE HSSR data can be selected, examined, summarized, and downloaded by political boundaries (State and County), by quadrangle (1:250,000-scale, 1:100,000-scale, and 1:63,360-scale for Alaska or 1:24,000-scale for the Lower 48 States), and by hydrologic unit (drainage region, subregion, river basin, or sub-basin). Selected data can be downloaded as a dBase file, a shapefile, an HTML table, or ASCII text (tab- or comma-delimited).
Duluth Quadrangle Water Data - 800 records
The water samples were reportedly collected in the field without any filtering but, with the exception of 3 samples, they were acidified. (See the SAMPTYP coding explanation in the On-Line Manual for USGS-Reformatted NURE HSSR Data Files for descriptions of different Sample Types). However, the samples were filtered later in the laboratory through a 0.45 micron membrane filter before analysis. Therefore, the analytical data from these samples may not be directly comparable with other water samples in adjacent quadrangles.
Latitude-longitude coordinates were reported in the original data files, as decimal degrees, to only 3 decimal places. Therefore, the precision of these coordinates is limited to +/- 0.001 degrees or +/- 3.6 seconds. This translates to a minimum precision of +/- 365 feet (111 m) for latitude values and between +/- 259 feet (79 m) to +/- 235 feet (72 m) for longitude values (calculated at latitudes of 45° and 50°N, respectively.)
East-Central Minnesota Detailed Survey
During the East-Central Minnesota Detailed Geochemical Survey 200 rock samples were collected and analyzed. The data for these samples were not included in the digital data file accompanying the published report. These data are available only as tabulated appendices within the Detailed Geochemical Survey for East-Central Minnesota GJBX-60(80) report.
Back to Wisconsin NURE data
Back to Minnesota NURE data
Frequently Asked Questions Concerning NURE HSSR Data
Home Page: USGS National Geochemical Database - NURE HSSR data
Page written by Bryan G. Moravec and Steven M. Smith
Contact: Steven M. Smith (smsmith@usgs.gov)
Version 1.10: July 29, 1999
Version 1.20: August 07, 2000
Version 1.30: September 11, 2001
Version 1.41: February 23, 2006
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