OFR 97-492: McDermitt Quadrangle NURE HSSR Study
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[See History of NURE HSSR Program for a summary of the entire program.]
The responsibility for the McDermitt Quadrangle NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) study was assigned first to the Lawrence Livermore Laboratory (LLL). Prior to 1979, LLL collected at least 1,089 sediment samples from the quadrangle but did not analyze them. When LLL participation in the NURE HSSR program ended in about 1979, the responsibility for the McDermitt quadrangle was assigned to the Savannah River Laboratory (SRL). SRL analyzed these LLL sediment samples for uranium and 16 other elements and the analytical data were released as the GJBX-117(80) report. SRL also assigned each LLL sample a new ID number, but apparently used a prefix of MC (Marble Canyon quadrangle) instead of MT (McDermitt quadrangle).
SRL completed the McDermitt quadrangle HSSR study by collecting an additional 1,340 sediment and 302 water samples in February, June, and July of 1979. These samples were analyzed by SRL for uranium and other elements (16 additional elements in sediments and 9 in waters) and the analytical data were released in the GJBX-173(80) report. The samples collected by SRL were then sent to other laboratories for "supplemental analyses." The supplemental analytical data, with results for 23 elements in sediments and 31 elements in waters, were not released in a separate report.
In 1982, SRL released a summary report and data files for 50 quadrangles in the Western United States. This report, GJBX-132(82), contains both the SRL analytical data and the supplemental analytical data for the SRL samples from the McDermitt quadrangle but the concentration values often differ from those reported in the GJBX-173(80) quadrangle report. The introduction section of the GJBX-132(82) summary report states:
"The data in the present report may not be identical to those reported previously. This is due to the use of different "scrub" procedures for the preparation of the data for release. The differences should be minor."
SRL analyses of light hydrocarbons (methane, ethane, propane, and butane) in ground waters were released in the GJBX-131(82) summary report for 44 western quadrangles and 3 eastern quadrangles within the United States. This report includes data for 218 of the McDermitt quadrangle ground water samples.
Data for gold analyses of sediments by SRL neutron activation were released in the GJBX-135(82) summary report. The introduction of that report states:
"This report contains previously unreported neutron-activation analyses of gold in sediment samples determined at SRL. These data were not included in the standard SRL NURE data reports because the gold spectrum was not measured in the original analytical procedure and the report format was designed without the gold analyses being included. Gold analyses became available as the analytical procedure was refined, but the report format was not modified to incorporate these data."
Only those sediment samples that had detectable concentrations of gold by neutron activation analysis were given in the GJBX-135(82) report. Sediment samples with concentrations below detection limits were not reported and can only be ascertained by identifying which samples were actually analyzed by neutron activation at SRL.
The following is a list of all sample types collected and reported for NURE studies in the McDermitt quadrangle. The actual number of records in the NEW-FORMAT NURE data files may be greater because of the multiple records needed to preserve all the data.
| Sediment Sample Type | Number of Samples | Water Sample Type | Number of Samples |
|---|---|---|---|
| Wet Streams | 1,131 | Streams | 41 |
| Dry Streams | 43 | Wells | 94 |
| Soils | 1,242 | Springs | 164 |
| Talus | 4 | Other | 3 |
| Playa | 1 | ||
| Hot Springs Sinter | 1 | ||
| Other (may include mine tailings) | 7 | ||
| Total Sediments | 2,429 | Total Waters | 302 |
These McDermitt quadrangle samples were analyzed by one or more of the following methods:
Sediment Samples
Water Samples
The data in the NEW-FORMAT NURE data files consist of records from all of the above reports. In order to reduce the number of records, a decision was made to use the data from the GJBX-132(82) western U.S. summary report rather than the GJBX-173(80) McDermitt quadrangle report. The rationale for choosing this data set was that (1) it represents a later compilation of the data and (2) it should be more consistent across quadrangle boundaries because of the common "scrubbing procedure." Every record was checked against the "equivalent" record in the earlier GJBX-173(80) quadrangle report and any major differences were noted in the REFORMAT comment field. These slightly different but unused quadrangle report records were combined and saved as extra files which may be accessed below.
The supplemental water data were missing from the original digital file and were hand entered from the GJBX-132(82) western U.S. summary report. The SRL analyses and supplemental analyses could NOT be combined because of overlapping determinations for 5 elements. Each water sample may therefore have 2 separate records - one for the SRL analysis and one for the supplemental analysis.
The digital sediment file contained the site information and analytical results for U, Al, and Mn for 41 surface water samples. These slightly different results were saved and included in the extra water data file which may be accessed below. Note that since these samples were originally included in the digital sediment file, the site data includes values for 6 fields not usually included in the digital water files. In order to preserve this information, these 6 fields are included in the extra water data file.
Hydrocarbon data from the GJBX-131(82) report were added to fields in the appropriate ground water records and this addition was noted for each record in the REFORMAT comment field.
Gold concentrations from the GJBX-135(82) report were added to the appropriate sediment records. A value of -0.01 (<0.01 ppm Au) was added to all other sediment samples determined to have been analyzed by SRL neutron activation. This value was chosen because 0.01 is the lowest reported gold concentration in the entire report.
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 websites, 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).
McDermitt Quadrangle Sediment Data - 2,429 records
McDermitt Quadrangle Water Data - 606 records
Unused set of quadrangle sediment records - mcdermsx.dbf.gz
Unused set of quadrangle water records - mcdermwx.dbf.gz
Many records contain analytical values with insignificant digits. Most data should only have 2 or 3 significant digits. Differences after the second or third digit should be ignored.
A summary evaluation report was prepared for the McDermitt quadrangle by the Nevada Bureau of Mines and Geology [PGJ/F-045(82)]. Samples of 563 rocks were collected in the quadrangle to aid in the interpretation of uranium anomalies. 552 of the samples were analyzed for uranium by fluorometry, for mercury by atomic absorption, and for 29 other elements by emission spectroscopy. These data were released only as microfiche appendices accompanying the summary report.
Back to Nevada NURE data
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Frequently Asked Questions Concerning NURE HSSR Data
Home Page: USGS National Geochemical Database - NURE HSSR data
Page written by Andrew W. Holt 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 1.40: January 13, 2006
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