OFR 97-492: Prescott Quadrangle NURE HSSR Study
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[See History of NURE HSSR Program for a summary of the entire program.]
In June of 1977, Lawrence Livermore Laboratory (LLL) conducted an orientation study in the Artillery Peak 15 minute quadrangle (Between latitudes 34.25° to 34.5° north and longitudes 113.5° to 113.75° west) to "characterize an arid area of the Mohave subprovince of the Basin and Range province that contains known uranium occurrences". Totals of 312 dry stream-sediment, 10 wet stream-sediment, 1 wet lake-sediment, and 12 rock samples were collected near identified uranium occurrences. These samples were analyzed for uranium and up to 25 additional elements. The analytical data were reported in the Artillery Peak Orientation Study GJBX-72(79) report. No digital data files could be found but the data exists on hardcopy and as microfiche appendices accompanying this report.
The Lawrence Livermore Laboratory was responsible for the collection and analysis of NURE samples from the Prescott quadrangle. Contractors were hired to collect the reconnaissance samples. The University of Nevada-Desert Research Institute collected a total of 282 water samples (232 reconnaissance samples and 50 site duplicate samples) between December, 1977 and August, 1978. Contract geologists and the Bendix Field Engineering Corporation collected a total of 2,209 sediment samples (1,962 reconnaissance samples, 197 site duplicate samples, and 50 analytical duplicate samples) between August of 1977 and August of 1978. LLL crews resampled 177 sediment sites as part of their quality assurance program during October, November, and December of 1977. (These resampled sites are identified by a cross reference to the corresponding reconnaissance sample number). All samples were analyzed by LLL for uranium and several other elements and the analytical data were released in the LLL Prescott Quadrangle NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) study GJBX-122(79) report.
During June and July of 1979, the Oak Ridge Gaseous Diffusion Plant (ORGDP) ran a detailed geochemical survey of the Date Creek Basin study area in the southwest corner of the Prescott 2° quadrangle. Personnel from Union Carbide Corporation (the operating company for ORGDP) collected 242 stream sediment samples and took 246 scintillometer readings as part of this study. The sediment samples were analyzed by ORGDP for uranium and 34 additional elements and the analytical data were released in the Date Creek Basin Detailed Geochemical Survey GJBX-164(80) report. As a supplement to the Date Creek Basin detailed study, another report (GJBX-243(81)) was prepared which discussed the results of multielement statistical analysis of this stream sediment data.
The following is a list of all sample types (including site and analytical duplicates) collected in the Prescott quadrangle and included in the NEW-FORMAT NURE data files.
| Sediment Sample Type | Number of Samples | Water Sample Type | Number of Samples |
|---|---|---|---|
| Wet Streams | 150 | Streams | 38 |
| Dry Streams | 2,478 | Wells | 120 |
| Dry Streams (Scintillometer only) | 39 | Springs | 144 |
| Bedrock (Scintillometer only) | 8 | ||
| Total Sediments | 2,675 | Total Waters | 282 |
These Prescott quadrangle samples were analyzed by one or more of the following methods:
Sediment Samples
Water Samples
The data in the NEW-FORMAT NURE of records from both the LLL GJBX-122(79) report and the ORGDP GJBX-164(80) report. None of the Artillery Peak Orientation study (GJBX-72(79)) records have been entered at this time. Any problems or changes to records were noted in the REFORMAT comment field.
Unlike data from other laboratories, the original LLL sediment data files do not indicate when elemental concentrations fall below analytical determination limits. Other laboratories usually report these values as "less than the lower analytical determination limit" (represented by a negative number). These data (negative values) were added to the NEW-FORMAT NURE data files based upon the approximate lower limits of detection given in Table 2 of the GJBX-122(79) report.
The original LLL files also contained numerical estimates of the absolute error associated with each elemental concentration. These data were not included in the NEW-FORMAT NURE data files but were placed into additional supplemental data files. The Absolute Error Extra Data Format is explained later in this document.
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).
Prescott Quadrangle Sediment Data - 2,675 records
Prescott Quadrangle Water Data - 282 records
LLL Error Estimates Data for Sediment Analyses - presctsx.dbf.gz
LLL Error Estimates Data for Water Analyses - presctwx.dbf.gz
Note that the sediment samples have been analyzed by two different laboratories and by different analytical techniques. Comparing data between labs may be complicated by different analytical bias inherent in the values reported.
The sediment samples collected by each Laboratory have differing SAMPTYP codes which reflect a difference in sieving. The LLL samples are -18 mesh (1000 microns) and +35 mesh (500 microns); the finer fractions were removed from the sample to avoid windblown contamination. The ORGDP samples were sieved at -100 mesh (150 microns) and this finer fraction was used for all analyses.
The site duplicate water samples were collected differently, with respect to filtering and acidification, than the reconnaissance samples. (See the SAMPTYP coding explanation in the On-Line Manual for New-Format NURE HSSR Data Files for descriptions of different Sample Types). Analytical data may not be directly comparable for water samples collected by different methods.
Users of past versions of the Prescott quadrangle sediment data have had problems with LLL data because the fields were blank when the element concentration fell below the lower analytical determination limits. This absence of the lower end of the data population was responsible for skewing the data in statistical and contouring programs to levels that were higher than expected. As described above, the NEW-NURE FORMAT attempts to solve this problem by replacing those blanks with "less than" values based on reported lower determination limits.
The Bendix Field Engineering Corporation of Grand Junction, Colorado prepared a summary evaluation of the Prescott quadrangle [GJQ-015(82)]. An additional 528 rock samples were collected and analyzed for uranium and up to 30 additional elements. About a quarter of these rock samples were also analyzed for major element oxides. An additional 226 water samples were collected and analyzed for uranium (data also includes pH measurements). The multielement data were released only as microfiche appendices and accompany the summary report.
Data for the Artillery Peak Orientation study, described above, is available only as tables on microfiche which accompany the GJBX-72(79) report.
Explanations are only included here for fields unique to these files. For the explanation of common fields consult the On-Line Manual for New-Format NURE HSSR Data Files. After each field name is a format code. A format code of (N) means that the field is formatted as an Numeric field.
A statistical estimate of measurement uncertainty associated with quantifying the corresponding uranium concentration determined by Delayed-Neutron Counting Analysis. (expressed as a percentage of the uranium concentration found in field U_DN_PPM for sediment data or U_DN_PPB for water data in the NEW-NURE FORMAT data files).
(Where EL represents different element symbols.) A numerical estimate of the uncertainties associated with quantifying the corresponding elemental concentration determined by Neutron Activation Analysis. (expressed in the same concentration units as the element concentration found in the NEW-NURE FORMAT data files).
Back to Arizona NURE data
Frequently Asked Questions Concerning NURE HSSR Data
Home Page: USGS National Geochemical Database - NURE HSSR data
Page written by 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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