OFR 97-492: Roanoke Quadrangle NURE HSSR Study

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National Geochemical Database—Reformatted Data from the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) Program

By Steven M. Smith
Version 1.40 (2006)

Brief History and Description of Data

[See History of NURE HSSR Program for a summary of the entire program.]

Virginia
Subcontractors for the Savannah River Laboratory (SRL) collected at least 5,667 stream-sediment, 2,598 surface-water, and 4,834 ground-water samples within 96 counties from Virginia as part of the NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program. The sediment samples were collected during July - October 1976; August - September 1977; and April - November 1978, and water samples were collected during December 1976 - September 1977; April - October 1978; and June - August 1979. Sample coverage included portions of the Baltimore, Bluefield, Charlottesville, Chincoteague, Cumberland, Currituck Sound, Greensboro, Jenkins, Johnson City, Norfolk, Richmond, Roanoke, Salisbury, Washington, and Winston-Salem 1:250,000-scale quadrangles. (A total of 1,234 stream-sediment, 1,044 surface-water, and 775 ground-water samples were collected within the Roanoke quadrangle.) These samples were sent to SRL for analysis of uranium and additional elements (16 in sediments and 9 in waters). SRL was able to analyze 5,522 sediments and 7,416 waters from Virginia; this includes 1,234 sediment and 1,815 water samples from the Roanoke quadrangle. The analytical and site location data for all Virginia samples were released in the Delaware, Maryland, Virginia, and West Virginia Data Report [GJBX-103(82)].

SRL sent 2,719 sediment samples from Virginia to an unnamed contract laboratory for "Supplemental Analyses." Supplemental analytical determinations for up to 23 elements were reported for 2,711 of these samples in the Delaware, Maryland, Virginia, and West Virginia Data Report [GJBX-103(82)]. The digital data file accompanying this report includes Supplemental Analyses for 963 Virginia sediment samples within the Roanoke quadrangle.

SRL: Roanoke Quadrangle
SRL released a separate quadrangle report for the Roanoke NTMS quadrangle, which includes data for 1,235 stream-sediment, 1,044 surface-water, and 766 ground-water samples. With minor differences, these sample data are the same as the that for corresponding samples found in the Virginia State report. SRL released the analytical data as the Roanoke Quadrangle GJBX-73(81) Abbreviated Data Report. The site coding information for this data set is summarized within the text of this report.

Gold Analyses
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.

Summary Tables
Because of the various laboratories and analytical methods used, some SRL samples may have been analyzed once, twice, or not at all. The following table summarizes the analysis of Roanoke quadrangle samples.

Combination of laboratories that analyzed samples for the Roanoke quadrangle.
Laboratory Analysis Sediments Waters
Only SRL 270 1,815
Both SRL and Supplemental Labs 964 0
Second SRL analysis on sample 1 0
None 0 4
Total Samples 1,234 1,819
Total Data Records 1,235 1,819

The following is a list of all sediment and water sample types collected and reported for NURE studies in the Roanoke quadrangle.

Summary of Roanoke quadrangle sample types.
Sediment Sample Type Number of Samples Water Sample Type Number of Samples
Wet Streams 1,234 Streams 1,044
    Wells 617
    Springs 158
Total Sediments 1,234 Total Waters 1,819

These Roanoke quadrangle samples were analyzed by one or more of the following methods:

Sediment Samples

Water Samples



Discussion of the Reformatting Process for Roanoke Quadrangle

Sediment Records
The Roanoke quadrangle sediment data consist of reformatted records from the Roanoke Quadrangle GJBX-73(82) Data Report. These records were compared with corresponding sample records from the the Virginia portion of the Delaware, Maryland, Virginia, and West Virginia [GJBX-103(82)] Data Report. The following problems were found and addressed during the comparison and reformatting stages for the Roanoke quadrangle sediment data:

  1. The analytical values for many Ce, Eu, Fe, La, and Lu determinations differed slightly between the Roanoke quadrangle files and the Virginia State files. These variations are apparently due only to differences in rounding versus truncation of reported values or to differences in the number of recorded significant digits. Since the variation was insignificant, only one set of the values was retained for the affected elements.
  2. For some records, analytical values for Al, Ce, Dy, Eu, Fe, Hf, La, Lu, Mn, Sc, Sm, Th, Ti, V, and Yb were found in the Roanoke quadrangle files but were missing in the corresponding records from the Virginia State files. These missing values were noted for each affected record in the REFORMAT comment field.
  3. The water temperature, sample collection date, and date on which a sample was analyzed by Neutron Activation Analysis was only recorded in the State digital data files from the Virginia [GJBX-103(82)] Data Report. This information was added to each of combined sediment data records.
  4. During reformatting, contamination codes for "residential" and "recreation" were found to be missing from each State's CONTAMC field. The presence of one of these two codes was indicated only by a "." (period). These contamination codes were also not present in the original quadrangle file. The missing codes were assigned a value of "unknown" in the CONTAMC field within the final water data file.
  5. One stream-sediment sample was collected at a latitude of exactly 37°N, the dividing line between the Roanoke quadrangle and the Greensboro quadrangle. The two data records for this sample were assigned to the Roanoke quadrangle.
  6. A second stream-sediment sample was also collected at a latitude of exactly 37°N, the dividing line between the Roanoke quadrangle and the Greensboro quadrangle. The two data records for this sample were assigned to the Greensboro quadrangle.
  7. An unlikely sample collection date was found for one sample. This date was removed from the SAMPDAT field and the original SAMPDAT value with the most likely correct value was added as a comment to the REFORMAT field.
  8. 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.

Water Records
The Roanoke quadrangle water data consist of reformatted records from the Roanoke Quadrangle GJBX-73(82) Data Report. These records were compared with corresponding sample records from the the Virginia portion of the Delaware, Maryland, Virginia, and West Virginia [GJBX-103(82)] Data Report. The following problems were found and addressed during the comparison and reformatting stages for the Roanoke quadrangle sediment data:

  1. For several records, analytical values for Cl, Mg, and Na were found in the Virginia State files but were missing in the corresponding records from the Roanoke quadrangle files. These values were added and that change was noted for each affected record in the REFORMAT comment field.
  2. The sample collection date was only recorded in the State digital data files from the Virginia [GJBX-103(82)] Data Report. This information was added to each of combined water data records.
  3. One well-water sample was collected at a longitude of exactly 80°W, the dividing line between the Roanoke quadrangle and the Bluefield quadrangle and reported in the Virginia State files. The record was assigned to the Bluefield quadrangle.
  4. The original NURE format for surface-water files did not include much information about the character of the sample location. This missing information includes observations taken at each site on the stream width, depth, and flow, water color, surrounding vegetation, local relief, weather, and possible contaminants. This information is given in records for stream-sediment samples that were collected at the same locations. The available site descriptive information for stream-water sites were compared with the corresponding stream-sediment site records. The missing site descriptive data were then added to stream-water records from the corresponding stream-sediment sample records. Sources of data and any problems found are described in the REFORMAT comment field.
  5. During reformatting, contamination codes for "residential" and "recreation" were found to be missing from each State's CONTAMC field. The presence of one of these two codes was indicated only by a "." (period). These contamination codes were also not present in the original quadrangle file. The missing codes were assigned a value of "unknown" in the CONTAMC field within the final water data file.
  6. Unlikely sample collection dates were found for three samples. These dates were removed from the SAMPDAT field. For each record, the original SAMPDAT value and the most likely correct value was added as a comment to the REFORMAT field.
  7. Nine ground-water samples were identified with a SRLID in the 700's. All of these samples were missing latitude and longitude coordinates. Evidence from original sample site field notes strongly suggests that these are duplicate samples collected later from a previously sampled 500's series site (i.e. SRLID site number ABCD718R is the same location as ABCD518R). The coordinates from the original 500's series sites were added to the matching 700's records and this change was noted in the REFORMAT and COORDPRB comment fields.


Download The Data

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).

Roanoke Quadrangle Sediment Data - 1,235 records
Roanoke Quadrangle Water Data - 1,819 records



Notes for Data Users

In the eastern United States, SRL collected samples primarily by county. Often, not all counties within a quadrangle were completely sampled. Sample coverage in the Roanoke quadrangle is complete and includes samples from Albemarle, Alleghany, Amelia, Amherst, Appomattox, Augusta, Bath, Bedford, Botetourt, Buckingham, Campbell, Charlotte, Craig, Cumberland, Fluvanna, Franklin, Goochland, Halifax, Louisa, Lunenburg, Nelson, Nottoway, Pittsylvania, Powhatan, Prince Edward, Roanoke, and Rockbridge Counties in Virginia. The laboratory and analytical methods used also may vary by county such that adjacent counties often have very different analytical coverage.

Four water samples within the Roanoke quadrangle were not analyzed by any of the various laboratories. The following table summarizes the locations of those unanalyzed samples.

General locations of unanalyzed samples.
State County Sample Media Unanalyzed Samples Total Samples
Virginia Albemarle Water 1 71
Virginia Appomattix Water 1 90
Virginia Franklin Water 2 24



Other NURE Geochemical Data for the Roanoke Quadrangle

Dan River - Danville Triassic Basin Detailed Study
A surface geochemical reconnaissance survey was conducted by SRL in the Dan River - Danville Triassic Basin of north-central North Carolina and south central Virginia [GJBX-204(82)]. In 1979, SRL collected rock samples from 380 sites from the Winston-Salem, Greensboro, and Roanoke NTMS quadrangles. Sedimentary rock samples were analyzed for uranium by Neutron Activation and for Al, Ce, Dy, Eu, Fe, Hf, La, Lu, Mn, Na, Sc, Sm, Th, Ti, V, and Yb by an unspecified method. In addition, a detailed four-channel spectrometric survey was conducted over the Dan River-Danville Triassic Basin and the adjacent Piedmont. Data tables of analytical results are included within the report. No digital data files were available for reformatting.

Characteristics of the Southeastern Piedmont
Bendix Field Engineering Corporation released a report that contains stream-sediment, hydrogeochemical, and aeromagnetic data for 16 contiguous NTMS quadrangles in the eastern United States [GJBX-40(83)]. This compilation report is limited in scope to features that have specific interest to the geoscience community. Included in the report are aeromagnetic and geochemical maps, and tectonic and igneous rock distribution maps. When used together, these maps show geochemical, tectonic, and magnetic features unique to many of the geologic and physiographic provinces in the region. This report primarily covers the Southeastern Piedmont region and includes the Athens, Augusta, Bluefield, Charlotte, Florence, Georgetown, Greensboro, Greenville, Knoxville, Norfolk, Raleigh, Richmond, Roanoke, Rocky Mount, Spartanburg and Winston-Salem 1:250,000-scale quadrangles. The color maps are in 35mm-slide format. No digital data files accompany this report.

North America and Africa Plutonic Rocks Special Study
The SRL in contract with the Department of Geology of the University of North Carolina conducted a special study to investigate the association of uranium deposits with granitic source or host rocks. The analytical results from 441 samples of 92 plutons were released in the North America and Africa Plutonic Rocks Special Study GJBX-221(82) report. See the North America and Africa Plutonic Rocks Special Study for the data and a more detailed description of this study. Plutons that were apparently sampled in the Roanoke quadrangle include the Hatcher (3 samples).



Roanoke Quadrangle NURE Bibliography



Links Within Open-File Report 97-492

Back to Virginia NURE data
Frequently Asked Questions Concerning NURE 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 1.41: February 23, 2006

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