OFR 97-492: Greensboro 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.]

North Carolina
Subcontractors for the Savannah River Laboratory (SRL) collected at least 6,666 stream-sediment, 295 surface-water, and 5,778 ground-water samples within 100 counties from North Carolina as part of the NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program. The sediment samples were collected during June - December 1976; July - August 1977; and April - May 1978, and water samples were collected during December 1976 - August 1977 and June - July 1978. Sample coverage included portions of the Beaufort, Charlotte, Chattanooga, Currituck Sound, Florence, Georgetown, Greensboro, Greenville, Johnson City, Knoxville, Manteo, Norfolk, Raleigh, Rocky Mount, Rome, Spartanburg, and Winston-Salem 1:250,000-scale quadrangles. (A total of 718 stream-sediment and 427 ground-water samples were collected within the Greensboro 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 6,597 sediments and 6,040 waters from North Carolina; this includes 718 sediment and 426 water samples from the Greensboro quadrangle. The analytical and site location data for all North Carolina samples were released in the North and South Carolina Data Report [GJBX-102(82)].

SRL sent 4,677 sediment samples from North Carolina to an unnamed contract laboratory for "Supplemental Analyses." Supplemental analytical determinations for up to 23 elements were reported for 4,660 of these samples in the North and South Carolina Data Report [GJBX-102(82)]. The digital data file accompanying this report includes Supplemental Analyses for 718 North Carolina sediment samples within the Greensboro quadrangle.

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 590 stream-sediment and 350 ground-water samples were collected within the Greensboro 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 586 sediment and 350 water samples from the Greensboro 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 544 Virginia sediment samples within the Greensboro quadrangle.

SRL: Greensboro Quadrangle
SRL released a separate quadrangle report for the Greensboro NTMS quadrangle, which includes data for 1,240 stream-sediment and 774 ground-water samples. With differences, these sample data correspond with samples found in the North and South Carolina State reports. SRL released the analytical data as the Greensboro Quadrangle GJBX-74(78) Preliminary Basic 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 Greensboro quadrangle samples.

Combination of laboratories that analyzed samples for the Greensboro quadrangle.
Laboratory Analysis Sediments Waters
Only SRL 46 776
Only Supplemental Lab 7 0
Both SRL and Supplemental Labs 1,255 0
Second SRL analysis on sample 1,233 0
None 0 1
Total Samples 1,308 777
Total Data Records 2,541 777

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

Summary of Greensboro quadrangle sample types.
Sediment Sample Type Number of Samples Water Sample Type Number of Samples
Wet Streams 1,308 Wells 744
    Springs 33
Total Sediments 1,308 Total Waters 777

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

Sediment Samples

Water Samples



Discussion of the Reformatting Process for Greensboro Quadrangle

Sediment Records
The Greensboro quadrangle sediment data consist of reformatted records from the North Carolina portion of the North and South Carolina [GJBX-102(82)] Data Report and sample records from the Virginia portion of the Delaware, Maryland, Virginia, and West Virginia [GJBX-103(82)] Data Report. These records were compared with corresponding sample records from the Greensboro Quadrangle GJBX-74(78) Data Report. The following problems were found and addressed during the comparison and reformatting stages for the Greensboro quadrangle sediment data:

  1. For 1,233 records, Greensboro quadrangle Neutron Activation Analysis values were significantly different from that found in the corresponding records from the North Carolina and Virginia State files. For all of these affected records, the differences between Greensboro quadrangle files and North Carolina and Virginia State files required the creation of two separate records for each sample to preserve all the data.
  2. The date on which a sample was analyzed by Neutron Activation Analysis was only recorded in the State digital data files from the North Carolina [GJBX-102(82)] Data Report and from the Virginia [GJBX-103(82)] Data Report. This information was added to each of combined sediment data records.
  3. 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). Most, but not all of these contamination codes were present in the original quadrangle file. When possible, the missing contamination codes were replaced, otherwise the missing codes were assigned a value of "unknown" in the CONTAMC field within the final sediment data file.
  4. 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.
  5. 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.
  6. An analysis of latitude-longitude site coordinates identified several stream-sediment samples that were missing coordinates, did not plot within expected state, county, or map boundaries, or had differing coordinates in corresponding records. To correct or confirm sample coordinates, the original field collection maps for Caswell and Durham Counties, North Carolina were obtained and re-digitized. The newly re-digitized coordinates were added to the database and the coordinates from the original file(s) were recorded in the COORDPRB comment field. When the newly re-digitized coordinates were not significantly different, that confirmation of the site location was also noted in the COORDPRB comment field.
  7. Seven stream-sediment samples were identified with a SRLID in the 300'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 000's series site (i.e. SRLID site number ABCD318S1 is the same location as ABCD018S1). The coordinates from the original 000's series sites were added to the matching 300's records and this change was noted in the REFORMAT and COORDPRB comment fields.
  8. Three samples are represented only by incomplete data records from the State supplemental analysis files. All three of the samples have an SRLID value in the 300's series but none of the original field sheets for these samples have been found. It is suspected that the SRLID value is incorrect for each of these samples. Since these 3 records do not contain latitude and longitude coordinates, they cannot be retrieved on a geographical basis.
  9. The latitude and longitude coordinates for one stream-sediment sample collected within Vance County in North Carolina were not found in the data during the reformatting process. The record for this sample cannot be retrieved on a geographical basis.
  10. 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 Greensboro quadrangle water data consist of reformatted records from the Greensboro Quadrangle GJBX-74(78) Data Report. These records were compared with corresponding sample records from the the North Carolina portion of the North and South Carolina [GJBX-102(82)] Data Report and sample records from 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 Greensboro quadrangle water data:

  1. The analytical values for many U, Al, Br, Dy, and Mn determinations differed slightly between the Greensboro quadrangle files and the North Carolina and 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 6 records, analytical values for Mn were found in the Greensboro quadrangle file but were missing in the corresponding records from the North Carolina and Virginia State files. These missing values were noted for each affected record in the REFORMAT comment field.
  3. For many records, analytical values for U, Al, Br, Cl, Dy, F, Mg, Mn, Na, and V were found in the North Carolina and Virginia State files but were missing in the corresponding records from the Greensboro quadrangle files. These values were added and that change was noted for each affected record in the REFORMAT comment field.
  4. Three 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.
  5. An analysis of latitude-longitude site coordinates identified several ground-water samples that were missing coordinates, did not plot within expected state, county, or map boundaries, or had differing coordinates in corresponding records. To correct or confirm sample coordinates, the original field collection maps for Guilford and Wake Counties, North Carolina; and Brunswick County, Virginia were obtained and re-digitized. The newly re-digitized coordinates were added to the database and the coordinates from the original file(s) were recorded in the COORDPRB comment field. When the newly re-digitized coordinates were not significantly different, that confirmation of the site location was also noted in the COORDPRB comment field.


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).

Greensboro Quadrangle Sediment Data - 2,537 records
Greensboro Quadrangle Water Data - 777 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 Greensboro quadrangle is complete and includes samples from Alamance, Caswell, Durham, Franklin, Granville, Guilford, Halifax, Nash, Orange, Person, Rockingham, Vance, Wake, and Warren Counties in North Carolina; and Brunswick, Charlotte, Franklin, Halifax, Henry, Lunenburg, Mecklenburg, and Pittsylvania Counties in Virginia. The laboratory and analytical methods used also may vary by county such that adjacent counties often have very different analytical coverage.

One well sample within the Greensboro quadrangle (Nash County, North Carolina) was not analyzed by any of the various laboratories.



Other NURE Geochemical Data for the Greensboro Quadrangle

Durham Triassic Basin Detailed Study
A surface geochemical reconnaissance survey was conducted by SRL in the Northern part of the Durham Triassic Basin and adjacent Piedmont, in the Greensboro NTMS quadrangle, North Carolina [GJBX-402(81)]. SRL subcontractors collected gamma-ray spectrometric measurements at 112 localities representing 136 different lithologies within the study area. Data tables of analytical results are included within the report. No digital data files were available for reformatting.

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.

Geochemical Anomaly Evaluation Study
As part of the development program to support the interpretation of collected HSSR data, SRL conducted several "anomaly verification" field studies in areas that contain a geochemical anomaly found in reconnaissance data [GJBX-417(81)]. In the Greensboro NTMS quadrangle, a subcontractor for SRL conducted a field scintillometer survey and compiled geologic maps to verify geochemical anomalies found during HSSR data collection and to aid in geochemical interpretation. A total of 229 measurements were collected by a GR-410 four-channel gamma-ray spectrometer within the quadrangle. Data tables of analytical results are included within the report. No digital data files were available for reformatting.

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 Greensboro quadrangle include the Castalia (4 samples).

Greensboro Quadrangle NURE Summary
Bendix Field Engineering Corporation produced a uranium exploration summary for the Greensboro quadrangle (PGJ/F-063(82)) in 1982. As part of this process, a total of 473 rock, saprolite, and soil samples were collected and analyzed for uranium by fluorometry. The rock, saprolite, and soil samples were also analyzed for an additional 30 elements by an unspecified analytical method. The results of this investigation suggest environments favorable for allogenic uranium deposits in metamorphic rocks adjacent to the intrusive margins of the Rolesville, Castalia, Redoak, and Shelton Plutons, and sandstone-type deposits in the sediments of the Durham and Dan River Triassic basin systems. 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.



Greensboro Quadrangle NURE Bibliography



Links Within Open-File Report 97-492

Back to North Carolina NURE data
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 1.30: September 11, 2001
Version 1.41: February 23, 2006

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