OFR 97-492: Richmond 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 610 stream-sediment, 139 surface-water, and 758 ground-water samples were collected within the Richmond 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 599 sediment and 893 water samples from the Richmond 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 83 Virginia sediment samples within the Richmond quadrangle.

Maryland
Subcontractors for the Savannah River Laboratory (SRL) collected at least 1,322 stream-sediment, 837 surface-water, and 1,188 ground-water samples within 23 counties from Maryland as part of the NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program. The sediment samples were collected during May - August 1978, and water samples were collected during May - June 1977; December 1977; and July - October 1978. Sample coverage included portions of the Baltimore, Chincoteague, Cumberland, Salisbury, Washington, and Wilmington 1:250,000-scale quadrangles. (None of these samples were collected within the Richmond quadrangle.) The analytical and site location data for all Maryland samples were released in the Delaware, Maryland, Virginia, and West Virginia Data Report [GJBX-103(82)].

SRL: Richmond and Northern Eastville Quadrangles
SRL released a separate quadrangle report for the Richmond and Northern Eastville (Chincoteague) NTMS quadrangles, which includes data for 673 stream-sediment and 840 ground-water samples (a total of 610 stream-sediment and 746 ground-water samples from Richmond). SRL released the analytical data as the Richmond and Northern Eastville Quadrangle GJBX-18(81) Preliminary Basic Data Report. The site coding information for this data set is summarized within the text of this report. However, these separate quadrangle data for the Richmond and Chincoteague quadrangles were not found in digital format and are not included in the Richmond digital data file presented here. The hard copy of this preliminary data is available in the [GJBX-18(81)] data release. A preliminary comparison of the [GJBX-18(81)] data suggests that, there are some differences between this set of HSSR data and that found for corresponding samples in the Virginia and Maryland State reports. One minor difference is that analytical data values found in the digital state files are slightly different from the hard copy tables. 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.

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 Richmond quadrangle samples.

Combination of laboratories that analyzed samples for the Richmond quadrangle.
Laboratory Analysis Sediments Waters
Only SRL 516 893
Both SRL and Supplemental Labs 83 0
None 11 4
Total Samples 610 897
Total Data Records 610 897

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

Summary of Richmond quadrangle sample types.
Sediment Sample Type Number of Samples Water Sample Type Number of Samples
Wet Streams 610 Streams 139
    Wells 750
    Springs 8
Total Sediments 610 Total Waters 897

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

Sediment Samples

Water Samples



Discussion of the Reformatting Process for Richmond Quadrangle

Sediment Records
The Richmond quadrangle sediment data consist of reformatted 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 Richmond quadrangle sediment data:

  1. 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). The missing codes were assigned a value of "unknown" in the CONTAMC field within the final sediment data file.
  2. 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 Henrico and Mathews Counties, 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.
  3. 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 Richmond quadrangle water data consist of reformatted 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 Washington quadrangle water data:

  1. 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.
  2. 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). The missing codes were assigned a value of "unknown" in the CONTAMC field within the final sediment data file.
  3. 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.
  4. The latitude and longitude coordinates for 3 water samples collected within Louisa County, Virginia were not found in the data during the reformatting process. The records for these 3 samples cannot be retrieved on a geographical basis.


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).

Richmond Quadrangle Sediment Data - 610 records
Richmond Quadrangle Water Data - 894 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 Richmond quadrangle is complete and includes samples from Amelia, Caroline, Charles City, Chesterfield, Dinwiddie, Essex, Gloucester, Goochland, Hanover, Henrico, Isle of Wright, James City, King and Queen, King William, Lancaster, Louisa, Mathews, Middlesex, New Kent, Northumberland, Nottoway, Powhatan, Prince George, Richmond (water only), Surry, Sussex, Westmoreland, and York Counties in Virginia. The laboratory and analytical methods used also may vary by county such that adjacent counties often have very different analytical coverage.

Eleven sediment and four water samples within the Richmond 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 Caroline Sediment 3 22
Virginia Charles City Sediment 1 21
Virginia Chesterfield Water 2 45
Virginia Essex Water 1 35
Virginia Gloucester Sediment 2 25
Virginia Mathews Sediment 2 15
Virginia New Kent Sediment 3 18
Virginia Powhatan Water 1 43



Other NURE Geochemical Data for the Richmond Quadrangle

Uranium Anomalies in East-Central Virginia
A brief follow-up investigation was conducted by the Bendix Field Engineering Corporation to investigate the anomalies found within the Hylas Zone which lies in the eastern Piedmont Province of Virginia near the Richmond Basin. This area is discussed in the GJBX-222(82) report on uranium anomalies. This report contained only a summary of the radiometric surveys, gamma spectrometry, and emission spectroscopy data. No additional geochemical data were found in the report. The results of this investigation suggests that this area may have zones of uranium-enriched source rocks. In addition, this area has a high potential for pegmatite and sandstone type uranium mineralization.

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.




Richmond Quadrangle NURE Bibliography



Links Within Open-File Report 97-492

Back to Virginia NURE data
Back to Maryland 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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