OFR 97-492: Shreveport 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.]

Subcontractors for the Savannah River Laboratory (SRL) collected at least 1,017 stream-sediment samples within 15 parishes of central Louisiana as part of the NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program. The sampling effort was completed between August and October of 1978 and included portions of the Alexandria, Baton Rouge, Jackson, Lake Charles, Natchez, Palestine, Shreveport, and Tyler 1:250,000-scale quadrangles. (A total of 165 stream-sediment samples were collected within the Shreveport quadrangle.) These sediment samples were sent to SRL for analysis of uranium and 16 additional elements. SRL was able to analyze only 28 Louisiana stream sediment samples; this includes 5 samples from the Shreveport quadrangle. The analytical and site location data for all Louisiana sediment samples were released as a separate file in the Arkansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas Data Report [GJBX-104(82)].

SRL: Shreveport Quadrangle
SRL did not release a separate report for the Shreveport quadrangle.

ORGDP: Jackson, Shreveport, and Tyler Quadrangles
SRL sent several Louisiana sediment samples to the Oak Ridge Gaseous Diffusion Plant (ORGDP) for analysis of uranium and 31 additional elements. ORGDP released the analytical data for 209 samples in the Jackson, Shreveport, and Tyler Quadrangles GJBX-68(82) Data Report. This report includes data for 160 sediment samples from the Shreveport quadrangle. The site coding information for this data set was summarized in the GJBX-51(82) 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 Shreveport quadrangle samples.

Combination of laboratories that analyzed samples for the Shreveport quadrangle.
Laboratory Analysis Sediments Waters
Only SRL 0 0
Only ORGDP 155 0
Both SRL and ORGDP (2 records needed) 5 0
None 5 0
Total Samples 165 0
Total Data Records 170 0

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

Summary of Shreveport quadrangle sample types.
Sediment Sample Type Number of Samples Water Sample Type Number of Samples
Wet Streams 165    
Total Sediments 165 Total Waters 0

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

Sediment Samples

Water Samples

Discussion of the Reformatting Process for Shreveport Quadrangle

Sediment Records
The Shreveport quadrangle sediment data consist of records from the Louisiana portion of the Arkansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas GJBX-104(82) Data Report combined with records from the ORGDP Jackson, Shreveport, and Tyler Quadrangles GJBX-68(82) Data Report. When combining sample records, site descriptive information and coordinates were compared for all corresponding records. The following problems were found and addressed during the comparison and reformatting stages for the Shreveport quadrangle sediment data:

  1. The SRL and the ORGDP Laboratory each analyzed the same 5 stream-sediment samples from Louisiana. Because of overlapping data fields, it was necessary to create two data records for each sample to preserve all the data.
  2. The original ORGDP file for the Jackson, Shreveport, and Tyler quadrangles did not include all of the 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. In addition, the longitude coordinate reported in the ORGDP file only had 3 decimal places instead of the 4 decimal places found in the corresponding records from SRL State files. When combining corresponding SRL and ORGDP records, all of the site descriptive data and the longitude values to 4 decimal places from the SRL data files were preserved in the final database.
  3. 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 De Soto Parish, Louisiana 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.
  4. 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.

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).

Shreveport Quadrangle Sediment Data - 170 records

Notes for Data Users

In the eastern United States, SRL collected samples primarily by county or parish. Often, not all counties or parishes within a quadrangle were completely sampled. Sample coverage in the Shreveport quadrangle is limited to the Caldwell, De Soto, Natchitoches, Red River, and Winn Parishes. These parishes are found only along the southernmost border of the Shreveport quadrangle. The laboratory and analytical methods used also may vary by county or parish such that adjacent counties or parishes often have very different analytical coverages.

Five sediment samples within the Shreveport 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 or Parish Sample Media Unanalyzed Samples Total Samples
Louisiana Red River Sediment 4 28
Louisiana Winn Sediment 1 38

Other NURE Geochemical Data for the Shreveport Quadrangle

None found.

Shreveport Quadrangle NURE Bibliography

Links Within Open-File Report 97-492

Back to Louisiana NURE data
Back to Texas 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 1.20: August 07, 2000
Version 1.30: September 11, 2001
Version 1.41: February 23, 2006

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