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Arkansas
Subcontractors for the Savannah River Laboratory (SRL) collected at least 3,292 stream-sediment, 5,121 ground-water, and 1,711 stream-water samples within 43 counties of central Arkansas as part of the NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program. The sampling effort was completed between May and October of 1978 and included portions of the El Dorado, Fort Smith, Greenwood, Harrison, Helena, Little Rock, McAlester, Memphis, Poplar Bluff, Russellville, Texarkana, and Tulsa 1:250,000-scale quadrangles. (A total of 948 stream-sediment, 707 surface-water, and 1,210 ground-water samples were collected within the Little Rock quadrangle.) These samples were sent to SRL for analysis of uranium and 16 additional elements. SRL was able to analyze only 2,416 Arkansas stream-sediment samples and 6,831 Arkansas water samples; this includes 943 stream-sediment and 1,912 water samples from the Little Rock quadrangle. The analytical and site location data for all Arkansas sediment and water samples were released as separate files in the Arkansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas Data Report [GJBX-104(82)].

SRL: Little Rock and El Dorado Quadrangles and Adjacent Areas of Arkansas

In 1981, SRL released an abbreviated data report for the Little Rock and El Dorado Quadrangles and Adjacent Areas of Arkansas [GJBX-349(81)]. This report includes neutron activation analytical data from SRL. Stream samples (surface-sediment and, if flowing, water samples) were collected at 943 sites in the Little Rock quadrangle, 806 sites in the El Dorado quadrangle, 121 sites in the Helena quadrangle, 292 sites in the Russellville quadrangle, and 77 sites in the Greenwood quadrangle. Ground-water samples were collected at 1,211 sites in the Little Rock quadrangle, 1,369 sites in the El Dorado quadrangle, 186 sites in the Helena quadrangle, 470 sites in the Russellville quadrangle, and 138 sites in the Greenwood quadrangle. Data tables with analyses are included within the microfiche accompanying this report. Data found in this report appear to be the same data as that found in the state digital data files. No digital data files accompany this report.

ORGDP: Ardmore, McAlester, Little Rock, and Helena Quadrangles
SRL sent several Arkansas sediment samples to the Oak Ridge Gaseous Diffusion Plant (ORGDP) for analysis of uranium and 31 additional elements. ORGDP released the analytical data for 639 samples in the Ardmore, McAlester, Little Rock, and Helena Quadrangles GJBX-70(82) Data Report. This report includes data for 72 sediment samples from the Little Rock 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 Little Rock quadrangle samples.

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

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

Sediment Samples

• SR1: Savannah River Neutron Activation Analysis - Neutron Counting of sediments for U.
• SR2: Savannah River Neutron Activation Analysis of sediments for Al, Ce, Dy, Eu, Fe, Hf, La, Lu, Mn, Na, Sc, Sm, Th, Ti, V, and Yb. (Note: Au values were reported later for this method.)
• OR2: Oak Ridge Neutron Activation Analysis of sediments for U.
• OR7: Oak Ridge Emission Spectrochemical Analysis of sediments for Ag, Al, B, Ba, Be, Ca, Ce, Co, Cr, Cu, Fe, Hf, K, La, Li, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Sc, Sr, Th, Ti, V, Y, Zn, and Zr.

Water Samples

• SR4: Savannah River Neutron Activation Analysis - Neutron Counting of waters for U.
• SR5: Savannah River Neutron Activation Analysis of waters for Al, Br, Cl, Dy, F, Mn, Na, and V. (Note: Mg may also be reported by this method.)

Discussion of the Reformatting Process for Little Rock Quadrangle

Sediment Records
The Little Rock quadrangle sediment data consist of records from the Arkansas portion of the Arkansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas GJBX-104(82) Data Report combined with records from the ORGDP Ardmore, McAlester, Little Rock, and Helena Quadrangles GJBX-70(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 Little Rock quadrangle sediment data:

1. The SRL and the ORGDP Laboratory each analyzed the same 72 stream-sediment samples from Arkansas. 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 files for the Ardmore, McAlester, Little Rock, and Helena 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. The missing site descriptive data and the complete longitude value were added to ORGDP records from the corresponding SRL State file records. Sources of data and any problems found are described in the REFORMAT comment field.
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 Clark, Garland, Lonoke, Perry, Pulaski, Saline, and Yell Counties, Arkansas 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. After re-digitizing, three stream-sediment samples from Clark County, Arkansas originally located in the El Dorado quadrangle now plot in the adjacent Little Rock quadrangle.
5. After re-digitizing, one stream-sediment sample from Perry County, Arkansas originally located in the Little Rock quadrangle now plots in the adjacent Russellville quadrangle.
6. After re-digitizing, one stream-sediment sample from Perry County, Arkansas and one stream-sediment sample from Yell County, Arkansas originally located in the Russellville quadrangle now plot in the adjacent Little Rock quadrangle.
7. 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 Little Rock quadrangle water data consist of reformatted records from the Arkansas portion of the Arkansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas GJBX-104(82) Data Report. The following problems were found and addressed during the comparison and reformatting stages for the Little Rock 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. An analysis of latitude-longitude site coordinates identified several stream-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 Clark, Garland, Lonoke, Perry, Pulaski, Saline, and Yell Counties, Arkansas 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. After re-digitizing, three stream-water samples from Clark County, Arkansas originally located in the El Dorado quadrangle now plot in the adjacent Little Rock quadrangle.
4. After re-digitizing, one stream-water sample from Perry County, Arkansas originally located in the Russellville quadrangle now plots in the adjacent Little Rock quadrangle.
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 Faulkner, Garland, Jefferson, Lonoke, Pike, and Yell Counties, Arkansas 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.
6. After re-digitizing, two well-water samples from Lonoke County, Arkansas originally located in the El Little Rock quadrangle now plot in the adjacent Russellville quadrangle.
7. The latitude and longitude coordinates for one ground-water sample collected within Yell County, Arkansas were not found in the data or on field maps during the reformatting process. The records for this sample 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).

Little Rock Quadrangle Sediment Data - 1,020 records
Little Rock Quadrangle Water Data - 1,916 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. All counties within the Little Rock quadrangle (Clark, Cleveland, Dallas, Faulkner, Garland, Grant, Hot Spring, Howard, Jefferson, Lonoke, Perry, Polk, Pulaski, Saline, Scott, and Yell Counties) were sampled. The laboratory and analytical methods used also may vary by county such that adjacent counties often have very different analytical coverages.

Five sediment and five water samples within the Little Rock quadrangle were not analyzed by any of the various laboratories. The following table summarizes the locations of those unanalyzed samples.

Other NURE Geochemical Data for the Little Rock Quadrangle

Igneous Rocks of Arkansas
SRL conducted a study of potential uranium source rocks within parts of the Little Rock and Russellville quadrangles of Arkansas [GJBX-129(82)]. A total of 76 igneous rock samples were collected from small outcrops (dikes and sills) and from major alkalic intrusions at Granite Mountain, Bauxite, Magnet Cove, Potash Sulphur Springs, and Murfreesboro, Arkansas. These rocks were of interest because of their potential to be source rocks for uranium deposits and their possible relationships to volcanic tuffs associated with black shales in the area. All sampled rocks are considered to be Cretaceous in age. SRL analyzed the rock samples by neutron activation for uranium, and Th, Na, Al, Sc, Ti, V, Mn, Fe, La, Ce, Sm, Eu, Dy, Yb, Lu, and Hf. The analytical data can only be found in tables within the report.

Central Arkansas Orientation Study
SRL conducted an orientation study in the Ouachita Mountain and Gulf Coastal Plain regions of central Arkansas with Little Rock quadrangle (GJBX-214(82)). Analyses for 335 stream-sediment and 335 water samples collected in Garland, Grant, Hot Spring, and Saline Counties are given in tables within the report. The water samples were analyzed by neutron activation analysis for U, Br, Cl, F, Mn, Na, Al, and Dy. In addition, the ground-water samples were analyzed for He. Sediment samples were analyzed by neutron activation analysis for U, Th, Hf, Ce, Fe, Mn, Sc, Ti, V, Al, Dy, Eu, La, Sm, Yb, and Lu. The results of this study suggest that black shales, tuffs, and intrusive rocks, and sediments of the Gulf Coastal Plain provide an environment that could be favorable to the formation of uranium deposits.

Ouachita Mountains Orientation Studies
A hydrogeochemical ground-water orientation study was conducted in the area of the Ouachita Mountains, Arkansas in order to evaluate the usefulness of ground water as a sampling medium for uranium exploration in similar areas (GJBX-208(82)). A total of 93 springs and 9 wells were sampled in Clark, Garland, Hot Springs, Howard, Montgomery, Pike, Polk, and Sevier Counties of Arkansas within the El Dorado, Little Rock, and McAlester 1:250,000-scale quadrangles. Manganese, barite, celestite, cinnabar, stibnite, and sulfides of copper, lead, and zinc are present in the study area. Analyses and measurements were included in the text for the following: pH, conductivity, alkalinity, nitrate, ammonia, sulfates, phosphates, uranium, and 9 additional elements. Results of this study show that the minerals significantly affect the chemistry of the ground water. Data tables of analyses were included only in the text.

Within the Ouachita Mountains or Arkansas ground-water samples were collected periodically to establish whether or not ground-water chemistry is effected by seasonal changes (GJBX-199(82)). Samples from 13 ground-water sites (10 springs and 3 wells) were collected nine times during a 16-month period. "Daily" sampling of 6 sites was carried out over an 11-day period, with rain during this period. And finally, 1 site was sampled hourly over a 7-hour period. These samples were analyzed for pH, conductivity, temperature, total alkalinity, nitrate, ammonia, sulfate, phosphate, chloride, U, plus 21 other elements. The results of this study show that even though the dry season is during the late summer, and the wet season is during the late spring and late fall, there was no significant change in the ground water chemistry with season. Likewise, there was no significant change due to rain storm events ("daily" sampling) or hourly sampling. Samples were collected in Clark, Garland, Montgomery, Polk, and Pike Counties of Arkansas within the Little Rock and McAlester 1:250,000-scale quadrangles. Data tables of analyses were included in the text.

Little Rock Quadrangle NURE Bibliography

• Fay, W.M., and Cook, J.R., 1982, Gold analyses by neutron activation from SRL NURE samples: E.I. du Pont de Nemours & Co., Savannah River Laboratory, Aiken, S.C., SRL Internal Doc. DPST-81-141-38, U.S. Department of Energy, Grand Junction, Colo., GJBX-135(82), 45 p.
• Fay, W.M., Sargent, K.A., and Cook, J.R., 1982, Data Report: Arkansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas: E.I. du Pont de Nemours & Co., Savannah River Laboratory, Aiken, S.C., SRL Internal Doc. DPST-81-146-24, U.S. Department of Energy, Grand Junction, Colo., GJBX-104(82), 37 p.
• Steele, K.F., 1982, Orientation study, Ouachita Mountain area, Arkansas: E.I. du Pont de Nemours & Co., Savannah River Laboratory, Aiken, S.C., SRL Internal Doc. DPST-81-141-26, U.S. Department of Energy, Grand Junction, Colo., GJBX-208(82), 38 p.
• Steele, K.F., 1982, Orientation study of central Arkansas: E.I. du Pont de Nemours & Co., Savannah River Laboratory, Aiken, S.C., SRL Internal Doc. DPST-81-141-40, U.S. Department of Energy, Grand Junction, Colo., GJBX-214(82), 129 p.
• Steele, K.F., 1982, Uranium and other element analyses of igneous rocks of Arkansas: E.I. du Pont de Nemours & Co., Savannah River Laboratory, Aiken, S.C., SRL Internal Doc. DPST-81-141-17, U.S. Department of Energy, Grand Junction, Colo., GJBX-129(82), 15 p.
• Steele, K.F., and Cook, J.R., 1981, Little Rock and El Dorado 1° x 2° NTMS quadrangles and adjacent areas, Arkansas, data report (abbreviated): E.I. du Pont de Nemours & Co., Savannah River Laboratory, Aiken, S.C., SRL Internal Doc. DPST-81-146-17, U.S. Department of Energy, Grand Junction, Colo., GJBX-349(81), 20 p.
• Steele, K.F., Fay, W.M., and Cavendor, P.N., 1982, Seasonal effect on ground water chemistry of the Ouachita Mountains: E.I. du Pont de Nemours & Co., Savannah River Laboratory, Aiken, S.C., SRL Internal Doc. DPST-81-141-27, U.S. Department of Energy, Grand Junction, Colo., GJBX-199(82), 63 p.
• Uranium Resource Evaluation Project, 1982, Hydrogeochemical and stream sediment reconnaissance basic data for Ardmore, McAlester, Little Rock, and Helena quadrangles, Oklahoma; Arkansas; Mississippi: Union Carbide Corporation, Nuclear Division, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Tenn., K/UR-425, U.S. Department of Energy, Grand Junction, Colo., GJBX-70(82), 61 p.
• Uranium Resource Evaluation Project, 1982, Supplement to hydrogeochemical and stream sediment reconnaissance basic data reports K/UR-405 and K/UR-408 through K/UR-443 [GJBX-52(82) through GJBX-88(82)]: Union Carbide Corporation, Nuclear Division, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Tenn., K/UR-412, U.S. Department of Energy, Grand Junction, Colo., GJBX-51(82), 25 p.

Links Within Open-File Report 97-492

Back to Arkansas NURE data
Frequently Asked Questions Concerning NURE HSSR 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 1.20: August 07, 2000
Version 1.30: September 11, 2001
Version 1.41: February 23, 2006

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