OFR 97-492: Laredo Quadrangle NURE HSSR Study
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[See History of NURE HSSR Program for a summary of the entire program.]
ORGDP: Texas Wide-Spaced Uranium Geochemical Survey
Early in the NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program, personnel from the Oak Ridge Gaseous Diffusion Plant (ORGDP) sampled several areas with a wide-spaced sample coverage (Phase I sampling). Phase I samples were generally collected in stream basins averaging 250 square kilometers in area and from wells at about a 16 km spacing. The purpose of the Phase I sampling was to define uranium provinces that warranted additional sampling at a higher density (Phase II sampling). These samples were sent to the ORGDP and analyzed for uranium and other elements. For many 1:250,000-scale 2-degree quadrangles, Phase I samples were included with later Phase II samples and utilized in the individual HSSR basic data quadrangle reports. Some Phase I samples were never utilized in basic data quadrangle reporting. ORGDP issued the Hydrogeochemical and Stream Sediment Wide-Spaced Sample Basic Data Release for Texas GJBX-131(81) report for several of these Phase I samples. This report includes data for 261 stream sediment and 406 water samples collected during 1976-77 in the Abilene, Austin, Brownwood, Corpus Christi, Del Rio, Eagle Pass, Houston, Llano, San Angelo, Sonora, and Waco quadrangles. The Wide-Spaced Sample Basic Data Release for Texas GJBX-131(81) report only contains data tables for Phase I samples; no explanatory text accompanies this report. One stream-sediment sample, one water sample, and one plant sample were collected within the Laredo quadrangle.
ORGDP: Laredo Quadrangle
Totals of 246 stream-sediment and 655 well-water samples were collected from the Laredo quadrangle as part of the Oak Ridge Gaseous Diffusion Plant (ORGDP) Laredo Quadrangle NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) study. Field sampling was conducted by ORGDP personnel between November, 1978 and May, 1979. These samples were analyzed by the ORGDP for uranium and other elements. The analytical data were released as the Laredo Quadrangle NURE HSSR study GJBX-14(80) report.
Summary Tables
The following is a list of NURE sample types collected in the Laredo quadrangle.
Sediment Sample Type | No. of Samples | Water Sample Type | No. of Samples | Plant Sample Type | No. of Samples |
---|---|---|---|---|---|
Dry Streams | 178 | Wells | 656 | Deciduous Tree (1 type) | 1 |
Wet Streams | 69 | ||||
Total Sediments | 247 | Total Waters | 656 | Total Plants | 1 |
These Laredo quadrangle samples were analyzed by one or more of the following methods:
Sediment Samples
Water Samples
Plant Samples
The Laredo quadrangle sediment and water data consist of reformatted records from the Wide-Spaced Sample Basic Data Release for Texas GJBX-131(81) report and reformatted records from the Laredo Quadrangle NURE HSSR study GJBX-14(80) report. The following problems were found and addressed during the comparison and reformatting stages for the Laredo quadrangle data:
Sediment Records
Water Records
Plant Records
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).
Laredo Quadrangle Sediment Data - 247 records
Laredo Quadrangle Water Data - 656 records
The ORGDP water samples were reportedly collected in the field without any filtering or acidification. (See the SAMPTYP coding explanation in the On-Line Manual for USGS-Reformatted NURE HSSR Data Files for descriptions of different Sample Types). However, the samples were filtered later in the laboratory through a 0.45 micron membrane filter before analysis. Therefore, the samples were not true "untreated water" samples and the analytical data may not be directly comparable for other quadrangle water samples of the same SAMPTYP when collected by a different laboratory. Since this was the standard procedure for Oak Ridge, water data from other Oak Ridge quadrangles should be comparable.
Latitude-longitude coordinates were reported in the original data files, as decimal degrees, to only 3 decimal places. Therefore, the precision of these coordinates is limited to +/- 0.001 degrees or +/- 3.6 seconds. This translates to a minimum precision of +/- 363 feet (111 m) for latitude values and between +/- 331 feet (101 m) to +/- 317 feet (97 m) for longitude values (calculated at latitudes of 25° and 30°N, respectively.)
Laredo Quadrangle NURE Summary
A summary evaluation of the Laredo quadrangle was prepared by the Bendix Field Engineering Corporation [PGJ/F-069(82)]. A total of 20 rock samples were collected and analyzed for uranium by fluorometry and for 29 additional elements by an unlisted method. Results from these analyses suggest that 63 areas are favorable for Texas roll-type uranium deposits. These environments include areas that are in the Goliad, Oakville, Catahoula, Frio, and Whittsett Formations. Data for this study were only found in tables on the microfiche accompanying the report.
Back to Texas 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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