OFR 97-492: Port Isabel 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.]

ORGDP: Brownsville and McAllen Quadrangles
Totals of 175 stream-sediment and 428 well-water samples were collected from the Brownsville, Port Isabel, and McAllen quadrangles as part of the Oak Ridge Gaseous Diffusion Plant (ORGDP) Brownsville-McAllen Quadrangle NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) study. Of these, 74 stream-sediment and 105 well-water samples were collected from the Port Isabel quadrangle (formerly northern half of the Brownsville quadrangle). Field sampling was conducted by ORGDP personnel between March and April of 1980. These samples were analyzed by the ORGDP for uranium and other elements. The analytical data were released as the Brownsville-McAllen Quadrangles NURE HSSR GJBX-249(80) report.

Summary Tables
The following is a list of NURE sample types collected in the Port Isabel quadrangle.

Summary of Port Isabel quadrangle sample types.
Sediment Sample Type Number of Samples Water Sample Type Number of Samples
Wet Streams 60 Wells 105
Dry Streams 14    
Total Sediments 74 Total Waters 105

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

Sediment Samples

Water Samples

Discussion of the Reformatting Process for Port Isabel Quadrangle

The Port Isabel quadrangle sediment and water data consist of reformatted records from the Brownsville-McAllen Quadrangles NURE HSSR GJBX-249(80) report. The following problems were found and addressed during the comparison and reformatting stages for the Port Isabel quadrangle data:

Sediment Records

  1. Two sample records had incomplete or conflicting information about the sample type. Sample type codes for these three samples were added to the SAMPTYP field based on information found in the field notes on microfiche that accompany the reports.

Water Records

  1. One analytical result in the digital data files had a value of 99999. This value was confirmed in the published quadrangle report. It is not clear if this value is a valid value, a null value, or a value indicating that the analytical result was greater than the upper limit of determination. This value was left in the data record and noted in the REFORMAT 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).

Brownsville Quadrangle Sediment Data (Brownsville and Port Isabel quadrangles) - 83 records
Brownsville Quadrangle Water Data (Brownsville and Port Isabel quadrangles) - 113 records

Notes for Data Users

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.)

Three stream-sediment samples collected in the Port Isabel quadrangle were not analyzed by any method.

Other NURE Geochemical Data for the Port Isabel Quadrangle

Brownsville and McAllen Quadrangles NURE Summary
A summary evaluation of the Brownsville, McAllen, (and Port Isabel) quadrangles was prepared by the Bendix Field Engineering Corporation [PGJ/F-134(82)]. A total of 8 rock samples were collected and analyzed for uranium by fluorometry and for 26 additional elements by an unlisted method. Results from these analyses suggest that 36 areas in the Goliad, Fleming-Oakville, Catahoula-Frio, and Whitsett Formations of the Brownsville, McAllen, (and Port Isabel) quadrangles are favorable environments for Texas roll-type sandstone uranium deposits. Data for this study were only found in tables on the microfiche accompanying the report.

Port Isabel Quadrangle NURE Bibliography

Links Within Open-File Report 97-492

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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