Use of radiometric (Cs-137, Pb-210), geomorphic, and stratigraphic techniques to date recent oxbow sediments in the Rio Puerco drainage Grants uranium region, New Mexico

Journal Article · Wed Jun 01 00:00:00 EDT 1988 · Environmental Geology and Water Sciences; (United States)

DOI:https://doi.org/10.1007/BF02574815· OSTI ID:6126886

Popp, C J; Dehn, M ^[1]; Hawley, J W; Love, D W ^[2]

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1. New Mexico Inst. of Mining and Tech., Socorro (United States)
2. New Mexico Bureau of Mines and Mineral Resources, Socorro (United States)

In the absence of historic geochemical baseline data for the Grants uranium region, environmental changes resulting from uranium mine-mill activities can be determined only by indirect methods. A methodology for determining the age of recent sediments in streams draining the region has been established based on combined geomorphic, stratigraphic, and radiometric dating techniques. Because clay-rich sediments retain possible radionuclides and heavy metals derived from mineralization and mined sources, sample sites which contain fine-grained deposits that both predate and postdate mine-mill activity were located in abandoned-channel segments (oxbows) of major streams draining the eastern Grants uranium region. Aerial photographs (and derivative maps) taken between 1935 and 1971 provided the historical and geomorphic documentation of approximate dates of oxbow formation and ages of alluvial fills in the abandoned-channel segments. Pits were dug at these oxbow sites to determine stratigraphy and composition of the deposits. Samples collected from pit walls and auger holes below the pits were subjected to radiometric analysis by gamma ray spectrometry for the artificial radionuclide Cs-137 and the natural radionuclide Pb-210 as well as other U-238 and Th-232 daughters. Because of the dynamic nature of the system, absolute dating with Cs-137 was not possible but samples could be dated as either pre- or post-1950. The 1950 date is important because it marked the beginning of the uranium exploitation in the region. The Pb-210 dating was not possible because background Pb-210 was very high relative to fallout Pb-210.

• OSTI ID: 6126886
• Journal Information: Environmental Geology and Water Sciences; (United States), Vol. 11:3; ISSN 0177-5146
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
54 ENVIRONMENTAL SCIENCES
NEW MEXICO
URANIUM MINES
STREAMS
GEOCHEMICAL SURVEYS
WATER POLLUTION
ENVIRONMENTAL EFFECTS
CESIUM 137
GEOCHEMISTRY
HISTORICAL ASPECTS
ISOTOPE DATING
LEAD 210
SEDIMENTS
STRATIGRAPHY
WATER QUALITY
AGE ESTIMATION
ALKALI METAL ISOTOPES
ALPHA DECAY RADIOISOTOPES
BETA DECAY RADIOISOTOPES
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CHEMISTRY
DEVELOPED COUNTRIES
ENVIRONMENTAL QUALITY
EVEN-EVEN NUCLEI
FEDERAL REGION VI
GEOLOGY
HEAVY NUCLEI
INTERMEDIATE MASS NUCLEI
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NORTH AMERICA
NUCLEI
ODD-EVEN NUCLEI
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053002* - Nuclear Fuels- Environmental Aspects- Radioactive Effluents- (1992-)
540330 - Environment
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