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Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States

Journal of Geochemical Exploration

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DOI: 10.1016/0375-6742(90)90076-M

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Abstract

Aerial gamma-ray surveys of the natural environment measure the flux of gamma rays produced by the radioactive decay of 40K, 214Bi, and 208Tl in the upper 10–20 cm of surface materials. 40K is a radioactive potassium isotope which can be used to estimate the total amount of potassium in the soils and rocks. 214Bi is a decay product of the 238U radioactive decay series and is used to estimate the uranium concentrations, and 208Tl, a decay product of the 232Th radioactive decay series, is used to estimate thorium concentrations. Aerial gamma-ray data covering the 48 contiguous states of the United States have been compiled to produce maps showing the distributions of equivalent uranium, equivalent thorium, and potassium. This compilation involved processing the aerial survey data from about 470 1° × 2° quadrangle maps.

The aerial gamma-ray data were obtained as part of the National Uranium Resource Evaluation (NURE) Program sponsored by the U.S. Department of Energy during the period 1975-1983. References for the Open-File Reports that describe the surveys and data collection can be found in Bendix Field Engineering Corp. (1983). The aerial surveys were flown by contractors using fixed-wing and helicopter systems with 33-50 L (liters) of thallium-activated sodium iodide (NaI (TI)) crystals. The nominal survey altitude used is 122 m. The survey lines were generally east-west with line spacings of 1.6-10 km. Tie lines were flown perpendicular to the flight lines at intervals of 16- 30 km. The data were corrected for background from aircraft contamination and cosmic rays, altitude variations, airborne 214Bi, and Compton scattering. The gamma-ray systems were calibrated using the calibrations pads at Grand Junction, Colorado (Ward, 1978 ) and the dynamic test strip at Lake Mead, Arizona (Geodata International, Inc., 1977).

 

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States
Series title:
Journal of Geochemical Exploration
DOI:
10.1016/0375-6742(90)90076-M
Volume:
39
Issue:
1-2
Year Published:
1990
Language:
English
Publisher:
Elsevier
Publisher location:
New York, NY
Description:
5 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Geochemical Exploration
First page:
249
Last page:
253
Country:
United States
Online Only (Y/N):
N
Additional Online Files (Y/N):
N