Natural variations in uranium isotope ratios of uranium ore concentrates: Understanding the 238U/235U fractionation mechanism

Gregory A. Brennecka, Lars E. Borg, Ian D. Hutcheon, Michael A. Sharp, Ariel Anbar

Research output: Contribution to journalArticle

107 Citations (Scopus)

Abstract

Precise measurement of the 238U/235U ratio in geologic samples is now possible with modern techniques and mass spectrometers. Natural variations in this ratio have been shown in previous studies. In this study, data obtained from uranium ore concentrates of mining facilities around the world show clear evidence that the depositional redox environment in which uranium is precipitated is the primary factor affecting 238U/235U fractionation. Low-temperature uranium deposits are, on average, isotopically ∼ 0.4‰ heavier than uranium deposited at high temperatures or by non-redox processes. 238U/235U ratios coupled with 235U/234U ratios in the same sample provide evidence that the redox transition (UVI → UIV) at low temperatures is the primary mechanism of 238U/235U fractionation and that aqueous alteration plays a very limited, if any, role in fractionation of the 238U/235U ratio. The isotopic variation of U is therefore a potential signature that can be used to trace the origin of uranium ore concentrate.

Original languageEnglish (US)
Pages (from-to)228-233
Number of pages6
JournalEarth and Planetary Science Letters
Volume291
Issue number1-4
DOIs
StatePublished - Mar 1 2010

Fingerprint

uranium isotopes
uranium isotope
Uranium
isotope ratios
Fractionation
fractionation
Isotopes
Ores
uranium
minerals
Uranium deposits
Mass spectrometers
Temperature
mass spectrometers
spectrometer
deposits
signatures
ore
spectrometers
Oxidation-Reduction

Keywords

  • fractionation
  • geolocation
  • isotopes
  • UOC
  • uranium

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Natural variations in uranium isotope ratios of uranium ore concentrates : Understanding the 238U/235U fractionation mechanism. / Brennecka, Gregory A.; Borg, Lars E.; Hutcheon, Ian D.; Sharp, Michael A.; Anbar, Ariel.

In: Earth and Planetary Science Letters, Vol. 291, No. 1-4, 01.03.2010, p. 228-233.

Research output: Contribution to journalArticle

Brennecka, Gregory A. ; Borg, Lars E. ; Hutcheon, Ian D. ; Sharp, Michael A. ; Anbar, Ariel. / Natural variations in uranium isotope ratios of uranium ore concentrates : Understanding the 238U/235U fractionation mechanism. In: Earth and Planetary Science Letters. 2010 ; Vol. 291, No. 1-4. pp. 228-233.
@article{a3b2f4fc887d4a369caeafe60d43751f,
title = "Natural variations in uranium isotope ratios of uranium ore concentrates: Understanding the 238U/235U fractionation mechanism",
abstract = "Precise measurement of the 238U/235U ratio in geologic samples is now possible with modern techniques and mass spectrometers. Natural variations in this ratio have been shown in previous studies. In this study, data obtained from uranium ore concentrates of mining facilities around the world show clear evidence that the depositional redox environment in which uranium is precipitated is the primary factor affecting 238U/235U fractionation. Low-temperature uranium deposits are, on average, isotopically ∼ 0.4‰ heavier than uranium deposited at high temperatures or by non-redox processes. 238U/235U ratios coupled with 235U/234U ratios in the same sample provide evidence that the redox transition (UVI → UIV) at low temperatures is the primary mechanism of 238U/235U fractionation and that aqueous alteration plays a very limited, if any, role in fractionation of the 238U/235U ratio. The isotopic variation of U is therefore a potential signature that can be used to trace the origin of uranium ore concentrate.",
keywords = "fractionation, geolocation, isotopes, UOC, uranium",
author = "Brennecka, {Gregory A.} and Borg, {Lars E.} and Hutcheon, {Ian D.} and Sharp, {Michael A.} and Ariel Anbar",
year = "2010",
month = "3",
day = "1",
doi = "10.1016/j.epsl.2010.01.023",
language = "English (US)",
volume = "291",
pages = "228--233",
journal = "Earth and Planetary Sciences Letters",
issn = "0012-821X",
publisher = "Elsevier",
number = "1-4",

}

TY - JOUR

T1 - Natural variations in uranium isotope ratios of uranium ore concentrates

T2 - Understanding the 238U/235U fractionation mechanism

AU - Brennecka, Gregory A.

AU - Borg, Lars E.

AU - Hutcheon, Ian D.

AU - Sharp, Michael A.

AU - Anbar, Ariel

PY - 2010/3/1

Y1 - 2010/3/1

N2 - Precise measurement of the 238U/235U ratio in geologic samples is now possible with modern techniques and mass spectrometers. Natural variations in this ratio have been shown in previous studies. In this study, data obtained from uranium ore concentrates of mining facilities around the world show clear evidence that the depositional redox environment in which uranium is precipitated is the primary factor affecting 238U/235U fractionation. Low-temperature uranium deposits are, on average, isotopically ∼ 0.4‰ heavier than uranium deposited at high temperatures or by non-redox processes. 238U/235U ratios coupled with 235U/234U ratios in the same sample provide evidence that the redox transition (UVI → UIV) at low temperatures is the primary mechanism of 238U/235U fractionation and that aqueous alteration plays a very limited, if any, role in fractionation of the 238U/235U ratio. The isotopic variation of U is therefore a potential signature that can be used to trace the origin of uranium ore concentrate.

AB - Precise measurement of the 238U/235U ratio in geologic samples is now possible with modern techniques and mass spectrometers. Natural variations in this ratio have been shown in previous studies. In this study, data obtained from uranium ore concentrates of mining facilities around the world show clear evidence that the depositional redox environment in which uranium is precipitated is the primary factor affecting 238U/235U fractionation. Low-temperature uranium deposits are, on average, isotopically ∼ 0.4‰ heavier than uranium deposited at high temperatures or by non-redox processes. 238U/235U ratios coupled with 235U/234U ratios in the same sample provide evidence that the redox transition (UVI → UIV) at low temperatures is the primary mechanism of 238U/235U fractionation and that aqueous alteration plays a very limited, if any, role in fractionation of the 238U/235U ratio. The isotopic variation of U is therefore a potential signature that can be used to trace the origin of uranium ore concentrate.

KW - fractionation

KW - geolocation

KW - isotopes

KW - UOC

KW - uranium

UR - http://www.scopus.com/inward/record.url?scp=75949092982&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=75949092982&partnerID=8YFLogxK

U2 - 10.1016/j.epsl.2010.01.023

DO - 10.1016/j.epsl.2010.01.023

M3 - Article

AN - SCOPUS:75949092982

VL - 291

SP - 228

EP - 233

JO - Earth and Planetary Sciences Letters

JF - Earth and Planetary Sciences Letters

SN - 0012-821X

IS - 1-4

ER -