Matches in SemOpenAlex for { <https://semopenalex.org/work/W2913774923> ?p ?o ?g. }
- W2913774923 endingPage "159" @default.
- W2913774923 startingPage "138" @default.
- W2913774923 abstract "This study presents systematic chemical (U, Pb, Ca, Si, Fe) mapping coupled with in situ analyses of major, minor and trace elements, U/Pb, 207Pb/206Pb, and O isotopic compositions of natural uraninites (UO2) from two samples of the high-grade uranium ore from the Cigar Lake unconformity-related uranium deposit (Athabasca Basin, Saskatchewan, Canada). The studied uraninites are characterized by major chemical and isotopic heterogeneities expressed at small scale (µm to tens of µm), from almost pristine zones to strongly altered material. The 206Pb/238U and 207Pb/235U ratios of the different areas are widely spread and depict two similar and well-defined Discordia, providing an upper intercept age of crystallization at ca. 1300 Ma (1299 ± 4 and 1308 ± 14 Ma, respectively) and lower intercepts at 38 ± 13 and 72 ± 22 Ma, respectively. The freshest areas are characterized by sub-concordant 206Pb/238U and 207Pb/235U ratios, identical chemical compositions and similar very low δ18O values (−39.3 to −31.4‰). These data indicate that the two uraninites both crystallized at ca. 1300 Ma, from the same fluid and under identical physico-chemical conditions. Alteration is characterized by (i) the progressive incorporation of Ca, Si, and Fe, reaching several wt.%, which substitute to the radiogenic Pb and cause a progressive decrease in the Pb/U isotopic ratios. The radiogenic Pb is also substituted by water during the alteration, (ii) concomitant variations in trace element contents (As, Mn, V, LREEs, Sr, Th, B, Ba, Nb, for example) and (iii) heavier δ18O signatures (−22.5 to −8.91‰), typical of meteoric waters, in the altered zones. This combined approach demonstrates that fluid-driven post-crystallization exchanges affected each uraninite during recent fluid flow events (ca. 40 Ma and 70 Ma respectively). The relatively high dispersion of the Pb/U ratios in relation to the Discordia for both samples is considered as linked to a local (nm to µm-scale) differential mobility between lead and uranium within the uranium oxides. The chemical changes affecting elements previously considered as immobile in uraninite, such as REEs, indicate that these elements are not preserved during the post-crystallization alteration process studied here. Alteration processes may therefore have a major impact on the classical geochemical tracers, such as REE patterns or LREE/HREE ratios, currently used in nuclear forensic studies. The isotopic and chemical tracers currently used to track back the origin, age and history of natural uraninites should therefore be considered with a high degree of caution to avoid misleading and erroneous conclusions. Moreover, the comparison of calculated U-Th-Pb chemical, 207Pb/206Pb, and Pb/U isotopic ages shows that the use of age clustering for determining U-Th-Pb chemical ages and 206Pb/207Pb ages is not appropriate for constraining crystallization stage(s) of altered uraninites and for deciphering the different fluid events that potentially altered or recrystallized the uraninites over time. This study also indicates that estimation of the crystallization age of uraninite from substitution trends of Pb to Ca is not applicable to unconformity-related U deposits and results in overestimated ages because of an initial integration of calcium in the uraninite lattice at the time of crystallization." @default.
- W2913774923 created "2019-02-21" @default.
- W2913774923 creator A5001331214 @default.
- W2913774923 creator A5004356113 @default.
- W2913774923 creator A5009159747 @default.
- W2913774923 creator A5009518565 @default.
- W2913774923 creator A5022583629 @default.
- W2913774923 creator A5025710432 @default.
- W2913774923 creator A5038057915 @default.
- W2913774923 creator A5065943340 @default.
- W2913774923 creator A5068516775 @default.
- W2913774923 date "2019-03-01" @default.
- W2913774923 modified "2023-10-06" @default.
- W2913774923 title "Post-crystallization alteration of natural uraninites: Implications for dating, tracing, and nuclear forensics" @default.
- W2913774923 cites W1186678697 @default.
- W2913774923 cites W1508852928 @default.
- W2913774923 cites W1601037315 @default.
- W2913774923 cites W1862223677 @default.
- W2913774923 cites W1892074142 @default.
- W2913774923 cites W1943636449 @default.
- W2913774923 cites W1965739749 @default.
- W2913774923 cites W1967722095 @default.
- W2913774923 cites W1971179416 @default.
- W2913774923 cites W1973224493 @default.
- W2913774923 cites W1978334516 @default.
- W2913774923 cites W1982090880 @default.
- W2913774923 cites W1987515641 @default.
- W2913774923 cites W1988582117 @default.
- W2913774923 cites W1990116280 @default.
- W2913774923 cites W1997690860 @default.
- W2913774923 cites W1999350133 @default.
- W2913774923 cites W2002615293 @default.
- W2913774923 cites W2003704271 @default.
- W2913774923 cites W2006378845 @default.
- W2913774923 cites W2007105153 @default.
- W2913774923 cites W2013934368 @default.
- W2913774923 cites W2015807353 @default.
- W2913774923 cites W2016316073 @default.
- W2913774923 cites W2023817180 @default.
- W2913774923 cites W2033466026 @default.
- W2913774923 cites W2037450372 @default.
- W2913774923 cites W2041530430 @default.
- W2913774923 cites W2044621372 @default.
- W2913774923 cites W2044633001 @default.
- W2913774923 cites W2044822081 @default.
- W2913774923 cites W2046888051 @default.
- W2913774923 cites W2048770443 @default.
- W2913774923 cites W2049524331 @default.
- W2913774923 cites W2049839539 @default.
- W2913774923 cites W2054842898 @default.
- W2913774923 cites W2057208829 @default.
- W2913774923 cites W2058317629 @default.
- W2913774923 cites W2060064926 @default.
- W2913774923 cites W2063000672 @default.
- W2913774923 cites W2063461334 @default.
- W2913774923 cites W2067952300 @default.
- W2913774923 cites W2068212877 @default.
- W2913774923 cites W2070219421 @default.
- W2913774923 cites W2072062807 @default.
- W2913774923 cites W2072206241 @default.
- W2913774923 cites W2083544414 @default.
- W2913774923 cites W2085064498 @default.
- W2913774923 cites W2086526909 @default.
- W2913774923 cites W2089507620 @default.
- W2913774923 cites W2095294818 @default.
- W2913774923 cites W2097330636 @default.
- W2913774923 cites W2103113626 @default.
- W2913774923 cites W2106462953 @default.
- W2913774923 cites W2139918478 @default.
- W2913774923 cites W2146304116 @default.
- W2913774923 cites W2149710803 @default.
- W2913774923 cites W2152423430 @default.
- W2913774923 cites W2157681159 @default.
- W2913774923 cites W2162933590 @default.
- W2913774923 cites W2167590372 @default.
- W2913774923 cites W2169655739 @default.
- W2913774923 cites W2380975349 @default.
- W2913774923 cites W2416435222 @default.
- W2913774923 cites W2463341531 @default.
- W2913774923 cites W2465499279 @default.
- W2913774923 cites W2472663166 @default.
- W2913774923 cites W2518440047 @default.
- W2913774923 cites W2529769427 @default.
- W2913774923 cites W2571274646 @default.
- W2913774923 cites W2583733641 @default.
- W2913774923 cites W2592329148 @default.
- W2913774923 cites W2606927531 @default.
- W2913774923 cites W2607291805 @default.
- W2913774923 cites W2620190191 @default.
- W2913774923 cites W2771606550 @default.
- W2913774923 doi "https://doi.org/10.1016/j.gca.2019.01.025" @default.
- W2913774923 hasPublicationYear "2019" @default.
- W2913774923 type Work @default.
- W2913774923 sameAs 2913774923 @default.
- W2913774923 citedByCount "28" @default.
- W2913774923 countsByYear W29137749232019 @default.
- W2913774923 countsByYear W29137749232020 @default.
- W2913774923 countsByYear W29137749232021 @default.