| Item type |
デフォルトアイテムタイプ_（フル）(1) |
| 公開日 |
2023-03-18 |
| タイトル |
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タイトル |
Geochemical fixation of rare earth elements into secondary minerals in sandstones beneath a natural fission reactor at Bangombé, Gabon |
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言語 |
en |
| 作成者 |
Hidaka, Hiroshi
Janeczek, Janusz
Skomurski, Francis N.
Ewing, Rodney C.
Gauthier-Lafaye, Francois
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| アクセス権 |
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アクセス権 |
open access |
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アクセス権URI |
http://purl.org/coar/access_right/c_abf2 |
| 権利情報 |
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権利情報 |
Copyright (c) 2005 Elsevier Ltd |
| 主題 |
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主題Scheme |
NDC |
|
主題 |
440 |
| 内容記述 |
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内容記述 |
To study geochemical processes for migration and fixation of fissiogenic rare earth elements (REE) in association with uranium dissolution, in situ isotopic analyses using an ion microprobe were performed on U- and REE-bearing secondary minerals, such as coffinite, françoisite, uraniferous goethite, and uraninite found in a sandstone layer 30 to 110 cm beneath a natural fission reactor at Bangombé, Gabon. Phosphate minerals such as phosphatian coffinite and françoisite with depleted 235U (235U/238U = 0.00609 to 0.00638) contained large amount of fissiogenic light REE, while micro-sized uraninite grains in a solid bitumen aggregate have normal U isotopic values (235U/238U = 0.00725) and small amount of fissiogenic REE components. The proportions of fissiogenic and non-fissiogenic REE components in four samples from the core of BAX03 vary in depth ranging from 30 cm to 130 cm beneath the reactor, which suggests mixing between fissiogenic isotopes from the reactor and non-fissiogenic isotopes from original minerals in the sandstone. Significant chemical fractionation was observed between Ce and the other REE in the secondary minerals, which shows evidence of an oxidizing atmosphere during their formation. Pb-isotopic analyses of individual minerals do not directly provide chronological information because of the disturbance of U-Pb decay system due to recent geologic alteration. However, systematic Pb-isotopic results from all of the minerals reveal the mobilization of fissiogenic isotopes, Pb and U from the reactor in association with dolerite dyke intrusion ∼0.798 Ga ago and the formation of the secondary minerals by mixing event between 2.05 Ga-old original minerals and reactor materials due to recent alteration. |
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言語 |
en |
| 出版者 |
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出版者 |
Elsevier Ltd |
| 言語 |
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言語 |
eng |
| 資源タイプ |
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資源タイプ識別子 |
http://purl.org/coar/resource_type/c_6501 |
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資源タイプ |
journal article |
| 出版タイプ |
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出版タイプ |
AO |
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出版タイプResource |
http://purl.org/coar/version/c_b1a7d7d4d402bcce |
| 関連情報 |
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識別子タイプ |
DOI |
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関連識別子 |
10.1016/j.gca.2004.07.019 |
| 関連情報 |
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関連タイプ |
isVersionOf |
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|
識別子タイプ |
DOI |
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|
関連識別子 |
http://dx.doi.org/10.1016/j.gca.2004.07.019 |
| 収録物識別子 |
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収録物識別子タイプ |
ISSN |
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収録物識別子 |
0016-7037 |
| 収録物識別子 |
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収録物識別子タイプ |
NCID |
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収録物識別子 |
AA00655038 |
| 開始ページ |
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開始ページ |
685 |
| 書誌情報 |
Geochimica et Cosmochimica Acta
Geochimica et Cosmochimica Acta
巻 69,
号 3,
p. 685-694,
発行日 2005-02
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| 旧ID |
15030 |
GCA_69_685.pdf (1.7 MB)
