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ID 15028
本文ファイル
著者
Horie, Kenji
Gauthier-Lafaye, Francois
キーワード
Alteration
Bidoudouma
Incorporation
Metamict zircon
REE
U-Pb systematics
NDC
天文学・宇宙科学
抄録(英)
Isotopic analyses of U, Pb and REE in 144 zircon grains from the Bidoudouma stream, the Republic of Gabon, were performed to study correlation of elemental distribution with geological alteration effects. The U-Pb isotopic results reveal that the zircons formed around 2.8-2.1 Ga ago and altered around 500 Ma ago by igneous activity in association with dolerite dyke intrusion. The REE abundance patterns of the U-Pb discordant zircons are characterized by high contents of REE (977-98,154 ppm), small LREE-HREE fractionations and distinctly positive Eu anomalies. The discordant zircons also contain significant amounts of non-formula elements such as Ca, Mn, Al and Fe; whereas, their contents of Zr and Si are 1-150wer than those of concordant zircon. Non-formula elements and REE, especially LREE, were incorporated into metamict zircon in association with Pb-loss, which indicates that the non-formula elements and REE substituted for Zr and Si. Judging from this correlation among the contents of non-formula elements, when zircon was initially altered, Fe substituted for major elements of zircon. After the saturation of Fe, Ca and Mn were incorporated into zircon together with REE and Al followed by Ca. The metamict zircons contain large amount of U (∼8215 ppm), which indicates that U had not migrated from zircon grain in association with the Pb-loss
掲載誌名
Physics and Chemistry of the Earth
31巻
10-14号
開始ページ
587
終了ページ
592
出版年月日
2006
出版者
Elsevier Ltd
ISSN
1474-7065
NCID
出版者DOI
言語
英語
NII資源タイプ
学術雑誌論文
広大資料タイプ
学術雑誌論文
DCMIタイプ
text
フォーマット
application/pdf
著者版フラグ
author
権利情報
Copyright (c) 2006 Elsevier Ltd
関連情報URL(IsVersionOf)
http://dx.doi.org/10.1016/j.pce.2006.01.001
部局名
理学研究科