書誌事項
- タイトル別名
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- Using multiple sulfur isotopes to understand the Earth's surface environments during the Archean era
- イオウ ドウイタイ カラ ヨミトル タイコダイ チキュウ ノ ヒョウソウ カンキョウ : ゲンジョウ ト ソノ モンダイテン
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説明
Since the discovery of Anomalous Isotope Fractionation (AIF) of sulfur, or more commonly termed Mass-Independent Fractionation (MIF) of sulfur, in many sedimentary rocks older than 2.45Ga, and its virtual absence in younger rocks, the AIF record has been cited by many researchers as unequivocal evidence for a dramatic change from an anoxic to oxic atmosphere around 2.45Ga. However, multiple sulfur isotope data from these natural samples have been interpreted based on the assumption that sulfur chemistry in gas phase is only responsible for AIF of sulfur in nature. The objective of this review is to evaluate this assumption. First, results of ab initio calculations for equilibrium isotope exchange between S-bearing species show that deviations from the mass-dependent relationships during equilibrium processes are much smaller than those found in Archean sedimentary rocks. Consequently, AIF requires a property that is a discontinuous function of mass (e.g., nuclear volume, magnetic moment, asymmetry of molecules, isotopic abundance). The number of bound states may be another discontinuous function of mass, which fractionates S isotopes anomalously during chemisorption at a high temperature (e.g., >100℃). A recent experimental study also showed that thermochemical sulfate reduction by simple amino acids produces AIF of sulfur. These results suggest that an alternative process, such as reactions between organic matter in sediments and sulfate-rich hydrothermal solutions, may have caused AIF signatures of sulfur in Archean sedimentary rocks.
収録刊行物
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- 地球化学
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地球化学 45 (4), 251-264, 2011-12-25
一般社団法人日本地球化学会
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詳細情報 詳細情報について
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- CRID
- 1390282680718970880
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- NII論文ID
- 110008913807
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- NII書誌ID
- AN00141280
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- ISSN
- 21885923
- 03864073
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- NDL書誌ID
- 023464451
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- 本文言語コード
- ja
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- データソース種別
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- JaLC
- NDLサーチ
- CiNii Articles
- KAKEN
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- 使用不可