アーケイアのコマチートに宿るニッケル鉱床における大気中の硫黄
Andrey Bekker1, Mark E Barley, Marco L Fiorentini
1Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, USA. bekker@cc.umanitoba.ca
まとめ
古代の鉄・ニッケル硫化物埋蔵の硫黄は,大気中の処理と海底の蓄積から発生した. マントルに由来するマグマは,この硫黄を吸収し,海洋が硫黄に乏しいときに堆積物を形成しました.
科学分野:
- 地質化学 地質化学
- 経済地質学 経済地質学
- プレカンブリア紀前パレオバイオロジー
背景:
- 巨大な鉄・ニッケル (Fe-Ni) 硫化物鉱石鉱床は,アルカインと初期プロテロゾイク時代に形成された.
- 金属と硫黄の発生源を理解することは,その形成の鍵となる.
- 古代の海は硫黄の濃度が低いことが特徴でした.
研究 の 目的:
- 古代コマチートに宿るFe-Ni硫化物堆積物における硫黄の起源を調査する.
- これらの重要な鉱石の産生に関わるプロセスを解明する.
主な方法:
- アルカイのコマチートに宿るFe-Ni硫化物堆積物からの複数の硫黄同位体データの分析.
- 大気から海洋環境への硫黄循環経路の再構築.
主要な成果:
- 硫黄イソトープのデータは,それ以前に大気中に処理され,その後海底に蓄積されたことを示唆しています.
- 証拠によると,硫黄は海底の水熱硫化物と硫化石シェルから得られていた.
- マントルに由来するコマチートマグマは,この加工された硫黄を同化した.
結論:
- アーケイア時代のFe-Ni硫化物堆積物の硫黄は,大気と海洋の貯水池から発生した.
- コマチートマグマは,この硫黄を吸収して鉱石の鉱床を形成する上で重要な役割を果たしました.
- この研究は,硫黄に限られた初期の地球海における鉱石形成過程に光を当てています.
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