Experimental simulation of atmosphere-seawater relations in the Archaean eon of Earth's history

地球历史太古代大气-海水关系的实验模拟

• 批准号: 240900066
• 负责人: Professor Dr. Christian Gerhard Ballhaus
• 金额: --
• 依托单位: Abteilung Geochemie/Petrologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/240900066?language=en
• 关键词: Experimental; simulation; atmosphere; seawater; relations

Atmospheric and seawater compositions can only be reconstructed from sediments and their fossil inventory. For the Phanerozoic eon, this seems straightforward because a wide range of climate-sensitive proxies exists. For the early Earth, environmental reconstructions are more problematic. Unmetamorphosed Archaean sediments are rare, and many sediments from the Archaean and early Proterozoic eons do not have actualistic equivalents. In this project, experimental techniques are introduced that allow to react oxidized and reduced H-C-N-O atmospheres with seawater. The aim is to constrain the atmosphere-seawater combinations permissible for the Archaean eon. Key phases are iron hydroxides and Fe2+ carbonate phases that may be precursors to common minerals in banded iron formations (BIF). The thermodynamic stabilities of these phases may place narrow limits on the Fe2+ (aq) concentrations, the pH ranges, and the carbonate alkalinities of the seawater, as well as on the pCO2 and pO2 ranges of the atmospheric compositions in equilibrium with surface seawater. The results may contribute to a better understanding of the Archaean environmental conditions when BIF were common marine sediments, as well as place constraints on the atmospheric compositions of past epochs of the Earth's history.

大气和海水的成分只能根据沉积物及其化石库存来重建。对于显生宙来说，这似乎很简单，因为存在广泛的气候敏感指标。对于早期地球来说，环境重建问题更大。未变质的太古宙沉积物非常罕见，许多来自太古宙和早元古代的沉积物没有实际的对应物。在该项目中，介绍了使氧化和还原的 H-C-N-O 气氛与海水发生反应的实验技术。目的是限制太古宙允许的大气-海水组合。关键相是铁氢氧化物和 Fe2+ 碳酸盐相，它们可能是带状铁地层 (BIF) 中常见矿物的前体。这些相的热力学稳定性可能对海水的 Fe2+ (aq) 浓度、pH 范围和碳酸盐碱度以及与表层海水平衡的大气成分的 pCO2 和 pO2 范围产生狭窄的限制。这些结果可能有助于更好地了解当 BIF 是常见海洋沉积物时的太古宙环境条件，并对地球历史上过去各个时期的大气成分进行限制。

项目成果

Siderite cannot be used as CO2 sensor for Archaean atmospheres

• DOI: 10.1016/j.gca.2017.07.027
• 发表时间: 2017-10
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: Fabian Gäb;C. Ballhaus;J. Siemens;A. Heuser;M. Lissner;T. Geisler;D. Garbe‐Schönberg