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.

大气和海水成分只能从沉积物及其化石清单中重建。对于Phanerozoic Eon来说，这似乎很简单，因为存在广泛的气候敏感代理。对于地球早期而言，环境重建更加有问题。无形的古细菌沉积物很少见，古代和早期proterorogic eons的许多沉积物都不具有现实性。在该项目中，引入了实验技术，可以与海水反应氧化和减少H-C-N-O大气的反应。目的是限制古细菌允许的大气 - 水水组合。关键阶段是铁氧化铁和Fe2+碳酸盐阶段，可能是带状铁层（BIF）中常见矿物的前体。这些阶段的热力学稳定性可能会在Fe2+（aq）浓度，pH值和海水的碳酸盐碱范围内以及pCO2和PO2范围的PCO2和PO2范围等于平衡的PCO2和PO2范围上。当BIF是常见的海洋沉积物时，结果可能有助于更好地理解古细菌的环境条件，并在地球历史上过去时期的大气组成上构成限制。

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