Coupled Cr and Mo isotope investigations of post-GOE Paleoproterozoic sediments: Testing the hypothesis of an oxygen overshoot in atmospheric O2 levels

GOE 后古元古代沉积物的 Cr 和 Mo 同位素耦合研究：检验大气 O2 水平中氧超调的假设

• 批准号: 398425896
• 负责人: Professor Dr. Ronny Schönberg, Ph.D.
• 金额: --
• 依托单位: Arbeitsgruppe Isotopengeochemie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398425896?language=en
• 关键词: Coupled; Cr; Mo; isotope; investigations

Coupled isotope investigations of the redox-sensitive elements Cr and Mo in 2.5 – 2.0-Gyr-old sediments of the Pechenga Greenstone Belt (PGB) and the Onega Basin (OB) in Russia will be used to reconstruct the redox evolution of the atmosphere and oceans postdating the Great Oxidation Event (GOE). The GOE marks the first significant increase in atmospheric oxygen levels and defines the transitions from anoxic to oxic environmental conditions. The aftermath of the GOE is characterized by major perturbations of the oxygen, carbon, and sulfur cycle - probably global - during the 2.22 – 2.05-Gyr-old Lomagundi and the following Shunga events. While the post-GOE sediments archive evidence for the burial of vast amounts of organic carbon, the expansion and contraction of the seawater sulfate reservoir, a proposed oxygen overshoot and the onset of effective continental weathering, the timing and response between the oxygenation of the atmosphere and oceans is poorly constrained. Moreover and more puzzling, even though the GOE marks the onset of oxygen-rich atmospheric conditions that was probably followed by an oxygen overshoot, Cr isotopes that are suggested as a tracer for free oxygen fail to identify oxygen-rich conditions in the Paleoproterozoic. This project seeks to perform detailed coupled Cr and Mo isotope investigations on various near-shore sedimentary environments from the Kuetsjärvi, Kolosjoki (PGB) and Zaonezhskaya (OB) formations. The first part of the project will characterize the paleoenvironmental conditions by major and trace elements and carbon isotopes, whereas the second part focuses on the combined Cr and Mo isotope investigations. Complementary geochemical investigations will be carried out on near-shore sediments from the 2.2 – 2.1-Gyr-old Pretoria Group (Botswana), because these sediments also capture the Lomagundi Event and will help to provide a more detailed, and probably global, understanding of the Paleoproterozoic atmosphere-ocean system.

对俄罗斯佩琴加绿岩带 (PGB) 和奥涅加盆地 (OB) 2.5 – 2.0 古沉积物中氧化还原敏感元素 Cr 和 Mo 的耦合同位素研究将用于重建大气和奥涅加盆地的氧化还原演化。大氧化事件（GOE）后的海洋标志着大气中氧气水平的首次显着增加，并定义了从缺氧到有氧环境条件的转变。 GOE 的后果的特点是在 2.22 – 2.05 吉里的洛马贡迪 (Lomagundi) 和随后的 Shunga 事件期间，氧、碳和硫循环发生了重大扰动，而 GOE 后的沉积物则提供了埋藏的证据。大量有机碳、海水硫酸盐储层的膨胀和收缩、拟议的氧超调和有效大陆风化的开始、海水氧化之间的时间和响应此外，更令人费解的是，尽管GOE标志着富氧大气条件的开始，随后可能会出现氧超调，但被建议作为游离氧示踪剂的Cr同位素却无法识别氧。该项目旨在对库茨耶尔维 (Kuetsjärvi)、科洛斯约基 (PGB) 和科洛斯约基 (PGB) 的各种近岸沉积环境进行详细的铬和钼同位素耦合研究。该项目的第一部分将通过主量元素、微量元素和碳同位素来表征古环境条件，而第二部分将重点进行铬和钼同位素的综合研究。来自 2.2 – 2.1 吉里的比勒陀利亚群（博茨瓦纳）的海岸沉积物，因为这些沉积物也捕获了洛马贡迪事件，并将有助于提供对古元古代大气-海洋系统进行更详细、可能是全球性的了解。

项目成果

The onset of oxidative weathering traced by uranium isotopes

铀同位素追踪氧化风化的开始

• DOI: 10.1016/j.precamres.2019.105583
• 发表时间: 2020-03-01
• 期刊: Precambrian Research
• 影响因子: 3.8
• 作者: Annika Brüske;A. N. Martin;P. Rammensee;S. Eroglu;M. Lazarov;G. Albut;S. Schuth;S. Aulbach;R. Schoenberg;N. Beukes;A. Hofmann;T. Nägler;S. Weyer
• 通讯作者: S. Weyer

Weathering, alteration and reconstructing Earth's oxygenation

风化、改变和重建地球的氧合

• DOI: 10.1098/rsfs.2019.0140
• 发表时间: 2020-06-12
• 期刊: Interface Focus
• 影响因子: 4.4
• 作者: N. Planavsky;L. Robbins;B. Kamber;R. Schoenberg
• 通讯作者: R. Schoenberg