Towards an understanding of the Proterozoic carbon isotope curve

了解元古代碳同位素曲线

• 批准号: 2547170
• 金额: --
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2547170
• 关键词: Towards; understanding; Proterozoic; carbon; isotope

The carbon cycle is central to investigating Earth's past environment, particularly its oxygenation history. Past perturbations in the carbon cycle can be identified by changes in the carbon isotope composition (delta c thirteen) of ancient seawater, preserved in marine carbonate rocks. My project will involve collating unpublished and published carbonate delta c thirteen data from the Proterozoic (c. 2,500-539 Ma) to develop the first comprehensive carbon isotope curve for this Eon. New data will also be gathered via fieldwork (e.g., the Scottish Hebrides), extensive laboratory work and international collaboration. The carbon isotope curve will be supplemented with other geochemical proxies, allowing me to investigate weathering rates (Sr-isotopes), seawater redox conditions (U-isotopes) and productivity levels (Cd-isotopes) across key intervals. The geochemical data will be integrated with a biogeochemical model to predict the controls and evolution of the biotic and abiotic components of Earth's system throughout the Proterozoic, specifically across major perturbations in the carbon cycle (e.g., the Lomagundi and Shuram Excursions). The project aims to address key questions such as: 1) What were the dominant geological and/or biological drivers of the major carbon isotope excursions during the Proterozoic?; 2) Are carbon isotope excursions good indications for oxygenation events?; and 3) Was the Mesoproterozoic a time of carbon isotope stability and thus Earth system stasis?

碳循环是研究地球过去环境的核心，特别是它的氧化历史。碳循环中过去的扰动可以通过保存在海洋碳酸盐岩中的古海水的碳同位素组成（δ c 13）的变化来识别。我的项目将涉及整理未发表和已发表的碳酸盐三角洲c十三数据从元古宙（c。2，500 -539 Ma），绘制了该Eon的第一条综合碳同位素曲线。还将通过实地工作收集新数据（例如，苏格兰赫布里底群岛），广泛的实验室工作和国际合作。碳同位素曲线将补充其他地球化学代理，使我能够调查风化率（Sr同位素），海水氧化还原条件（U同位素）和生产力水平（Cd同位素）在关键间隔。地球化学数据将与地球化学模型相结合，以预测整个元古代地球系统生物和非生物成分的控制和演变，特别是在碳循环的主要扰动（例如，Lomagundi和Shuram游览）。该项目的目的是解决关键问题，如：1）什么是主要的地质和/或生物驱动器的主要碳同位素漂移在元古界？2)碳同位素偏移是氧合事件的良好指示吗？中元古代是碳同位素稳定的时期，因而地球系统处于停滞状态吗？