Constraining the interplay of geodynamics with the biosphere and atmosphere across the Archean-Proterozoic boundary

限制太古代-元古代边界地球动力学与生物圈和大气的相互作用

• 批准号: RGPIN-2020-05639
• 负责人: Spencer, Christopher
• 金额: $ 2.55万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754994
• 关键词: Constraining; interplay; geodynamics; biosphere; atmosphere

This study aims to track changes in global geodynamics across the Archean-Proterozoic boundary to characterize the potential link between tectonics and the evolution of the biosphere and atmosphere. Earth's present-day surface environments are the product of 4.5 billion years of change that reflects global-scale geologic, atmospheric, and biologic processes. This secular evolution is punctuated with a handful of hallmark events that permanently and irreversibly altered chemical and biological systems worldwide. In particular, the transition from the Archean to Proterozoic Eons (2.5 billion years ago) is considered by many to have been the most significant period of time in Earth history. The geologic changes at this time carry implications for significant shifts in geodynamics which in turn may have influenced biologic evolution and atmospheric oxygenation. Numerous recent studies have demonstrated significant shifts in the geologic record from ~2.5 to ~2.1 billion years ago, including changes in the composition of igneous and sedimentary rocks, zircon, and atmosphere. The Archean-Proterozoic transition is also characterized by a lull in the preserved geologic record, rapid rise of continental crust above sea level, and the earliest episode of low-latitude glaciation. The short-term goals of this proposal are (1) to provide high resolution temporal constraints on shifts of oxygen and sulfur isotopic signatures in sedimentary and igneous rocks associated with Archean-Proterozoic transition and (2) to evaluate the geodynamics of discrete geologic regions during the geologic lull of 2.5-2.1 billion years ago, and the relationship between mountain building, rise of continents above sea-level, and the transfer of sedimentary material into the deep Earth. The isotopic research of this project will use cutting-edge micro-analytical techniques at leading geochemical facilities in Canada including the large-geometry ion probe facility at the University of Alberta as well as the analytical facilities at Queen's University. The current research program will support the research of eight HQPs (2 PhD, 2 MSc, 4 BSc). Students will receive an education in field geology, laboratory and analytical methods, and the process of interpreting and communicating scientific data to the scientific community and general public. The long-term goal of this research program is to provide a link between secular changes in the mantle that profoundly influenced the evolution of the biosphere and atmosphere that led to changes in the composition of sediment and the igneous rocks derived from deep in Earth's crust. The importance of this research program is a demonstration of the intertwined processes of the deep Earth with the biosphere and atmosphere. The new testable framework resulting from this research will provide avenues of continued science inquiry for many years to come.

这项研究旨在追踪太古代-元古代边界的全球地球动力学变化，以表征构造与生物圈和大气演化之间的潜在联系。地球目前的表面环境是 45 亿年变化的产物，反映了全球范围的地质、大气和生物过程。这种长期的进化过程中夹杂着一些标志性事件，这些事件永久且不可逆转地改变了全世界的化学和生物系统。特别是，从太古代到元古代（25亿年前）的过渡被许多人认为是地球历史上最重要的时期。此时的地质变化对地球动力学的重大变化产生了影响，而这反过来又可能影响生物进化和大气氧化。最近的大量研究表明，从约 2.5 亿年前到约 21 亿年前，地质记录发生了重大变化，包括火成岩和沉积岩、锆石和大气成分的变化。太古宙-元古代过渡的另一个特点是保存的地质记录的间歇期、大陆地壳迅速上升到海平面以上以及最早的低纬度冰川作用。该提案的短期目标是（1）为与太古宙-元古代过渡相关的沉积岩和火成岩中氧和硫同位素特征的变化提供高分辨率时间约束，以及（2）评估2.5-21亿年前的地质平静期，以及造山、大陆海拔上升以及沉积物质向地球深处转移之间的关系。该项目的同位素研究将使用加拿大领先的地球化学设施的尖端微分析技术，包括阿尔伯塔大学的大几何离子探针设施以及女王大学的分析设施。目前的研究计划将支持八名高级人才（2名博士、2名硕士、4名理学士）的研究。学生将接受野外地质学、实验室和分析方法以及向科学界和公众解释和传播科学数据的过程的教育。该研究计划的长期目标是提供地幔的长期变化之间的联系，这种变化深刻地影响了生物圈和大气的演化，导致了沉积物和地壳深处的火成岩成分的变化。该研究计划的重要性在于展示了地球深处与生物圈和大气层相互交织的过程。这项研究产生的新的可测试框架将为未来许多年持续的科学探究提供途径。