A Robust Temporal Framework for the Paleoproterozoic Crash of Atmospheric Oxygen

大气氧的持续上升对生物进化轨迹和全球养分循环具有重要意义。这项工作将测试古元古代大规模环境变化与生物宏观进化之间的联系。研究人员将获得俄罗斯奥涅加盆地和加蓬拉斯托斯维尔盆地沉积物的年龄限制，以评估碳埋藏事件的同步性，这些事件可能与古元古代大气氧水平的超调和崩塌有关。他们获得的地球化学限制条件将允许批判性地评估海洋条件和氧气水平的同步性和范围，在地球历史上可能对碳循环造成最严重干扰的结束。这些努力将与科学视频记录系列“Terralingua：阅读岩石记录”相配合，该系列将通过社交媒体上的traveling地质学家平台广泛传播，覆盖全球100多万观众。该系列将提供内容，重点介绍地球科学家完成的各种任务，包括在俄罗斯与国际合作者团队进行的实地工作，地球化学实验室和质谱工作，还将涵盖进入地球科学和学术界的常见障碍。该项目的目的是提高我们对俄罗斯Onega盆地和加蓬Lastoursville盆地~2.3-2.0 Ga Lomagundi-Jatuli （LJ）正碳同位素漂移和随后的Shunga负碳同位素漂移期间大气氧的轨迹的理解。提出的研究将解决：1)氧化风化在这些碳同位素漂移过程中是如何变化的？2)在Onega盆地和Lastoursville盆地，lj末和Shunga事件是否同步发生？确定的岩石学、同位素和时间限制将允许全球相关性，并在这个关键时刻为氧化风化和全球碳循环的兴起提供新的见解。这将通过培养一名博士生和博士后，制作广泛传播的地球化学视频系列（Terralingua：阅读岩石记录），以及促进实地和实验室地球科学领域以及更广泛的学术界的包容性，支持教育、推广和多样性倡议。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The protracted rise of atmospheric oxygen has important implications for the trajectory of biological evolution and global nutrient cycling. This work will test ties between large-scale environmental changes and biotic macroevolution in the Paleoproterozoic. Investigators will obtain age constraints for sediments within the Onega Basin of Russia and the Lastoursville Basin of Gabon to evaluate the synchroneity of carbon burial episodes potentially associated with an overshoot and crash of atmospheric oxygen levels in the Paleoproterozoic era. The geochemical constraints they obtain will allow to critically evaluate the synchronicity and extent of marine conditions and oxygen levels at the termination of what may have been the most dramatic disturbance to the carbon cycle in Earth history. These efforts will be paired with a science video-logging series, Terralingua: Reading the Rock Record, which will be broadly disseminated through the TravelingGeologist platform on social media, reaching a total audience of over one million globally. This series will provide content highlighting the variety of tasks that geoscientists complete, including field work in Russia with a team of international collaborators, geochemistry laboratory and mass spectrometry work, and will also cover common barriers to entry in the geosciences and academia.The goal of this project is to improve our understanding of the trajectory of atmospheric oxygen during the ~2.3-2.0 Ga Lomagundi-Jatuli (LJ) positive carbon isotope excursion and the subsequent Shunga negative carbon isotope excursion in the Onega Basin of Russia and the Lastoursville Basin of Gabon. The proposed research will address: 1) How did oxidative weathering vary during these carbon isotope excursions? 2) Do the end-LJ and the Shunga Event occur synchronously in the Onega and Lastoursville Basins? The petrologic, isotopic and temporal constraints to be determined will permit global correlations and shed novel insights into the rise of oxidative weathering and global carbon cycling at this critical juncture. This will support education, outreach, and diversity initiatives through the training of a PhD student and postdoc and the production of a broadly disseminated videologging series (Terralingua: Reading the Rock Record) focused on geochemistry as well as promoting inclusivity in field- and laboratory-based geoscience fields and more broadly within academia.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.