NSFGEO-NERC: Collaborative Research: Developing a new Lower Cretaceous time scale: Foundation for the next generation of paleoceanographic and biogeochemical studies

NSFGEO-NERC：合作研究：制定新的下白垩世时间尺度：下一代古海洋学和生物地球化学研究的基础

• 批准号: 1951835
• 负责人: Bradley Sageman
• 金额: $ 30.19万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-11-15 至 2024-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951835&HistoricalAwards=false
• 关键词: NSFGEO; NERC; Collaborative; Research; Developing

The Cretaceous was a time of global warming during which atmospheric carbon dioxide levels surpassed 800 ppm, similar to those predicted for 2100 by “business-as-usual” emission scenarios. Cretaceous rocks record high sea levels, high biological productivity, massive volcanism, and major perturbations of the carbon cycle during several ocean anoxic events (OAEs). Understanding these phenomena can provide deep-time analogs for future greenhouse scenarios. Marine sediments that record these crises are globally widespread but weaving these records into a common temporal framework is essential if they are to reveal the causes. This project aims to generate a new temporal framework spanning 125 to 93 million years ago during which several major OAEs occurred. This will permit examination of repeated deteriorations of marine ecosystems across the Pacific, Atlantic, and Mediterranean oceans. The team will be involved in novel outreach, international collaboration, and training of future earth science leaders. They will bring deep-time science to the public via presence at the Sturgis Motorcycle Rally. The favored hypothesis for ocean anoxic events involves volcanic initiation leading to a cascade of processes amplifying global marine production; key factors are the nature of volcanism and the source of increased nutrients. Yet geographic differences in proxy records (Carbon and Osmium isotopes) indicate additional complexities, such as sea level and ocean circulation. The goals for the project are to establish: (1) A new time scale for global geochemical and paleobiologic datasets; (2) Chemostratigraphic correlation of the new time scale to European sections using isotope stratigraphy, and (3) A new global time scale for improved understanding of major biogeochemical perturbations. The team will: (i) Determine radioisotopic ages of rhyolitic tuffs in sediments of Japan, (ii) Integrate these new ages with new Osmium and Carbon isotope chemostratigraphy in Europe, (iii) Compile global geochemical proxy data for OAE 1a within a common temporal and stratigraphic framework, and analyze trends and patterns from the Pacific to Europe, (iv) Evaluate the volcanic versus climatic/orbital hypotheses for OAE initiation, and (v) Explore the significance of geography in the timing and magnitude of geochemical signals.This is a project that is jointly funded by the National Science Foundation’s Directorate of Geosciences (NSF/GEO) and the National Environment Research Council (UKRI/NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award, each Agency funds the proportion of the budget and the investigators associated with its own investigators and component of the work.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.

白垩纪是全球变暖的时期，大气中二氧化碳含量超过 800 ppm，与“一切照旧”排放情景预测的 2100 年类似。白垩纪岩石记录了高海平面、高生物生产力、大规模火山活动以及几次海洋缺氧事件（OAE）期间碳循环的重大扰动。了解这些现象可以为未来的温室场景提供深度模拟。记录这些危机的海洋沉积物在全球范围内广泛存在，但如果要揭示危机的原因，将这些记录编织到一个共同的时间框架中至关重要。 该项目旨在生成一个跨越 125 至 9300 万年前的新时间框架，在此期间发生了几次主要的 OAE。这将有助于检查太平洋、大西洋和地中海海洋生态系统的反复恶化。该团队将参与新颖的外展活动、国际合作以及未来地球科学领导者的培训。他们将通过参加斯特吉斯摩托车拉力赛向公众带来深度科学。 对于海洋缺氧事件，人们所青睐的假设涉及火山喷发，导致一系列放大全球海洋生产的过程；关键因素是火山活动的性质和增加的营养物质的来源。然而，代理记录（碳和锇同位素）的地理差异表明了额外的复杂性，例如海平面和海洋环流。该项目的目标是建立：（1）全球地球化学和古生物学数据集的新时间​​尺度； (2) 使用同位素地层学将新的时间尺度与欧洲剖面进行化学地层关联，以及 (3) 新的全球时间尺度，以提高对主要生物地球化学扰动的理解。该团队将：(i) 确定日本沉积物中流纹质凝灰岩的放射性同位素年龄，(ii) 将这些新年龄与欧洲新的锇和碳同位素化学地层学相结合，(iii) 在共同的时间和地层框架内编制 OAE 1a 的全球地球化学代理数据，并分析从太平洋到欧洲的趋势和模式，(iv) 评估火山 与气候/轨道假设对 OAE 启动的影响，以及 (v) 探索地理在地球化学信号的时间和幅度方面的重要性。该项目由美国国家科学基金会地球科学理事会 (NSF/GEO) 和英国国家环境研究委员会 (UKRI/NERC) 通过 NSF/GEO-NERC 牵头机构协议共同资助。该协议允许美国/英国的单一联合提案由其调查人员拥有最大预算比例的机构提交并进行同行评审。在成功联合确定奖项后，每个机构将资助一定比例的预算以及与自己的调查人员和工作组成部分相关的调查人员。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。