Collaborative Research: EAR Climate: Earth-System Responses to the Penultimate Icehouse-Greenhouse Transition

合作研究：EAR 气候：地球系统对倒数第二个冰室-温室转变的反应

• 批准号: 2317597
• 负责人: Jahandar Ramezani
• 金额: $ 17.28万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-10-01 至 2028-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2317597&HistoricalAwards=false
• 关键词: Collaborative; Research; EAR; Climate; Earth

About 300 million years ago, large glaciers and ice sheets at high latitudes waxed and waned as Earth’s climate alternated between glacial and interglacial states, continuing a pattern that had persisted for several millions of years. Shortly thereafter, however, the glaciers collapsed entirely, and the Earth system lurched beyond an ice-free state into an increasingly severe “hothouse” climate, powered in large part by a massive and sustained release of greenhouse gases into the atmosphere, ultimately culminating in the largest extinction of life known in Earth history. This project will examine a complete record of this dramatic transition by recovering and studying a 2000 m-long rock core from what was, at that time, the equatorial region of the planet, which is now the US midcontinent (Oklahoma). The principal goal is to uncover the driving forces for these extreme environmental changes, shedding light on the fundamental workings of the Earth system (geosphere-atmosphere-biosphere connections) during an interval of unprecedented upheaval. This project involves many students and early-career researchers across twelve US research institutions, in addition to international collaborators, and additionally will engage Native American youth, educators, scientists, artists and poets in Oklahoma and beyond.This project seeks to elucidate paleoenvironments, biogeochemical cycling, and responses of the terrestrial biosphere to climate forcing during the Permian Period, a critical time in the evolution of Earth and life. A drill core will be taken in the Anadarko Basin (Oklahoma), which is a deep continental basin that preserves a globally unique and stratigraphically complete archive of the continental Permian in equatorial Pangaea. A well-preserved paralic-to-continental transition is overlain by a succession of red-bed, paleo-loess/dust, lacustrine, and evaporite deposits that collectively record the demise of the Late Paleozoic Ice Age and an intensifying greenhouse climate, culminating in the most severe mass extinction in Earth history. The project will establish a high-resolution chronostratigraphic framework by integrating U-Pb geochronology, astrochronology, magnetostratigraphy, and biostratigraphy. The resulting framework will serve as the scaffolding for subsequent research designed to test hypotheses focused on the interrelationships among climatic, orogenic, and biotic changes during an interval characterized by pronounced Earth-system upheavals. This research addresses major questions relevant to both Earth’s past and its future, as it will elucidate various mechanistic linkages, e.g. among atmospheric dust, climate, mountains, and the biosphere on an Earth experiencing a cold-to-hot climate transition. Owing to the known importance but great uncertainty of the role of dust in the Earth system, exploration of these links will measurably expand the knowledge of Earth system behavior across the Phanerozoic.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.

大约3亿年前，随着地球气候在冰期和间冰期之间交替，高纬度地区的大型冰川和冰盖出现消长，延续了数百万年的模式。然而，此后不久，冰川完全崩溃，地球系统从无冰状态转变为日益严重的“温室”气候，这在很大程度上是由大量持续释放到大气中的温室气体驱动的，最终导致地球历史上最大的生命灭绝。该项目将通过恢复和研究一个2000米长的岩石核心来检查这一戏剧性转变的完整记录，该核心来自当时的地球赤道地区，现在是美国中部大陆（俄克拉荷马州）。主要目标是揭示这些极端环境变化的驱动力，揭示地球系统（地圈-大气-生物圈连接）在前所未有的动荡时期的基本运作。该项目涉及美国12个研究机构的许多学生和早期职业研究人员，以及国际合作者，此外还将吸引俄克拉荷马州及其他地区的美洲原住民青年，教育家，科学家，艺术家和诗人。该项目旨在阐明二叠纪时期的古环境，地球化学循环以及陆地生物圈对气候强迫的反应，地球和生命进化的关键时期将在阿纳达科盆地（俄克拉荷马州）采集岩心，该盆地是一个深陆盆地，保存了全球唯一的、在地层学上完整的赤道泛大陆大陆二叠纪档案。一个保存完好的白垩纪到大陆的过渡被一系列红层、古黄土/尘埃、湖泊和蒸发岩沉积物覆盖，这些沉积物共同记录了晚古生代冰河时代的消亡和温室气候的加剧，最终导致了地球历史上最严重的大规模灭绝。该项目将通过整合U-Pb地质年代学、天体年代学、磁性地层学和生物地层学，建立一个高分辨率的年代地层格架。由此产生的框架将作为后续研究的脚手架，旨在测试假设集中在气候，造山和生物变化之间的相互关系，在一个时间间隔的特点是明显的地球系统的动荡。这项研究解决了与地球的过去和未来有关的主要问题，因为它将阐明各种机械联系，例如在经历冷到热气候转变的地球上的大气尘埃，气候，山脉和生物圈之间的联系。由于尘埃在地球系统中的作用具有已知的重要性，但存在很大的不确定性，对这些联系的探索将大大扩展对显生宙地球系统行为的了解。该奖项反映了NSF的法定使命，并且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。