EAR-PF: Mid-Miocene climate, vegetation, and disturbance dynamics of the Pacific Northwest

该奖项全部或部分根据2021年美国救援计划法案（公法117-2）资助。Christopher Schiller博士被授予NSF博士后奖学金，在Caroline Stromberg博士和Mark D.的指导下，在华盛顿大学和博伊西州立大学进行研究，专业发展和推广活动。施密茨，分别。了解比现在更温暖的气候下的地球系统，是了解人类引起的气候变化导致的未来变暖后果的有用方法。地球历史上的一个温暖时期是大约1700 - 1400万年前的中新世中期气候适宜期（MMCO），当时全球气温比现代工业化前时期高4-7°C。来自MMCO的化石植物组合已被用于了解当时的气候和生态系统如何在长时间（数百万年）的时间尺度上发挥作用。然而，在较短的时间尺度上（几十万年或更短）发挥作用的气候和生态系统过程的重要性往往没有得到考虑。新的研究表明，短时间尺度的气候变化和频繁的大规模火山爆发可能极大地影响了MMCO生态系统。因此，目前还不清楚在化石植物组合中看到的生态系统变化是代表长期气候条件还是对短期过程的反应。这项研究的MMCO植被在太平洋西北部的目的是了解生态系统变化的原因，在化石植物。将研究化石花粉组合，以检查生态系统在短时间内的变化，以及气候，火灾或火山爆发是否可能导致这些变化。 具体而言，本项目将研究俄勒冈州的两个中新世中期古植物群，Succor Creek植物群和Mascall植物群，（高分辨率）植被状态将从花粉重建，几种类型的同期生态干扰将从木炭（火），多环芳烃（火），元素地球化学（景观稳定性）和详细的岩性描述（景观稳定性和火山爆发）。短期记录将与长期（粗分辨率）植被记录进行比较，后者将从同一植物群的较长地层剖面和从一个同时进行的项目（1924390）产生的中新世长度记录中产生。从每个植物群的U-Pb锆石日期套件将允许一个强大的年表，所有植被干扰重建，并使相关的日照解决方案和海洋气候记录。该项目将有助于对未充分研究的前第四纪孢粉学领域进行现代检查，调查植被对过去一段时期剧烈气候变化和强烈火山活动的反应，并应用多种代理来了解MMCO生态系统功能，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响评审标准。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Dr. Christopher Schiller has been awarded an NSF EAR Postdoctoral Fellowship to conduct research, professional development, and outreach activities at the University of Washington and Boise State University under the mentorship of Drs. Caroline Stromberg and Mark D. Schmitz, respectively. Understanding the Earth system under climates warmer than today is a useful approach for understanding the consequences of future warming resulting from human-caused climate change. One such warm period in the Earth’s history is the Mid-Miocene Climatic Optimum (MMCO), approximately 17-14 million years ago, when global temperatures were 4-7°C warmer than the modern, pre-industrial period. Fossil plant assemblages from the MMCO have been used to understand how the climate and ecosystems of that time functioned on long (millions of years) timescales. However, the importance of climate and ecosystem processes that function on shorter (hundreds of thousands of years and shorter) timescales has not often been considered. New research has suggested that climate change on short timescales and large, frequent volcanic eruptions may have greatly affected MMCO ecosystems. Therefore, it becomes unclear if ecosystem changes seen in fossil plant assemblages are representative of long-term climate conditions or a response to short-term processes. This study of MMCO vegetation in the Pacific Northwest aims to understand the cause of ecosystem change seen in fossil plants. Fossil pollen assemblages will be studied to examine ecosystem change over short timescales and if climate, fire, or volcanic eruptions may have caused those changes. Specifically, this project will examine two mid-Miocene paleofloras in Oregon, the Succor Creek Flora and Mascall Flora, from which short-term (high-resolution) vegetation states will be reconstructed from pollen and contemporaneous ecological disturbances of several types will be constructed from charcoal (fire), polycyclic aromatic hydrocarbons (fire), elemental geochemistry (landscape stability), and detailed lithological descriptions (landscape stability and volcanic eruptions). Short-term records will be compared with long-term (coarse-resolution) vegetation records, which will be produced from longer stratigraphic sections from the same floras and Miocene-length records produced from a concurrent project (EAR-1924390). Suites of U-Pb zircon dates from each flora will allow for a robust chronology for all vegetation-disturbance reconstructions and enable correlation with insolation solutions and marine climate records. This project will contribute a modern examination of the understudied field of pre-Quaternary palynology, an investigation of the response of vegetation to a past period of dramatic climate change and intense volcanism, and an application of multiple proxies to understand MMCO ecosystem function, and mentorship of undergraduate science students.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.