EAGER: Dating Arctic Lake Sediments with Beryllium-10 Markers of Solar Proton Events

EAGER：利用太阳质子事件的铍 10 标记测定北极湖沉积物的年代

• 批准号: 2404514
• 负责人: Raymond Bradley
• 金额: $ 26.99万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2404514&HistoricalAwards=false
• 关键词: EAGER; Dating; Arctic; Lake; Sediments

Arctic lake sediment records often have clear layers, called laminations, which form due to the uniqueness of the Arctic seasons. During the short melt season, sediments become mobilized and transported into lakes by streams, where the material is deposited on the lake bottom. This is followed by a lengthy winter characterized by lake surface freezing and the slow settling of fine grained material. Consequently, an annual couplet of sediment, referred to as a varve is formed, with coarser material underlying a fine-grained clay cap. These varved records offer valuable information about past climate and environmental changes. However, it is crucial to confirm their timeline using an independent method to ensure confidence in the established time scale. Solar Proton Events (SPEs) are one such potential independent method. SPEs are bursts of high-energy particles released from the Sun during specific solar activities. When these particles reach Earth, they can interact with atmospheric gases, creating isotopes like 10Be, which make their way onto the land surface and eventually into lake sediments. This study proposes to use 10Be anomalies from SPEs as a tool for verifying varve records. By analyzing and comparing 10Be concentrations in laminated sediments collected from various locations across the sub- to high-Arctic, this research aims to determine if 10Be increases associated with SPEs can be used as a reliable method for confirming varved record chronologies. If this method is confirmed, demonstrating that sediment 10Be increases associated with SPEs can verify varve records, it would be a transformative development, allowing precise comparisons between different varved lake sedimentary records and various other records like ice cores, tree rings, and lacustrine (lake-related) records. Ultimately, this could significantly improve our understanding of past climate changes and variability. The research plan includes STEM opportunities for high school students to learn about climate change and to better understand their local environment. This will involve an active learning workshop. The project will also involve students from the University’s Honors College (Commonwealth College) who will participate in lab work and gain research experience.As a consequence of the short Arctic melt season, when sediment is mobilized and then carried by streams and deposited in lakes, followed by a long period when the surface is frozen and fine-grained material settles to the sediment surface, many Arctic lake sediment records are well-laminated, with an annual couplet of sediment (a varve); a layer of coarse material overlain by a fine-grained clay cap. These laminated layers have the potential to serve as a paleo-clock (a chronology). However, to provide confidence in this clock, it needs to be confirmed by an independent method. This study focuses on such a confirmation. The investigator proposes to identify 10Be anomalies resulting from solar proton events (SPEs) in a set of laminated sediments collected from lakes in different locations, ranging from the sub- to high Arctic, to test whether 10Be increases associated with SPEs can be used to confirm varved record chronology. If successful, this work would represent a transformative development, allowing high-resolution comparisons to be made between different varved lake sedimentary records and between ice cores, tree rings, and lake sediments. The research plan includes STEM opportunities for high school students to learn about climate change and to better understand their local environment. This will involve an active learning workshop. The project will also involve students from the University’s Honors College (Commonwealth College) who will participate in lab work and gain research experience.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.

北极湖泊沉积物记录通常具有清晰的层，称为层状层，这是由于北极季节的独特性而形成的，沉积物被流动并通过溪流输送到湖泊中，物质沉积在湖底。接下来是漫长的冬季，其特点是湖面结冰，细粒物质缓慢沉降，形成了一年一度的沉积物，称为“泥瓦”，在细粒粘土盖层下面有较粗的物质。提供然而，使用独立方法确认其时间表以确保对既定时间尺度的信心至关重要，太阳质子事件（SPE）是一种潜在的高强度爆发。当这些粒子到达地球时，它们会与大气中的气体相互作用，产生 10Be 等同位素，这些同位素会进入陆地表面并最终进入湖泊沉积物。 SPE 异常作为验证 varve 记录的工具 通过分析和比较从亚北极到高纬度地区收集的层状沉积物中的 10Be 浓度，本研究旨在确定与 SPE 相关的 10Be 增加是否可以用作可靠的证据。确认 varve 记录年代学的方法如果该方法得到证实，证明与 SPE 相关的沉积物 10Be 增加可以验证 varve 记录，这将是一项革命性的发展，可以实现精确的记录。不同的湖泊沉积记录和各种其他记录（如冰芯、树木年轮和湖泊（与湖泊相关）记录）之间的比较最终可以显着提高我们对过去气候变化和变异性的理解。该项目还将让大学荣誉学院（联邦学院）的学生参与实验室工作并获得研究经验。一个后果在短暂的北极融化季节中，沉积物被流动，然后被溪流携带并沉积在湖泊中，随后是地表冻结且细粒物质沉降到沉积物表面的较长时期，许多北极湖泊沉积物记录都很好。层压，具有一年一度的沉积物（a varve）；一层由细粒粘土覆盖的粗糙材料，这些层压层有可能充当古钟（年代学）。为了对这个时钟充满信心，本研究的重点是确定从不同地点的湖泊收集的一组层状沉积物中由太阳质子事件（SPE）引起的 10Be 异常。范围从北极到北极，以测试与 SPE 相关的 10Be 增加是否可用于确认 varved 记录年代学。如果成功，这项工作将代表一项变革性的发展，允许进行高分辨率比较。该研究计划包括为高中生提供 STEM 机会，让他们了解气候变化并更好地了解当地环境。该项目还将邀请来自大学荣誉学院（联邦学院）的学生参加实验室工作并获得研究经验。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优势和更广泛的评估，被认为值得支持。影响审查标准。