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有清晰的层状，称为层状，这是由于北极季节的独特性而形成的。在短暂的融化季节，沉积物被动员起来，并通过溪流进入湖泊，在那里物质沉积在湖底。接下来是一个漫长的冬季，其特点是湖面结冰，细粒物质缓慢沉淀。因此，形成了一个每年的沉积物对联，称为阀，在细粒粘土盖层下有较粗的物质。这些阀记录提供了有关过去气候和环境变化的宝贵信息。然而，至关重要的是要用一种独立的方法来确认他们的时间表，以确保对既定时间尺度的信心。太阳质子事件（spe）就是这样一种与电位无关的方法。太阳耀斑是太阳在特定活动期间释放的高能粒子爆发。当这些粒子到达地球时，它们会与大气气体相互作用，产生像10Be这样的同位素，这些同位素会进入陆地表面，最终进入湖泊沉积物。本研究建议使用spe的10Be异常作为验证阀门记录的工具。通过分析和比较从亚北极到高北极不同地点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增加是否可以作为确认不同记录年表的可靠方法。如果这种方法得到证实，表明与spe相关的沉积物10Be增加可以验证阀记录，这将是一个革命性的发展，可以在不同的阀湖沉积记录与各种其他记录(如冰芯、树木年轮和湖泊（湖泊相关）记录之间进行精确比较。最终，这将大大提高我们对过去气候变化和变异的理解。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。这将包括一个积极的学习研讨会。该项目还将涉及大学荣誉学院（联邦学院）的学生，他们将参与实验室工作并获得研究经验。由于北极融化季节较短，沉积物被动员起来，然后被河流携带并沉积在湖泊中，随后是表面冻结和细颗粒物质沉积到沉积物表面的很长一段时间，许多北极湖泊沉积物记录是很好的层压，每年都有沉积物对偶（一个变量）；一层粗糙的材料，上面覆盖着一层细粒粘土。这些层压层有可能作为古时钟（年表）。然而，为了提供对这个时钟的信心，它需要通过一个独立的方法来确认。本研究着重于这一证实。研究人员建议在从亚北极到高北极的不同地点的湖泊收集的一组层状沉积物中确定由太阳质子事件（spe）引起的10Be异常，以测试与spe相关的10Be增加是否可以用于确认不同的记录年代学。如果成功，这项工作将代表着一个革命性的发展，使不同的湖泊沉积记录之间以及冰芯，树木年轮和湖泊沉积物之间的高分辨率比较成为可能。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。这将包括一个积极的学习研讨会。该项目还将涉及大学荣誉学院（联邦学院）的学生，他们将参与实验室工作并获得研究经验。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。