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

北极湖沉积物记录通常有清晰的层，称为纹层，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，通过溪流输送到湖泊中，在那里物质沉积在湖底。随之而来的是漫长的冬天，湖面结冰，细粒物质缓慢沉降。因此，形成了一年一度的沉积物对联，称为凹槽，在细粒粘土的盖子下面有较粗的物质。这些不同的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，必须使用独立的方法确认它们的时间表，以确保对既定时间表的信心。太阳质子事件(SPE)就是这样一种潜在的独立方法。SPE是太阳在特定太阳活动期间释放出的高能粒子的爆发。当这些颗粒到达地球时，它们可以与大气气体相互作用，产生像10Be这样的同位素，这些同位素进入陆地表面，最终进入湖泊沉积物。这项研究建议使用SPE的10Be异常作为验证VAVE记录的工具。通过分析和比较从亚北极到北极高地不同地点采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定不同记录年表的可靠方法。如果这一方法得到证实，证明与SPE相关的沉积物10Be增加可以验证VOLE记录，这将是一个革命性的发展，可以在不同的VARVE湖泊沉积记录与各种其他记录(如冰芯、树木年轮和湖泊相关)之间进行精确比较。最终，这可以显著提高我们对过去气候变化和可变性的理解。该研究计划包括为高中生提供STEM机会，以了解气候变化和更好地了解当地环境。这将包括一个积极的学习研讨会。该项目还将涉及来自该大学荣誉学院(英联邦学院)的学生，他们将参与实验室工作并获得研究经验。由于北极短暂的融化季节，沉积物被动员起来，然后被溪流携带并沉积在湖泊中，随后是一段长时间的表面冻结和细粒物质沉积到沉积物表面的时期，许多北极湖泊沉积物记录都是分层的，每年都有一对沉积物(一个凹槽)；覆盖着一层粗物质，上面覆盖着一个细粒的粘土盖子。这些叠层有可能充当古钟(年表)。然而，为了提供对这一时钟的信心，它需要通过一种独立的方法来确认。本研究的重点就是这一点的确认。这位研究人员建议在从北极次北极到高海拔不同地点的湖泊收集的一组层状沉积物中识别由太阳质子事件(SPE)引起的10Be异常，以测试与SPE相关的10Be增加是否可以用来确认不同的记录年代学。如果成功，这项工作将代表着一项变革性的发展，允许在不同的不同湖泊沉积记录之间以及在冰芯、树木年轮和湖泊沉积物之间进行高分辨率比较。该研究计划包括为高中生提供STEM机会，以了解气候变化和更好地了解当地环境。这将包括一个积极的学习研讨会。该项目还将包括来自该大学荣誉学院(英联邦学院)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NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.