Targeted Basic Research to Enable Antarctic Science Applications of Cosmogenic-Nuclide Geochemistry

有针对性的基础研究使宇宙成因核素地球化学在南极科学应用成为可能

• 批准号: 2139497
• 负责人: Gregory Balco
• 金额: $ 39.91万
• 依托单位: Berkeley Geochronology Center
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-15 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2139497&HistoricalAwards=false
• 关键词: Targeted; Basic; Research; Enable; Antarctic

This project will conduct basic research into geological dating techniques that are useful for determining the age of glacial deposits in polar regions, Antarctica in particular. These techniques are necessary for determining how large the polar ice sheets were in the geologic past, including during past periods of warm climate that likely resemble present and near-future conditions. Thus, they represent an important technical capability needed for estimating the response of polar ice sheets to climate warming. Because changes in the size of polar ice sheets are the largest potential contribution to future global sea-level change, this capability is also relevant to understanding likely sea-level impacts of future climate change. The research in this project comprises several observational and experimental approaches to improving the speed, efficiency, cost, and accuracy of these techniques, as well as a scientific outreach program aimed at making the resulting capabilities more broadly available to other researchers. The project supports a postdoctoral scholar and contributes to human resources development in polar and climate science.The project focuses on several areas of cosmogenic-nuclide geochemistry, which is a geochemical dating method that relies on the production and decay of cosmic-ray-produced radionuclides in surface rocks. Measurements of these nuclides can be used to quantify the duration of surface exposure and ice cover at locations in Antarctica that are covered and uncovered by changes in the size of the Antarctic ice sheets, thus providing a means of reconstructing past ice-sheet change. The first proposed set of experiments are aimed at implementing a 'virtual mineral separation' approach to cosmogenic noble gas analysis that may allow measurement of nuclide concentrations in certain minerals without physically separating the minerals from the host rock. If feasible, this would realize significant speed and cost improvements for this type of analysis. A second set of experiments will focus on means of identifying and quantifying non-cosmogenic background inventories of some relevant nuclides, which is intended to improve the measurement sensitivity and precision for cosmic-ray-produced inventories of these nuclides. A third focus area aims to improve capabilities to measure multiple cosmic-ray-produced nuclides in the same sample, which has the potential to improve the accuracy of dating methods based on these nuclides and to expand the situations in which these methods can be applied. If successful, these experiments are likely to improve a number of applications of cosmogenic-nuclide geochemistry relevant to Antarctic research, including subglacial bedrock exposure dating, dating of multimillion-year-old glacial deposits, and surface-process studies useful in understanding landform evolution and ecosystem dynamics.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.

该项目将对地质日期技术进行基础研究，这些研究对于确定极地区域（尤其是南极洲）的冰川沉积物的年龄很有用。这些技术对于确定极地冰盖在地质过去的大小是必要的，包括在过去的温暖气候中，可能类似于当前和近乎未来的条件。因此，它们代表了估计极地冰盖对气候变暖的响应所需的重要技术能力。由于极地冰盖的大小的变化是对未来全球海平面变化的最大潜在贡献，因此这种能力也与了解未来气候变化的海平面影响可能有关。该项目的研究包括几种观察和实验方法，可提高这些技术的速度，效率，成本和准确性，以及旨在使所得能力更广泛地可为其他研究人员提供的科学外展计划。该项目支持一位博士后学者，并为极地和气候科学的人力资源发展做出了贡献。该项目着重于宇宙基因核核酸化学的多个领域，这是一种地球化学约会方法，依赖于宇宙射线产生和衰减在地面岩石中产生的放射性核素的生产和衰减。这些核能的测量值可用于量化南极洲的表面暴露和冰盖的持续时间，这些核能被南极冰盖大小的变化所覆盖和发现，从而提供了一种重建过去冰杆变化的手段。第一套提出的实验集旨在实施一种“虚拟矿物分离”方法，以实现宇宙贵族气体分析，该方法可以允许在某些矿物质中测量核素浓度，而不会物理地将矿物从宿主岩中分离出来。如果可行的话，这将实现此类分析的显着速度和成本提高。第二组实验将集中在识别和量化某些相关核素的非颜色背景清单的手段上，这旨在提高这些核素产生的宇宙射线产生的清单的测量灵敏度和精度。第三个焦点区域旨在提高在同一样品中测量多个宇宙射线产生的核素的能力，这有可能根据这些核素提高约会方法的准确性，并扩大可以应用这些方法的情况。如果成功，这些实验可能会改善与南极研究相关的宇宙核核核地球化学的许多应用，包括冰川下基岩的暴露年代约会，数百万年前的冰川沉积物的日期，表面过程和表面程序过程有用，可用于理解地面和生态系统动力学。智力优点和更广泛的影响审查标准。