RII Track-4: Why are Young Volcanic Rocks Undateable: Chemistry, Environment, or Instrumentation?

RII Track-4：为什么年轻的火山岩无法测年：化学、环境或仪器？

• 批准号: 1833105
• 负责人: Jeff Benowitz
• 金额: $ 22万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-10-01 至 2020-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1833105&HistoricalAwards=false
• 关键词: RII; Track; Why; Young; Volcanic

Nontechnical Description Geochronology is the field of science that determines the age of earth materials using trace radioisotopes contained in rocks and other minerals when they were formed. Different methods used for radiometric dating apply to different materials and vary in the timescales over which they are accurate. This fellowship enables an early career researcher at the University of Alaska Fairbanks and a graduate student trainee to collaborate with researchers at the Oregon State University. While there they will use state-of-the art equipment to determine the age of young volcanic rocks from Alaska's Aleutian and Wrangell arcs. Precise geological dating of young volcanic rocks is important in understanding the eruptive history of volcanoes in Alaska, volcanic and seismic hazards assessment, and tectonic reconstructions. The project will investigate how the chemistry and environments of the samples and the sensitivity and precision of available measurement instrumentation contribute to the uncertainties in determining the age of young volcanic rocks. The research will enable the development of new methods to accurately date young volcanic rocks and lead to improved research capabilities for the PI at his home institution. The training and collaborations accrued through this project will enrich the careers of the participating faculty and students. Technical Description This award will allow researchers at the University of Alaska-Fairbanks to collaborate with the Oregon State University Argon Geochronology Laboratory (OSU-AGL) to produce high-precision 40Ar/39Ar geochronology data to determine the age of volcanic rocks and products from Alaska?s Aleutian and Wrangell arcs. Accurate dating of these young volcanic rocks is hampered by uncertainties arising from radiochemistry within the samples, limitations on the available instrumentation, and mass fractionation processes in the magma chamber. This project overcomes some of these difficulties through systematic experimentation of the volcanic rocks using the noble gas multi-collector mass spectrometer and software available at the OSU-AGL. The researchers will select samples from a broad range of tectonic-magmatic settings, for example, monogenic cones, intraplate, arc-transform magmatism, and arc magmatism, to investigate potential mass fractionation influences. The PI and his graduate student will extend their expertise with the use of a noble gas mass spectrometer by peak-hopping on a single detector and will be trained in the operation of modern instrumentation with the potential to enhance the research instrumentation and capabilities at their home institution.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.

非技术描述 地质年代学是一门科学领域，它利用岩石和其他矿物形成时所含的痕量放射性同位素来确定地球材料的年龄。 用于放射性测年的不同方法适用于不同的材料，并且其准确的时间尺度也有所不同。 该奖学金使阿拉斯加大学费尔班克斯分校的早期职业研究员和研究生实习生能够与俄勒冈州立大学的研究人员合作。 在那里，他们将使用最先进的设备来确定阿拉斯加阿留申群岛和兰格尔群岛弧上年轻火山岩的年龄。 对年轻火山岩进行精确的地质年代测定对于了解阿拉斯加火山喷发历史、火山和地震危害评估以及构造重建具有重要意义。 该项目将研究样本的化学成分和环境以及现有测量仪器的灵敏度和精度如何影响确定年轻火山岩年龄的不确定性。 这项研究将有助于开发新方法来准确测定年轻火山岩的年代，并提高 PI 在其所在机构的研究能力。 通过该项目获得的培训和合作将丰富参与教师和学生的职业生涯。 技术描述 该奖项将使阿拉斯加大学费尔班克斯分校的研究人员能够与俄勒冈州立大学氩地质年代学实验室 (OSU-AGL) 合作，生成高精度 40Ar/39Ar 地质年代学数据，以确定阿拉斯加火山岩和产品的年龄阿留申岛弧和兰格尔弧。这些年轻火山岩的准确年代测定受到样本内放射化学产生的不确定性、可用仪器的限制以及岩浆室中的质量分馏过程的阻碍。 该项目通过使用 OSU-AGL 提供的惰性气体多接收器质谱仪和软件对火山岩进行系统实验，克服了其中一些困难。 研究人员将从广泛的构造岩浆环境中选择样本，例如单源锥体、板内岩浆作用、弧变换岩浆作用和弧岩浆作用，以研究潜在的质量分馏影响。 PI 和他的研究生将通过在单个检测器上跳峰来扩展他们使用惰性气体质谱仪的专业知识，并将接受现代仪器操作的培训，有可能增强他们家里的研究仪器和能力该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。