Collaborative Research: Cosmogenic Radionuclides in the WAIS Divide Ice Core

合作研究：WAIS 分水岭冰芯中的宇宙放射性核素

• 批准号: 0636815
• 负责人: Marc Caffee
• 金额: $ 17.5万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-15 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0636815&HistoricalAwards=false
• 关键词: Collaborative; Research; Cosmogenic; Radionuclides; WAIS

Caffee/0636815This award supports a 2-year project to measure the concentrations of the cosmogenic radionuclides, 10Be, 26Al and 36Cl, in Antarctic ice samples using accelerator mass spectrometry (AMS). This project is a pilot study for the future analysis of radionuclides from up to 1000 individual ice samples of the WAIS Divide deep ice core. Because of the large number of samples that are involved in these ice core studies, and the importance of a timely analysis of cosmogenic radionuclides, we are proposing to set up a second chemical separation line, at Purdue University, identical to the one developed at UC Berkeley for the Siple Dome and GISP-2 ice cores. After a thorough interlaboratory comparison on 12-16 test ice samples, we will use both extraction lines to measure cosmogenic radionuclides in a shallow ice core from the WAIS Divide. It is to be expected that the use of two chemical separation lines will increase the sample throughput by a factor of two, and ensure a timely analysis of the cosmogenic radionuclides by AMS at Purdue University. The intellectual merit of the project is that these measurements will enable scientists to separate local from global effects. By measuring several radionculides in ice cores from different locations one can disentangle whether variations in absolute radionuclide concentrations and their ratios are due to local effects such as variations in atmospheric circulation, deposition mechanisms, and snow accumulation rates; or whether they are due to variations in solar activity and geomagnetic field strength, the primary processes influencing the global production rates of cosmogenic nuclides in the atmosphere. Finally, a comparison of the 26Al/10Be ratios in the WAIS Divide shallow core with those measured in the GISP2 ice core will demonstrate if this ratio can be used as an absolute chronometer of old Antarctic ice. The broader impacts of this project include the formation of a multi-disciplinary team of collaborators for the interpretation of future analyses of cosmogenic radionuclide data from the WAIS Divide ice core, the involvement and training of undergraduate and graduate students in the chemical processing of ice samples and interpretation of the cosmogenic nuclide data in the wider scope of climate change research, and explaining the importance of ice core and climate change studies to a wide range of lab visitors and students from local schools.

Caffee/0636815该奖项支持一个为期 2 年的项目，该项目使用加速器质谱 (AMS) 测量南极冰样本中的宇宙放射性核素 10Be、26Al 和 36Cl 的浓度。该项目是一项试点研究，旨在未来对来自 WAIS Divide 深冰芯的多达 1000 个冰样本中的放射性核素进行分析。由于这些冰芯研究涉及大量样本，以及及时分析宇宙放射性核素的重要性，我们建议在普渡大学建立第二条化学分离线，与加州大学开发的化学分离线相同伯克利的 Siple Dome 和 GISP-2 冰芯。在对 12-16 个测试冰样本进行彻底的实验室间比较后，我们将使用两条提取线来测量 WAIS 分水岭浅冰芯中的宇宙放射性核素。预计两条化学分离线的使用将使样品通量增加两倍，并确保普渡大学 AMS 及时分析宇宙放射性核素。 该项目的智力价值在于，这些测量将使科学家能够区分局部效应和全球效应。通过测量不同地点冰芯中的几种放射性核素，我们可以弄清楚放射性核素绝对浓度及其比率的变化是否是由于大气环流、沉积机制和积雪速率变化等局部影响造成的；或者它们是否是由于太阳活动和地磁场强度的变化造成的，而太阳活动和地磁场强度是影响大气中宇宙成因核素的全球生产率的主要过程。最后，将 WAIS Divide 浅层冰芯中的 26Al/10Be 比率与 GISP2 冰芯中测量的比率进行比较，将证明该比率是否可以用作旧南极冰的绝对计时表。 该项目的更广泛影响包括组建一个多学科合作团队，以解释未来对 WAIS Divide 冰芯宇宙成因放射性核素数据的分析、本科生和研究生参与冰样本化学处理并对其进行培训以及在更广泛的气候变化研究中解释宇宙成因核素数据，并向广大实验室参观者和当地学校的学生解释冰芯和气候变化研究的重要性。