Collaborative Research: Cosmogenic Radionuclides in the WAIS Divide Ice Core

Welten/0636964该奖项支持一个为期2年的项目，使用加速器质谱仪（AMS）测量南极冰样品中宇宙成因放射性核素10 Be，26 Al和36 Cl的浓度。该项目是一项试点研究，用于今后分析来自西澳大利亚州国际空间科学协会分水岭深冰芯的多达1 000个冰样中的放射性核素。由于这些冰芯研究涉及大量样品，以及及时分析宇宙成因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，与加州大学伯克利分校为Siple Dome和GISP-2冰芯开发的化学分离线相同。在对12-16个测试冰样品进行彻底的实验室间比较后，我们将使用两条提取线测量WAIS分水岭浅冰芯中的宇宙成因放射性核素。预计使用两条化学分离线将使样品处理量增加两倍，并确保普渡大学的AMS及时分析宇宙成因放射性核素。 该项目的智力价值在于，这些测量将使科学家能够将局部影响与全球影响分开。通过测量不同地点冰芯中的几种放射性核素，人们可以弄清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、沉积机制和雪积累率的变化等局部效应造成的;或者是由于太阳活动和地磁场强度的变化，影响大气中宇宙成因核素全球生产率的主要过程。最后，在WAIS分水岭浅芯与GISP 2冰芯中测量的26 Al/10 Be比率的比较将证明，如果这个比率可以被用作旧南极冰的绝对计时器。 这一项目的更广泛影响包括：组建一个多学科合作者小组，以解释今后对来自西澳大利亚国际空间科学院分水岭冰芯的宇宙成因放射性核素数据进行的分析;对本科生和研究生进行冰样化学处理方面的参与和培训;在更广泛的气候变化研究范围内解释宇宙成因核素数据;并向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。

Welten/0636964This 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.