Collaborative Research: A Proposal for the Cosmic-Ray prOduced NUclide Systematics on Earth (CRONUS-Earth) Project

合作研究：地球上宇宙射线产生的核素系统学（CRONUS-Earth）项目的提案

• 批准号: 0345820
• 负责人: Marc Caffee
• 金额: $ 20.29万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0345820&HistoricalAwards=false
• 关键词: Collaborative; Research; Proposal; Cosmic; Ray

ABSTRACTTerrestrial- in situ- cosmogenic nuclide (TCN) methods for surface exposure dating and otherearth-science applications were first demonstrated in 1986. During the subsequent 17 years these methods have developed into versatile and indispensable tools in many fields of modern Earth Sciences, including paleoclimatology, geomorphology, tectonics, hydrology, and volcanology. The TCN that have been demonstrated to be widely applicable are 3H, 10Be, 14C, 21Ne, 26Al, and 36Cl. This rapid development has been facilitated by methodological progress, including improvements in sampling strategies, sample preparation procedures and analyses of cosmogenic nuclides (by accelerator mass spectrometry (AMS) and noble gas mass spectrometry). In order to remain at the cutting edge of the earth sciences the accuracy of TCN methods must be significantly improved. However, it is the consensus of practitioners in the field that further developments are instead moving toward an impasse. This limitation is imposed, not by methodological considerations, but rather by incomplete understanding of the fundamental physical processes, and by lack of rigorous intercomparability between different investigators and methods. The global distribution of cosmogenic nuclide production depends on a number of interrelated factors, and thesefactors must be simultaneously controlled in order to arrive at the equations and parameters that accurately define production rates at all points, and over geological time. This task is far beyond the capability of any individual investigator.In order to achieve this next, necessary, step the CRONUS-Earth Project is proposed. The projecthas the following goals: (i) to establish a rigorous basis for intercomparison between measurement of different nuclides and by different investigators, (ii) to provide a firm linkage between cosmic-ray physics and the systematics of the TCN produced by the cosmic rays, and (iii) to produce generally-accepted formulations and parameters for calculation of TCN production. The ultimate goal is to advance the precision and accuracy of all TCN methods from its current range of ~10% to 20% toward a 5% level. This project is envisioned as an international, collaborative effort. CRONUS-Earth consists of six major components: (i) A methodological intercomparison, including sample preparation as well as analytical measurement. (ii) Spatial/temporal distribution of cosmic-ray fluxes, through "mining" existing neutron monitor datasets, modeling of neutron monitor responses, and measurement of saturated in situ 14C altitude/latitude profiles. (iii) Emplacement of artificial targets for 3He, 21Ne, 10Be, 32P and 36Cl production, to link contemporary cosmic-ray fluxes to production rates and scaling factors. (iv) Measurement of production cross-sections using laboratory neutron beams. (v) A numerical modeling effort to integrate the observations and to calculate the effects of past geomagnetic and paleoclimatic changes on cosmogenicnuclide production. (vi) Geological calibration of nuclide production rates, based on independently-dated surfaces worldwide. These will be classified by quality into primary calibration sites and secondary, or "verification", sites that will be used to test the overall production-rate model. These six components comprise a synergistic and coordinated approach to a problem that is clearly beyond the scope of individuals and small research teams. We propose a consortium approach to managing the project, involving multiple investigators, annual meetings to monitor progress, compile data, and exchange with the community, rapid electronic distribution of results, and integration of the final products through a project office charged with disseminating the results to the community. A linked CRONUS-Europe proposal has been submitted to the EU and will be closely coordinated with CRONUS-Earth.The CRONUS-Earth Project will address the NSF intellectual merit review criterion throughestablishing an improved, quantitative, physically-based, understanding of TCN production andaccumulation that can be applied to solve a wide variety of problems in the earth sciences. The Project will address the broader impacts criterion by providing formulations, parameters, and computer codes that will constitute an intellectual infrastructure enabling more consistent, accurate, and widespread application of TCN methods in the earth sciences. Furthermore, the Project will provide a basis for a more formal and organized future approach to promoting consistency in application of TCN methods, such as committees to provide recommended values for parameters. Finally, it will include a component to directly involve undergraduates, and especially minority students, in research in aspects of earth science related to CRONUS.

在1986年首次证明了在现场宇宙核素（TCN）的表面暴露日期和其他术语科学应用的方法。在随后的17年中，这些方法已发展为现代地球科学的许多领域，包括古老的科学的许多领域， ，地貌，构造学，水文学和火山学。已被证明广泛适用的TCN为3H，10BE，14C，21NE，26AL和36Cl。方法学进步已经促进了这种快速发展，包括改进采样策略，样本制备程序和宇宙核素的分析（通过加速器质谱法（AMS）和贵重气体质谱法）。为了保持在地球科学的最前沿，必须显着提高TCN方法的准确性。但是，正是该领域的从业者共识，而是进一步发展朝着僵局发展。这种局限性不是通过方法上的考虑因素来实施的，而是由于对基本物理过程的不完全理解，并且由于不同研究者和方法之间缺乏严格的之间性。宇宙核素产生的全球分布取决于许多相互关联的因素，并且必须同时控制这些因素才能到达在所有点和地质时间上准确定义生产率的方程式和参数。这项任务远远超出了任何个人调查员的能力。为了实现下一个必要的步骤，提出了Cronus-Earth项目。 Projecthas以下目标：（i）为不同核素的测量和不同研究者之间的比较建立严格的基础，（ii）提供宇宙射线物理学与宇宙射线产生的TCN系统之间的牢固联系。 ，（iii）生产普遍认可的公式和参数来计算TCN产生。最终目标是将所有TCN方法的精确性和准确性从目前的范围从约10％到20％提高到5％的水平。该项目被认为是国际协作的努力。 Cronus-Areth由六个主要组成部分组成：（i）方法论对比，包括样品制备和分析测量。 （ii）通过“采矿”现有的中子监视器数据集，中子监视器响应的建模以及测量饱和的原位14C高度/纬度轮廓的测量，宇宙射线通量的空间/时间分布。 （iii）将3HE，21NE，10BE，32P和36Cl生产的人工靶标添加，以将当代宇宙射线助焊剂与生产率和扩展因子联系起来。 （iv）使用实验室中子束测量生产横截面。 （v）一项数值建模努力，以整合观察结果并计算过去的地磁和古气候变化对宇宙核苷酸产生的影响。 （vi）基于全球独立的表面的核素生产率的地质校准。这些将通过质量分类为主要校准位点以及将用于测试整体生产率模型的次要或“验证”站点。这六个组件包括一种协同和协调的方法，显然超出了个人和小型研究团队的范围。我们提出了一种管理项目的联盟方法，涉及多个调查人员，年度会议，以监控进度，与社区交流，快速电子分配结果以及通过负责传播结果的项目办公室集成最终产品向社区。链接的cronus-europe提案已提交给欧盟，并将与Cronus-Earth密切协调。Cronus-Earth项目将解决NSF知识绩效审查标准，通过改进的，定量的，基于物理的，对TCN生产的理解，并了解TCN的生产，并了解TCN。可以应用于解决地球科学中各种各样的问题。该项目将通过提供构成智力基础架构的公式，参数和计算机代码来解决更广泛的影响标准，从而使TCN方法在地球科学中更加一致，准确且广泛地应用。此外，该项目将为更正式和有组织的未来方法提供基础，以促进TCN方法的应用一致性，例如委员会为参数提供建议的价值。最后，它将包括直接涉及本科生，尤其是少数族裔学生的组成部分，参与与克罗努斯有关的地球科学方面的研究。