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: 0345440
• 负责人: Marek Zreda
• 金额: $ 59.41万
• 依托单位: University of Arizona
• 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 2012-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0345440&HistoricalAwards=false
• 关键词: Collaborative; Research; Proposal; Cosmic; Ray

Terrestrial- 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.

1986年首次演示了用于地表暴露定年和其他地球科学应用的地球原位宇宙成因核素（TCN）方法。在随后的17年里，这些方法已经发展成为现代地球科学许多领域中通用和不可或缺的工具，包括古气候学，地貌学，构造学，水文学和火山学。已被证明广泛适用的TCN是3 H，10 Be，14 C，21 Ne，26 Al和36 Cl。这一迅速发展得益于方法上的进步，包括采样战略、样品制备程序和宇宙成因核素分析（加速器质谱法和惰性气体质谱法）的改进。为了保持在地球科学的前沿，TCN方法的准确性必须大大提高。然而，这一领域的从业人员一致认为，进一步的发展正走向僵局。造成这种限制的原因不是方法上的考虑，而是对基本物理过程的不完全理解，以及不同研究者和方法之间缺乏严格的相互可比性。宇宙成因核素生产的全球分布取决于若干相互关联的因素，必须同时控制这些因素，以得出准确界定所有地点和地质时期生产率的方程式和参数。这项任务远远超出了任何一个独立研究者的能力。为了实现这一下一个必要的步骤，提出了CRONUS-地球项目。该项目的目标如下：（一）为不同研究人员对不同核素的测量结果进行相互比较建立严格的基础;（二）在宇宙射线物理学与宇宙射线产生的TCN系统学之间建立牢固的联系;（三）为计算TCN的产生量制定普遍接受的公式和参数。最终目标是将所有TCN方法的精密度和准确度从目前的约10%至20%提高到5%的水平。该项目被设想为一项国际合作努力。CRONUS-Earth由六个主要组成部分组成：㈠方法上的相互比较，包括样品制备和分析测量。(ii)宇宙射线通量的空间/时间分布，通过“挖掘”现有的中子监测器数据集，中子监测器响应的建模，以及饱和的原位14 C高度/纬度剖面的测量。(iii)为3 He、21 Ne、10 Be、32 P和36 Cl的生产安置人造靶，将当代宇宙射线通量与生产率和比例因子联系起来。(iv)利用实验室中子束测量生产截面。(v)一个数值模拟的努力，整合的观测和计算的影响，过去的地磁和古气候变化的宇宙成因核素的生产。(vi)根据世界各地独立定年的地表，对核素生产率进行地质校准。这些地点将按质量分为主要校准地点和次要或“验证”地点，后者将用于测试总体生产率模型。这六个组成部分包括一个协同和协调的方法来解决一个问题，显然超出了个人和小型研究小组的范围。我们提出了一个财团的方法来管理该项目，涉及多个调查员，年度会议，以监测进展情况，汇编数据，并与社区交流，快速电子分发的结果，并通过一个项目办公室负责传播的结果，以社区的最终产品的整合。一项与欧洲大陆核研究中心有关的提案已提交给欧盟，并将与欧洲大陆核研究中心地球项目密切协调。欧洲大陆核研究中心地球项目将通过建立一种改进的、定量的、以物理为基础的对TCN生产和积累的理解，来解决地球科学中的各种问题，从而解决NSF的智力价值审查标准。该项目将通过提供公式、参数和计算机代码来解决更广泛的影响标准，这些公式、参数和计算机代码将构成一个智能基础设施，使TCN方法能够在地球科学中得到更一致、更准确和更广泛的应用。此外，该项目将为今后采取更正式和更有组织的方法提供基础，以促进TCN方法应用的一致性，例如委员会提供参数的建议值。最后，它将包括一个组成部分，使本科生，特别是少数民族学生直接参与与CRONUS有关的地球科学方面的研究。