Establishment and exploration of a gas ion source for micro-scale radiocarbon dating of glaciers and groundwater

冰川和地下水微尺度放射性碳测年气体离子源的建立与探索

• 批准号: 236452962
• 负责人: Professor Dr. Werner Aeschbach, since 1/2015
• 金额: --
• 依托单位: Institut für Umweltphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/236452962?language=en
• 关键词: Establishment; exploration; gas; ion; source

Recent progress in the operation of CO2 gas ion sources for accelerator mass spectrometer (AMS) 14C analysis on microgram-size samples opens a wide range of new applications in dating studies, e.g. for environmental and archeological applications. This proposal aims at implementing a gas ion source at the AMS system MICADAS at the Klaus-Tschira Laboratory of the Curt-Engelhorn-Zentrum für Archäometrie (CEZA) in Mannheim and to use this new capability for cutting-edge applications in environmental studies, namely the dating of small amounts of organic carbon contained in glacier ice and of specific organic compounds in ground water. Cold glaciers hold unique records on past climate and atmospheric composition. Mid-latitude ice cores furthermore enable reconstructions of recent ice chemistry changes, but cannot be dated by stratigraphic methods. For such ice bodies, only radiometric dating based on 14C analysis of organic matter contained in the ice matrix presently offers a reasonable dating potential in the late Holocene and beyond. The challenge of this approach lies in the very restricted availability of this matter, but the ability to analyse microgram samples of organic carbon from ice via a gas ion source should now enable reliable 14C dating of ice. Ground water constitutes an important water resource worldwide, especially in semi-arid regions, and in addition constitutes a useful climate archive. Dating of ground water by 14C in the dissolved inorganic carbon (DIC) is standard but problematic due to the complex carbonate geochemistry. Dating of ground water based on dissolved organic carbon (DOC) has been attempted with mixed success, but now the new analytical developments enable compound-specific 14C analyses of the various DOC components, offering the chance to identify compounds suitable for dating. This project is based on the extensive experience of the collaborating scientists in 14C analytics and applications as well as in the use of glacier ice and ground water as archives, including the development and application of 14C dating methods for these systems. It will establish 14C-measurements at the MICADAS AMS of the CEZA via a gas ion source on a routine base to analyse CO2-samples in the range of 5 to 40 microgram C at a precision down to 0,5 %. By improving existing sample preparation techniques for glacier ice samples, reliable 14C values of the particulate and dissolved organic fractions from small (some 100 g) ice samples shall be obtained. This capability will be applied to constrain ages of cold, sedimentary glaciers as well as of small scale, cold Alpine congelation ice bodies. The project will further develop and test the tools required for micro-scale, compound-specific radiocarbon dating of ground water via its organic fraction. For this purpose, ground water samples from the Upper Rhine Graben area will be analysed, where extensive isotopic data, including DIC 14C values, are available for comparison.

近年来，用于加速器质谱仪（AMS）14 C分析的CO2气体离子源在微克级样品上的应用取得了新的进展，为测年研究开辟了新的应用领域，如环境和考古应用。该提案旨在在曼海姆Curt-Engelhorn-Zentrum für Archäometrie（CEZA）Klaus-Tschira实验室的AMS系统MICADAS中安装气体离子源，并将这一新能力用于环境研究的尖端应用，即测定冰川冰中所含少量有机碳和地下水中特定有机化合物的年代。寒冷的冰川对过去的气候和大气成分有着独特的记录。此外，中纬度冰芯能够重建最近的冰化学变化，但不能通过地层学方法确定年代。对于此类冰体，目前只有基于冰基质中所含有机物的14 C分析的放射性测年才能提供全新世晚期及以后的合理测年潜力。这种方法的挑战在于这种物质的可用性非常有限，但是通过气体离子源分析冰中有机碳的微克样品的能力现在应该能够可靠地测定冰的14 C年代。地下水是全世界，特别是半干旱地区的一种重要水资源，此外，它还是一种有用的气候档案。通过溶解无机碳（DIC）中的14 C测定地下水的年龄是标准的，但由于复杂的碳酸盐地球化学，存在问题。基于溶解有机碳（DOC）的地下水定年已经尝试取得了成功，但现在新的分析发展能够对各种DOC组分进行化合物特定的14 C分析，从而有机会识别适合定年的化合物。该项目基于合作科学家在14 C分析和应用以及使用冰川冰和地下水作为档案方面的广泛经验，包括为这些系统开发和应用14 C测年方法。它将在CEZA的MICADAS AMS上通过常规基础上的气体离子源建立14 C测量，以分析5至40微克C范围内的CO2样本，精度低至0.5%。通过改进冰川冰样品的现有样品制备技术，将从小的（约100克）冰样品中获得颗粒和溶解有机部分的可靠的14 C值。这种能力将被应用于限制年龄的冷，沉积冰川以及小规模，冷阿尔卑斯山冰川体。该项目将进一步开发和测试通过地下水的有机部分对地下水进行微型、特定化合物放射性碳测年所需的工具。为此，将对上莱茵河地堑区的地下水样本进行分析，其中包括DIC 14 C值在内的大量同位素数据可供比较。

项目成果

Temperature and mineral dust variability recorded in two low-accumulation Alpine ice cores over the last millennium

• DOI: 10.5194/cp-14-21-2018
• 发表时间: 2018-01-10
• 期刊: CLIMATE OF THE PAST
• 影响因子: 4.3
• 作者: Bohleber, Pascal;Erhardt, Tobias;Mayewski, Paul
• 通讯作者: Mayewski, Paul

Status report: Implementation of gas measurements at the MAMS 14 C AMS facility in Mannheim, Germany

状态报告：在德国曼海姆的 MAMS 14 C AMS 设施实施气体测量

• DOI: 10.1016/j.nimb.2017.08.018
• 发表时间: 2017
• 期刊: Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
• 影响因子: 1.3
• 作者: Hoffmann;Friedrich;Kromer;Fahrni
• 通讯作者: Fahrni

Micro radiocarbon dating of the particulate organic carbon fraction in Alpine glacier ice: method refinement, critical evaluation and dating applications

• DOI: 10.11588/heidok.00020712
• 发表时间: 2016
• 作者: H. Hoffmann

Next‐generation ice core technology reveals true minimum natural levels of lead (Pb) in the atmosphere: Insights from the Black Death

• DOI: 10.1002/2017gh000064
• 发表时间: 2017-06
• 期刊: GeoHealth
• 影响因子: 4.8
• 作者: A. More;N. Spaulding;P. Bohleber;M. Handley;H. Hoffmann;E. Korotkikh;A. Kurbatov;Christopher P. Loveluck;S. Sneed;M. McCormick;P. Mayewski

A NEW SAMPLE PREPARATION SYSTEM FOR MICRO-14C DATING OF GLACIER ICE WITH A FIRST APPLICATION TO A HIGH ALPINE ICE CORE FROM COLLE GNIFETTI (SWITZERLAND)

• DOI: 10.1017/rdc.2017.99
• 发表时间: 2018-04-01
• 期刊: RADIOCARBON
• 影响因子: 8.3
• 作者: Hoffmann, Helene;Preunkert, Susanne;Wagenbach, Dietmar
• 通讯作者: Wagenbach, Dietmar