Radiocarbon Determination of Particulate Organic Carbon in Non-Temperated, Alpine Glacier Ice
Radiocarbon Determination of Particulate Organic Carbon in Non-Temperated, Alpine Glacier Ice
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DOI：
10.1017/s0033822200035402
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发表时间：
2006
期刊：
影响因子：
8.3
通讯作者：
P. Steier;R. Drosg;M. Fedi;W. Kutschera;M. Schock;D. Wagenbach;E. Wild
中科院分区：
文献类型：
--
作者：
P. Steier;R. Drosg;M. Fedi;W. Kutschera;M. Schock;D. Wagenbach;E. Wild
通过放射性碳测定冰川冰样的年代是一项挑战，需要进行系统的调查。这项工作描述了一种提取和加速器质谱仪(AMS)14C分析冰川冰样中颗粒有机碳(POC)组分的方法。在VERA(维也纳环境研究加速器)对主要来自格伦兹格勒施勒(格伦茨冰川)系统(瑞士阿尔卑斯山蒙特罗萨山)非温度消融区的冰样进行了测量。样品取自大致位于同一流水线上的两个采样点。所使用的样品质量在0.3千克到1.4千克冰之间，产生18千克到307千克μ的碳作为POC。在样品加工过程中引入的碳污染物在5.4gC至33μg C之间，主要来自加工过程中使用的石英过滤器和漂洗液。在我们实验室，成功的二氧化碳石墨化的最小样品尺寸可以减少到<；10μg碳，石墨化过程的背景是40-∼碳的0.5μg。通过11个Grizgletscher样本对整个过程进行评估，发现PMC值的分散程度令人惊讶。我们得到了从公元前2100年到公元900年的平均校准年龄(95.4%的置信度)，这在两个采样点没有显著差异。对这些结果的讨论表明，冰川POC的单一14C年龄目前意义有限。为了充分挖掘POC测年的潜力，提出了在分析精度和样品表征方面的进一步改进。
Dating ice samples from glaciers via radiocarbon is a challenge that requires systematic investigations. This work describes an approach for extraction and accelerator mass spectrometry (AMS) 14C analysis of the particulate organic carbon (POC) fraction in glacier ice samples. Measurements were performed at VERA (Vienna Environmental Research Accelerator) on ice samples obtained mainly from the non-temperated ablation zone of the Grenzgletscher (Grenz Glacier) system (Monte Rosa Massif, Swiss Alps). The samples were obtained from 2 sampling sites situated roughly on a common flow line. The sample masses used were between 0.3 and 1.4 kg of ice, yielding between 18 and 307 μg of carbon as POC. The carbon contamination introduced during sample processing varied between 5.4 and 33 μg C and originated mainly from the quartz filters and the rinsing liquids used in processing. Minimum sample sizes for successful graphitization of CO2 in our laboratory could be reduced to <10 μg carbon, with a background in the graphitization process of ∼0.5 μg of 40-pMC carbon. Evaluation of the whole procedure via 11 Grenzgletscher samples revealed a surprisingly large scatter of pMC values. We obtain a mean calibrated age of 2100 BC to AD 900 (95.4% confidence level), which is not significantly different for the 2 sampling sites. Discussions of these results suggest that single 14C dates of glacial POC are presently of limited significance. Future improvements with respect to analytical precision and sample characterization are proposed in order to fully explore the POC dating potential.