Radiocarbon as a Dating Tool and Tracer in Paleoceanography
Radiocarbon as a Dating Tool and Tracer in Paleoceanography
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DOI：
10.1029/2020rg000720
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发表时间：
2022-01
影响因子：
25.2
通讯作者：
L. Skinner;E. Bard
中科院分区：
文献类型：
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作者：
L. Skinner;E. Bard
放射性碳是一种非常有用的碳循环示踪剂和放射性测年工具。在这里，我们回顾了在古海洋学中使用放射性碳的主要原则和挑战。首先，我们提出了一个概念框架，其中有三种可能的用途的放射性碳测量：（a）获得一个日历的年龄间隔，或化石实体的年龄;（B）获得一个碳库的过去放射性碳活动的估计;或（c）比较两个当代碳库的相对放射性碳活动。我们讨论了海洋化石材料的分析，大气参考曲线的生成，以及海洋放射性碳“通风指标”与此参考曲线的解释。强调海洋放射性碳综合了以下因素的影响：不断变化的放射性碳生产;海面的海气交换效应;海洋内部的运输时间;以及来自海面的不同运输时间的水包的混合，以及不同的海面来源。这些控制使放射性碳成为如此强大的古海洋学示踪剂，尽管解开它们的困难使海洋放射性碳定年和示踪剂研究如此具有挑战性。我们讨论了放射性碳在数值模式中的应用，并探索了将放射性碳和CO2的海洋-大气分配联系起来的理论。最后，我们回顾了过去2.5万年来海洋放射性碳变化的现有记录，这些记录突出了海洋-大气碳交换对过去大气CO2和气候的影响，并指出了解决全球放射性碳和碳预算的新机会。
Radiocarbon is an extremely useful carbon cycle tracer and radiometric dating tool. Here, we review the main principles and challenges involved in the use of radiocarbon in paleoceanography. First, we present a conceptual framework in which there are three possible uses of a radiocarbon measurement: (a) to obtain a calendar age interval, or a fossil entity's age; (b) to obtain an estimate of a carbon reservoir's past radiocarbon activity; or (c) to compare the relative radiocarbon activities of two contemporary carbon reservoirs. We discuss the analysis of marine fossil material, the generation of an atmospheric reference curve, and the interpretation of marine radiocarbon “ventilation metrics” in relation to this reference curve. It is emphasized that marine radiocarbon integrates the influences of: changing radiocarbon production; air‐sea gas exchange effects at the sea surface; transport times within the ocean interior; and the mixing of water parcels with different transit times from the sea surface, and different sea‐surface sources. These controls are what make radiocarbon such a powerful paleoceanographic tracer, though the difficulty of disentangling them is what makes marine radiocarbon dating and tracer studies so challenging. We discuss the implementation of radiocarbon in numerical models, and explore the theory linking ocean‐atmosphere partitioning of radiocarbon and CO2. Finally, we review existing records of marine radiocarbon variability over the last ∼25,000 years, which highlight the influence of ocean‐atmosphere carbon exchange on past atmospheric CO2 and climate, and point to emerging opportunities for resolving the global radiocarbon‐ and carbon budgets over the last glacial cycle.