Constant Holocene Southern-Ocean 14C reservoir ages and ice-shelf flow rates
Constant Holocene Southern-Ocean 14C reservoir ages and ice-shelf flow rates
复制标题
DOI：
10.1016/j.epsl.2010.04.054
复制
发表时间：
2010-07-15
影响因子：
5.3
通讯作者：
Kellogg, Thomas B.
中科院分区：
文献类型：
--
作者：
Hall, Brenda L.;Henderson, Gideon M.;Kellogg, Thomas B.
南大洋的放射性碳储层年龄（即海水中的非零放射性碳年龄）是世界表层海洋中最高的。限制这些水库年龄在现在和过去是很重要的，不仅因为未知的水库年龄限制了南极放射性碳年代学的解释，而且因为水库年龄提供有关海洋环流的信息（作为过去的循环记录，并作为在今天的海洋主要深水质量的终端成员）。在这项研究中，我们使用成对的U/Th和C-14年龄的一组不寻常的孤立的珊瑚样本被困边缘冰架在罗斯海提供的第一个详细的研究全新世水库年龄为南大洋。我们的研究结果表明，相对恒定的海洋放射性碳水库年龄为1144 +/- 120年，在过去的6000年。这些结果与其他地方看到的C-14和碱度之间的关系的外推是一致的，支持在高纬度地区使用这种经验关系。研究结果还揭示了全新世海洋环流和海气交换的持续性，为现代海洋环流模式的调整提供了一个很好的目标。将珊瑚的新年龄与它们与现代冰架接地线的距离相结合，提供了任何地区冰架速度的一些第一个长期记录，并表明麦克默多冰架在全新世期间以类似于今天观察到的速度不断流动。(C)2010 Elsevier BV保留所有权利。
Southern Ocean radiocarbon reservoir ages (i.e. non-zero radiocarbon ages in seawater) are the highest in the world's surface ocean. Constraining these reservoir ages at present and in the past is important not only because unknown reservoir ages limit the interpretation of Antarctic radiocarbon chronologies, but also because reservoir ages provide information about ocean circulation (as a recorder of past circulation and as an end member for major deep-water masses in today's ocean). In this study, we use paired U/Th and C-14 ages of an unusual set of solitary coral samples trapped by fringing ice shelves in the Ross Sea to provide the first detailed study of Holocene reservoir ages for the Southern Ocean. Our results indicate a relatively constant marine radiocarbon reservoir age of 1144 +/- 120 years for the past 6000 years. These results are consistent with extrapolation of the relationship between C-14 and alkalinity seen elsewhere, supporting the use of this empirical relationship in high latitudes. The results also suggest constant deep-ocean circulation and air-sea exchange during the Holocene and provide a good target for tuning ocean models of modern circulation. Combining the new ages for corals with their distance from the modern-day ice-shelf grounding line provides some of the first long-term records of ice-shelf velocities for any region and indicates constant flow of the McMurdo Ice Shelf during the Holocene, at a rate similar to that observed today. (C) 2010 Elsevier B.V. All rights reserved.