Towards a Decadally-Resolved Radiocarbon Calibration for the Last Glacial Period (30,000-11,700 years ago) Using New Zealand Kauri (Agathis australis)

使用新西兰贝壳杉 (Agathis australis) 实现末次冰期（30,000-11,700 年前）的十年分辨率放射性碳校准

• 批准号: NE/H007865/1
• 负责人: Christopher Ramsey
• 金额: $ 14.51万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH007865%2F1
• 关键词: Towards; Decadally; Resolved; Radiocarbon; Calibration

Past climate change provides a critical baseline against which to compare present and future warming. Unfortunately, however, although numerous reconstructions spanning the last ice age have been made, most of the records cannot be precisely correlated to one another. The main problem is the vast majority of records have been radiocarbon dated for which no internationally-accepted calibration curve exists, precluding the placement of reconstructions on a calendar timescale and preventing robust comparisons with high-resolution and absolutely dated sequences (such as ice cores). This is a significant problem for the scientific community. 'Calibration' of radiocarbon-dated records can result in the conclusion that climate change led, lagged or was synchronous around the world depending on which conversion is used, preventing the scientific community from gaining a detailed understanding of mechanisms of change in the Earth system. An accurate and precise radiocarbon calibration curve should be based on an absolutely dated record that has carbon incorporated directly from the atmosphere at the time of formation. Tree rings have proven to be an excellent resource for this purpose. At the moment, the internationally-accepted absolutely-dated calibration curve based on North American and European tree-ring dated material only extends back to 12,410 years; the prospect of significantly extending the records in the northern hemisphere is not high due to destruction of material by past ice sheets. Buried in peat bogs across northern New Zealand are ancient conifer trees called kauri. We know of nowhere else in the world with such a rich resource of subfossil wood that is capable of capturing the complete range of radiocarbon. The time span preserved within these bogs is truly enormous; spanning more than 130,000 years. These trees are of vast proportions and almost perfectly preserved; individual trees can measure up to 4 metres across and live for up to 2000 years. Within this precious archive is an annual record of changing atmospheric radiocarbon levels and past climate. This is a unique resource. Unfortunately, however, the timber is also highly-prized for household furniture, arts and crafts. The result is the buried wood is being mined at an alarming rate and will be exhausted within ten years. In this project, we will collect and analyze the kauri before it is lost forever. We will focus on undertaking comprehensive dating of the tree rings to determine changing levels of radiocarbon in the atmosphere using ancient logs that have been collected within the period spanning 30,000 to 11,700 years ago. The results from this study will help to precisely calibrate radiocarbon-dated sequences of past climate, environmental and archaeological change, thereby helping us to improve our understanding the Earth system.

过去的气候变化为比较当前和未来的变暖提供了一个重要的基线。然而，不幸的是，尽管对最后一个冰河时期进行了大量的重建，但大多数记录不能精确地相互关联。主要问题是，绝大多数记录都是放射性碳定年的，没有国际公认的校准曲线，这就排除了在日历时间尺度上进行重建的可能性，也阻碍了与高分辨率和绝对定年序列（如冰芯）的可靠比较。这是科学界面临的一个重大问题。对放射性碳定年记录的“校准”可能会得出这样的结论，即气候变化在全球范围内导致、滞后或同步，这取决于所使用的转换方式，这阻碍了科学界对地球系统变化机制的详细了解。准确和精确的放射性碳校准曲线应该建立在一个绝对有年代记录的基础上，该记录包含了在形成时直接从大气中吸收的碳。树木年轮已被证明是一个很好的资源。目前，国际公认的基于北美和欧洲树木年轮的绝对定年校准曲线只能追溯到12410年前；由于过去冰盖对物质的破坏，北半球显著延长记录的可能性不大。在新西兰北部的泥炭沼泽中，埋藏着一种叫做贝壳杉的古老针叶树。据我们所知，世界上没有其他任何地方有如此丰富的亚化石木材资源，能够捕获全部放射性碳。在这些沼泽中保存的时间跨度确实是巨大的；跨度超过13万年。这些树木规模庞大，几乎保存完好；每棵树的直径可达4米，寿命可达2000年。在这个珍贵的档案中，有关于大气放射性碳水平变化和过去气候的年度记录。这是一种独特的资源。然而，不幸的是，这种木材也被高度珍视为家用家具、艺术品和工艺品。其结果是，埋藏的木材正以惊人的速度被开采，并将在十年内枯竭。在这个项目中，我们将在贝壳杉永远消失之前收集和分析它。我们将重点对树木年轮进行全面测年，以确定大气中放射性碳的变化水平，使用的是收集于3万至11700年前的古代原木。这项研究的结果将有助于精确校准过去气候、环境和考古变化的放射性碳年代序列，从而帮助我们提高对地球系统的理解。

项目成果

Reanalysis of the Atmospheric Radiocarbon Calibration Record from Lake Suigetsu, Japan

• DOI: 10.1017/rdc.2020.18
• 发表时间: 2020-03
• 期刊: Radiocarbon
• 影响因子: 8.3
• 作者: C. Bronk Ramsey;T. Heaton;G. Schlolaut;R. Staff;C. Bryant;A. Brauer;H. Lamb;M. Marshall;T. Nakagawa

Punctuated Shutdown of Atlantic Meridional Overturning Circulation during Greenland Stadial 1.

• DOI: 10.1038/srep25902
• 发表时间: 2016-05-19
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Hogg A;Southon J;Turney C;Palmer J;Bronk Ramsey C;Fenwick P;Boswijk G;Friedrich M;Helle G;Hughen K;Jones R;Kromer B;Noronha A;Reynard L;Staff R;Wacker L
• 通讯作者: Wacker L

Statistical approaches and tools for IntCal20

IntCal20 的统计方法和工具

• DOI: 10.5194/egusphere-egu2020-9336
• 发表时间: 2020
• 作者: Bronk Ramsey C

New approaches to radiocarbon calibration arising from statistical developments in IntCal20

IntCal20 统计发展带来的放射性碳校准新方法

• DOI: 10.5194/egusphere-egu2020-9422
• 发表时间: 2020
• 作者: Bronk Ramsey C

The New Zealand Kauri ( Agathis Australis ) Research Project: A Radiocarbon Dating Intercomparison of Younger Dryas Wood and Implications for IntCal13

新西兰贝壳杉 (Agathis Australis) 研究项目：新仙女木木材的放射性碳测年对比及其对 IntCal13 的影响

• DOI: 10.2458/azu_js_rc.v55i2.16217
• 发表时间: 2016
• 期刊: Radiocarbon
• 影响因子: 8.3
• 作者: Hogg A