MARINE20-THE MARINE RADIOCARBON AGE CALIBRATION CURVE (0-55,000 CAL BP)
MARINE20-THE MARINE RADIOCARBON AGE CALIBRATION CURVE (0-55,000 CAL BP)
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DOI：
10.1017/rdc.2020.68
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发表时间：
2020-08-01
期刊：
影响因子：
8.3
通讯作者：
Skinner, Luke C.
中科院分区：
文献类型：
--
作者：
Heaton, Timothy J.;Koehler, Peter;Skinner, Luke C.
放射性碳（C-14）的浓度在海洋和大气中是不同的。因此，从海洋环境中获得C-14的样品中进行放射性碳测定需要一个海洋特定的校准曲线，不能直接根据基于大气的IntCal 20曲线进行校准。本文介绍了Marine 20，这是对国际商定的海洋放射性碳年龄校准曲线的更新，该曲线提供了0-55 cal kBP的非极地全球平均海洋放射性碳记录，并作为区域海洋变化的基线。Marine 20用于校准来自非极地区域的海洋放射性碳样品;它不适合在极地区域进行校准，因为在这些区域，海冰范围、海洋上升流和海气交换的变化可能会导致海洋放射性碳浓度的较大变化。海洋20曲线是基于500模拟与海洋/大气/生物圈箱模型的全球碳循环，已被迫后实现我们的北方半球大气IntCal 20 C-14曲线和重建的变化，从冰芯数据获得的CO2。这些强迫使我们能够将碳循环动力学和大气中的C-14水平的时间变化。全球平均海洋放射性碳储层年龄的箱型模型模拟与更复杂的三维海洋环流模型模拟相似。然而，盒子模型的简单性和速度使我们能够使用蒙特卡罗方法来严格传播大气中C-14的历史浓度和碳循环的其他关键参数的不确定性，直到我们最终的Marine 20校准曲线。这种不确定性的稳健传播对于为海洋样品的放射性碳年龄校准提供可靠的精度至关重要。我们朝着去卷积不同过程对总不确定性的贡献迈出了第一步;讨论Marine 20与之前年龄校准曲线Marine 13的主要差异;并确定我们方法的局限性以及进一步工作的关键领域。Delta R的更新值，即根据Marine 20校准所需的区域海洋放射性碳储层年龄校正，可在数据库http://calib.org/marine/中找到。
The concentration of radiocarbon (C-14) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their C-14 in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-average marine record of radiocarbon from 0-55 cal kBP and serves as a baseline for regional oceanic variation. Marine20 is intended for calibration of marine radiocarbon samples from non-polar regions; it is not suitable for calibration in polar regions where variability in sea ice extent, ocean upwelling and air-sea gas exchange may have caused larger changes to concentrations of marine radiocarbon. The Marine20 curve is based upon 500 simulations with an ocean/atmosphere/biosphere box-model of the global carbon cycle that has been forced by posterior realizations of our Northern Hemispheric atmospheric IntCal20 C-14 curve and reconstructed changes in CO2 obtained from ice core data. These forcings enable us to incorporate carbon cycle dynamics and temporal changes in the atmospheric C-14 level. The box-model simulations of the global-average marine radiocarbon reservoir age are similar to those of a more complex three-dimensional ocean general circulation model. However, simplicity and speed of the box model allow us to use a Monte Carlo approach to rigorously propagate the uncertainty in both the historic concentration of atmospheric C-14 and other key parameters of the carbon cycle through to our final Marine20 calibration curve. This robust propagation of uncertainty is fundamental to providing reliable precision for the radiocarbon age calibration of marine based samples. We make a first step towards deconvolving the contributions of different processes to the total uncertainty; discuss the main differences of Marine20 from the previous age calibration curve Marine13; and identify the limitations of our approach together with key areas for further work. The updated values for Delta R, the regional marine radiocarbon reservoir age corrections required to calibrate against Marine20, can be found at the data base http://calib.org/marine/.