Abstract. As an extended comment on the paper by Sarnthein et al. (2020), we express strong reservations about the methodology of the so-called ¹⁴C plateau tuning (PT) technique used to date marine sediment records and its implications on the determination of ¹⁴C marine reservoir ages (MRA). The main problems are linked to: the assumption of constant MRA during ¹⁴C-age plateaus; the lack of consideration of foraminifera abundance changes coupled to bioturbation that can create spurious plateaus in marine sediments; the assumption that plateaus have the same shapes and durations in atmospheric and oceanic records; the implication that atmospheric ¹⁴C/¹²C peaked instantaneously from one plateau to the next; that the ¹⁴C plateaus represent 82 % of the total time spent between 14,000 and 29,000 cal yr BP, whereas during the remaining 18 % of the time, the radiocarbon clock was running almost 5 times too fast; that the sparsity, combined with the level of analytical uncertainties and additional noise, in both atmospheric and marine data do not currently allow one to reliably or robustly identify plateaus (should they exist) beyond 15,000 cal yr BP; and that the determination and identification of plateaus is reliant upon significant changes in sedimentation rate within the marine sediments which are, a priori, unknown and are not verified with an independent method. The concerns we raise are supported and strengthened with carbon cycle box-model experiments and statistical simulations of pseudo-atmospheric and pseudo-marine records, allowing us to test the ability to identify and tune ¹⁴C-age plateaus, in the context of noisy and sparse data.

中文翻译：

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关于调整大气和海洋¹⁴ C记录的高原以推导出深海岩心的日历年代和¹⁴ C海洋储层年龄变化的记录

摘要。作为对Sarnthein等人论文的扩展评论。（2020年），我们对用于日期海洋沉积物记录的所谓的¹⁴ C高原调整（PT）技术的方法学及其对确定¹⁴ C海洋水库年龄（MRA）的影响表示强烈保留。主要问题与以下有关：假设在¹⁴ C年龄高原期间MRA恒定；没有考虑有孔虫的丰度变化以及可能在海洋沉积物中造成虚假高原的生物扰动；高原在大气和海洋记录中具有相同的形状和持续时间的假设；大气¹⁴ C / ¹²的含义C从一个平台到另一个平台瞬间达到峰值；那¹⁴C高原代表在14,000到29,000 cal yr BP之间花费的总时间的82％，而在其余18％的时间中，放射性碳时钟的运行速度快了将近5倍；当前，大气和海洋数据中的稀疏性以及分析不确定性和额外噪声的水平，使得人们无法可靠或可靠地识别出超过15,000 cal BP的高原（如果存在）；高原的确定和识别取决于先验，未知且未经独立方法验证的海洋沉积物中沉积速率的重大变化。我们提出的问题得到了碳循环箱模型实验和伪大气和伪海洋记录的统计模拟的支持和加强，在嘈杂和稀疏数据的背景下，出现了^14个C阶高原。