Sediments up to about 50 ka old can be dated by radiocarbon (¹⁴C), and typically biogenic carbonate minerals formed by organisms like foraminifera or mollusks are the primary choice for dating. However, carbonate-poor environments, typical for polar seas, limit the possibilities for ¹⁴C dating to bulk organic matter (OM), which is typically biased by the old carbon. In this study, ramped pyrolysis-oxidation (RPO) ¹⁴C dating of bulk OM was applied to two Arctic Ocean sediment cores with independent age constraints from prior studies in order to assess its applicability in this environment. Application of RPO to Arctic sediment samples yielded a series of progressively older ages with increasing pyrolysis temperatures and with sediment depth, similar to previous applications in Antarctica. The difference between the independently dated carbonate ages and the RPO-derived ages was proportional to the gradient of ¹⁴C ages of the released carbon vs. the pyrolysis temperature. Using this empirical relationship, we propose a new method to estimate sediment age based on RPO ¹⁴C data. Ages derived by this method in our data set show offsets from the independent age controls mostly under ~700 years. These results are much closer to the actual ages than the bulk OM data. This simple method may have a broad application to sediments with biogenic carbonate deficiency whereby dating is reliant on bulk OM.

可以通过放射性碳 ( ¹⁴ C)对年龄高达约 50 ka 的沉积物进行测年，通常由有孔虫或软体动物等生物形成的生物碳酸盐矿物是测年的主要选择。然而，极地海洋典型的贫碳环境限制了¹⁴ C 定年到大块有机物质 (OM)的可能性，这通常会受到旧碳的影响。在本研究中，加速热解氧化 (RPO) ¹⁴大量 OM 的 C 测年被应用于两个北冰洋沉积物核心，这些岩心具有来自先前研究的独立年龄限制，以评估其在该环境中的适用性。将 RPO 应用于北极沉积物样品产生了一系列逐渐变老的年代，随着热解温度和沉积物深度的增加，类似于以前在南极洲的应用。独立测年的碳酸盐年龄和 RPO 衍生年龄之间的差异与释放的碳的¹⁴ C 年龄与热解温度的梯度成正比。使用这种经验关系，我们提出了一种基于 RPO ¹⁴估算沉积物年龄的新方法C 数据。在我们的数据集中通过这种方法得出的年龄显示了与独立年龄对照的偏差，大部分低于 700 年。这些结果比大量 OM 数据更接近实际年龄。这种简单的方法可能广泛应用于具有生物碳酸盐缺乏的沉积物，其中测年依赖于大量 OM。