Accurate chronologies are crucial when comparing paleo-climate records, especially in the case of terrestrial and marine comparisons. It is essential to understand temporal variability of the radiocarbon reservoir effect to produce an accurate chronology. Here we establish a high-resolution Bayesian chronology for a northern South China Sea (SCS) sediment core. By applying a piece-wise linear regression method, we observe a distinct shift in the marine radiocarbon reservoir age at ~16.9 ka BP from our core. This shift hampers the accuracy of chronology, even though within higher dating resolution. Together with chronologies within different resolution, we show that the piece-wise linear regression approach is potential in producing accurate chronology for marine sediment. Based on comparisons with other sediment records from the region we show that the shift in radiocarbon reservoir age was pervasive throughout the SCS basin, coeval with the opening of the Balabac Strait, as global sea level rose. Hence, we highlight that the opening of the Balabac strait had a basin-wide effect on surface ocean circulation in the SCS.

中文翻译：

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巴拉巴克海峡开放导致南海海洋放射性碳库年龄的变化

在比较古气候记录时，尤其是在陆地和海洋比较时，准确的年表至关重要。了解放射性碳库效应的时间变化对于产生准确的年代学至关重要。在这里，我们为南海北部（SCS）沉积岩心建立了高分辨率贝叶斯年代学。通过应用分段线性回归方法，我们观察到海洋放射性碳储层年龄在距我们核心约 16.9 ka BP 处发生明显变化。这种转变妨碍了年代学的准确性，即使在更高的约会分辨率内也是如此。与不同分辨率的年代学一起，我们表明分段线性回归方法有可能产生准确的海洋沉积物年代学。通过与该地区其他沉积物记录的比较，我们发现，随着全球海平面的上升，放射性碳库年龄的变化在整个南海盆地普遍存在，与巴拉巴克海峡的开放同时发生。因此，我们强调巴拉巴克海峡的开放对南海表层海洋环流产生了全盆地的影响。