We constrain the age of a cobble beach ridge system in Greenland using Optically Stimulated Luminescence (OSL) dating of buried cobble surfaces. Luminescence signals from six cobbles are measured using infrared (IR) stimulation at 50 °C (IR₅₀) and 180 °C (pIRIR₁₈₀); these cobbles represent four progressively younger beach ridges lying between ~35 and ~6 m above present sea level. Luminescence–depth profiles show that the IR₅₀ signals in all the samples and pIRIR₁₈₀ signals in four out of six samples are well bleached to depths >1.2 mm into the cobble surfaces. Equivalent doses in well‐bleached cobble surface slices (i.e. <1.2 mm) are measured and divided by the effective environmental dose rate to the cobble surfaces in order to derive burial ages. Both IR signals are corrected for anomalous fading using the sample‐specific ratio of the field to the laboratory saturation levels. Our results are consistent with a depositional model predicting that the investigated portion of the beach ridge system built out continuously during relative sea level fall between ~5.3 and ~1.9 ka ago. The optical ages suggest that the rate of construction varied considerably, with the highest rates ~3.4 ka ago. Additionally, the lowest‐elevation beach ridge investigated here provides the first evidence for a higher‐than‐present relative sea level, between 1.5 and 2 ka ago, in the Disko coastal region.

中文翻译：

---

鹅卵石表面的光学年代测定决定了格陵兰全新世海滩山脊的年代

我们使用掩埋的鹅卵石表面的光刺激发光（OSL）年代来限制格陵兰的鹅卵石海滩山脊系统的年龄。在50°C（IR ₅₀）和180°C（pIRIR ₁₈₀）下使用红外（IR）刺激测量来自六个鹅卵石的发光信号；这些鹅卵石代表着四个逐渐年轻的海滩山脊，它们位于当前海平面以上约35至约6 m之间。发光深度曲线表明，所有样品中的IR ₅₀信号和pIRIR ₁₈₀六个样本中有四个样本的信号被很好地漂白到卵石表面> 1.2 mm的深度。测量漂白充分的鹅卵石表面切片中的等效剂量（即<1.2 mm），并将其除以鹅卵石表面的有效环境剂量率，以得出埋葬年龄。使用场对实验室饱和度的特定于样本的比率，可以校正两个IR信号的异常衰落。我们的结果与沉积模型相符，该沉积模型预测在相对海平面在约5.3到1.9 ka之前连续建立的海滩山脊系统的被调查部分。光学时代表明，构造速率相差很大，最高速率约为3.4 ka以前。此外，