Age determination of sediment core Kråkenes_502-47-01

The Younger Dryas/Holocene transition (YD/H) in the sediments of Kråkenes Lake, western Nor way, is well marked both lithologically and palaeobiologically at 756.5 cm in the investigated core. A series of 70 AMS radiocarbon dates on terrestrial plant macrofossils and the NaOH-soluble fraction of lake sediment was measured between 585 and 840 cm, covering the time span c. 10 440 to 7915 BP on the radiocarbon timescale. Forty-three of these dates above 760 cm were wiggle-matched against the German oak-pine dendro calibration curve (IntCal 93) with recent corrections in both the oak and the pine sections. With an increase in age of the pine dendro-series of 200 6 20 yr, the calendar age of the YD/H lithostratigraphic boundary at Kråkenes is estimated to 11 530 (+40 -60) cal. BP. By using a date of 9750 BP (11 170 cal. BP) on the transition between the 10 000 and 9600 14C plateaux as a time marker, this result is compared with recent results from other archives. It is consistent with many of them, including the GRIP ice core, German pine series, Lake Go?ciaz, south Swedish lakes, and Baltic varves, suggesting that the Younger Dryas-Holocene transition in the North Atlantic region occurred within the range 11 500-11 600 cal. BP.挪威西部克拉肯湖（Kråkenes Lake）沉积物中的新仙女木/全新世过渡（Younger Dryas/Holocene transition, YD/H），在本次研究的岩芯756.5 cm深度处，于岩石地层学与古生物学层面均存在清晰标识。研究团队在585至840 cm的深度区间内，针对陆生植物大化石与湖泊沉积物的氢氧化钠可溶组分，完成了共计70次加速器质谱放射性碳定年（AMS radiocarbon dates），覆盖放射性碳年代标尺下约10440至7915 BP的时间跨度。其中760 cm以上的43个定年数据，结合德国栎松树木年轮校准曲线（IntCal 93）并纳入近年对栎木、松木序列的校正结果进行了摆动定标（wiggle-match）。鉴于松木树木年轮序列的年龄增量为200±20年，克拉肯湖YD/H岩石地层界线的日历年龄被估算为11530（+40/-60）cal. BP。以10000与9600¹⁴C平台间过渡层位的9750 BP（对应11170 cal. BP）定年结果作为时间标记，本研究结果与其他近年的古气候档案记录结果进行对比后发现，其与格陵兰冰芯项目冰芯（GRIP ice core）、德国松木年轮序列、瑞典南部戈西亚茨湖（Lake Go?ciaz）、南瑞典湖泊及波罗的海纹泥（Baltic varves）的多数相关结果均吻合良好，这表明北大西洋区域的新仙女木-全新世过渡事件发生于11500~11600 cal. BP的时间区间内。