This study examines the first precisely dated and temporally highly resolved speleothem record from Iberia that reconstructs the Oldest Dryas (OD). The onset of cold conditions in the study area, contemporary with the beginning of Heinrich Stadial 1, is recorded at 18.13 ± 0.08 ka, with a pronounced drop of 6.1‰ in δ13C in 250 years. Henceforth, stadial conditions depict a period of instability in the Atlantic Meridional Overturning Circulation, peaking in freshwater input from iceberg melting during Heinrich Event 1. Anomalies in the δ18O of the stalagmite attributed to such a freshwater event are found from 16.17 to 15.89 ka. Such absolute dates given to the onset of the OD in Iberia and to the main iceberg discharges are reliable anchor points for non-absolute chronologies. Two periods are identified in the OD: OD-a (18.13–16.17 ka) is characterized by wet conditions and a faster growth rate, and OD-b (15.89–14.81 ka) exhibits relative dryness and a slower growth rate. The sudden release of fresh water is considered to be the reason for the disruption of rainfall patterns in eastern Iberia. The present study also highlights the existence of heterogeneous and complex hydrological conditions during the OD in Iberia when both Atlantic and Mediterranean realms are considered.

中文翻译：

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海因里希事件 1 冰山排放后伊比利亚半岛东部最古老的仙人掌水文气候重组

这项研究检查了来自伊比利亚的第一个精确年代和时间高度分辨的 speleothem 记录，该记录重建了最古老的仙女木 (OD)。与 Heinrich Stadial 1 开始同时的研究区寒冷条件的开始记录为 18.13 ± 0.08 ka，δ 显着下降 6.1‰13C 250 年。此后，天体条件描述了大西洋经向翻转环流的不稳定时期，海因里希事件 1 期间冰山融化的淡水输入达到峰值。18在 16.17 至 15.89 ka 之间发现了归因于这种淡水事件的石笋 O。伊比利亚 OD 开始和主要冰山排放的绝对日期是非绝对年表的可靠锚点。OD中确定了两个时期：OD-a（18.13-16.17 ka）以潮湿条件和较快的生长速度为特征，OD-b（15.89-14.81 ka）表现出相对干燥和较慢的生长速度。淡水的突然释放被认为是伊比利亚东部降雨模式中断的原因。本研究还强调了在考虑大西洋和地中海地区时，伊比利亚 OD 期间存在异质和复杂的水文条件。