Institute of Geology, University of Innsbruck, Innrain 52f, 6020, Innsbruck, Austria.
Queens University Belfast, Belfast, BT7 1NN, UK.
Sci Rep. 2022 Jul 5;12(1):11374. doi: 10.1038/s41598-022-15516-9.
Mid-latitude alpine caves preserve a record of past solid precipitation during winter, locally spanning several centuries to millennia. Dating organic macro-remains trapped in ice layers allows the determination of timing and duration of past periods of positive and negative ice mass balance. We present here the largest comparative study of ice cave sites yet published, using Bayesian age-modelling on a database comprising 107 radiocarbon dates, spread over eight caves in the Austrian Alps. We show that periods of positive mass balance coincide with past glacier advances. We find organic and macro-remain rich layers dated to the Medieval Climate Anomaly (between 850 and 1200 CE) marking widespread ice retreat. We demonstrate positive ice mass balance at all studied sites for the Little Ice Age, coinciding with the largest glacier advances in the Holocene between 1400 and 1850 CE. At the sites with records spanning over 2000 years, positive mass balance is also observed during the periods from 300 BCE to 100 CE and 600-800 CE. These subterranean ice deposits show widespread evidence of accelerated negative mass balances in recent years and their record is under imminent threat of disappearing.
中纬度高山洞穴保存了冬季过去的固态降水记录，局部跨越数百年到数千年。对被困在冰层中的有机宏观遗迹进行年代测定，可以确定过去正冰量和负冰量平衡时期的时间和持续时间。我们在这里展示了迄今为止发表的最大规模的洞穴比较研究，使用贝叶斯年龄建模方法，对包含 107 个放射性碳日期的数据库进行了分析，这些日期分布在奥地利阿尔卑斯山的 8 个洞穴中。我们表明，正冰量平衡时期与过去的冰川前进时期相吻合。我们发现，有机和宏观丰富层的年代可追溯到中世纪气候异常时期（公元 850 年至 1200 年），标志着冰川广泛退缩。我们证明，在小冰期期间，所有研究地点的冰量都呈正平衡状态，与公元 1400 年至 1850 年之间全新世最大的冰川前进时期相吻合。在记录跨越 2000 多年的地点，公元前 300 年至 100 年和公元 600 年至 800 年期间也观察到正冰量平衡。这些地下冰沉积物显示出近年来加速负冰量平衡的广泛证据，它们的记录正面临消失的威胁。
