Holocene glacier change in the Silvretta Massif (Austrian Alps) constrained by a new 10Be chronology, historical records and modern observations
Holocene glacier change in the Silvretta Massif (Austrian Alps) constrained by a new 10Be chronology, historical records and modern observations
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DOI：
10.1016/j.quascirev.2020.106493
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发表时间：
2020-10-01
影响因子：
4
通讯作者：
Fiebig, Markus
中科院分区：
文献类型：
--
作者：
Braumann, Sandra M.;Schaefer, Joerg M.;Fiebig, Markus
高山冰川是高寒地区重要的水资源，对气候变化非常敏感。重建冰川振荡可以提高我们对气候变率的幅度和频率的理解，并解决气候系统过渡时期的问题——从全新世开始的冰期到间冰期，以及工业化过程中从自然控制系统到人为影响系统。通过这项研究，我们提供了一个全新世的东欧阿尔卑斯山脉冰川年表。研究区位于Silvretta地块的早侏罗系，具有明显的全新世冰碛垄，是一个重要的水电流域。我们提出了18个新的基岩露头（n = 2）和巨石（n = 16）的Be-10暴露年龄。我们用历史记录和仪器时间序列来补充Be-10冰川年表，并将其与全新世不同时期已有的气候代理记录相关联，以获取冰缘位置。通过与欧洲阿尔卑斯山脉的宇宙成因核素冰碛记录进行对比，研究了整个阿尔卑斯山脉从新仙女木期（约12.9 ~ 11.7 ka）到全新世（约11.7 ka至今）的过渡过程。结果表明，早世期冰川从晚冰期后退后，稳定在保存完好的全新世冰碛位置（约9.9 +/- 0.7 ka）。这一全新世冰碛形成间隔与在瑞士和奥地利阿尔卑斯山的一些气候代理记录中发现的一个寒冷期同时发生，即中欧寒冷期1 （CE-1）。在中全新世时期，冰川可能要小得多，并且在小冰期（LIA; c. 1250 - 1850 CE）期间，冰川推进到接近保存完好的早全新世冰碛的位置。LIA 1°Be的年龄范围从390 +/- 20年到135 +/- 5年，并指出了这一时期的多次进展，最有力的证据表明在18世纪达到了顶峰。Be-10记录与历史冰川记录重叠且非常一致，这表明Be-10表面暴露测年即使对年轻的冰川沉积物也能产生可靠的年龄。在过去的170年里，Ochsentaler冰川退缩了2.3公里，这突出了最近变暖对高山冰川的影响。(C) 2020作者。Elsevier Ltd.出版。
Mountain glaciers are important water resources in Alpine regions and are sensitive to climate change. Reconstructing glacier oscillations improves our understanding of the amplitude and the frequency of climate variability and resolves time periods when the climate system was in transition - from glacial to interglacial conditions at the beginning of the Holocene, and from a naturally controlled system to an anthropogenically influenced system in the course of industrialization.With this study, we contribute a new Holocene mountain glacier chronology from the Eastern European Alps. The study area, the Ochsental in the Silvretta Massif, features pronounced Holocene moraine ridges and is an important catchment for hydropower production. We present 18 new Be-10 exposure ages of bedrock outcrops (n = 2) and boulders (n = 16). We complement the Be-10 glacier chronology with historical records and instrumental time series and correlate it with pre-existing climate proxy records for capturing ice margin positions at different times during the Holocene. The Ochsental chronology is compared to cosmogenic nuclide moraine records across the European Alps to provide an Alpine-wide perspective on the transition from the Younger Dryas (YD; c. 12.9 to 11.7 ka) to the Holocene (c. 11.7 ka to present).Results show that glaciers in the Ochsental stabilized at the position of a preserved Holocene moraine c. 9.9 +/- 0.7 ka after retreating from their Late Glacial position. This Holocene moraine formation interval is concurrent with a cold spell detected in some climate proxy records in the Swiss and Austrian Alps, the Central European Cold Phase 1 (CE-1). Glaciers were presumably much smaller during the Mid-Holocene and readvanced to a position close to the preserved Early Holocene moraine during the Little Ice Age (LIA; c. 1250 to 1850 CE). LIA 1 degrees Be ages range from 390 +/- 20 yrs to 135 +/- 5 yrs and point to multiple advances within this time period with most robust evidence for a culmination during the 18th century. The Be-10 record and the historical glacier records overlap and are remarkably consistent, which demonstrates that Be-10 surface exposure dating produces reliable ages even for young glacial deposits. Within the last c. 170 years, Ochsentaler glacier has retreated c. 2.3 km, which highlights the impact of recent warming on Alpine mountain glaciers. (C) 2020 The Author(s). Published by Elsevier Ltd.