Division of Hydrologic Sciences, Desert Research Institute, Reno, NV 89512;
School of Earth and Environmental Sciences, University of St. Andrews, St. Andrews, KY16 9AL United Kingdom.
Proc Natl Acad Sci U S A. 2017 Sep 19;114(38):10035-10040. doi: 10.1073/pnas.1705595114. Epub 2017 Sep 5.
Glacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ∼17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts. We used high-resolution chemical measurements in the West Antarctic Ice Sheet Divide, Byrd, and other ice cores to document a unique, ∼192-y series of halogen-rich volcanic eruptions exactly at the start of accelerated deglaciation, with tephra identifying the nearby Mount Takahe volcano as the source. Extensive fallout from these massive eruptions has been found >2,800 km from Mount Takahe. Sulfur isotope anomalies and marked decreases in ice core bromine consistent with increased surface UV radiation indicate that the eruptions led to stratospheric ozone depletion. Rather than a highly improbable coincidence, circulation and climate changes extending from the Antarctic Peninsula to the subtropics-similar to those associated with modern stratospheric ozone depletion over Antarctica-plausibly link the Mount Takahe eruptions to the onset of accelerated Southern Hemisphere deglaciation ∼17.7 ka.
冰期温室气体浓度和南半球气候条件一直持续到约 17.7 千年前，当时在南半球大部分地区的古气候代用指标中记录到冰川消退的几乎同步加速，许多变化归因于南半球西风的突然向极移动以及随后的气候影响。我们使用南极冰盖分界、伯德等地的高分辨率化学测量来记录一个独特的、约 192 年的富含卤素的火山爆发系列，正好在冰川消退加速的开始，火山灰确定附近的塔卡赫火山是源头。这些大规模喷发的大量沉降物在距离塔卡赫火山 2800 多公里的地方被发现。硫同位素异常和冰芯溴的显著减少与地表紫外线辐射增加一致，表明喷发导致平流层臭氧消耗。从南极半岛到亚热带的环流和气候变化的延伸——类似于与现代南极平流层臭氧消耗相关的变化——可能将塔卡赫火山的喷发与大约 17.7 千年前的南半球冰川消退加速联系起来，而不是一个极不可能的巧合。
