Paleoclimate records from maar Monticchio

Oxygen-isotope records from Greenland ice cores indicate numerous rapid climate fluctuations during the last glacial period. North Atlantic marine sediment cores show comparable variability in sea surface temperature and the deposition of icerafted debris. In contrast, very few continental records of this time period provide the temporal resolution and environmental sensitivity necessary to reveal the extent and effects of these environmental fluctuations on the continents. Here we present high-resolution geochemical, physical and pollen data from lake sediments in Italy and from a Mediterranean sediment core, linked by a common tephrochronology. Our lacustrine sequence extends to the past 102,000 years. Many of its features correlate well with the Greenland ice-core records, demonstrating that the closely coupled ocean-atmosphere system of the Northern Hemisphere during the last glacial extended its influence at least as far as the central Mediterranean region. Numerous vegetation changes were rapid, frequently occurring in less than 200 years, showing that the terrestrial biosphere participated fully in lastglacial climate variability. Earlier than 65,000 years ago, our record shows more climate fluctuations than are apparent in the Greenland ice cores. Together, the multi-proxy data from the continental and marine records reveal differences in the seasonal character of climate during successive interstadials, and provide a step towards determining the underlying mechanisms of the centennial-millennial-scale variability.

格陵兰冰芯的氧同位素（oxygen-isotope）记录显示，末次冰期期间存在大量快速气候波动事件。北大西洋海洋沉积岩芯则呈现出海表温度与浮冰碎屑沉积的相似变化特征。与之形成鲜明对比的是，同期的大陆记录极少能够具备足够的时间分辨率与环境敏感度，以揭示这些环境波动在大陆范围内的波及范围与影响效应。本研究呈现了基于统一火山灰年代学（tephrochronology）框架的意大利湖泊沉积物与地中海海洋沉积岩芯的高分辨率地球化学、物理及孢粉（pollen）数据。我们的湖泊沉积序列时间跨度可达距今10.2万年。该序列的诸多特征与格陵兰冰芯记录高度吻合，证实末次冰期北半球紧密耦合的海气系统，其影响范围至少可延伸至地中海中部区域。诸多植被变化过程极为迅速，通常可在不足200年内完成，这表明陆地生物圈完全参与了末次冰期的气候波动过程。在距今6.5万年之前，本记录所揭示的气候波动数量多于格陵兰冰芯记录中呈现的波动事件。综合大陆与海洋记录的多代用指标数据，本研究揭示了连续间冰段（interstadials）时期气候的季节特征差异，并为阐明百年-千年尺度气候波动的潜在机制迈出了关键一步。