Gigantic volcanic eruptions and climatic change in the early Eocene
Gigantic volcanic eruptions and climatic change in the early Eocene
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始新世早期的巨大火山喷发和气候变化
DOI：
10.1007/s00531-006-0085-7
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发表时间：
2006
影响因子：
2.3
通讯作者：
E. Brückl
中科院分区：
文献类型：
--
作者：
H. Egger;E. Brückl
摘要在奥地利阿尔卑斯山脉离源区约1900 km的始新世早期沉积中，发现了23层来自北大西洋火成岩省的蚀变火山灰（膨润土）。奥地利的膨润土是丹麦和北海盆地的“主灰相”的远端等级物。我们计算出该系列的总喷发量为21,000 km3，发生在60万年。这个系列中最强大的一次喷发发生在5400万年前（Ma），喷出了大约1200立方千米的火山灰物质，这使它成为地质历史上最大的玄武岩火山碎屑喷发之一。在始新世早期，群聚的火山喷发一定通过不断产生平流层尘埃和气溶胶云而显著地影响了入射的太阳辐射。氧同位素值证实了这一假设，表明在这一爆炸性火山活动的主要阶段，全球海洋表面温度下降了1至2°C。
Abstract23 layers of altered volcanic ash (bentonites) originating from the North Atlantic Igneous Province have been recorded in early Eocene deposits of the Austrian Alps, about 1,900 km away from the source area. The Austrian bentonites are distal equivalents of the “main ash-phase” in Denmark and the North Sea basin. We have calculated the total eruption volume of this series as 21,000 km3, which occurred in 600,000 years. The most powerful single eruption of this series took place 54.0 million years ago (Ma) and ejected ca. 1,200 km3 of ash material, which makes it one of the largest basaltic pyroclastic eruptions in geological history. The clustering of eruptions must have significantly affected the incoming solar radiation in the early Eocene by the continuous production of stratospheric dust and aerosol clouds. This hypothesis is corroborated by oxygen isotope values, which indicate a global decrease of sea surface temperatures between 1 and 2°C during this major phase of explosive volcanism.