Transatlantic distribution of the Alaskan White River Ash
Transatlantic distribution of the Alaskan White River Ash
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DOI：
10.1130/g35945.1
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发表时间：
2014-10-01
期刊：
影响因子：
5.8
通讯作者：
Pilcher, Jonathan R.
中科院分区：
文献类型：
--
作者：
Jensen, Britta J. L.;Pyne-O'Donnell, Sean;Pilcher, Jonathan R.
保存在地质记录中的火山灰层代表了精确的时间标记，这些时间标记将不同的沉积环境联系起来，并使地球系统和考古科学中的同步和/或异步行为的调查成为可能。然而，人们通常认为，只有特别强大的事件，如超级爆发（≥ 450 km（3）的喷出物作为致密岩石当量;重复间隔类似于10（5）年），才能广泛地分布灰烬，足以对人类社会产生影响，或者让我们能够解决洲际范围内的地质，气候和文化问题。在这里，我们使用地球化学，年龄和形态学的证据表明，阿拉斯加怀特河灰（东叶;公元833-850）相关的“AD 860 B”灰（公元846-848）在格陵兰岛和北方欧洲发现。这些事件代表了超过7000公里的火山灰分布，连接海洋，陆地和冰芯记录。我们的研究结果表明，火山灰从更多的中等规模的喷发，复发间隔类似于100年，可以有更大的分布比以前认为的，直接影响火山扩散研究，广泛分布的代理记录的相关性，和火山灾害评估。
Volcanic ash layers preserved within the geologic record represent precise time markers that correlate disparate depositional environments and enable the investigation of synchronous and/or asynchronous behaviors in Earth system and archaeological sciences. However, it is generally assumed that only exceptionally powerful events, such as supereruptions (>= 450 km(3) of ejecta as dense-rock equivalent; recurrence interval of similar to 10(5) yr), distribute ash broadly enough to have an impact on human society, or allow us to address geologic, climatic, and cultural questions on an intercontinental scale. Here we use geochemical, age, and morphological evidence to show that the Alaskan White River Ash (eastern lobe; A.D. 833-850) correlates to the "AD860B" ash (A.D. 846-848) found in Greenland and northern Europe. These occurrences represent the distribution of an ash over 7000 km, linking marine, terrestrial, and ice-core records. Our results indicate that tephra from more moderate-size eruptions, with recurrence intervals of similar to 100 yr, can have substantially greater distributions than previously thought, with direct implications for volcanic dispersal studies, correlation of widely distributed proxy records, and volcanic hazard assessment.