Mount Churchill, Alaska, produced two of the largest North American eruptions of the last 2,000 years. The younger event dispersed a minimum of 50 km3 of ash to the east of the volcano, which is preserved as a visible tephra bed (known as the White River Ash east lobe, or WRAe) >1,000 km from source, and is represented by cryptotephra ("AD860B") in European sites >7,000 km away. It has been postulated that the substantial ash deposition had a major regional impact on wildlife and triggered the migration of Athapaskan-speaking people from the Yukon Territory to the American South-West. The recent identification of tephra in Greenland ice cores dates the eruption precisely to AD 853±1 enabling the event now to be considered in light of historical records for unsettled weather in the summer of 855 and extreme cold in the winter of 855/6, despite what appears to have been a modest atmospheric aerosol loading. Here we examine palaeohydrological and palynological data from peatlands in North America and Europe in which WRAe/AD860B tephra has been found to evaluate the wider environmental and cultural impact of the eruption. We assess the role of high latitude eruptions in terms of their contribution to extra-regional climate change and we consider the challenges of discerning the legacy of volcanic impacts in non-annual proxy records.
|Number of pages||1|
|Publication status||Published - May 2017|
|Event||PAGES 5th Open Science Meeting - Zaragoza, Spain|
Duration: 09 May 2017 → 13 May 2017
|Conference||PAGES 5th Open Science Meeting|
|Period||09/05/2017 → 13/05/2017|