Multi-proxy dating of Iceland's major pre-settlement Katla eruption to 822-823 CE ...

• Main Authors: Büntgen, U, Eggertsson, Ó, Wacker, L, Sigl, M, Ljungqvist, FC, Di Cosmo, N, Plunkett, G, Krusic, PJ, Newfield, TP, Esper, J, Lane, C, Reinig, F, Oppenheimer, C
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of America 2017
• Subjects: 37 Earth Sciences; 3709 Physical Geography and Environmental Geoscience; 3705 Geology; 13 Climate Action; Greenland; Katla; Fennoscandia; Greenland ice cores; Iceland
• Online Access: https://dx.doi.org/10.17863/cam.11141; https://www.repository.cam.ac.uk/handle/1810/266913

Investigations of the impacts of past volcanic eruptions on climate, environment, and society require accurate chronologies. However, eruptions that are not recorded in historical documents can seldom be dated exactly. Here we use annually resolved radiocarbon ($^{14}$C) measurements to isolate the 775 CE cosmogenic $^{14}$C peak in a subfossil birch tree that was buried by a glacial outburst flood in southern Iceland. We employ this absolute time marker to date a subglacial eruption of Katla volcano at late 822 CE to early 823 CE. We argue for correlation between the 822–823 CE eruption and a conspicuous sulfur anomaly evident in Greenland ice cores, which follows in the wake of an even larger volcanic signal (ca. 818–820 CE) as yet not attributed to a known eruption. An abrupt summer cooling in 824 CE, evident in tree-ring reconstructions for Fennoscandia and the Northern Hemisphere, suggests a climatic response to the Katla eruption. Written historical sources from Europe and China corroborate our ...