Archaeologica.org

The source of an eruption that scattered ash from pole to pole has been pinpointed as Samalas volcano on Indonesia's Lombok Island. The research team, led by geographer Franck Lavigne of the Université Paris 1 Panthéon-Sorbonne, has now dated the event to between May and October of 1257.

The cataclysm blasted 10 cubic miles (40 cubic kilometers) of debris up to 27 miles (43 kilometers) high into the sky, producing fallout that settled around the world. Near the volcano itself, it settled into thick deposits that the team sampled in over 130 places to produce a stratigraphic and sedimentologic picture of the way the eruption unfolded.