Tephra and Tephrochonology
Brian Jones, Robin W. Renaut, Helgi Torfason, R. Bernhart Owen; The geological history of Geysir, Iceland: a tephrochronological approach to the dating of sinter. Journal of the Geological Society ; 6 : — The vertical succession through the discharge apron of Geysir, up to 3. Katla tephra in Unit D has been largely altered to …