North Atlantic Ocean-Rafted Pumice: A Distal Record of Icelandic Volcanic Activity and Jökulhlaups

Ocean-transported pumice is found along coasts throughout the northern North Atlantic region from Arctic Canada, Greenland, Iceland, the British Isles, Norway, Sweden, Denmark to Svalbard.  This pumice is found on raised shorelines, present-day beaches and in archaeological sites (mainly coastal) dating back to the early Holocene.  Geochemical analysis (major, minor and trace element) shows that this mainly dacitic pumice was erupted from the Katla volcanic system and can be correlated to the volcanic activity which produced the silicic SILK layers, with some of the oldest pumice being geochemically correlated to late-glacial Vedde-type activity.  A deposit of the Vedde-type pumice on the southern slopes of Katla is locally well known, but recent research has uncovered the younger dacitic pumice along the probable routes the jökulhlaups would have taken.  These widespread deposits provide useful insights into silicic activity and hazard mapping at Katla and information on ocean circulation patterns throughout the Holocene.  The pumice has also been utilised by people from across a large geographical area, from different cultures and through thousands of years of time.