HS4_2008 (entity_id = 253) and HS4_2013 (entity_id = 254): The floating layer-counted chronology is tied to the 9 Bayesian U/Th ages by sliding the whole floating section to older or younger ages until the minimum average deviation from the U/Th ages is achieved. This layer-counted age model does not refine the absolute chronology for the 8.2 kyr event relative to that achieved from the U/Th chronology, but allows the duration of the event to be constrained at close to annual precision. See supplementary material DOI: 10.1038/ngeo1708 for further details.