δ34SCAS and δ18OCAS records during the Frasnian–Famennian (Late Devonian) transition and their bearing on mass extinction models

Many proposed extinction mechanisms for the Late Devonian (Frasnian–Famennian boundary — FFB) mass extinction event include the spread of anoxia in bottom waters during the two Kellwasser anoxic events, which have in turn been linked to changes in continental weathering, volcanic/hydrothermal fluxes, sea-level and climate change. Although there is strong evidence for bottom water anoxia in epicontinental seas at tropical/equatorial...