Compound-specific isotope analysis across the Frasnian- Famennian boundary

The Frasnian-Famelmian extinction events represents one of the big five mass extinction events during the Phanerozoic with the decline of the Devonian stromatoporoid-coral reef ecosystem representing one of the most prominent crises in reef history. Inorganic carbon isotope investigations of FrasnianFamennian boundary sections show two +3%o excursions during the late Frasnian with the second excurs ion marking the Frasn ian-Famennian boundary. The 513C excursions are observed on a global scale and in part coincide with the deposition of black shales (Kellwasser horizons). An increased burial of 13C depleted organic carbon was interpreted to enrich surface waters in 13C and to lower oceanic dissolved COe and atmospheric CO2 concentrations (Joachimski and Buggisch 1993). The latter may result in climatic changes that may have stressed in particular the shallow water ecosystems.