Аннотация:A perturbation of the global carbon cycle has often been used for interpreting the Frasnian‐Famennian (F‐F) mass extinction. However, the changes of atmospheric CO 2 level ( p CO 2 ) during this interval are much debatable. To illustrate the carbon cycle during F‐F transition, paired inorganic ( δ 13 C carb ) and organic ( δ 13 C org ) carbon isotope analyses were carried out on two late Devonian carbonate sequences (Dongcun and Yangdi) from south China. The larger amplitude shift of δ 13 C org compared to δ 13 C carb and its resultant Δ 13 C (Δ 13 C = δ 13 C carb − δ 13 C org ) decrease indicate decreased atmospheric CO 2 level around the F‐F boundary. The onset of p CO 2 level decrease predates that of marine regressions, which coincide with the beginning of conodont extinctions, suggesting that temperature decrease induced by decreased greenhouse effect of atmospheric CO 2 might have contributed to the F‐F mass extinction.
