Carbon isotopic record from Upper Devonian carbonates at Dongcun in Guilin, southern China, supporting the worldwide pattern of carbon isotope excursions during Frasnian-Famennian transition

Two positive δ13 C excursions are presented in records from the FrasnianFamennian (F-F) marine carbonate sediments in Europe, America, Africa, and Australia, having been considered as a worldwide pattern, and attributed to enhanced organic carbon burial during the F-F biological mass extinction. However, this worldwide pattern has not been revealed from the welldeposited Late Devonian sequences in southern China. In this paper, a detailed investigation has been made on the Late Devonian section at Dongcun, Guilin, southern China to constrain perturbations in δ13 C of carbonates in the F-F deposited sequence. The result from this section also indicates two positive δ13 C excursions during the F-F transition. The first excursion with an amplitude of 1.5‰ occurred at the bottom oflinguiformis Zone, later than the early excursion existing in the Laterhenana Zone of the Late Devonian profiles in other continents, especially, in central Europe. This difference has been expected to be a result as conodontPalmatolepis linguiformis occurred earlier in southern China than other sites. The second excursion with an amplitude of 2.1‰ is located at the F-F boundary, same as the records from other continents. This result strongly supports the view that two carbon isotope positive excursions during the F-F transition are common in carbonate sediments, resulting from worldwide increases of organic carbon burial intensity.