First Records of Late Triassic Conodont Fauna and ?13Ccarb from the Dengdengqiao Section, Dangchang County, Gansu Province, Northwestern China

Based on a study of 49 conodont and 57 geochemical samples from the Upper Triassic, carbonate-dominated Dengdengqiao Formation, Qinling Basin, China, Carnian conodonts carbon isotope records are first reported. Two genera four species have been identified amongst 87 elements: Mosherella praebudaensis, Mo. longnanensis sp. nov., sp., “Misikella” longidentata. The presence praebudaensis indicates that lower part (bed 2) formation is attributable to Julian (lower Carnian) substage. A radiolarian fauna in previous belongs upper Carnian, but sampling horizon unclear. ?13Ccarb curve shows ?1.8‰ negative excursion beginning bed 3, its stratigraphic location uncertain. Formation clearly at least partly age could include younger strata. abundant calcareous algae section probably due some transport rather than preserved site. unusual ecosystem with rare marine organisms may reflect long-term stressful unfavorable conditions Dengdengqiao.