Ediacaran δ13C chemostratigraphy of South China

We report new δ13C chemostratigraphic data of the Ediacaran System in South China. Using litho- and biostratigraphic markers as independent calibrators, we combine new and previously published δ13C data to construct a composite δ13C profile for the Ediacaran System in South China. The composite curve shows, in chronostratigraphic order, 1) a negative δ13C excursion (EN1) in the Doushantuo cap carbonate that overlies the Ghaub-age Nantuo diamictite; 2) a pronounced positive δ13C excursion (EP1) in the lower Doushantuo Formation where Doushantuo-type acanthomorphic acritarchs, red algae, and animal embryos first appear; 3) a mild negative δ13C excursion (EN2) in the middle Doushantuo Formation; 4) a positive δ13C excursion (EP2) in the upper Doushantuo Formation where Doushantuo-type acanthomorphic acritarchs, micrometazoans, and stem group florideophyte red algae become abundant and diverse; 5) a pronounced negative δ13C excursion (EN3) near the uppermost Doushantuo Formation; 6) a strongly positive δ13C excursion (up to + 6.3‰ PDB; EP3) in the lower Dengying Formation; 7) a stable δ13C plateau (ca. + 2.5‰ PDB; EI) in the middle and upper Dengying Formation where abundant vendotaenid algae, macroscopic Ediacaran fossils, biomineralized animal tubes, and mostly horizontal animal traces occur; and 8) a − 10‰ negative δ13C excursion (EN4) immediately below the Ediacaran–Cambrian boundary. The general pattern of this composite δ13C curve is robust, despite a considerable amount of variation among the δ13C profiles of different sections. This composite δ13C curve provides a first-order chemostratigraphic framework for the subdivision and correlation of the Ediacaran System in South China.