The North China Steptoean Positive Carbon Isotope Event: New insights towards understanding a global phenomenon

Precise biostratigraphic correlation of the base of the Paibian Stage, Cambrian, within and beyond the North China craton has been difficult, mostly because of the strong endemism of the trilobite fauna on the shallow platform facies. The use of the Steptoean Positive Carbon Isotope Excursion (SPICE) in defining the Guzhangian-Paibian stage boundary has become a standard practice. Thus, a chemostratigraphic study of the Huangyangshan section from North China has been carried out. This section in Shandong Province clearly records the SPICE, with the most detailed fossil and carbonate carbon isotope data to date. Compared to other sections in the world, all the published SPICE in North China display both reduced peak and reduced difference (Δ13C) values. These may imply unique conditions on the North China craton during the upper Guzhangian to Paibian stages. This study shows that the SPICE is recorded in relatively condensed sections in North China; thus, ≤ 0.5 m sampling density is suggested here in order to evaluate the presence of the SPICE in North China and condensed sections.