Carbon isotopic vital effect and organic diagenesis, Lower Cambrian Forteau Formation, northwest Newfoundland: Implications for δ13C chemostratigraphy

Lithology and diagenesis are important components in δ¹³C_carb stratigraphic variation in Lower Cambrian Forteau Formation limestones. The δ¹³C values of ooids indicate that shallow seawater ΣCO₂ was -1.0‰ to 0.0‰. Salterella and archaeocyathans probably exerted a vital effect on the carbon isotopic composition of their skeletal CaCO₃. The diversification of early skeletal organisms complicated the biogeochemical cycling of carbon isotopes during the Precambrian-Cambrian transition, making δ¹³C chemostratigraphy and isotopic mass-balance calculations more difficult in Lower Cambrian and younger deposits. Similar studies should be carried out on other Lower Cambrian sections before the carbon isotopic chemostratigraphic technique can be validated for this important interval.