Secular variation in Late Cretaceous carbon isotopes: a new δ¹³C carbonate reference curve for the Cenomanian–Campanian (99.6–70.6 Ma)

Carbon stable-isotope variation through the Cenomanian–Santonian stages is characterized using data for 1769 bulk pelagic carbonate samples collected from seven Chalk successions in England. The sections show consistent stratigraphic trends and δ 13 C values that provide a basis for high-resolution correlation. Positive and negative δ 13 C excursions and inflection points on the isotope profiles are used to define 72 isotope events. Key markers...