- © The Mineralogical Society Of America
Stratigraphic variation in the carbon isotopic (δ13C) value of marine carbonate and organic matter preserved within it has become a popular tool for supporting paleoclimatic hypotheses and refining stratigraphic correlation. Virtually every important biostratigraphic and sequence stratigraphic event of the last 800 million years has had a δ13C dataset collected to aid in interpreting the causal environmental factors that contributed to the event. The stratigraphic resolution obtainable using δ13C has yielded critical temporal constraints on the interplay between carbon cycle variation and environmental events such as mass extinction and eustasy. Although the non-uniqueness of the carbon isotopic response to different environmental stimuli has frustrated the identification of a unified mechanism linking marine δ13C variation with distinct environmental forcing functions, the interpretation of δ13C variation can nonetheless provide important insights into processes that influence major global climatic and surficial systems.
Early studies of marine carbonate minerals suggested that the δ13C value of ancient oceans was essentially 0‰ versus the Peedee belemnite standard (PDB) (Clayton and Degens 1959; Schidlowski et al. 1975; see also Keith and Weber 1964). It was later recognized, however, that departures from the PDB standard represented secular variation in the δ13C values of the marine environment rather than analytical noise, that the record was potentially rich with stratigraphic and paleoenvironmental information (Scholle and Arthur 1980; Veizer et al. 1980; Wadleigh and Veizer 1982; Arthur et al. 1985; Holser et al. 1986; Zachos and Arthur 1986) and that variation was intimately linked to the global carbon, oxygen, and sulfur cycles (Kump and Garrels 1986; Holser et al. 1988). It is now well established that carbonate δ13C values vary within ±3‰ from the PDB standard for …