Abstract:
The Paleocene-Eocene Thermal Maximum (PETM; ca. 55.8 Ma) is associated with a rapid and large carbon cycle perturbation, transient warming, and deep-sea acidification. Although this event is widely known from pelagic, hemipelagic, and continental records, the lack of in situ, shallow-water carbonate platform sections inhibits interpretations of whether the PETM had a significant effect on shallow-water carbonate ecosystems. Limalok Guyot (Ocean Drilling Program Site 871) in the Pacific Ocean comprises a volcanic pedestal topped by a Paleogene carbonate platform that drowned in the Middle Eocene. Carbon isotope stratigraphy of the platform carbonate sediments is used, in conjunction with existing biostratigraphy, to refine the stratigraphic framework of the carbonate platform. Although core recovery was poor, the major Late Paleocene-Middle Eocene stratigraphic trends in carbon isotopes are recognized, including a prominent approximately 3 per mil negative carbon isotope excursion, recording the onset of the PETM. The lithological and paleontological record of the PETM on Limalok Guyot shows no major evidence for a carbonate production crisis, suggesting that the effects of any changes in temperatures or surface ocean pH were relatively short lived or relatively minor.