Temperatures and oxygen isotopic composition of Phanerozoic oceans

The temperature of ancient oceans is an important constraint for understanding the climate history of our planet. The classical oxygen isotope paleothermometry on fossil shells, while very proficient when applied to the younger (Cenozoic) portion of the geologic record, is believed to yield only unreliable results for the Phanerozoic “deep time”, either because the empirically well documented secular trend to more negative δ18O values with...