Figure F1. Compilation of benthic oxygen isotope data from Cenozoic deep-sea cores (after Zachos et al., 2001). Note prominent delta18O decrease of >1 per mil during the late Oligocene at ~26 Ma against the long-term Cenozoic delta18O increase. VPDB = Vienna Peedee belemnite.

Figure F1. Compilation of benthic oxygen isotope data from Cenozoic deep-sea cores (after Zachos et al., 2001). Note prominent

¹⁸O decrease of >1

during the late Oligocene at ~26 Ma against the long-term Cenozoic

¹⁸O increase. VPDB = Vienna Peedee belemnite.