Fig. 14

Evolution of the Cretaceous ocean temperature estimated from oxygen isotopic records. Circles, triangles, and squares represent data from Hedbergella (planktic foraminifera), globular form planktic foraminifera, and surface dwelling vertebrate remains, respectively. Colors for each symbol indicate the paleolatitude where the data were obtained. While foraminifers were recovered from deep-sea cores, vertebrate remains occurred in outcrops, implying that vertebrate remains may not record open ocean temperatures. δ¹⁸O_SW is estimated as − 1 (‰, VSMOW) (Shackleton and Kennett 1975). δ¹⁸O_SW is adjusted for latitudinal gradient in surface water δ¹⁸O_SW (Zachos et al. 1994). Isotopic temperatures were calculated using the equations of Bemis et al. (1998) for foraminiferal calcites and Pucéat et al. (2010) for vertebrate remains. Paleolatitudes were computed by the Paleolatitude Calculator for Paleoclimate Studies (version 2.1) (van Hinsbergen et al. 2015) if they were not provided in the literature. Data are cited from Huber et al. (1999, 2002), Bice et al. (2003, 2006), Moriya et al. (2003; 2007; 2011), Pucéat et al. (2003, 2007), Forster et al. (2007), and Bornemann et al. (2008). Maa. Maastrichtian, Sa. Santonian, Co. Coniacian, Tur. Turonian, Cenom. Cenomanian, Barr. Barremian, Ha. Hauterivian, Valang. Valanginian, Berri. Berriacian, WPWP Western Pacific Warm Pool