(a) Ages for Hole 1218A according to Pälike et al. (2006); age determinations for Hole 574C using the position of datum levels in Barron et al. (1985), with numerical ages adapted to the age model of Pälike et al. (2006) following Zachos et al. (2004).(b) 2smean = 2s/n0.5 calculated from repeated TIMS measurements of an individual sample.(c) n = number of TIMS analyses on a single sample.(d) Duplicate samples processed from barite dissolution and cation separation to TIMS analysis.