On the time-scale of deglaciation: Atlantic deep-sea sediments and gulf of Mexico

Deglaciation as seen in the δ¹⁸O record of deep-sea sediments starts about 14,000 yrs. ago. Measured bulk ¹⁴C ages are too old by 1000–2000 yrs. in the central Atlantic compared with ages derived from climate correlation. This conclusion rests on the observation that deglaciation occurs in two major steps, separated by a pause, and on the hypothesis that this pause is correlative to the Younger Dryas cold period. The Gulf of Mexico record is readily correlated with the deep-sea record if it is assumed that the appearance of Globorotalia menardii is retarded with respect to the tropical Atlantic, by about 2000 yrs. The major meltwater spike then dates near 9000 yrs. ago, rather than at 13,500 yrs. B.P. (as assumed by Kennett and Shackleton, 1975) or 11,500 yrs. B.P. (as in Emiliani et al., 1975).