Termination 1 timing in radiocarbon‐dated regional benthic δ 18 O stacks

Benthic δ 18 O changes are often assumed to be globally synchronous, but studies comparing 2–9 radiocarbon‐dated records over the most recent deglaciation (Termination 1) have proposed differences in the timing of benthic δ 18 O change between the Atlantic and Pacific, intermediate and deep, and North and South Atlantic. Because of the relatively small number of records used in these previous studies, it has remained unclear whether these differences are local or regional in scale. Here we present seven regional benthic δ 18 O stacks for 0–40 kyr B.P. that include 252 records with independent regional age models constrained by 852 planktonic foraminiferal 14 C dates from 61 of these cores. We find a 4000 year difference between the earliest termination onset in the intermediate South Atlantic at 18.5 (95% confidence interval: 17.9–19.0) kyr B.P. and the latest in the deep Indian at 14.5 (14.1–15.0) kyr B.P. The termination onset occurs at 17.5 kyr B.P. in the intermediate and deep North Atlantic, deep South Atlantic, and deep Pacific. However, throughout the termination deep North Atlantic benthic δ 18 O leads the deep Pacific by an average of 1000 year and a maximum of 1700 year. Additionally, the intermediate Pacific termination onset at 16.5 (16.1–16.9) kyr B.P. demonstrates that intermediate‐depth benthic δ 18 O change was not globally synchronous. These regional stacks provide better age models than a global stack across Termination 1 and potentially important constraints on deglacial ocean circulation changes.