Subtropical Atlantic salinity variability and Atlantic meridional circulation during the last deglaciation

TitleSubtropical Atlantic salinity variability and Atlantic meridional circulation during the last deglaciation
Publication TypeJournal Article
Year of Publication2008
AuthorsCarlson, AE, Oppo, DW, Came, RE, LeGrande, AN, Keigwin, LD, Curry, WB
JournalGeology
Volume36
Issue12
Pagination991-994
ISSN0091-7613
Abstract

During the last deglaciation (ca. 21-10 ka), freshening of the North Atlantic surface likely caused reductions in Atlantic meridional overturning circulation (AMOC); the mechanisms related to AMOC recovery remain poorly understood. Here we present three new deglacial surface temperature and delta O-18(seawater) (delta O-18(sw)) reconstructions from the western subtropical North and South Atlantic. Similarities to tropical Caribbean and western Atlantic delta O-18(sw) records suggest that a salty surface water mass accumulated in the western Atlantic from 27 degrees S to 33 degrees N during periods of reduced AMOC. However, delta O-18(sw) decreases led deep AMOC resumption by hundreds of years. We suggest that the northward export of salt previously trapped in the western Atlantic resulted in the early establishment of a shallow overturning circulation that eventually culminated in deep AMOC resumption, implying that AMOC may constitute a self-limiting system.

DOI10.1130/g25080a.1