The last five glacial‐interglacial transitions: A high‐resolution 450,000‐year record from the subantarctic Atlantic

Abstract

A submillennial resolution, radiolarian‐based record of summer sea surface temperature (SST) documents the last five glacial to interglacial transitions at the subtropical front, southern Atlantic Ocean. Rapid fluctuations occur both during glacial and interglacial intervals, and sudden cooling episodes at glacial terminations are recurrent. Surface hydrography and global ice volume proxies from the same core suggest that summer SST increases prior to terminations lead global ice‐volume decreases by 4.7 ± 3.7 ka (in the eccentricity band), 6.9 ± 2.5 ka (obliquity), and 2.7 ± 0.9 ka (precession). A comparison between SST and benthic δ13C suggests a decoupling in the response of northern subantarctic surface, intermediate, and deep water masses to cold events in the North Atlantic. The matching features between our SST record and the one from core MD97‐2120 (southwest Pacific) suggests that the super‐regional expression of climatic events is substantially affected by a single climatic agent: the Subtropical Front, amplifier and vehicle for the transfer of climatic change. The direct correlation between warmer ΔTsite at Vostok and warmer SST at ODP Site 1089 suggests that warmer oceanic/atmospheric conditions imply a more southward placed frontal system, weaker gradients, and therefore stronger Agulhas input to the Atlantic Ocean.