Late Cenozoic sea-surface-temperature evolution of the South Atlantic Ocean

Abstract ∼ ∘ C exists across the Southern Ocean, maintained by the Antarctic Circumpolar Current (ACC) and a set of complex frontal systems. Together with the Antarctic ice masses, this system has formed one of the most important global climate regulators. The timing of the onset of the ACC system, its development towards modern-day strength and the consequences for the latitudinal SST gradient around the southern Atlantic Ocean are still uncertain. Here we present new TEX86 (TetraEther indeX of tetraethers consisting of 86 carbon atoms)-derived SST records from two sites located east of Drake Passage (south-western South Atlantic) to assist in better understanding two critical time intervals of prominent climate transitions during the Cenozoic: the late Eocene–early Oligocene (Ocean Drilling Program, ODP, Site 696) and Middle–Late Miocene (IODP Site U1536) transitions. Our results show temperate conditions (20–11 ∘ C) during the first time interval, with a weaker latitudinal SST gradient (∼ ∘ C) across the Atlantic sector of the Southern Ocean compared to present day. We ascribe the similarity in SSTs between Sites 696 and 511 in the late Eocene–early Oligocene South Atlantic to a persistent, strong subpolar gyre circulation connecting the sites, which can only exist in the absence of a strong throughflow across the Drake Passage. Surprisingly, the southern South Atlantic record Site 696 shows comparable SSTs (∼ ∘ C) during both the earliest Oligocene oxygen isotope step (EOIS, ∼ ∼ ∼ ∘ C during the Middle Miocene Climate Transition (MMCT, 14 Ma), making it the coldest oceanic region in the poorly recorded Antarctic realm and likely the main location for deep-water formation. The already-cold south-western South Atlantic conditions at the MMCT with relatively moderate additional cooling during the Late Miocene contrasts with the profound cooling in the lower latitudes and other sectors of the Southern Ocean due to northward expansion of the Southern Ocean frontal systems.

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch

Verweise und Beziehungen

• Erschienen in: Late Cenozoic sea-surface-temperature evolution of the South Atlantic Ocean ; volume:19 ; number:10 ; year:2023 ; pages:1931-1949 ; extent:19 ; Climate of the past ; 19, Heft 10 (2023), 1931-1949 (gesamt 19)

Beteiligte, Orts- und Zeitangaben

• Urheber: Hoem, Frida S. ; López-Quirós, Adrián ; van de Lagemaat, Suzanna ; Etourneau, Johan ; Sicre, Marie-Alexandrine ; Escutia, Carlota ; Brinkhuis, Henk ; Peterse, Francien ; Sangiorgi, Francesca ; Bijl, Peter K.

Weitere Informationen

• DOI: 10.5194/cp-19-1931-2023
• URN: urn:nbn:de:101:1-2023101904285947841609
• Rechteinformation: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 14.08.2025, 10:51 MESZ