Mid-Pliocene shifts in ocean overturning circulation and the onset of Quaternary-style climates ...

• Main Authors: Sarnthein, Michael, Bartoli, Gretta, Prange, Matthias, Schmittner, Andreas, Schneider, Birgit, Weinelt, M., Andersen, Nils, Garbe-Schönberg, Dieter
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2009
• Subjects: North Atlantic
• Online Access: https://dx.doi.org/10.3929/ethz-b-000019019; http://hdl.handle.net/20.500.11850/19019

A major tipping point of Earth's history occurred during the mid-Pliocene: the onset of major Northern-Hemisphere Glaciation (NHG) and of pronounced, Quaternary-style cycles of glacial-to-interglacial climates, that contrast with more uniform climates over most of the preceding Cenozoic and continue until today (Zachos et al., 2001). The severe deterioration of climate occurred in three steps between 3.2 Ma (warm MIS K3) and 2.7 Ma (glacial MIS G6/4) (Lisiecki and Raymo, 2005). Various models (sensu Driscoll and Haug, 1998) and paleoceanographic records (intercalibrated using orbital age control) suggest clear linkages between the onset of NHG and the three steps in the final closure of the Central American Seaways (CAS), deduced from rising salinity differences between Caribbean and the East Pacific. Each closing event led to an enhanced North Atlantic meridional overturning circulation and this strengthened the poleward transport of salt and heat (warmings of +2–3°C) (Bartoli et al., 2005). Also, the ... : Climate of the Past, 5 (2) ...