North Atlantic euphotic ocean temperatures derived from coccolith clumped isotopes and alkenones from ODP Site 162-982 since the Miocene (1.99-16 Ma)@en

Accurate predictions of the future climate response to CO2 depend on the ability of climate models to simulate past analog warmer climates, like the Miocene. However, one key unresolved issue in paleoclimate modeling is reproducing the pronounced high-latitude warmth and relatively flat latitudinal temperature gradients inferred from proxy records. Here, we use clumped isotope thermometry—a method that sidesteps limitations of conventional proxies—on pure coccolith calcite from the high-latitude North Atlantic ODP Site 982, extending from the Mid Miocene to the Quaternary (16-1.99 Ma; 524.55-43.99 m (mcd)), and compare to alkenone-derived temperatures from the same samples. We also measured clumped isotopes from a sediment trap sample from the Iceland Sea (70.23° N; 9.75° W; 1884 m) which in July 1999 registered the largest surface bloom ever recorded in this area, containing 99% of the subpolar north Atlantic Coccolithus pelagicus. […]