Strong climate coupling of terrestrial and marine environments in the Miocene of northwest Europe

A palynological and organic geochemical record from a shallow marine paleoenvironmental setting in SE Netherlands documents the coupled marine and terrestrial climate evolution from the late Burdigalian (∼ 17 Ma) through the early Zanclean (∼ 4.5 Ma). Proxy climate records show several coeval variations in both relative sea surface (deduced from percent cool dinocysts) and terrestrial (subtropical vs. cool temperate pollen) temperature indices. The terrestrial climatic trend is confirmed by a quantitative reconstruction of annual mean air temperature based on the distribution of fossil branched glycerol dialkyl glycerol tetraethers, showing a cooling from ∼ 27 °C to ∼ 14 °C between 17 and 5 Ma punctuated by short-term variations. Decreases in sea surface temperature broadly correlate to inferred third-order sea level variations and correspond to isotope glacial events Mi-3 through Mi-7. An additional strong SST decrease occurs around ∼ 8.4 Ma, coincident with a strong reduction and regional disappearance of subtropical pollen types. This cooling phase seems associated with lowered sea levels, but it has not yet been described from the deep sea δ18O record.