Terrestrial climate evolution in northwest Germany over the last 25 million years

The first detailed reconstruction of the continental paleoclimate evolution of the Northwest German Tertiary (Late Oligocene to Pliocene) is presented . The paleoclimate data are derived from the paleobotanical record using th e coexistence approach, a method recently introduced that employs climatic requirements of the Nearest Living Relatives of a fossil flora. Twenty six megafloras (fruits and seeds, leaves, woods) from the Tertiary succession o f the Lower Rhine Basin. and neighboring areas are analyzed with respect to ten meteorological parameters. Additionally two sample sets from Late Mioc ene to Early Pliocene sediments comprising 396 palynofloras are analyzed by the same method providing a higher temporal resolution. The temperature cu rves show a comparatively cooler phase in the Late Oligocene, a warm interv al the Middle Miocene, and a cooling starting at 14 Ma. The cooling trend p ersisted until Late Pliocene with a few higher frequency temperature variat ions observed. From the beginning of Late Miocene to the present, the seaso nality increases and climate appears to have been less stable. As indicated by the precipitation data, a Cfa climate with wet summers persisted in NW Germany from Late Oligocene to Late Pliocene. The results obtained are well in accordance with regional and global isotop e curves derived from the marine record, and allow for a refined correlatio n of the Tertiary succession in the Lower Rhine Basin with the internationa l standard. It is shown that the reconstructed data are largely consistent with the continental climate record for the Northern Hemisphere, as reporte d by various authors. Discrepancies with previous reconstructions are discu ssed in detail.