The use of pollen floras as a tool to estimate palaeoaltitude of mountains: The eastern Pyrenees in the Late Neogene, a case study

Northern Hemisphere vegetation is generally zoned as a consequence of latitudinal and altitudinal gradients. Temperature reconstruction from three successive pollen floral assemblages (of Tortonian, Messinian and Zanclean age) from the eastern Pyrenees has been used to estimate the altitudinal evolution of the uplifted Cerdanya Basin and its surrounding massifs. A new method has been developed for the uplifted basins, which completes that already applied to pollen floras from coastal marine deposits close to mountains. In contrast to previous hypotheses, it seems that the eastern Pyrenees occurred at a lower altitude in the Late Miocene before continuous uplift began 10 Ma ago. The rate of this uplift ranged between 0.06 and 0.12 mm/yr. Key-words: Pollen flora – Palaeotemperature – Mountain palaeoelevation – Uplifted basins.