Molds preserved on travertines constitute exceptional species-informative material to reconstruct past vegetation. These are common on the High Ebro region. Here, the fluvial system erosion and karstification of the Mesozoic limestone since the Late Tertiary, origins extensive travertine complexes like the one studied in Tubilla del Agua (Burgos). In this site, three different travertine complexes are observed. The older one is represented by two disconnected edifices incised by the Valoria river. The age of this structure is established between > 300,000 and 240,000 yr BP, as from the U/Th dating on its base and top. The subsequent incision lasted until at least 90,000 yr BP, when another edifice erected upstream on the older one. The second travertine group comprises three platforms aged 60,000 yr BP the lower one, and 18,000 yr BP the middle one. The third travertine group is a lake-barrier complex 12,000 yr BP old, on which Tubilla del Agua was built, and a stratified travertine body that covers the valley bottom 10,000 to 2700 cal yr BP old. Some of the ages of the oldest travertines, and the most modern ones, coincide with the principal travertine formation cycles described by Durán (1996) for Spain. The matrix of precipitated calcium carbonate of all these complexes are rich in plant remain molds (mosses, stems, leaves, cones) of the surrounding flora. Pinus nigra Arnold cone molds have been localized and identified by comparative morphology studies. These remains are of high valuable information about the Pleistocene and Holocene presence of this taxon, in a site where no natural presence can be found today. This work was funded by project CGL2008-06005
