Las huellas de un bosque carboníferouna colonización costera y su ocaso

Abstract

The Carboniferous forest at Verdeña (Palencia province), a protected site (by the autonomous government of Castilla-León, since 1998), shows the imprint of tree bases as well as fallen tree trunks of Sigillaria (Lycopsida) and a probable Cordaites (Coniferopsida) on a sandstone surface which represents the final stage of a marine deltaic sequence of Cantabrian age. This sandstone occurs in vertical position due to post-early Barruelian folding of the Asturian phase. The two different kinds of tree occupied separate but adjacent areas, probably due to different ecological requirements. The Sigillaria forest shows the presence of two different generations. The first, pioneer generation, represented by large-size imprints, seems to have died at old age before the second generation had a chance to establish itself. The trees of the second generation did not reach full size at the time when a catastrophic influx of sea water cut down the trees separating the trunks from their Stigmaria bases. The flattened tree trunks were oriented in the direction of the current. The Cordaites trees, of stronger build due to a large development of wood, were not cut down but uprooted. Fallen trees are characterised by deep imprints. The basal imprint of these woody trees shows the presence of tap roots as well as a laterally extensive rooting system.