Early Pliocene riparian vegetation and climate at the Puerto de la Cadena site, Murcia, Southeast Spain

Abstract

The Early Pliocene deposits of Puerto de la Cadena (Murcia, Southeast Spain) are best known for their rich vertebrate fauna, and co-occuring plant macrofossils have remained unstudied. In this paper, fossil plant assemblages are considered from a taxonomic and palaeoecological perspective. These remains were found in the VLP3B level of the Cigarrón Unit, which is of Zanclean age (ca. 4.997 to 4.896 Ma). Sedimentological, stratigraphic and taphonomic evidence suggests that they were initially deposited in a fluvial environment before being reworked into a shallow littoral environment, being deposited by hyperpycnal flows. The flora represents an azonal riparian association of mainly Arcto-Tertiary species, many of which occur frequently in Miocene and Pliocene assemblages in Europe. Deciduous broad-leaved species (Alnus gaudinii, Populus cf. balsamoides, Ulmus carpinoides, Acer tricuspidatum or Salix cf. angusta) are dominant, although there are also some evergreen elements (Daphnogene polymorpha, Quercus Group Ilex). From a floristic point of view, the Puerto de la Cadena assemblage is similar to that of same-aged Zanclean sites at Casa del Pino, Bruixes and Andalucía G1 elsewhere in Iberia. Some clear affinities with the floristic complex of Azambuja (Portugal) can also be inferred. Temperature values obtained by CLAMP analysis (MAT, WMMT, and CMMT) suggest strong seasonality. Precipitation values (GSP, MMGSP, Three_WET, and Three_DRY) indicate also a clear seasonal contrast in precipitation throughout the year. The inferred climate is similar to that calculated for other coeval Iberian sites and is cooler and more humid than the current climate in the area.