Evidence for Holocene sea level and climate change from Almenara marsh (western Mediterranean)

Abstract

In the Almenara marsh (western Mediterranean), four cores were analyzed to establish the relationship between the marsh record of the Almenara marshlands and the environmental factors responsible for its evolution during the Holocene. One hundred and eighty-six samples were collected for sedimentologic and paleontological study: 63 for biomarker analysis; 5 for amino acid racemization (AAR) dating; and 5 for 14C dating. Litho and biofacies analyses identified distinct paleoenvironments, with the presence of a marsh environment alternating with inputs of alluvial material and marine sediments. Biomarkers indicated the constant presence of terrestrial (herbaceous) plants, together with a variable development of aquatic macrophytes. During the Holocene transgression, the Almenara marsh was occupied by oligohaline marsh facies with an oscillating water level and peat formation, which was established at the bottom of the record at 7570 cal yr BP and persisted until 3100±780 yr (AAR). Maximum surface flooding occurred at 5480 cal yr BP, registered 450m from the current coastline. At least three peat beds (dated with 14C dating and AAR) correlated with Bond (episode 5900 cal yr BP) and Wanner (episodes 4800–4500 and 3300–3500 cal yr BP) cycles and thus correspond to a regional model that affected the Northern Hemisphere.

Socio-ecological adaptation to Early-Holocene sea-level rise in the western Mediterranean

“…In the Valencian gulf, the maximal inland position of the beach dated at 7500-7200 cal. BP (Carmona and Ruiz, 2011) has also been associated with the desiccation of several coastal lagoons (Marco-Barba et al, 2013;Blázquez et al, 2017). In very detailed sequences, this evolution has been constrained at 7700-7000 cal.…”

“…(caption on next page) deltas (Anthony et al, 2014;Amorosi et al, 2013a), coastal barrier system constructions and large development of lagoon environments (Marco-Barba et al, 2013;Blázquez et al, 2017;Melis et al, 2017;Melis et al, 2018;Pascucci et al, 2018).…”

Aridity events during the last 4000 years in Western Mediterranean marshes (Almenara and Benicasim marshes, E Spain)

“…For most of the last 4000 years, coastal wetlands have no direct connection to the sea. In the case of the marshes of Almenara and Benicasim, the paleoecological studies (foraminifers and ostracods) show that they were oligohaline marshes only affected by small fluctuations in their water levels (Usera et al, 1996;Mediato, 2016;Blázquez et al, 2017Blázquez et al, , 2018Rodríguez-Pérez et al, 2018). These authors did not reach conclusive paleoecological data that allowed distinguishing relative changes in salinity of wetlands during the period.…”

“…They are typical features of the coastal plain landscapes of the Spanish Mediterranean coast: Mar Menor, Valencia lagoon, Oliva-Pego marsh, Almenara, Benicasim and Torreblanca-Cabanes marshes. Previous sedimentological, geomorphological and paleontological studies focused on their paleoenvironmental reconstruction during the Holocene (Dupré et al, 1988;Usera et al, 1996Usera et al, , 2002Mediato and Santisteban, 2006;Carmona and Ruiz, 2011;Marco-Barba et al, 2013, Carmona et al, 2016Mediato, 2016;Blázquez et al, 2017Blázquez et al, , 2018Rodríguez-Pérez et al, 2018;Ruiz-Pérez and Carmona, 2019;López-Belzunce et al, 2020). These studies concluded that the Holocene paleoenvironmental changes were related to the eustatic variations that took place since the Last Glacial Maximum and climate was a minor forcing of local interest.…”

Evolución paleoambiental de una turbera finiholocena en el sector suroccidental del Parque Nacional de Doñana (S.O. España)

“…En los últimos años, han proliferado los estudios sobre el registro holoceno de medios costeros, con especial atención a la incidencia de los cambios climáticos y las fluctuaciones del nivel del mar sobre ellos (Cohen et al, 2016;Fanget et al, 2016;Araujo et al, 2017;. Sus resultados suelen basarse en el análisis pluridisciplinar de testigos continuos o secciones superficiales, que a menudo incluye la identificación de diatomeas o polen para poder deducir su evolución paleogeográfica y ambiental (Anderson, 2000;Leventer et al, 2010;Prieto et al, 2017;Blázquez et al, 2017;Quick et al, 2018).…”