Browsing by Author "Costas, Susana"
Now showing 1 - 10 of 16
Results Per Page
Sort Options
- 3D facies architecture and dynamics of a beach barrier-lagoon complex (Ría de Vigo, Galicia, Spain)Publication . Clemente, F.; Pérez-Arlucea, Marta; Alejo, Irene; Nombela, Miguel Ángel; González, D.; Costas, Susana; Bernárdez, Patrícia; González, R.; González Villanueva, Rita
- Benchmarks and sediment source(s) of the 1755 Lisbon tsunami deposit at Boca do Rio EstuaryPublication . Font, Eric; Pires, Cristina Veiga; Pozo, Manuel; Nave, Silvia; Costas, Susana; Ruiz Muñoz, Francisco; Abad, Manuel; Simões, Nuno; Duarte, Sílvia; Rodríguez-Vidal, JoaquínStandardizing the signature of tsunami deposits has been identified as a major limitation for the identification of paleo-tsunami deposits. This limitation mostly arises from the strongly source-dependent nature of these deposits, which in turn determines their composition and depositional architecture, and from the effect of the local morphology of the corresponding depositional environment. Here, we provide new high-resolution mineralogical, geochemical and micro/macrofauna data of the 1755 tsunami layer of Boca do Rio estuary (Algarve, Portugal) with the aim of unraveling the signatures of estuarine tsunami deposits and linking them to possible sediment sources. We also apply for the first time diffuse reflectance spectrophotometry (DRS) analysis. Our results show that the 1755 tsunami deposit of the Boca do Rio estuary is featured by an enhancement in Sr and Ca, which are linked to the input of biogenic and detrital carbonates (shell fragments and limestone clasts) from the beach foreshore and a strong depletion in most terrestrial- and marine-sensitive indicators. The latter is interpreted as resulting from the reworking of the estuarine clays and subsequent dilution within a huge volume of sand eroded from the coastal barrier. It confirms that in the case of the Boca do Rio estuary, the sediment source is essentially proximal and coastal. Textural and mineralogical features between the base and the top of the tsunami layer suggest the imprint of run-up and backwash currents derived from a unique wave. Micro and macrofauna analysis and DRS data of the siliciclastic fraction show slight but significant environmental changes occurring just after the tsunami, which could be provoked by an eventual closure of the estuary mouth.
- Benchmarks, sediment source and hydrodynamics of the 1755 Lisbon tsunami deposit at Boca do Rio EstuaryPublication . Font, Eric; Pires, Cristina Veiga; Pozo, Manuel; Nave, Silvia; Costas, Susana; Ruiz Muñoz, Francisco; Abad, Manuel; Simões, Nuno; Duarte, Sílvia
- Climate-driven episodes of dune mobilization and barrier growth along the central coast of PortugalPublication . Costas, Susana; Brito, Pedro Oliveira; FitzGerald, Duncan; Goble, Ronald
- Evolución sedimentaria desde el último máximo glacial en la costa y plataforma continental de las Rías Baixas (Galicia, NW de la Península Ibérica)Publication . Nombela, Miguel Ángel; Alejo, Irene; Bernárdez, Patrícia; Clemente, F.; Costas, Susana; Diz, Paula; Fernández-Bastero, S.; Francés, Guillermo; Gago-Duport, L.; García, T.; González-Alonso, D.; González-Álvarez, R.; González-Villanueva, R.; Liquete, C.; Pena, L. D.; Pérez-Arlucea, Marta
- Identification of tsunami deposits and their impact on coastal zones : a study case of the Boca do Rio estuary (Algarve, Portugal)Publication . Font, Eric; Pires, Cristina Veiga; Pozo, Manuel; Nave, Silvia; Costas, Susana; Ruiz Muñoz, Francisco; Abad, Manuel; Simões, Nuno; Duarte, Sílvia
- Impact of atmospheric circulation patterns on coastal dune dynamics, NW SpainPublication . González-Villanueva, Rita; Costas, Susana; Pérez-Arlucea, Marta; Jerez, Sonia; Trigo, Ricardo MachadoDunes in temperate latitudes have experienced a significant stabilization in recent times, essentially as a consequence of the expansion of dense vegetation cover. Yet, the causes for this gradual stabilization as well as the causes promoting antecedent aeolian mobilization remain poorly understood. The Traba coastal dune field, located in NW Spain, was examined to explore the causes inducing aeolian activity and subsequent stabilization since 1940. Morphological changes were identified through the combination of aerial photographs and geophysical techniques. Local wind field regimes were simulated using a regional climate model to obtain the variability of the most relevant modes of atmospheric circulation in the North Atlantic and European regions; North Atlantic Oscillation (NAO), Eastern Atlantic (EA) and Scandinavian (SCAND). This allows us to identify the impact of these circulation modes over dune dynamics. Results document an episode of aeolian activity during the 1950s followed by a gradual stabilization and fixation of the dune coincident with a decrease on storm and wind intensity. Yet, aeolian sand movement remained active in small areas (blowouts), occurring mainly during the summer. NE winds associated with a negative phase of the EA explain the movement of sand within the dune field under favorable conditions of sand supply. On the other hand, sand supply to the dune field from the beach was promoted by NW winds coincident with the summer negative phase of NAO. During winter, the negative NAO favored frequent SW winds associated with the passage of intense storms, which in turn explain sand remobilization from the beach making sediment available for the NW winds to blow inland. With this work, it is proven that to understand past and future aeolian activity requires critical consideration of the variability and impact of the two principal modes of atmospheric circulation in the North Atlantic (NAO and EA). The SCAND mode explaining a lower percentage of the local wind field variability was also included to achieve higher significance levels of explained variance.
- Imprints of the 1755 tsunami in the Tróia Peninsula shoreline, PortugalPublication . Rebêlo, Luís Pina; Costas, Susana; Brito, Pedro Oliveira; Ferraz, Marco; Prudêncio, Maria Isabel; Burbidge, Christopher I.
- Pulses of aeolian activity and westerly winds intensification in the Portuguese coast during cooling climate eventsPublication . Costas, Susana; Jerez, Sonia; Trigo, Ricardo Machado; Goble, Ronald; Rebêlo, Luís Pina
- Reconstruction of shoreline orientation and progradation rates in the high-energy mesotidal Central Coast of PortugalPublication . Costas, Susana; Menezes, G.; Brito, Pedro Oliveira; Rebêlo, Luís Pina