Browsing by Author "Abad, Manuel"
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- Benchmarks and sediment source(s) of the 1755 Lisbon tsunami deposit at Boca do Rio EstuaryPublication . Font, Eric; Veiga-Pires, C.; Pozo, Manuel; Nave, Silvia; Costas, Susana; Ruiz, F.; Abad, Manuel; Simões, Nuno; Duarte, Sílvia; Rodriguez-Vidal, J.Standardizing 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 highresolution 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 and sediment source(s) of the 1755 Lisbon tsunami deposit at Boca do Rio EstuaryPublication . Font, Eric; Veiga-Pires, C.; Pozo, Manuel; Nave, Silvia; Costas, Susana; Muñoz, Francisco Ruiz; Abad, Manuel; Simões, Nuno; Duarte, SílviaStandardizing tite signature of tsunami deposits has been pointed as a major limitation on the identification paleo-tsunaml deposits. This limitation majorly arises from the strongly source-dependent nature of these deposits, which in turn determines their composition and Structure, and from the effect of the local morphology of the corresponding depositional environmemt. Here, we provide new high-resolution mineralogical, geochemical and paleontological data of the 1755 tsunami layer of Boca do Rio estuary (Algarve-Portugal.
- Benchmarks, sediment source and hydrodynamics of the 1755 Lisbon tsunami deposit at Boca do Rio EstuaryPublication . Font, Eric; Veiga-Pires, C.; Pozo, Manuel; Nave, Silvia; Costas, Susana; Muñoz, Francisco Ruiz; Abad, Manuel; Simões, Nuno; Duarte, SílviaStandardizing the signature of tsunami deposits has been pointed as a major limitation on the identification of paleo-tsunami deposits. This limitation majorly arises from the strongly source-dependent nature of these deposits, which in turn determines their composition and structure, and from the effect of the local morphology of the corresponding depositional environment. Here, we provide new high-resolution mineralogical, geochemical and paleontological data of the 1755 tsunami layer of Boca do Rio estuary (Algarve, Portugal) with the aim of unraveling the signatures of estuarine tsunami deposit and link them to sediment source.
- El contraste micropaleontológico de la Historia: el Lacus Ligustinus romanoPublication . Guerra, Liliana; C. Veiga-Pires, C.; González-Regalado, María Luz; Abad, Manuel; Toscano, Antonio; Muñoz, Juan Manuel; Ruiz, Francisco; Rodríguez Vidal, Joaquín; Cáceres, Luis Miguel; Izquierdo, Tatiana; Carretero, María Isabel; Pozo, Manuel; Monge, Guadalupe; Tosquella, Josep; Gómez, Paula; Romero, Verónica; Arroyo, Marta; Gómez, GabrlelDuring the Roman period (3rd century BC-5th century AD), the areas located near the present-day mouth of the Guadalquivir River were occupied by a lagoon with marine connection, according to the paleoenvironmental interpretation of benthic foraminiferal assemblages obtained in a core extracted in the Donana National Park. The inner zones of this lagoon were occupied by clayey tidal flats, which suffered the effects of a storm towards the end of the 1st century A.D. The comparison with the ostracod assemblages of the same core confirms this reconstruction and the paleogeographic data provided by various chroniclers, although these microcrustaceans better record the paleoenvironmental changes in these coastal sectors.
- Foraminifera as tsunami tracers in Holocene sequences of Southwestern SpainPublication . Guerra, Liliana; Ruiz, F.; Abad, Manuel; Veiga-Pires, C.El objetivo de este trabajo es la identificación de eventos de alta energia (tsunamis?) em el P.N. de Doñana a partir del análisis de asociaciones de foraminíferos, llevando a cabo en un testigo corto, y comparar estos datos con el registro del Tsunami de 1755 que tuvo lugar en el SO de la Península Ibérica, donde los foraminíferos se han mostrado como indicadores muy útiles para caracterizar los paleoambientes pre- y postsunami y delimitar capas tsunamigénicas. The southwestern Spanish coast is a low-probability tsunamigenic area (e.g., Reichester, 2001), although sixteen tsunami have been documented for the time-period between 218 BC and 1900 AD (Campos, 1991). These high-energy events have tremendous morphological effects and drastic ecological impacts in coastal areas (Borrero, 2005) and cause the deposition of sedimentary beds with characteristic textural and mineralogical features (e.g. Babu et al., 2007).
- From a marsh that was once sea: the geological evolution of Europe's largest biological reserve as told by its benthic foraminifera-a reviewPublication . González-Regalado, María Luz; Guerra, Liliana; Ruiz, Francisco; Veiga-Pires, Cristina; Abad, Manuel; Izquierdo, Tatiana; Vidal, Joaquín Rodríguez; Cáceres, Luis Miguel; Muñiz, Fernando; Carretero, María Isabel; Tosquella, Josep; Muñoz, Adolfo Francisco; Pozo, Manuel; Muñoz, Juan Manuel; Toscano, Antonio; Gómez, Paula; Romero, Verónica; Gómez, GabrielThis paper presents an updated list of benthic foraminifera found in brackish and marine (paleo-)environments of the Donana National Park (SW Spain) from the Lower Pliocene to the present-day. This list, based on published records, includes ninety-four species whose autoecology and temporal distribution in surface sections and continuous sediment cores allow us to infer the palaeogeographic evolution of this Biosphere Reserve over the last millions of years. During the Lower Pliocene, this area was occupied by a wide shallow bay with Nonion faba and Ammonia beccarii as the most representative species. During the Upper Pliocene, there was a transition to terrestrial environments, later dominated by fluvial dynamics for much of the Pleistocene and devoid of these aquatic microorganisms. During the Upper Pleistocene and part of the Holocene, the park was flooded during the MIS-1 transgression and a large lagoon was formed and progressively silted up. At this stage, benthic foraminiferal assemblages were dominated by the brackish species Ammonia morphogroup tepida and Haynesina germanica, which were occasionally replaced by marine species (mainly miliolids) during high-energy events. Currently, benthic foraminifera are mainly represented by Ammonia morphogroup tepida in the temporary lagoons and distributary channels, while Ammonia beccarii is dominant in their marginal marine areas. In summary, there is a clear correspondence between the palaeogeographic evolution of the park and its benthic foraminiferal associations, a review of which contributes to increase the knowledge of its remarkable present and past faunal diversity.
- Identification of Tsunami deposits and their impact on coastal zones : a study case of the Boca do Rio estuary (Algarve , Portugal)Publication . Font, Eric; Veiga-Pires, C.; Pozo, Manuel; Nave, Silvia; Costas, Susana; Muñoz, Francisco Ruiz; Abad, ManuelTsunamis are unforeseeable phenomena and therefore one of the most devastating natural disasters in terms of human and economic losses. Their impact on coastal and nearshore zones is substantial and need to be accurately evaluated to improve their prevention and management. In the last decades, numerous investigations focused on the identification of paleotsunamis in order to evaluate their frequency in the geological record. However, because storm- and tsunami-deposits are generated by similar depositional mechanisms, their discrimination using classic sedimentological methods is an elusive prospect. A promising approach is to couple classic geological criteria with geophysical and geochemical proxies to search for new benchmarks of tsunami deposits and to integrate them into a multi-disciplinary study. To test our method, we investigate the 1755 Lisbon tsunami deposit from the Boca do Rio estuary and other Tsunami-induced deposits from Algarve (Portugal). First results show that, Sr and Ca are enriched in the tsunami layer probably linked to the presence of shelled organism. Contrarily, others marine seawater indicators, such as Ba and Br, which are usually more concentrated in brackish than in fresh water, and heavy minerals, which are generally used as high energy event indicators, are depleted in the Tsunami deposit. Very low magnetic susceptibility values for the Tsunami deposit also indicate a dilution of iron oxides, reworked from the estuarine clays, within the huge volumes of quartz and carbonate (i.e. diamagnetic), issued from the abrasion of the littoral sandy dune and the surrounding carbonated cliffs. Diffusive Reflective Spectrophotometry analyses show changes in the siliclastic fraction on the sediments from above and below the tsunami layer. These apparent colour variations seem linked to the deposition of finer siliclastic particles after the tsunami, rather than to mineralogical composition. These data suggest that the high energy event affected the geomorphology of the estuary in such a way that it could induce a mis-interpretation of the geological record regarding local sea level changes and coastal evolution history.
- Morpho-sedimentary evidence of Holocene tsunamis in Southwestern Spain estuaries: a summaryPublication . Ruiz, F.; Rodriguez-Vidal, J.; Cáceres, L. M.; Carretero, M. I.; Pozo, Manuel; Gómez-Toscano, F.; Izquierdo, T.; Font, Eric; Guerra, Liliana; Veiga-Pires, C.; Abad, ManuelLos estuarios constituyen sistemas costeros excelentes para registrar tsunamis a través de un amplio tipo de evidencias geológicas. Este trabajo revisa y resume las evidencias de tsunamis prehistóricos e históricos en los quatro principales estuarios del suroeste de España. Las más frecuentes son erosión de playas y retroceso del litoral, ruptura y desbordamiento de flechas arenosas y depósito de capas bioclásticas. En la actualidad, estas características se encuentran particularmente bien estudiadas en los estuarios del Tinto-Odiel, Guadalquivir y Guadalete, mientras que son necesarios trabajos más detallados en el sector de influencia marina del estuario del Rio Guadiana.
- Relationship between substrate, physico-chemical parameters and foraminiferal tests in the Doñana National Park, a Biosphere Reserve in SW SpainPublication . Guerra, Liliana; C. Veiga-Pires, C.; González Regalado, María Luz; Abad, Manuel; Toscano, Antonio; Muñoz, Juan Manuel; Ruiz, Francisco; Rodríguez Vidal, Joaquín; Cáceres, Luis Miguel; Izquierdo, Tatiana; Carretero, María Isabel; Pozo, Manuel; Monge, Guadalupe; Tosquella, Josep; Prudencio, María Isabel; Dias, María Isabel; Marques, Rosa; Gómez, Paula; Romero, VerónicaA multidisciplinar analysis of sediments collected in diferent environments of the Doñana National Park (Guadalquivir estuary, SW Spain) provides an overview of the textural, mineralogical and physico-chemical parameters that control the distribution of benthic foraminiferal tests in this Biosphere Reserve. These microorganisms are absent in the fne quartzitic sands that constitute the substrate of temporary ponds with brief hydroperiods located in the dune systems and spits, as well as in other ponds with low conductivities or hypersaline conditions located in the inner marshlands or near the Guadalquivir river banks. Dead benthic foraminifera are mainly found on phyllosilicate-rich, silty-clayey substrates. The taphonomic analysis of the main species (Ammonia tepida, Haynesina germanica, Trochammina infata, Entzia macrescens) points to its deposit in situ. Cluster analysis permits to delimitate six foraminiferal assemblages. Cluster II (A. tepida+H. germanica) is the dominant assemblage in the central ponds and the margins of the main channels, while cluster IV (T. infata+E. macrescens) is restricted to some ponds located on the high marsh and cluster VI (Ammonia beccarii+Quinqueloculina spp.) is abundant on external beaches. Tidal fuxes cause the transport of these last marine benthic species and some plaktonic forms both to the inner areas of the estuary and to these beaches.
- Síntese da história da Evolução Holocénica do Parque Nacional de Doñana (Espanha): evolução paleoambiental, influência climática, eventos energéticos extremos e registro de foraminíferosPublication . Guerra, Liliana; Veiga-Pires, C.; Ruiz, F.; Abad, ManuelO presente trabalho tem como objectivo realizar uma síntese da evolução paleogeográfica do Parque Nacional de Doñana, através de uma compilação da informação previamente publicada sobre o assunto, incluindo a descrição geral das variações climáticas tardi-holocénicas na Península Ibérica. Dados sedimentológicos e de microfauna de dois cores e o registo histórico de eventos energéticos extremos em Portugal e Espanha são igualmente combinados e discutidos no que diz respeito ao reconhecimento dos intervalos climáticos e eventos tsunamigénicos. Os resultados mostram que a evolução paleogeográfica do Parque Nacional de Doñana parece certamente ligada às mudanças climáticas e à ocorrência de eventos energéticos extremos como observado para o tsunami de 2168-2159 B.P., durante o período Sub-Atlântico.