6 documents found, page 1 of 1
Single events and century-scale evolution of the northern margin of the Tagus R...
Costa, A.M.; Freitas, M.C.; Inácio, M.; Fatela, F.; Lopes, V.; Andrade, C.; Cachão, M.; Mendes, P.M.; Sarrazola, A.; Macedo, M.; Bettencourt, J.In this work we present preliminary results of the study of one sediment core (EDP1), collected near Cais do Sodré, Lisbon downtown, close to the present day Tagus riverfront. The results allowed differentiation of 4 major sediment units that present a signature of increasing anthropic influence over time. The lowermost unit (Unit 1) corresponds to a subtidal flat accreting in low energy and brackish condition...
Bromine enrichment in marsh sediments as a marker of environmental changes driv...
Moreno, J.; Fatela, F.; Leorri, E.; Araújo, M. F.; Moreno, F.; De la Rosa, J.; Freitas, M. C.; Valente, Teresa Maria Fernandes; Corbett, D. R.A sediment core collected in Caminha tidal marsh, NW Portugal, was used to assess bromine (Br) signal over the last ca. 1,700 years. The Br temporal variability reflects its close relationship with soil/sediment organic matter (OM) and also alterations in Br biogeochemical recycling in marsh environment. The highest Br enrichment in sediments was found during the Maunder Solar Minimum, a major solar event chara...
Optical dating of clastic deposits generated by an extreme marine coastal flood...
Cunha, Pedro P.; Buylaert, J. P.; Murray, A. S.; Andrade, C.; Freitas, M. C.; Fatela, F.; Munhá, J. M.; Martins, A. A.; Sugisaki, S.Identification of past tsunamis is important for risk assessment and management of coastal areas. Obtaining accurate and precise ages of sediments originating from such extreme marine coastal floods is crucial for a reliable estimation of the recurrence interval of these often devastating events. We present here the results of quartz optical dating and 14C dating of two sites (Boca do Rio and Martinhal) on the ...
Environmental constraints of foraminiferal assemblages distribution across a br...
Fatela, F.; Moreno, J.; Moreno, F.; Araújo, M. Fátima; Valente, Teresa Maria Fernandes; Antunes, Carlos; Taborda, Rui; Andrade, César; Drago, TeresaForaminiferal living assemblages from a brackish tidal marsh were studied across three sampling transects, under Spring and Autumn conditions. Foraminiferal analysis was also extended to the dead assemblages of Spring samples. Altimetric control of each sampling point was acquired through the connection to the national datum by GPS differential positioning combined with a regional geoid model. The influence of ...
A comparative study of the influence of geochemical parameters on the distribut...
Valente, Teresa Maria Fernandes; Fatela, F.; Moreno, J.; Moreno, F.; Guise, Lúcia; Patinha, C.The influence of typical geochemical parameters on living foraminiferal assemblages was examined and compared in two estuaries from northern Portugal: Minho and Lima. Seawater, river waters and interstitial waters from tidal marshes were analyzed for the following parameters: pH, electric conductivity, Redox potential, salinity, alkalinity (field measurements), sulphate, chloride, fluoride, bromide, sodium, pot...
Occurrence of calcareous foraminifera and calcite-carbonate equilibrium conditi...
Moreno, J.; Valente, Teresa Maria Fernandes; Moreno, F.; Fatela, F.; Guise, Lúcia; Patinha, C.The Minho/Coura estuary, northern Portugal, has been studied for the influence of hydrochemical and geochemical parameters on living (Rose Bengal stained) foraminiferal assemblages. Our previous works showed a prevalence of agglutinated species in the inner estuary and tidal marsh and significant abun- dance of calcareous species only in the estuary mouth. The new results clarify syndepositional aspects of the ca...