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- Contributo para a identificação dos processos responsáveis pela composição das águas termais da Região de LisboaPublication . Policarpo, A.; Marrero Diaz, Rayco; Carvalho, M.R.; Carvalho, J. M.
- Contributo para a identificação dos processos responsáveis pela composição das águas termais da Região de LisboaPublication . Policarpo, A.; Marrero Diaz, Rayco; Carvalho, M.R.; Carvalho, J. M.
- Hydrogeochemical study of thermo-mineral waters in Lisbon region (Portugal) : contributions for hydrogeological conceptual modelsPublication . Marrero Diaz, Rayco; Carvalho, M.R.; Policarpo, A.; Carreira, Paula M.
- Environmental Stable and Radioactive Isotopes in the Assessment of Thermomineral Waters in Lisbon Region (Portugal): Contributions for a Conceptual ModelPublication . Marrero Diaz, Rayco; Carvalho, M.R.; Carreira, Paula M.ABSTRACT: The existence of thermomineral waters in the Lisbon region (western Portugal), has been known for centuries. Several authors have investigated the characteristics of these thermomineral waters, but their conceptual model (recharge zone, processes controlling the origin and chemical evolution, depth of circulation, etc.) remains unknown. This work highlights the advantages of assessing the conceptual model in urban coastal areas, where different saline sources coexist, combining chemical analyses with environmental isotopes and geochemical modeling. The final physicochemical composition of thermomineral waters seems to be mainly controlled by water-rock interaction processes and different mixing degrees between HCO3-Ca regional groundwaters, cold dilute shallow groundwaters and highly salinized fluid (brackish or brine or non-recent seawater) probably trapped at depth. Based on these results, neither the contribution of polluted water nor the leaching of evaporite rocks seems to be the main salinization factor of the warmer and saline waters. A positive correlation exists between the lowest radiocarbon activities (average apparent ages similar to 6 ka BP) and highest water temperature and salinity (up to 39 degrees C and 6.3 g/L), suggesting progressive salinization and deeper circulation (up to 1200 m depth) into the hosting formations, where mixing with trapped salinized fluids probably took place, as confirmed by geochemical modeling. Finally, very favorable geological conditions in the Estoril region allow for fast rising and the occurrence of these thermomineral waters at relatively shallow depths.
- Modelo conceptual do recurso hidromineral das Quenturas, Vulcão das Furnas, Ilha de São Miguel: um contributoPublication . Freitas, Ana Rita; Sá, Henrique Aguiar; Carvalho, M.R.; Nunes, J. C.RESUMO: O Vulcão das Furnas, na ilha de São Miguel, comporta no seu interior uma grande variabilidade de nascentes, que se podem classificar em 5 tipos distintos, nomeadamente frias lisas, frias gasocarbónicas, termais ácidas, termais básicas e condensado de fumarola, de características marcadas e variadas, originando a designada “Hidrópole” das Furnas. A Concessão Hidromineral das Furnas comporta parte importante destas nascentes, entre elas o Recurso Hidromineral das Quenturas, ou Água Férrea das Quenturas, referida como “3”. Trata-se de uma água termal ácida, com 59 °C de temperatura, pH ácido e mineralização elevada, cuja origem se considera corresponder ao aquecimento de aquíferos mais superficiais por vapor hidrotermal que ascende do aquífero hidrotermal profundo, conferindo a estas águas temperatura e uma importante componente gasocarbónica. Dados isotópicos apontam uma altitude de recarga de cerca de 800 m para esta nascente e uma idade compreendida entre os 23 e os 30 anos.