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- Insights about the Sines massif: a reinterpretation of geophysical data to the assessment of the potential for CO2 storage through mineral carbonationPublication . Marques, Fábio; Pedro, J.; Araujo, A.; Moita, Patrícia; Carneiro, Júlio; Sousa, Pedro; Carvalho, João; Correia, AntonioABSTRACT: The InCarbon project aims to evaluate the potential for storage of captured CO2 using in-situ mineral carbonation in mafic and ultramafic plutonic rocks in Alentejo, Portugal. The Sines massif appears to be the most promising massif for mineral carbonation and its geochemistry, petrography, mineralogy, volume and extension are characterized. Its offshore volume and extension are evaluated through reinterpretation of previous geophysical data which confirms the occurrence of two well defined magnetic anomalies. The Sines magnetic anomaly is directly related with the outcropping area of the Sines massif to the continental shelf; three-dimensional modelling (3D) of apparent magnetic susceptibility correlates with a volume of 217 km3.The offshore magnetic anomaly presents an estimated volume of 226 km3 and is located about 10 km from the Sines anomaly to the Southwest. If both anomalies result from a single igneous body, the area of the Sines massif could as be large as 300 km2. However, the possibility of these that those two anomalies correspond distinct mafic igneous structures in the continental shelf cannot be discarded and should be further investigated.
- Avaliação do potencial geotérmico do Aquífero Cretácico Inferior na Região de LisboaPublication . Marrero Diaz, Rayco; Ramalho, Elsa; Costa, Augusto Marques da; Ribeiro, Maria Luísa; Carvalho, João; Pinto, Carlos C.; Rosa, Diogo; Correia, Antonio
- A microcosm approach to evaluate the degradation of tributyltin (TBT) by Aeromonas molluscorum Av27 in estuarine sedimentsPublication . Cruz, Andreia; Henriques, Isabel; Sousa, Ana C. A.; Baptista, Inês; Almeida, Adelaide; Takahashi, Shin; Tanabe, Shinsuke; Correia, Antonio; Suzuki, Satoru; Anselmo, Ana; Mendo, SóniaTributyltin (TBT) is a biocide extremely toxic to a wide range of organisms, which has been used for decades in antifouling paints. Despite its global ban in 2008, TBT is still a problem of great concern due to the high levels trapped in sediments. Aeromonas molluscorum Av27 is a TBT degrading bacterium that was isolated from an estuarine system. We investigated the ability and the role of this bacterium on TBT degradation in this estuarine system, using a microcosm approach in order to mimic environmental conditions. The experiment was established and followed for 150 days. Simultaneously, changes in the indigenous bacterial community structure were also investigated. The results revealed a maximum TBT degradation rate of 28% accompanied by the detection of the degradation products over time. Additionally, it was observed that TBT degradation was significantly enhanced by the presence of Av27. In addition a significantly higher TBT degradation occurred when the concentration of Av27 was higher. TBT degradation affected the bacterial community composition as revealed by the changes in the prevalence of Proteobacteria subdivisions, namely the increase of Deltaproteobacteria and the onset of Epsilonproteobacteria. However, the addition of Av27 strain did not affect the dominant phylotypes. Total bacterial number, bacterial biomass productivity, 16S rRNA gene and denaturing gradient gel electrophoresis (DGGE) analyses also indicated alterations on the bacterial community structure over time, with bacteria non-tolerant to pollutants increasing their representativeness, as, for instance, the increase of the number of Alphaproteobacteria clones from 6% in the beginning to 12% at the end of the experiment. The work herein presented confirms the potential of Av27 strain to be used in the decontamination of TBT-polluted environments.
- Updated geothermal assessment of Lower Cretaceous aquifer in Lisbon region, PortugalPublication . Marrero Diaz, Rayco; Ramalho, Elsa; Costa, Augusto Marques da; Ribeiro, Maria Luísa; Carvalho, João; Pinto, Carlos C.; Rosa, Diogo; Correia, Antonio
- Avaliação do potencial geotérmico do Aquífero Cretácico Inferior na Região de LisboaPublication . Marrero Diaz, Rayco; Ramalho, Elsa; Costa, Augusto Marques da; Ribeiro, Maria Luísa; Carvalho, João; Pinto, Carlos C.; Rosa, Diogo; Correia, Antonio
- Contributo para a caracterização térmica da crosta em Portugal continental: Análise e processamento de dados geotérmicos compilados até 1996Publication . Ramalho, Elsa; Correia, AntonioRESUMO: Nas últimas décadas tem havido um manisfesto interesse em estudar o regime térmico da Terra a uma escala global, o que originou uma intensa actividade nos domínios da obtenção, análise e interpretação de dados geotérmicos. É disso prova a constituição da Comissão Internacional para o Fluxo de Calor no âmbito da União Internacional de Geodesia e Geofísica. Este interesse, associado ao aparecimento de publicações científicas que têm como objectivo a reunião dos dados de densidade de fluxo de calor à superfície da Terra à escala mundial motivou uma análise exaustiva de todos os parâmetros geotérmicos recolhidos em Portugal Continental desde o final da década de 70. Estes estudos têm como objectivo obter um mapa de densidade de fluxo de calor à superfície e determinar o regime térmico da crosta em Portugal Continental. Assim, neste trabalho são compilados, analisados, processados e apresentados, sob a forma de tabelas e mapas, dados geotérmicos compilados até 1996, quer em publicações científicas, quer em relatórios internos de várias instituições portuguesas que se dedicam, ou dedicaram, a estudos desta natureza. De todos os furos compilados apenas 47 foram seleccionados para a determinação da densidade de fluxo de calor. Neste trabalho são descritos os critérios utilizados para a aceitação ou rejeição de dados obtidos em cada um dos 47 furos na determinação do gradiente geotérmico, da condutividade térmica das formações, da produção de calor e da densidade de fluxo de calor. Esses valores são apresentados em várias tabelas e utilizados para construir um mapa de densidade de fluxo de calor à superfície e mapas de temperatura a 500 e 1000 metros de profundidade. Dos 47 furos seleccionados para a determinação da densidade de fluxo de calor 30 são furos de água ou de prospecção mineira, com profundidades que variam entre 93 e 485 metros, e 17 são de pesquisa de petróleo, com profundidades que variam entre 1783 e 3934 metros. O valor da densidade de fluxo de calor para o conjunto dos 47 furos varia entre 42 e 115 mW/m². Com este trabalho pretende-se apresentar, de uma forma compacta e sistematizada, informação geotérmica que se encontrava dispersa, depois de analisada segundo critérios de qualidade internacionais.
- Heat Flow Density Estimations in the Portuguese Northern Hercynian Massif using Silica GeothermometryPublication . Correia, Antonio; Ramalho, ElsaABSTRACT: Surface heat flow density (HFD) estimates in the Portuguese northern Hercynian Massif are difficult to obtain using the usual Fourier method. As a matter of fact, this zone is mostly composed by granitoid and metamorphic rocks, and most wells drilled there are too shallow for reliable HFD calculations; furthermore, HFD estimates are scarce and their geographical distribution is still very irregular. All these conditions imply that a HFD map for this region must be obtained using alternative methods, such as the silica geothermometry method. Under certain conditions, the use of silica geothermometers to estimate HFD in mineral waters has proved to be an effective way to understand and establish the thermal regime in areas with scarce conventional HFD determinations. Because temperatures obtained with silica geothermometry are related to deep thermal conditions in the crust and to water-rock equilibrium, a regional HFD analysis may be carried out using those temperatures. The silica geothermometer, developed by Truesdell in 1976 (Truesdell, 1976), give good results for low SiO2 concentrations, which is the case for the Portuguese northern Hercynian Massif, and is applied to more than 30 samples of mineral water occurrences reported for the zone. This number of samples, even though small, is considerably higher and more evenly distributed than conventional HFD estimates for the same area. Application of silica geothermometry to northern Hercynian Massif waters shows a discrete reservoir temperature zoning, ranging from about 45 ºC, in its southwest limit, to more than 120 ºC, towards its northeast limit. Using temperatures obtained by silica geothermometry and heat flow density values calculated through the conventional method in an area of 1º x 1º in the study zone, an empirical linear relationship between HFD and temperatures obtained by silica geothermometry is obtained and used to construct a HFD map for the Portuguese northern Hercynian Massif. The resulting HFD map is compared with the general geological and structural framework, and an attempt to a geothermal characterisation of the Portuguese northern Hercynian Massif is made.