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Publications

Publications by Rui Moura

2022

GEOPHYSICAL EXPLORATION OF ANTIMONY MINERALIZATIONS: ALTO DO SOBRIDO AND RIBEIRO DA SERRA MINES (PORTUGAL)

Authors
Carvalho A.; Ribeiro R.; Moura R.; Lima A.;

Publication
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM

Abstract
The Alto do Sobrido and Ribeiro da Serra Mines, are two antimony-gold mines located in Gondomar, Portugal, and are part of the Dúrico-Beirão Mining District (DBMD). In this work, we use four geophysical methods, such as gravity, radiometry, magnetic and electromagnetic, to improve the knowledge about these mineralizations and the lithologies and structures associated with them. These four methods allowed us to study these mineralizations through different physical properties. The gravimetric method allowed us to add more data to the hypothesis that the gold-antimony mineralizations of the DBMD could be genetically associated with a non-outcropping granite intrusion, which functioned either as a heat engine that promoted the circulation of fluids and/or as a source of fluids and metals itself. A 2D model was proposed, created with both modelling and inversion, to show that the presence of this granite could indeed fit the response of the negative anomalies found in the residual anomaly. The radiometric method was used mainly as a mapping tool, where we were able to distinguish between some of the lithologies of the area, like the Lower Ordovician quartzites and the metasediments of the Middle Ordovician to the Carboniferous, but also to observe different element concentrations within the Pre-Ordovician Schist-Greywacke Complex (SGC). These variations within the SGC lithology don’t have a clear explanation as to why they occur. Still, we believe that they could occur due to the influence of the abovementioned non-outcropping granite. With the very low frequency (VLF) electromagnetic method, it was possible to locate areas of lower resistivities that correspond to the location of several known mineralized veins, as well as the probable location for a new vein. It was also possible to observe some weathered rocks near faults and fractures associated with the Dúrico-Beirão Shear Zone (DBSZ). With the magnetic method, it is possible to contribute to areas with the prevalence of lithologies and minerals with higher magnetic susceptibilities. Several magnetic anomalies found near the Alto do Sobrido mining works correspond to the mineralized veins paragenesis. Other anomalies appear to be related to the location of faults and fractures associated with the DBSZ. The use of all these methods allowed us to observe the mineralization responses and its associated lithologies and structures through the different geophysical properties while adding knowledge about the genesis of these mineralizations and possibly the location of new mineralized veins.

2022

Comparison Between Gravimetry and Radiometry Results: Alto do Sobrido-Ribeiro da Serra Case Study

Authors
Carvalho, A; Ribeiro, R; Moura, R; Lima, A;

Publication

Abstract
<p>The Alto do Sobrido (AS) and Ribeiro da Serra (RS) Mines are old Sb-Au explorations. These are located in Gondomar, Portugal, on the inverse limb of the well-known structure called Valongo Anticline. In the AS Mine, the mineralization occurs near the contact between the Schist-Greywacke Complex (CXG) (Precambrian and/or Cambrian(?)) and the breccia of the base of the Carboniferous. In the RS Mine, the mineralization occurs only on the CXG. In both mines, the Sb-Au mineralization occurs in quartz veins and some stockworks.</p><p>A spatial correlation between the Sb-Au mineralization and the post-orogenic granites occurs in the Dúrico-Beirã Region according to Gumiel & Arribas (1987). Couto et al. (2007) also acquired data that suggests a genetic connection between this mineralization and non-outcropping granites. These granites may have been the source of fluids and a heat source that improved hydrothermal circulation and they have been observed in one of the RS Mine’s galleries.</p><p>With this hypothesis in mind, we intend to compare the data from a radiometric survey, which is a method that is radiometrically sensitive to K, Th and U at the near-surface, to the data from a gravimetric survey, which is a method that is sensitive to density anomalies at greater depths, in order to show if these granites could have chemically influenced its embedding rocks.</p><p>To make this comparison, we used the residual anomaly map from our gravimetric survey and the four maps obtained in the radiometric survey (total concentrations, K, eTh and eU). Firstly, we normalized all the grid maps to obtain grids with values between -1 and 1. Once this was complete, we multiplied each of the four radiometry maps to the residual anomaly map, obtaining the comparison maps.</p><p>On the resulting maps, we can observe high values in 3 different areas. The first corresponds to a lower value of gravimetric anomaly and a lower value of concentrations of all the elements. This area is located where the hypothesized non-outcropping granites are situated. The second area corresponds to high values on both methods. This matches the location of the lithologies from the Middle Ordovician to the Carboniferous, which are rocks of higher densities and higher concentration values of K, eTh and eU. The third area consists of lower gravimetric anomalies and lower concentrations of K and eU, and coincides with the location of the Ordovician quartzites. This area isn’t as visible on the eTh map, which is consistent with what was observed on the field.</p><p>We consider this approach to be a practical method to correlate the results of these two methods and an attempt to understand how the granite located at depth could have influenced these lithologies that today outcrop.</p><p><strong>References</strong></p><p>Gumiel, P., Arribas, A., 1987. Antimony Deposits in the Iberian Peninsula. Economic Geology, Volume 82, pp 1453-1463.</p><p>Couto, H., Borges, F. S., Roger, G., 2007. Late Palaeozoic orogenic gold-antimony deposits from the Dúrico-Beirã area (North Portugal) and their relation with hidden granitic apexes. Ninth Biennial SGA Meeting, Dublin. pp 609-612.</p>

2024

Localised multi-hazard risk assessment in Kyrgyz Republic; [Ocena tveganja veckratnih nevarnosti v Kirgiški republiki]

Authors
Umaraliev, R; Zaginaev, V; Sakyev, D; Tockov, D; Amanova, M; Makhmu Dova, Z; Nazarkulo, K; Abdrakhmatov, K; Nizamiev, A; Moura, R; Blanchard, K;

Publication
Geologija

Abstract
One of the key tasks in ensuring national security is the ability of the state and society to recognise and effectively assess the conditions for disasters, and to prevent them from threatening the sustainable development of the country. The Kyrgyz Republic is highly vulnerable to the influence of climate change, which in turn affects the frequency and intensity of disasters. The Kyrgyz Republic is exposed to almost all types of geological and man-made hazards, including earthquakes, landslides, debris flows, flash floods, outbursts of mountain lakes, dam failures, avalanches, droughts, extreme temperature, epidemics and releases of hazardous substances. Analysis of information on existing risks and their control systems used to reduce their negative impact makes it possible to assess the degree of probability, the expected consequences of threats, determine the degree of risk, the adaptive potential of communities and select appropriate protective measures. Therefore, this study is conducted to assess the hazard, vulnerability and exposure of Suzak district (Jalal-Abad oblast) in order to quantify the risk of the study area using multi-parameter holistic assessment with field collecting of primary data and utilizing Index-based Risk Assessment approach based on applying INFORM Risk model. Collected data was used to downscale subnational INFORM Risk model for municipal and district level using a multi-layered structure. A risk score is calculated by combining 72 indicators that measure three main dimensions: hazard & exposure, vulnerability, and lack of coping capacity. These findings provide an opportunity to develop a more effective disaster risk management at the local and national levels, by prioritizing relevant actions and investments for municipalities – districts which are demonstrated relatively highest risk scores. Also, the possibility of applying localized risk assessment procedures provides an opportunity to obtain more accurate sub-national (district/oblast based) and national levels with effective assessing dynamics of risk. © Author(s) 2024. CC Atribution 4.0 License

2024

Localised multi-hazard risk assessment in Kyrgyz Republic

Authors
Umaraliev, R; Zaginaev, V; Sakyev, D; Tockov, D; Amanova, M; Makhmudova, Z; Nazarkulo, K; Abdrakhmatov, K; Nizamiev, A; Moura, R; Blanchard, K;

Publication
Geologija

Abstract
One of the key tasks in ensuring national security is the ability of the state and society to recognise and effectively assess the conditions for disasters, and to prevent them from threatening the sustainable development of the country. The Kyrgyz Republic is highly vulnerable to the influence of climate change, which in turn affects the frequency and intensity of disasters. The Kyrgyz Republic is exposed to almost all types of geological and man-made hazards, including earthquakes, landslides, debris flows, flash floods, outbursts of mountain lakes, dam failures, avalanches, droughts, extreme temperature, epidemics and releases of hazardous substances. Analysis of information on existing risks and their control systems used to reduce their negative impact makes it possible to assess the degree of probability, the expected consequences of threats, determine the degree of risk, the adaptive potential of communities and select appropriate protective measures. Therefore, this study is conducted to assess the hazard, vulnerability and exposure of Suzak district (Jalal-Abad oblast) in order to quantify the risk of the study area using multi-parameter holistic assessment with field collecting of primary data and utilizing Index-based Risk Assessment approach based on applying INFORM Risk model. Collected data was used to downscale subnational INFORM Risk model for municipal and district level using a multi-layered structure. A risk score is calculated by combining 72 indicators that measure three main dimensions: hazard & exposure, vulnerability, and lack of coping capacity. These findings provide an opportunity to develop a more effective disaster risk management at the local and national levels, by prioritizing relevant actions and investments for municipalities – districts which are demonstrated relatively highest risk scores. Also, the possibility of applying localized risk assessment procedures provides an opportunity to obtain more accurate sub-national (district/oblast based) and national levels with effective assessing dynamics of risk.

2015

Aplicação do modelo SIMWE na definição de áreas suscetíveis à erosão linear: estudo de caso na Região Demarcada do Douro (RDD)

Authors
Fernandes, Joana; Bateira, Carlos; Soares, Laura; Oliveira, Ana; Faria, Ana; Hermenegildo, Carlos; Teixeira, Manuel; Moura, Rui; Gonçalves, José;

Publication

Abstract
This paper focuses the evaluation of susceptibility to linear erosion in the RDD, presenting the results of SIMWE (Simulated Water Erosion) model application. Furthermore, we also proceed to the results analysis by comparing the hydrological characteristics (infiltration capacity, hydraulic conductivity), soil texture and structure (evaluated by the electrical resistivity) in the high erosion areas defined through SIMWE. The study shows an association between the spatial distribution of erosive features with high values of water depth and reduced water discharge values that are consistent with the reduced values of electrical resistivity sectors. The areas with the highest percentage of erosive features related to sediment flux, the transport capacity and the sediment concentration assume medium susceptibility values. These combined to a hydraulic conductivity and soil infiltration capacity at very low values is consistent with its fine texture, allowing increased runoff and the development of linear erosion.

2017

Caracterização multidisciplinar de eflorescências salinas no Mosteiro da Batalha

Authors
Almeida, Fernando; Moura, Rui; Barraca, Nuno; Costa, Cristiana; Terroso, Denise; Matias, Manuel;

Publication
Congresso da Reabilitação do Património, crepat 2017

Abstract
O Mosteiro da Batalha é uma relevante obra da arquitectura gótica, resultou do cumprimento da promessa feita por D. João I, após vitória na batalha de Aljubarrota. O mosteiro esteve na posse dos dominicanos até à extinção das ordens religiosas, sendo actualmente dependência da DGPC e Património da Humanidade pela UNESCO. Recentemente a Universidade Aveiro caracterizou estrutural do monumento. Entre as técnicas testadas considera-se aqui o potencial espontâneo, anteriormente aplicados na Igreja da Graça em Santarém (Martinho et. al, 2014). Seleccionou-se uma parede com eflorescências na qual se sobrepôs uma grelha de eléctrodos (12×5) espaçados de 0.5m. O mapeamento do potencial espontâneo foi realizado tendo como referência um eléctrodo sobre eflorescências. Concluiu-se que as zonas da parede com sais estão ao mesmo potencial, enquanto as zonas onde as eflorescências não ocorrem apresentam um potencial mais elevado. A composição mineralógica dos sais foi estudada por Difracção de Raios X.

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