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- Contribution to the Understanding of the Colour Change in Bluish-Grey LimestonesPublication . Silva, Teresa; De Oliveira, Daniel Pipa Soares; Veiga, JP; Lisboa, Jose; Carvalho, Jorge; Barreiros, M. Alexandra; Coutinho, ML; Salas-Colera, Eduardo; Vigário, RogérioABSTRACT: Bluish-grey limestones have been extensively used as ornamental stones for decoration purposes in buildings, as well as in works of art, and accordingly, have been the target of intense exploration. In Portugal, the Jurassic limestone massif known as the Macico Calcario Estremenho (MCE), has been the source of grey-coloured ornamental stones, namely the Azul Valverde (one of the most well-known bluish-grey limestones) and Atlantic Blue varieties, both of which may undergo colour changes in outdoor environments. In this sense, it is important to understand the sudden colour change from bluish-grey to yellow/beige in the same limestone block in a quarry, or even, what happens to the colour when polished limestone is placed outdoors. This study was undertaken using various techniques, namely XRF (X-ray fluorescence spectrometry), XRD (X-ray diffraction), SEM (scanning electron microscopy), DTA-TG (differential thermal analysis/thermogravimetry) and colourimetry. Synchrotron radiation was also used at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) where XANES (X-ray Absorption Near Edge Structure) spectra at Fe K-edge were collected to ascertain the speciation state of Fe in different coloured zones of the limestone, previously checked by EDXRF (energy dispersive X-ray fluorescence). The presence of Fe2+ and Fe3+ are responsible for the greyish and yellow/brown colour, respectively. On the other hand, the UV radiation from the sun causes a quickened and severe bleaching/fading on the dark blue/grey polished limestone.
- Recursos minerais na Região do Alentejo : potencial e ordenamento do territórioPublication . Catrapona, Afonso; Carvalho, Jorge
- A new Echinoderm Lagerstätte in Portugal : preliminary resultsPublication . Pereira, Bruno Claro; Pereira, Pedro; Machado, Susana; Carvalho, Jorge; Mergulhão, Lia
- Recursos minerais na Região de Lisboa e Vale do Tejo, a Norte da AMLPublication . Carvalho, Jorge
- Áreas potenciais de Portugal para recursos minerais do domínio públicoPublication . Carvalho, Jorge; Filipe, Augusto; Gonçalves, Pedro; Lisboa, Jose; Matos, João Xavier; Batista, Maria Joao; Salgueiro, Rute; de Oliveira, Daniel Pipa SoaresSUMMARY: Land-use planning is decisive for granting access to mineral resources. During the work to identify the actions to be taken for preparing the National Strategy for Geological Resources, a map of mineral potential areas for Portugal was produced. It provides the starting point scenario needed for the implementation of a methodology aimed at the delineation of mineral safeguarding areas.
- Potential benefits and constraints of development of critical raw materials' production in the EU: analysis of selected case studiesPublication . Guzik, Katarzyna; Galos, Krzysztof; Kot-Niewiadomska, Alicja; Eerola, Toni; Eilu, Pasi; Carvalho, Jorge; Fernández-Naranjo, Francisco Javier; Arvidsson, Ronald; Arvanitidis, Nikolaos; Raaness, AgnesABSTRACT: Major benefits and constraints related to mineral extraction within the EU have been identified on the examples of selected critical raw materials’ deposits. Analyzed case studies include the following ore deposits: Myszków Mo-W-Cu (Poland), Juomasuo Au-Co (Finland), S. Pedro das Águias W-Sn (Portugal), Penouta Nb-Ta-Sn (Spain), Norra Kärr REEs (Sweden) and Trælen graphite (Norway). They represent different stages of development, from the early/grassroot exploration stage, through advanced exploration and active mining, up to reopening of abandoned mines, and refer to different problems and constraints related to the possibility of exploitation commencement. The multi-criteria analysis of the cases has included geological and economic factors as well as environmental, land use, social acceptance and infrastructure factors. These factors, in terms of cost and benefit analysis, have been considered at three levels: local, country and EU levels. The analyzed cases indicated the major obstacles that occur in different stages of deposit development and need to be overcome in order to enable a new deposit exploitation commencement. These are environmental (Juomasuo and Myszków), spatial (Juomasuo) as well as social constraints (Norra Kärr, Juomasuo). In the analyzed cases, the most important constraints related to future deposit extraction occur primarily at a local level, while some important benefits are identified mainly at the country and the EU levels. These major benefits are related to securing long-term supplies for the national industries and strategically important EU industry sectors.
- Cartografia e caracterização de recursos minerais da região de Torres Vedras-Bombarral : Relatório final 2012Publication . Lisboa, Jose; Sardinha, Rui; Carvalho, Jorge; Oliveira, Álvaro
- Recursos geológicos e hidrogeológicos do Concelho de NisaPublication . Carvalho, Jorge; Catrapona, Afonso; Lourenço, Maria Carla
- Cartografia geológica em núcleos de pedreiras de rochas ornamentaisPublication . Carvalho, JorgeA cartografia geológica é uma ferramenta fundamental para a delimitação e caraterização de áreas com aptidão para a produção de rochas ornamentais. Com base em cartografia realizada na Área de Pé da Pedreira, Maciço Calcário Estremenho, refere-se a importância da terminologia usada em função dos destinatários dos mapas geológicos e os condicionalismos inerentes à artificialização do relevo.
- Recursos minerais na Região do Algarve : potencial e ordenamento do territórioPublication . Carvalho, Jorge