Volume 107 (2020) - Fascículo Especial III (Projeto Explora - Definição de novos vetores de conhecimento geológico, geofísico e geoquímico para a região setentrional de Neves-Corvo)
Permanent URI for this collection
Browse
Browsing Volume 107 (2020) - Fascículo Especial III (Projeto Explora - Definição de novos vetores de conhecimento geológico, geofísico e geoquímico para a região setentrional de Neves-Corvo) by Author "de Oliveira, Daniel Pipa Soares"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Carlos Inverno, an economic geologist in the service of sciencePublication . de Oliveira, Daniel Pipa SoaresABSTRACT: Carlos Manuel Clériguinho Inverno (born on 7/3/1953, Lisbon) was awarded degrees of BSc and License in Geology by the Univ. of Lisbon, Portugal, in 1973 and 1975, respectively. Under the supervision of Prof. Richard W. Hutchinson, a PhD in Geology (sp. Geochemistry) by the Colorado School of Mines followed in 1991, which granted equivalence as Doutor em Geologia (Metalogenia) by the Univ. of Lisbon in 1992. He was a postdoctoral researcher at the Univ. of Tasmania and its Centre for Ore Deposit Research (CODES) in 2000-2001 (advisor, Prof. Michael Solomon) and earned Tenure (Agregação) at the Univ. of Lisbon in 2008.
- Geochemistry of Iberian Pyrite Belt Portuguese sector massive sulfide deposits-related volcanic rocks. Considerations on hydrothermal alteration, petrology and tectonic evolutionPublication . Morais, Igor; Albardeiro, Luís; Batista, Maria Joao; Matos, João Xavier; Solá, A. Rita; de Oliveira, Daniel Pipa Soares; Salgueiro, Rute; Araújo, Vítor; Pacheco, NelsonABSTRACT: A geochemical compilation database of the main volcanic units of the Volcano-Sedimentary Complex (VSC) of the Iberian Pyrite Belt (IPB), one of the largest provinces of massive sulfides on a global scale, is presented and discussed. For this purpose, we used several mineral exploration rock geochemistry databases from six IPB areas, namely Cercal, Lagoa Salgada, Lousal, Aljustrel, Neves-Corvo and Chança, regarding unaltered/hydrothermaly altered felsic volcanic units interbedded in the Famennian-Late Visean volcano-sedimentary sequences of the VSC. Volcanic rocks within the Phyllite-Quartzite Formation (Givetian-Famennian) IPB basement were also considered. From this, Neves-Corvo sector rhyolites (Rhyolite type 1 and 2) present the most intense hydrothermal alteration, directly related with the age of mineralization and coeval with hosted VSC sedimentary formations. Similar cases were also observed in the volcanic units hosting Lagoa Salgada, Chança and Aljustrel Volcanic-hosted massive sulfide (VHMS) deposits. The variety of felsic and intermediate volcanic rocks in the IPB (and within each sector) reflect different petrogenetic processes and/or distinct crustal sources. Application of Zr vs TiO2 binary diagrams allows to define three main trends of andesitic (Lagoa Salgada and Chança sectors), dacitic-rhyodacitic (Aljustrel sector) and rhyolitic (Cercal, Neves-Corvo, Aljustrel and Lousal sectors) composition. Cercal rhyolites are the most evolved felsic rocks (Zr/TiO2 ≈ 1562), followed by Neves-Corvo rhyolites (Zr/TiO2 ≈ 936), Lousal (Zr/TiO2 ≈ 845) and Aljustrel (Zr/TiO2 ≈ 840). In addition, four distinct compositional clusters can be distinguished based on Al2O3/TiO2 vs Zr/TiO2 and Al2O3/Zr vs TiO2/Zr ratios according to its nature as, rhyolitic, rhyodacitic/dacitic and andesitic, probably reflecting differential partial melting rates. Ybn vs La/Yb(n) diagram ratio indicates that Neves-Corvo (mainly 2 types of rhyolites), Aljustrel (Tufo da Mina rhyolitic unit), as well as Lagoa Salgada sector rhyolites are projected along FIIIa and FIIIb rhyolite fields considered of higher metalliferous potential in the IPB, once their petrogenetic processes are considered ideal to trigger, sustain and host hydrothermal systems and consequently VHMS deposits. Future work, combining geochemical characterization of each volcanic unit with their stratigraphic positioning, is essential in order to achieve a correct correlation between the different sectors and, is therefore, a useful tool in IPB mineral exploration and drill-hole data correlation.
- Mineral sustainability of the Portuguese sector of the Iberian Pyrite BeltPublication . de Oliveira, Daniel Pipa Soares; Batista, Maria Joao; Matos, João Xavier; Silva, TeresaABSTRACT: The Iberian Pyrite Belt (IPB) is one of the most important volcanogenic massive sulphide districts in the world and has been mined during more than 5 000 years. Its early and rich mining history is known to have been very important in Tartessian and Roman times when working the oxidation and cementation zones of the deposits for gold, silver and copper preferentially took place in the outcropping deposits. Even after continuous metal extraction for more than 5000 years, the IPB retains exceptionally large metal reserves. The IPB remains a hub of continued research and exploration and as a consequence, sulphide reserves in the IPB are being continuously increased with new discoveries: Aguas Teñidas, Lagoa Salgada, Las Cruces, Migollas, Masa Valverde, Vallejin, Las Cruces, Semblana and Monte Branco, La Magdalena and Sesmarias. While today's mining activities are focused in massive and stockwork ores and confined to 7 Portuguese and Spanish districts: Aljustrel, Neves-Corvo, Sotiel-Migollas, Rio Tinto, Aznalcollar- Los Frailes, Tharsis and Las Cruces, the IPB retains a large potential for non-traditional (or accessory ores) products. In light of the critical raw materials and the concepts of the circular economy, the IPB has the potential to be an important source of accessory metals; sourced from both primary and secondary ores and mine waste, that fall both in the strategic and critical domains. Metals like indium, selenium, germanium, rhenium and the precious metals are targets to seek in future exploration scenarios within the IPB, particularly in the Portuguese sector and in key near mining areas.
- Multispectral and hyperspectral remote sensing as a source of knowledge in the Portuguese sector of the Iberian Pyrite BeltPublication . Quental, Lídia; Gonçalves, Pedro; de Oliveira, Daniel Pipa Soares; Batista, Maria Joao; Matos, João Xavier; Sousa, A. J.; Marsh, Stuart; Carreiras, Joao; Dias, Ruben PereiraABSTRACT: Remote sensing is an invaluable tool to increase geological and mining knowledge, due to its screening view and variable discrimination and identification capabilities of the target materials. In this study an overview of remote sensing research developed and ongoing within the Portuguese sector of the Iberian Pyrite Belt (PSIPB) since 2000 is given. Multispectral and hyperspectral datasets were processed using hybrid methods, related both to general and detailed characterization, to: 1) support geological, mineral and hydrothermal mapping, 2) generate products derived from multivariate analysis and band ratios, 3) enhance correlation with radiometric data, 4) provide elements for environmental assessment concerning mining activity, 5) map Acid Mine Drainage (AMD) based on spectral field signatures, 6) quantify AMD based on high correlation mineralogical mapping, and 7) monitor AMD. The results highlight the importance of the quantitative digital support given by remote sensing tools within the Portuguese Sector of the Iberian Pyrite Belt (PSIPB), ruled by georesource exploitation in different stages of the Mine Lyfe Cycle.