RM - Artigos em revistas internacionais
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- Age dependent variation of the magnetic fabric of dike swarms and implications for the volcanic structure of ocean islands: the example of the Maio Island, Cabo Verde archipelagoPublication . Moreira, Mário; Mata, João; Madeira, José; Represas, Patricia; Martins, SofiaABSTRACT: Magnetic fabric analysis of dikes is a powerful technique when assessing magma transfer processes. This study presents an integrated analysis combining magnetic susceptibility and anisotropy of magnetic susceptibility, magnetic mineralogy, geochemistry and new 40Ar/39 Ar dating of dikes intruding formations ranging from the Lower Cretaceous to the Miocene on the island of Maio, in the Cabo Verde archipelago. We show that the dikes, dated at ≈9.2 Ma, intruding the younger Miocene Casas Velhas formation, display a Ti-rich titanomagnetite composition, higher whole-rock TiO2 content and very high magnetic anisotropy. They are clearly distinguished from the dikes, ranging in age from ≈9.3 to 11.3 Ma, intruding older formations, which show a predominantly Ti-poor titanomagnetite composition with multiple magnetic phases, lower whole-rock TiO2 concentration, higher range of magnetic susceptibilities and very low anisotropy. Magnetic fabric is predominantly normal with no significant imbrication relative to the dike margins. Numerical analysis of fabric shows a dominant coaxiality between the magnetic lineation and the preferred orientation of opaques and phenocrystals suggesting that magnetic lineation is, therefore, the proxy of the magmatic flow axis orientation. Based on the orientation of the magnetic fabric, we infer that magmatic flow within the studied dikes is predominantly vertical. The differences observed between the younger dikes and all other dikes may be related to magma sourced from distinct magma chambers. One, probably shallow, underneath the Casas Velhas fm in the southwest of the island, which would explain the very high values of magnetic anisotropy and the inferred vertical flow, and another located in a central position in the island, responsible for the dikes intruding the older formations. The location of such magma reservoirs and the dikes ages suggest a hypothetical migration with age of the magmatic sources that fed the dikes from the central part of the island to the southwest region. The magnetic and mineralogical heterogeneities of the dikes intruding older Lower Cretaceous formations may also be a result of a wider age range of the intrusions.
- Ranked Mappable Criteria for Magmatic Units: Systematization of the Ossa-Morena Zone Rift-Related Alkaline BodiesPublication . Roseiro, José; Moreira, Noel; de Oliveira, Daniel Pipa Soares; Silva, Marcelo; Eguiluz, Luis; Nogueira, PedroABSTRACT: The Ossa-Morena Zone (SW Iberian Massif) hosts the largest set of Cambro-Ordovician alkaline magmatic plutons related to the Palaeozoic rifting of the northern Gondwana margin so far described. An organized framework for their classification at different scales is proposed through data-driven ranks based on their distinctive petrological features relative to other rift-related magmatic rocks found throughout western Europe. The classification method aims to enhance geological mapping at different scales, regional- and continental-scale correlations, and, as such, facilitate the petrogenetic interpretation of this magmatism. The hierarchical scheme, from highest to lowest rank, is as follows: rank-1 (supersuite) assembles rocks that have distinctive characteristics from other magmatic units emplaced in the same magmatic event; rank-2 (suite) categorizes the units based on their major textural features, indicating if the body is plutonic, sub-volcanic, or a strongly deformed magmatic-derived unit; rank-3 (subsuite) clusters according to their spatial arrangement (magmatic centres) or association to larger structures (e.g., shear zones or alignments); rank-4, the fundamental mapping unit, characterizes the lithotype (alkaline granite, alkaline gabbro, syenite, albitite, etc.) by considering higher ranks (alkalinity and textural aspects); rank-5 characterizes the geometry of individual plutons (with several intrusions) or swarms; rank-6 (smallest mappable unit) corresponds to each intrusion or individual body from a swarm. Although this classification scheme is currently presented solely for the Ossa-Morena Zone, the scheme can be easily extended to incorporate other co-magmatic alkaline bodies, such as those in the NW Iberian allochthonous units or other peri-Gondwanan zones or massifs, in order to facilitate regional correlations of the rift-related magmatism.
- The Geological Survey Organisations in delivering Critical Raw Materials autonomy through a Geological Service for EuropePublication . Hollis, Julie; Albert, Capucine; Bertrand, Guillaume; Cabidoche, Marina; de Oliveira, Daniel Pipa Soares; Dobnikar, Meta; Teran, Klemen; Tulstrup, JørgenABSTRACT: Europe’s dependence on foreign-sourced critical raw materials poses a significant threat to its strategic autonomy and competitiveness. In this paper, we examine the historical significance of mining in Europe, the current geopolitical complexities surrounding critical raw materials supply, and recent EU policy initiatives aimed at bolstering domestic critical raw materials production and processing and building resilient supply chains. We highlight the crucial role of National Geological Survey Organisations in delivering knowledge of Europe’s critical raw materials potential, as well as contributing to international partnerships through technical engagement and geoscientific diplomacy. National Geological Survey Organisations collect and compile data on mineral resources, often serving as a primary resource for national and regional decision-making. This work is now crucial at EU level, with National Geological Survey Organisations mandated under the EU Critical Raw Materials Act to deliver National Exploration Programs to promote exploration investment through technical de-risking, and to coordinate efforts and geoscientific data and knowledge management at pan-European level. The National Geological Survey Organisations already share knowledge and best practices on European mineral resources through EuroGeoSurveys. Future efforts to secure European critical raw materials resilience will be served through their shared vision of a Geological Service for Europe.
- Decision criteria for the exploration of ornamental-stone deposits: Application to the marbles of the Portuguese Estremoz AnticlinePublication . Falé, Patrícia; Carvalho, Jorge; Henriques, Paulo; Luís, GabrielABSTRACT: Ornamental stones are almost ready-made raw materials with a high economic value for the building-construction industry. The discovery of new near-surface deposits, the very low exploitation efficiency, the huge amounts of wastes produced, and the land-use accessibility conditions are the main challenges that the extractive industry for this mineral resource is facing nowadays. Research on advanced geological exploration tools and methodologies is needed to reply to those challenges. During the process of geological ornamental-stone deposits exploration, the unique and decisive criteria that should be considered are its dimensions, homogeneity, and fracturing state. Lithostructural geological mapping and in situ fracturing surveys are the basic indispensable tools for their field assessment. By applying these criteria and tools to a marble-rich area in the Portuguese Estremoz Anticline and a step-by-step numerical evaluation of the qualitative geological parameters, the delimitation of the best target areas for exploitation or environmental rehabilitation has been effectively mapped.
- Chemical and Mineralogical Characterization ofWaste from Abandoned Copper and Manganese Mines in the Iberian Pyrite Belt, Portugal: A First Step Towards the Waste-to-Value Recycling ProcessPublication . de Oliveira, Daniel Pipa Soares; Silva, Teresa; Morais, Igor; Fernandes, JoãoABSTRACT: This study examines the chemical and mineralogical composition of waste materials from abandoned copper and manganese mines in the Iberian Pyrite Belt, Portugal, as a first step toward their potential recycling for critical and strategic raw materials (CRM and SRM). Using portable X-ray fluorescence (pXRF) and other analytical techniques, this research highlights the presence of valuable elements, including copper, manganese, and rare earth elements, in concentrations significantly above their crustal abundance. The findings underscore the dual potential of these wastes: as sources of secondary raw materials and for mitigating environmental hazards such as acid mine drainage (AMD). Recovered materials include chalcopyrite, pyrolusite, and rhodochrosite, with critical elements like cobalt, lithium, and tungsten identified. pXRF proved to be a reliable, cost effective tool for rapid field and laboratory analyses, demonstrating high precision and good correlation with standard laboratory methods. The study emphasizes the importance of characterizing historical mining waste to support a circular economy, reduce reliance on foreign material imports, and address environmental challenges. This approach aligns with the European Union’s Critical Raw Materials Act, promoting sustainable resource use and the recovery of strategic resources from historical mining sites.
- Corrigendum to “Critical raw materials in the global high-throughput ceramic industry” [Sustainable Materials and Technologies 39 (2024) e00832]Publication . Garcia-Ten, Javier; Dondi, Michele; Lisboa, Jose; Cabedo, Monica Vicent; Perez-Villarejo, Luis; Rambaldi, Elisa; Zanelli, ChiaraABSTRACT: The authors regret that an error in the unit of the global output of boron occurred: the correct value is 4.13 million tons per year of borates, corresponding to 2.29 million tons B2O3 in 2018. Thus, the presumable consumption of borates by the ceramic industry (around 250,000 tons per year, B2O3 content) corresponds to 11 ± 1% of the global output of borates. In comparison, estimates from the mining industry (Orocobre 2019 Annual Report; EtiMaden 2022 Boron Report) place the borate demand for the production of ceramic frits at a share of 14%, corresponding to approximately 320,000 tons per year (B2O3 content).
- GEMAS: Boron as a geochemical proxy for weathering of European agricultural soilPublication . Négrel, Philippe; Ladenberger, Anna; Demetriades, Alecos; Reimann, Clemens; Birke, Manfred; Sadeghi, Martiya; The EuroGeoSurveys GEMAS Project TeamABSTRACT: bout a century ago, B was recognised as an essential element for the normal growth of plants and terrestrial organisms. Limitations for plant development have been recognised in agricultural systems, particularly in highly weathered soil. Boron is rarely analysed in whole rock or soil analysis, as it requires specific analytical techniques. It is often determined, after partial extraction (aqua regia or Ca-Cl), usually on a limited number of samples. Many more questions than answers exist about the environmental behaviour of B. We present B contents in agricultural soil samples (0-10 cm) collected in 33 European countries (5.6 million km2) during the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) continental-scale project. The B content, determined by ICP-MS following hot aqua regia extraction, varies in European agricultural soil from 0.5 to 49 mg/kg (median 2.42 mg/kg, n = 2108), which is somewhat similar to total B estimates for the Upper Continental Crust (17-47 mg/kg). Its spatial distribution in agricultural soil shows a patchy pattern with low values in regions with granitic bedrock and high contents in soil formed over limestone and in volcanic areas. Boron geochemical behaviour in soil is strongly dependent on other factors such as pH, CEC, presence of organic matter, clay and secondary oxides and hydroxides. Boron geochemical mapping at the continental scale in arable soil allows investigations of plant health, i.e., the beneficial and adverse effects due to the nutritional status of boron.
- Detrital zircon U-Pb geochronology of the Moatize and N’Cond´edzi coalfields, Zambezi Karoo Basin of Mozambique: Implications for provenance, sediment dispersal and basin evolutionPublication . Fernandes, Paulo; Jorge, Raul CG Santos; Albardeiro, Luís; Chew, David; Drakou, Foteini; Pereira, Zélia; Marques, JoãoABSTRACT: Detrital zircon U-Pb geochronology of the Moatize and N'Condedzi coalfields in the Zambezi Karoo Basin of Mozambique provides key insights into the regional provenance, sediment dispersal pathways and basin evolution. Borehole cores from the two coalfields reveal a stratigraphy spanning the early Roadian (middle Permian) to the Carnian (Upper Triassic). The Permian sandstones of the Moatize Coalfield (MC) yield three detrital zircon populations, with ages ranging from 1150 to 950 Ma, 900-780 Ma and 650-490 Ma. In contrast, the Permian sandstones of the N'Condedzi Coalfield (NC) have only one population, which ranges from 1150 to 950 Ma. During the Permian, the provenance area for the NC was the Tete-Chipata Terrane and Malawi Complex (1150-950 Ma) to the north-northeast. In the MC, the detrital zircon populations of the early lake delta depositional setting (Roadian to Wordian) indicate a main provenance in the Zambezi Belt (900-780 Ma) located to the south of the MC, with minor sourcing from the Nampula Block (1150-950 Ma and 650-490 Ma) to the east. The transition from a lake delta to an alluvial depositional setting is attributed to a major tectonic event in the MC, which involved the formation of a braided channel belt. Sandstones from this braided channel belt yield three detrital zircons populations (650-490 Ma, 900-780 Ma and 1150-950 Ma), indicating provenance from both the Zambezi Belt and the Nampula Block. The overlying sandstones in the MC show only a minor population from the Zambezi Belt (900-780 Ma), implying a shift in provenance to the Nampula Block that was likely induced by tectonics. The absence of detrital zircon populations of 900-780 Ma and 650-490 in the Permian sandstones of NC implies that the two coalfields were not connected during the mid to late Permian. It is likely that an intra-rift horst (the Mesoproterozoic Gabbro-Anorthosite Tete Suite) separated the two coalfields. The Lower Triassic sandstones of the NC yield a main detrital zircon population indicating provenance from the TeteChipata Terrane and Malawi Complex (1150-950 Ma). A minor population at 650-490 Ma is linked to increased aridity at the Permian - Triassic boundary, which caused expansion of the watershed across the Tete-Chipata Terrane and the Malawi Complex. The Upper Triassic sandstones in the NC yield a 1150-950 Ma detrital zircon population, indicating provenance from the Tete-Chipata Terrane and Malawi Complex and a return to the source-to-sink conditions seen in the mid to late Permian.
- Contact metamorphism and dolomitization overprint on Cambrian carbonates from the Ossa‑Morena Zone (SW Iberian Massif): implications to Sr‑chronology of carbonate rocksPublication . Roseiro, José; Moreira, Noel; Andrade, Laura; Nogueira, Pedro; de Oliveira, Daniel Pipa Soares; Eguiluz, Luis; Mirao, Jose; Moita, Patrícia; Santos, José Francisco; Ribeiro, Sara; Pedro, J.ABSTRACT: he Cambrian Series 2 Carbonate Formation from the Alter do Chão Elvas-Cumbres Mayores unit (Ossa-Morena Zone, SW Iberian Massif) is composed of regionally metamorphosed marbles and marlstones that underwent chlorite zone metamorphism and preserve the primaeval limestone 87Sr/86Sr ratios (0.7083–0.7088). These are consistent with the established Lower Cambrian seawater curve, and therefore used for age constraints in formations lacking fossil contents. The regional mineralogical and Sr-isotopic features of the carbonate rocks are frequently overprinted by the effects of contact metamorphism induced by magmatic bodies emplaced during rift-related and synorogenic events of the Palaeozoic, as well as by post-metamorphic dolomitization processes. The development of calc-silicate minerals due to contact metamorphism is common in the rocks of the Carbonate Formation and apparently results from the interaction of the protolith with fluids of different origin: (i) internally produced fluids released by conductive heating (observed in external contact aureoles) and (ii) external intrusion-expelled fluids that, besides leading to the appearance of distinctive assemblages, also promote an influx of strontium content (observed in roof pendants). Calc-silicate mineralogy varies substantially throughout the region, likely due to the heterogeneous distribution of silicate minerals of the protolith, progression of intrusion-driven fluids, and the irregular effect of thermal gradients. Results suggest that high-grade contact metamorphism (hornblende facies or higher) and dolomitization processes imposed on the Carbonate Formation significantly influence the isotopic signatures of the carbonates, providing limitations in applying Sr-isotopic chronology.
- A Geological Service for Europe: building trust through interdisciplinary and intersectoral collaborationPublication . Hollis, Julie; Calcagno, Philippe; Bertrand, Guillaume; de Oliveira, Daniel Pipa Soares; Negrel, Philippe; Díaz-Martínez, Enrique; La Vigna, Francesco; Poyiadji, Eleftheria; Tonné, Nathalie; Van Heteren, Sytze; Dakin, Nicola; Hinsby, Klaus; Van Der Keur, Peter; Siddiqi, Gunter; Čápová, Dana; Pizzocolo, FrancescoABSTRACT: Geology encompasses all of the Earth sciences and thus is multidisciplinary. It does not respect geopolitical borders, so requires teamwork across disciplines and between nations. Applying geological solutions to climate change increasingly requires transdisciplinary teamwork. This extends well beyond the geosciences to inform on issues of universal concern, e.g., deployment of renewable energy, management of groundwater resources, mitigation of climate-induced geohazards, and more. To achieve sustainability and success in these fields, it is essential to employ knowledge of subsurface, land, and subsea geology for the discovery, tracking, preservation, regulation, and exploitation of resources. This knowledge also supports integrated and coherent surface and subsurface spatial planning and the creation of cohesive laws guided by scientific insights. This in turn requires multi-stakeholder collaboration between scientific and governmental agencies, industry, and civil society, from research design to data and knowledge application. Such a broad spectrum of engagement is at the heart of the concept of a Geological Service for Europe, founded on a long history of collaboration between the Geological Surveys of Europe –extending networks, fostering innovation, sharing knowledge, building capacity and common standards. Given the current lack of public knowledge and negative perceptions of geology, collaborative efforts based on objective science can have a significant impact on building trust. This contribution highlights the collaboration of the Geological Surveys of Europe with non-geoscientific partners in serving society, supporting nature, and delivering the Green Deal.