Geologia e Cartografia Geológica - GCG
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Browsing Geologia e Cartografia Geológica - GCG by Field of Science and Technology (FOS) "Ciências Naturais::Ciências da Terra e do Ambiente"
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- Depositional environment and redox conditions of the Moncorvo Ironstone: Unveiling the evolution of ironstones under Rheic Ocean influencePublication . Urbano, Emilio Evo Magro Correa; Preto Gomes, Maria Elisa; Pinto de Meireles, Carlos Augusto; Brandão, Paulo Roberto Gomes; Hippertt, Joa Pedro T.M.; Scholz, Ricardo; Lana, CristianoABSTRACT: Ironstones, as key archives of past marine environments, provide invaluable insights into Paleozoic history. Their mineralogy may reflect the physical-chemical conditions of the environment and the nature of available sediments. This study focuses on the Moncorvo Ironstone, a Lower-Middle Ordovician deposit formed during the opening of the Rheic Ocean. Here, we use an integrated approach combining sedimentology, petrology, and geochemistry to constrain the depositional settings and the redox landscape associated with the ironstone deposition. The Moncorvo Ironstone present some unusual characteristics, such as the lack of ooids, an uncommon mineralogy, and a stratigraphic thickness that can reach over >45 m, a remarkable feature for an ironstone. Our investigation reveals that this iron-rich sequence is distributed in two distinct marine environments: an inner shelf and a middle to distal shelf. Each environment has a unique mineral assemblage. Despite the influence of metamorphism and deformation, evidence suggests that much of the mineralogy and texture of this deposit still preserve characteristics of the original sediments. Finally, our findings, alongside a careful assessment of the mineralogy of other ironstones of similar age, suggest a strong stratification of the Rheic Ocean throughout the Early and Middle Ordovician.
- Empowering Citizen Science Through Stakeholder EngagementPublication . Correia, Vítor; Romão, José; Tyrologou, Pavlos; Gomes, Rui Carrilho; Correia, Vítor; Bodó, BalazsABSTRACT: The chapter examines how citizen science projects, particularly in geohazard monitoring, can be strengthened through systematic stakeholder engagement. Using the AGEO project as a case study, with five established Citizen Observatories across Europe, it details how stakeholders were identified, classified, and engaged across political, economic, knowledge and socio-cultural systems. The paper identifies five crucial factors for successful engagement: relevance, accessibility, trust, recognition/incentives, and sustainability. It concludes that citizen science, supported by technological advances and proper stakeholder engagement, can make significant contributions to disaster preparedness and risk reduction, particularly in the context of climate change, by fostering collaboration between experts and communities.
- Megaglomerospora lealiae nov. gen., nov. sp. from the upper Carboniferous of Portugal: the largest glomeromycotan fungal sporesPublication . Correia, Pedro; Sá, Artur A.; Pereira, ZéliaABSTRACT: A new genus and species of fossil fungus, Megaglomerospora lealiae, is described from the Bu & ccedil;aco Carboniferous Basin (upper Stephanian C, Upper Pennsylvanian, upper Carboniferous), in central western Portugal. The new fossil fungus consists of a dense cluster of silicified large spores. These new fungal spores are oblong, subelliptical to subspherical-shaped, with a glabrous surface characterized by having a lipid-filled lumen, and display a strong septate-like hypha attached. The presence of lobe-shaped germination shields suggests close affinities to Diversisporales (Glomeromycota). Megaglomerospora lealiae nov. gen., nov. sp. is remarkably distinctive because it is by far the largest fossil fungal spore (similar to 1.6 mm long) documented for the phylum Glomeromycota. This is the first report of an endomycorrhizal-like fungus from the Carboniferous of Iberia. (c) 2025 Elsevier Masson SAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
- The old central igneous complexes of Sal, Boa Vista and Maio islands: Implications for 17 Ma of isotopic evolution of the Cape Verde archipelagoPublication . Villaseca, Carlos; Orejana, David; Huertas, Maria J.; Ancochea, Eumenio; Ignacio, Cristina; Mata, João; Caldeira, Rita; Garcia-Rodriguez, Maria; Moreno, Juan A.; Perez-Soba, CeciliaABSTRACT: The central igneous complexes of the easternmost islands (Sal, Boa Vista and Maio) preserve some of the most ancient outcropping rocks of the Cape Verde (CV) archipelago. These Early to Middle Miocene (about 25 to 12 Ma) complexes show marked isotopic differences between mafic rocks from the northern (Sal and Boa Vista) and the southern Maio Island, the latter showing lower 143Nd/144Nd, 206Pb/204Pb, 207Pb/204Pb, and higher 87Sr/86Sr ratios. The main mantle plume composition beneath Cape Verde is here considered to be dominated by the FOZO component. Our data supports previous models suggesting the incorporation to plume components of minor DMM mantle sources in the northern CV island alignment, whereas mixing with the EM1 pole is prevalent on the southern CV islands. These isotopic differences are evident since the early stages of Cape Verde magmatism. The Late Miocene to Holocene time period (7 to 1.7 Ma) is characterized by the irruption of silica-undersaturated and carbonatite magmas with a relatively homogeneous isotopic composition and highly radiogenic Pb signatures (206Pb/204Pb up to 20.6 in carbonatitic rocks and 20.2 in silicate rocks) throughout most of the Cape Verde archipelago. During this transitional stage, the input of this new HIMU mantle component overprinted the previous mixing of the main FOZO plume component with shallow mantle members (DMM, EM1) of minor contribution.