Geologia e Cartografia Geológica - GCG
URI permanente desta comunidade:
Navegar
Percorrer Geologia e Cartografia Geológica - GCG por Domínios Científicos e Tecnológicos (FOS) "Ciências Naturais::Ciências da Terra e do Ambiente"
A mostrar 1 - 10 de 15
Resultados por página
Opções de ordenação
- Cartografía Geológica del Plan Nacional de Geología de Angola (PLANAGEO)Publication . Merino-Martínez, E.; Rodrigues, José Feliciano; Martín-Banda, Raquel; Francés, Alain Pascal; Feria, María Carmen; López-Bahut, T.; Ferreira, Ezequiel; García-Lobón, J. L.; Gumiel, J. C.; Cuervo, I.; Victorino, Américo da Mata; Manuel, JoséRESUMEN: La cartografía geológica fue la actividad central en la que se basó el Plan Nacional de Geología de Angola (PLANAGEO). Los trabajos de cartografía geológica realizados por el consorcio UTE PLANAGEO (IGME/LNEG/IIA) en el sur de Angola (476.512 km2), desarrollados entre 2016 y 2020, comprendieron 44 cartas a escala 1:250.000, 15 cartas a escala 100.000, 8 mapas de síntesis a escala 1:500.000 y 4 mapas geotemáticos a escala 1:1.000.000. A partir de estos trabajos, fueron distinguidos diversos dominios geológicos en el sur del Escudo de Angola, delimitados por macroestructuras bien definidas en los modelos geofísicos. Los mapas y sus memorias asociadas reúnen todo el conocimiento generado durante PLANAGEO, siendo un manual de referencia geológica y un modelo para futuros estudios geológico-mineros. Los mapas geológicos realizados constituyen la base de una infraestructura regional de conocimiento geológico de la región sur de Angola, y proporcionan información básica para el aprovechamiento óptimo del territorio y desarrollar el potencial de los recursos naturales del país.
- 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.
- Ediacaran and early-palaeozoic bimodal volcanism in the Ossa-Morena Zone, SW Iberian Massif: New clues for intraplate rifting shortly after the Cadomian OrogenyPublication . Cachapuz, P.; Chichorro, Martim Afonso; Bento dos Santos, Telmo; Carvalho, D.; Linnemann, Ulf; Zieger-Hofmann, M.; Zieger, J.; Dantas, E.; Santos, R. V.; Moita, Patrícia; Beltrame, M.; Solá, A. Rita; Díaz-Azpíroz, M.; Fernández, C.ABSTRACT: This study focuses on bimodal meta-volcanic rocks present in the Iberian Massif, in the Evora-Aracena Metamorphic Belt of the Ossa-Morena Zone (OMZ), near the boundary with the South Portuguese Zone. New petrological, geochemical (whole-rock and Sr-Nd isotopes) and LA-ICP-MS U-Pb zircon geochronology data are presented to track the magmatic evolution of both felsic and mafic rocks and their respective geodynamic setting during the transition between the Cadomian Orogeny and subsequent Palaeozoic rifting events. Our research shows that the Evora-Aracena Metamorphic Belt (EAMB) in the southwestern OMZ possesses a significant record of the transition between the Cadomian and Variscan cycles. U-Pb geochronological data confirm the existence of both felsic and mafic Ediacaran igneous rocks (546 and 556 Ma, respectively), a novelty in the region. The Cadomian-related felsic rocks show geochemical similarities to meta-felsic rocks formed during the initial phases of the Cambrian rifting event, namely very negative epsilon Nd values (-10.1 to -11.8), depleted HREE patterns and orogenic signatures. Such similarities imply that meta-felsic rocks formed in the earliest stages of the Cambrian Rift-to-Drift event resulted from a shallower melting. Moreover, meta-felsic rocks formed in the early stages of the Cambrian rifting (525 Ma) present a significant amount of Ediacaran aged zircons, whereas the Cadomian-related counterparts display a few discordant Cambrian ages, likely a consequence of Pb-loss. This indicates that the convergent, subduction-related regime that prevailed during most of the Cryogenian-Ediacaran times along the boundaries of NW Gondwana was swiftly supplanted by a rift-dominated regime during the Cambrian, with no substantial gap between these two thermal events. Meanwhile, meta-felsic rocks formed during the Rift-to-Drift (525-480 Ma) event exhibit progressively higher epsilon Nd values (-5.0 to +3.0), HREE-enrichment, as well as anorogenic signatures, denoting an increasing contribution of mantle-derived melts. This increasing mantle contribution eventually led to the occurrence of bimodal magmatism in the Middle Cambrian Main Rift event. Such Cambrian mafic rocks, unlike the Ediacaran mafic rocks that present flat REE patterns and continental arc signatures, display varying degrees of LREE enrichment and N-MORB to E-MORB signatures.
- 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.
- Evaluating the role of physical mechanisms as possible triggers for turbidity currents in a deep ocean seamountPublication . Lebreiro, Susana M.; Peliz, Álvaro; Antón, Laura; Nave, Silvia; Reguera, M. Isabel; Lozano-Luz, Rocío; Waelbroeck, Claire; Crowhurst, Simon; Martrat, Belen; Lopez, Jordi F.; Hebert, Raphael; Lopez-Rodriguez, AlejandraABSTRACT: Turbidity currents on continental margins are often attributed to cyclic climate variability and sea-level change, while the causes of deep ocean turbidites are as yet to be tested. The Atlantic Iberian margin provides a unique setting to contrast deep ocean and continental environments, including depression features that further protect from resuspension and erosion by along-slope bottom currents. We present records of low-frequency, non-periodic, climate-independent turbidites from three deep cores covering up to 426,000 years in the Tore seamounts area. By evaluating a range of physical oceanographic mechanisms, the breaking of internal waves and mesoscale Mediterranean-eddies against unstable slopes in the seamounts area arises as the most likely triggers that precondition the recurrence pattern of the observed deep ocean turbidites.
- Evaluating the role of physical mechanisms as possible triggers for turbidity currents in a deep ocean seamount [Resumo]Publication . Lebreiro, Susana M.; Peliz, Álvaro; Antón, Laura; Nave, Silvia; Reguera, M. Isabel; Lozano-Luz, Rocío; Waelbroeck, Claire; Crowhurst, Simon; Martrat, Belen; Lopez, Jordi F.; Hebert, Raphael; Lopez-Rodriguez, AlejandraABSTRACT: Turbidity currents on continental margins are often attributed to cyclic climate variability and sea-level change, while the causes of deep ocean turbidites are as yet to be tested. The Atlantic Iberian margin provides a unique setting to contrast deep ocean and continental environments, including depression features that further protect from resuspension and erosion by along slope bottom currents. We present records of low-frequency, non-periodic, climate-independent turbidites from three exceptionally deep cores covering up to 426,000 years in the Tore seamounts area. Here we evaluate the possible role of a number of physical processes that, when combined, may induce sufficiently intense bottom boundary events and likely precondition the recurrence pattern of the observed deep ocean turbidites.
- Geochemical comparison of circular plutonic complexes with extrusive rocks from Sal Island (Cape Verde)Publication . Garcia-Rodriguez, Maria; Villaseca, Carlos; Ignacio, Cristina; Orejana, David; Mata, João; Caldeira, RitaABSTRACT: Sal island is located in the northeast and is the oldest of the Cape Verde archipelago, with magmatic activity starting ~25 Ma ago. It presents a series of circular plutons that could represent the subvolcanic roots of the exposed extrusive rocks. In this work we compare the geochemical characteristics of melagabbro-gabbro of circular (~16.3 Ma) intrusions in the Old Eruptive Complex, with basaltic and nephelinitic lavas of equivalent age (~15.8 and 14.2 Ma, Torres et al., 2010). This comparison allows observing a geochemical overlap between basalts and gabbros, and the similarity between trends of part of the samples in Harker-type diagrams and REE patterns. However, this compositional overlap is incomplete, with considerable differences and absence of fractionated (intermediate) lava types related to these terms of the circular complexes. This partial but incomplete overlap of the compositional fields of the plutonic and volcanic trends argues against the possibility of a direct genetic relationship between the two.
- Leveraging the ESA Network of Resources (NoR) for Ultra High-Resolution Monitoring of Coastal Morphodynamics: Praia d’el Rey Case Study [Poster]Publication . Nave, Silvia; Gonçalves, Pedro; Albardeiro, Luís; Mesquita Soares, Sofia
- 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.
- Monitorização Remota de Solos no Interior de Portugal: Integração de Dados Multiespectrais e LiDAR via VANT [Poster]Publication . Gonçalves, Pedro; Carvalho, J.; Torres, Rita; Morgado, Rita; Henriques, J.; Simões, B.; de Oliveira, Daniel Pipa Soares; Nave, Silvia