Review
Geochemistry & Geophysics
Encarnacion Roda-Robles, Pedro Pablo Gil-Crespo, Alfonso Pesquera, Alexandre Lima, Idoia Garate-Olave, Enrique Merino-Martinez, Joana Cardoso-Fernandes, Jon Errandonea-Martin
Summary: Apatite can serve as a useful tool for studying the evolution of granitic magmas and exploration of pegmatites. The composition of apatite varies in different types of rocks, with increasing manganese content associated with magma evolution, while decreasing rare earth elements content. Apatite can provide valuable information about the petrogenesis of pegmatites and granites.
Article
Geochemistry & Geophysics
Encarnacion Roda-Robles, Romeu Vieira, Alexandre Lima, Jon Errandonea-Martin, Alfonso Pesquera, Joana Cardoso-Fernandes, Idoia Garate-Olave
Summary: Based on field and petrographic observations, mineralogical, geochemical and geochronological data, this study classified the pegmatites and cassiterite-rich quartz veins in the Fregeneda-Almendra field and revealed their relationships with different magmatic events.
Article
Geosciences, Multidisciplinary
R. Dias, C. Coke, A. Ribeiro
Summary: The formation of the Ibero-Armorican Arc played an important role in the Variscan orogeny. The study revealed a heterogeneous sinistral transpressive regime and observed strain partitioning at different scales. The research also identified the coeval development of sedimentary rocks and fold structures related to the deformation.
JOURNAL OF STRUCTURAL GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Ana Goncalves, Helena Sant'Ovaia, Helena Cristina Brites Martins, Fernando Noronha
Summary: The Valpacos and Freixo de Numao granites in Northeastern Portugal were studied to understand the ascent and emplacement mechanisms and deformation patterns evolution. The magnetic fabrics of ValG were influenced by a combination of magmatic and tectonic fabrics, while FNG inherited a magmatic fabric from passive ascent and emplacement. Brittle structures recorded in both granites help reconstruct the rotation of maximum compressive stress.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2022)
Article
Geology
S. Leal, A. Lima, F. Noronha, J. Mortensen, D. MacKenzie
Summary: The Bigorne deposit is a orogenic gold system located in the northern Iberia, with gold-bearing veins cutting through synorogenic Variscan granites. The mineralization includes quartz-sulfide veins, disseminated sulfides, hydrothermal alteration, and oxidize fractures. The thermal evolution suggests that gold deposition occurred at lower temperatures. Isotope studies indicate that the gold-bearing fluid was generated from deep-crustal rocks during decompression triggered by crustal uplift.
ORE GEOLOGY REVIEWS
(2022)
Article
Geochemistry & Geophysics
A. Hildenbrand, F. O. Marques, X. Quidelleur, F. Noronha
Summary: This study investigates the cooling and exhumation history of granitic batholiths from the main structural zones of the Variscan orogen in Iberia using various geological methods. The results highlight different deformation and tectonic evolution characteristics during different periods.
Article
Geochemistry & Geophysics
Gultekin Topuz, Rainer Altherr, Osman Candan, Jia-Min Wang, Aral I. Okay, Fu-Yuan Wu, Ali Ergen, Thomas Zack, Wolfgang Siebel, Cosmas K. Shangh, Winfried H. Schwarz, Hans-Peter Meyer, Muharrem Satir
Summary: This study investigates the age and petrogenesis of mafic-ultramafic intrusions in the Pulur Complex. The intrusions consist of various rock types and were emplaced after the peak of high-grade metamorphism. The geochemical data suggests a genetic connection between the mafic-ultramafic intrusions and the high-K calc-alkaline granites in the region.
Editorial Material
Geochemistry & Geophysics
Ruben Diez Fernandez, Carlos Fernandez, Ricardo Arenas, Irene Novo-Fernandez
Summary: Geological mapping, structural data, and analytical modeling support the notion that the Central Unit belongs to a rootless Devonian suture zone that underwent late uplift and upright folding. However, other studies overlook this evidence and fail to interpret the structural dip angle accurately in seismic images. Overall, the model proposed by Diez Fernandez et al. remains valid.
Article
Geology
Francisco J. Rubio Pascual, Luis M. Martin Parra, Ruben Diez Fernandez, Pablo Valverde-Vaquero, Alejandro Diez-Montes, Manuel P. Hacar Rodriguez, Justo Iglesias, Gloria Gallastegui, L. Roberto Rodriguez Fernandez, Aratz Beranoaguirre
Summary: This study examines the geological structures and metamorphic processes in the NW Iberian section of the Variscan Orogen. By analyzing the metamorphic record of tectonic slices, it reveals the transitional process between subduction and collision zones, providing important clues for understanding the construction of orogens.
INTERNATIONAL GEOLOGY REVIEW
(2022)
Article
Geochemistry & Geophysics
Birger Rasmussen, Jian-Wei Zi, Janet R. Muhling
Summary: Tectonic fluid expulsion in permeable foreland basin sequences has been examined, and it has been discovered that fluids migrate through low-permeability successions. U-Pb data from the Hamersley region in Australia indicate that fluids expelled during tectonic compression migrated through older shales by fracture permeability and enhanced diffusion. The timing of veining was not random, but coincided with major orogenic events, linking fluid overpressure and hydraulic fracturing to the expulsion of heated orogenic fluids. These findings provide insight into fluid flow in geological processes.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Joana Alexandra Ferreira, Ines Pereira, Telmo Bento dos Santos, Joao Mata
Summary: The Figueira de Castelo Rodrigo-Lumbrales Anatectic Complex in the Central Iberian Zone has been studied for its metamorphic ages and exhumation history. The complex experienced peak metamorphism 316.8 +/- 2.0 million years ago, followed by rapid cooling and exhumation. The zircon ages of the complex are similar to those of the Excomungada Formation, suggesting a shared geological history. The detrital zircon ages of the Pinhao Formation indicate different sources from the Beiras Group, indicating the presence of a geological barrier. This study provides new insights into the geological evolution of the region.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2022)
Article
Geology
S. Leal, A. Lima, J. Morris, M. Pedro, F. Noronha
Summary: The Numao gold deposit in the northern part of the Iberian Variscan belt is controlled by second and third-order structures near the regional first-order Vilarica-Manteigas fault system. The deposit consists of disseminated sulfides, arsenopyrite-quartz veins, and sulfides-scheelite-quartz veins. The ore mineral assemblage includes scheelite, arsenopyrite, chalcopyrite, bismuth, and Au-Ag mineral phases.
ORE GEOLOGY REVIEWS
(2022)
Article
Geochemistry & Geophysics
Christophe Ballouard, Simon Couzinie, Pierre Bouilhol, Matthieu Harlaux, Julien Mercadier, Jean-Marc Montel
Summary: The Velay anatectic dome in the Variscan French Massif Central provides an ideal natural laboratory for studying the behavior of rare metals and fluxing elements during crustal melting. Through geochemical analysis and modeling, the study reveals the factors that affect the Li and F contents of granitic melts, such as melting pressure, temperature, H2O activity, and protolith composition. It also demonstrates that peraluminous orthogneiss anatexis can generate melts enriched in both F and Li, which can evolve into rare-metal granite compositions through fractional crystallization.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2023)
Article
Geology
Sara Criniti, Manuel Martin-Martin, Agustin Martin-Algarra
Summary: Carboniferous sandstone in southern Spain plays a significant role in the sedimentary budget of convergent plate boundaries during the Variscan s.s. to Paleotethysian orogenic period. The sandstone carries quartzolithic composition with high-to-medium-low grade metamorphic content, sourced from volcanic and ophiolitic detritus that could be as old as approximately 330 Ma. This detritus is likely derived from a lithic and transitional recycled orogen involved in plate convergence and uplifted during mid-Late Carboniferous time. The presence of serpentinite-like detritus suggests the dismantling of metamorphosed oceanic crust. The study of these Mid-Late Carboniferous sandstones contributes to paleogeographic reconstructions and provides constraints for the transitional area between the Iberian-French massifs and the African Paleo-Atlas Domain.
SEDIMENTARY GEOLOGY
(2023)
Article
Geosciences, Multidisciplinary
T. Bento dos Santos, J. F. Rodrigues, P. Castro, B. Cotrim, I. Pereira, J. A. Ferreira, C. Meireles, N. Ferreira, P. Ferreira, A. Ribeiro, F. Guimaraes
Summary: The Porto-Viseu Metamorphic Belt in the Iberian Variscan Massif displays a sharp metamorphic contrast between the anatectic complex and the host metasediments, with high-grade metamorphic peak conditions confirmed in metatexites. The presence of coeval and antithetical ductile shear zones bordering the belt suggests anatectic channel flow and extrusion tectonics within a compressive setting.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2021)
Article
Mineralogy
Axel Muller, William Simmons, Hartmut Beurlen, Rainer Thomas, Peter M. Ihlen, Michael Wise, Encarnacion Roda-Robles, Ana M. R. Neiva, Victor Zagorsky
Summary: This study is the precursor and complementary study for the classification of granitic pegmatites, analyzing existing classification criteria and proposing a new classification scheme.
CANADIAN MINERALOGIST
(2022)
Article
Geochemistry & Geophysics
Joana Cardoso-Fernandes, Jessica Lima, Alexandre Lima, Encarnacion Roda-Robles, Martin Koehler, Stefan Schaefer, Andreas Barth, Andreas Knobloch, Mario A. Goncalves, Filipe Goncalves, Ana Claudia Teodoro
Summary: The study reprocessed historical stream sediment datasets using spatial interpolation and catchment basin analysis methods to determine pathfinder elements for lithium mineralization and compared the performance of the two approaches. The results showed that the spatial interpolation method is more suitable for early-stage exploration, while the catchment basin method is more suitable for larger-scale exploration.
JOURNAL OF GEOCHEMICAL EXPLORATION
(2022)
Article
Geochemistry & Geophysics
Elin Figueiredo, Alexandra Rodrigues, Joao Fonte, Emmanuelle Meunier, Filipa Dias, Alexandre Lima, Jose Alberto Goncalves, Luis Goncalves-Seco, Filipe Goncalves, Manuel F. C. Pereira, Rui J. C. Silva, Joao P. Veiga
Summary: This study presents a detailed investigation of the Outeiro de Baltar hillfort, a rare find related to Iron Age metallurgical activities involving tin metal and mining. Analysis of metallurgical debris and artifacts found at the site revealed the use of various metals and alloys. Additionally, the integration of remote sensing data and Geographic Information System mapping provided insights into the landscape context and historical mining activities surrounding the hillfort.
Review
Geochemistry & Geophysics
Miguel Angel Galliski, Maria Florencia Marquez-Zavalia, Encarnacion Roda-Robles, Albrecht von Quadt
Summary: The Li-bearing pegmatites in the Pampean Pegmatite Province (PPP) are rare-element pegmatites occurring in a pegmatite belt in southwestern Gondwana. These pegmatites, belonging to the LCT petrogenetic family, exhibit enrichments of Li, Rb, Nb, Ta, Be, P, B, and Bi. They are thought to have formed through fractionation of granitic melts produced by anatexis of Gondwana-derived sediments. The pegmatites, mostly orogenic in nature, were emplaced during the Pampean and Famatinian orogenies, with a few being postorogenic and related to A-type granites. The known resources of spodumene in the area are estimated to be 200,000 tonnes, with the potential for future discoveries and resource expansion.
Article
Geology
Jon Errandonea-Martin, Idoia Garate-Olave, Encarnacion Roda-Robles, Joana Cardoso-Fernandes, Alexandre Lima, Maria dos Anjos Ribeiro, Ana Claudia Teodoro
Summary: Fluid-assisted mass transfer and re-equilibration of mineral phases are common consequences of metasomatism associated with igneous intrusions. Rare-element granitic pegmatites are of great importance in mineral exploration and geochemical studies of their related aureoles contribute to the development of exploration targeting techniques.
ORE GEOLOGY REVIEWS
(2022)
Review
Geochemistry & Geophysics
Encarnacion Roda-Robles, Pedro Pablo Gil-Crespo, Alfonso Pesquera, Alexandre Lima, Idoia Garate-Olave, Enrique Merino-Martinez, Joana Cardoso-Fernandes, Jon Errandonea-Martin
Summary: Apatite can serve as a useful tool for studying the evolution of granitic magmas and exploration of pegmatites. The composition of apatite varies in different types of rocks, with increasing manganese content associated with magma evolution, while decreasing rare earth elements content. Apatite can provide valuable information about the petrogenesis of pegmatites and granites.
Article
Anthropology
Emmanuelle Meunier, Filipa Dias, Joao Fonte, Alexandre Lima, Alexandra Rodrigues, Carlo Bottaini, Rui J. C. Silva, Joao P. Veiga, Manuel F. C. Pereira, Elin Figueiredo
Summary: This paper presents a comprehensive study on the evidence for ancient tin mining at the Ervedosa mine in Portugal. The geological context of the site indicates a rich cassiterite deposit, and ancient mining tools were recovered, providing evidence of prehistoric mining activities.
ARCHAEOLOGICAL AND ANTHROPOLOGICAL SCIENCES
(2023)
Editorial Material
Geochemistry & Geophysics
Axel Mueller, Encarnacion Roda-Robles
Article
Geochemistry & Geophysics
Filipa Dias, Ricardo Ribeiro, Filipe Goncalves, Alexandre Lima, Encarnacion Roda-Robles, Tania Martins
Summary: In pegmatites with abundant petalite and spodumene, calibrating a portable laser-induced breakdown spectroscopy (pLIBS) equipment to identify and analyze these minerals is challenging. Samples of spodumene, petalite, and spodumene + quartz were collected from aplite-pegmatites in the Barroso-Alvao (BA) field and analyzed using inductively coupled plasma-mass spectroscopy. One calibration for both minerals was impossible due to overlapping LIBS intensity ratios. Three calibrations were developed: one qualitative and two quantitative for each mineral. Thin sections and cathodoluminescence (CL) were used to verify sample purity and mineral paragenesis.
Article
Geochemistry & Geophysics
Encarnacion Roda-Robles, Romeu Vieira, Alexandre Lima, Jon Errandonea-Martin, Alfonso Pesquera, Joana Cardoso-Fernandes, Idoia Garate-Olave
Summary: Based on field and petrographic observations, mineralogical, geochemical and geochronological data, this study classified the pegmatites and cassiterite-rich quartz veins in the Fregeneda-Almendra field and revealed their relationships with different magmatic events.
Proceedings Paper
Geosciences, Multidisciplinary
Joana Cardoso-Fernandes, Douglas Santos, Alexandre Lima, Ana Claudia Teodoro
Summary: This study assesses the potential of PRISMA data to target lithium deposits through the detection of topaz as a proxy to the mineralization. The results demonstrate the potential of PRISMA data, although there may be limitations related to its spatial resolution. Comparison with other data shows the limitations of multispectral products.
2022 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2022)
(2022)