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51 Results Found

  • Article
  • Open Access
7 Citations
2,844 Views
24 Pages

Deciphering Iberian Variscan Orogen Magmatism Using the Anisotropy of Magnetic Susceptibility from Granites

  • Helena Sant’Ovaia,
  • Cláudia Cruz,
  • Ana Gonçalves,
  • Pedro Nogueira and
  • Fernando Noronha

15 March 2024

In this paper, we have synthesized the information derived from more than 20 papers and PhD theses on the anisotropy of the magnetic susceptibility (AMS) of 19 Variscan granite plutons, spanning the period between 320 Ma and 296 Ma. The AMS data are...

  • Article
  • Open Access
1,263 Views
30 Pages

Petrogenesis and U–Pb Dating of Variscan S-Type Granites from the Junqueira Batholith (Central Iberian Zone)

  • Luís Portela,
  • Maria Rosário Azevedo,
  • Beatriz Valle Aguado,
  • Maria Mafalda Costa and
  • Jorge Medina

4 May 2025

The Junqueira massif is a syn- to late-kinematic Variscan batholith intruded into Ediacaran-Cambrian metasedimentary rocks of the Douro-Beiras Supergroup (DBSG) in the Central Iberian Zone. The batholith occupies the axial zone of the Porto-Viseu ant...

  • Article
  • Open Access
16 Citations
4,676 Views
29 Pages

11 December 2019

The sources and critical enrichment processes for granite related tin ores are still not well understood. The Erzgebirge represents one of the classical regions for tin mineralization. We investigated the four largest plutons from the Western Erzgebi...

  • Article
  • Open Access
8 Citations
4,613 Views
43 Pages

20 June 2020

The Fundão–Serra da Estrela–Capinha (FSEC) region is characterized by peraluminous to metaluminous Variscan granites intrusive in a complex and thick metasedimentary sequence. This work seeks to characterize the Capinha granite (CG...

  • Article
  • Open Access
1,844 Views
29 Pages

Variscan Plutonism in the Geodynamic Evolution of the Central Iberian Zone of Portugal: Castelo Branco Pluton as Another Piece of the Puzzle

  • Cláudia Cruz,
  • Helena Sant’Ovaia,
  • Helena C. B. Martins,
  • Isabel M. H. R. Antunes,
  • Armando Rocha and
  • Fernando Noronha

A multidisciplinary analysis of the Pennsylvanian Castelo Branco pluton of Central Iberian Zone (Iberian Variscan belt) was made, focusing on its magnetic behavior and fabric, microstructures, microfractures, and radiometric and gravimetric anomalies...

  • Proceeding Paper
  • Open Access
1 Citations
2,334 Views
10 Pages

The SW Sardinian basement hosts various ore deposits linked to geological processes active from Cambrian to post-Variscan times. In particular, the Southern Arburèse district hosts several granite-related W-Sn-Mo deposits and a 10 km-long system of N...

  • Article
  • Open Access
6 Citations
3,953 Views
33 Pages

Fracture Transmissivity in Prospective Host Rocks for Enhanced Geothermal Systems (EGS)

  • Johannes Herrmann,
  • Valerian Schuster,
  • Chaojie Cheng,
  • Harald Milsch and
  • Erik Rybacki

We experimentally determined the hydraulic properties of fractures within various rock types, focusing on a variety of Variscan rocks. Flow-through experiments were performed on slate, graywacke, quartzite, granite, natural fault gouge, and claystone...

  • Article
  • Open Access
1 Citations
2,065 Views
14 Pages

19 November 2023

Long-term erosion of granite—a type of hard rock—by hydrothermal fluids and tectonic movement can lead to a fragmentation of the internal structure of the original rock, transfer/replacement of mineral elements, and alteration of the rock...

  • Article
  • Open Access
4 Citations
1,783 Views
12 Pages

29 October 2022

The magnetic susceptibility measured in an alternating field is made up of in-phase and out-of-phase components. The in-phase Anisotropy of Magnetic Susceptibility (ipAMS) measures the bulk response of all minerals in a sample; however, out-of-phase...

  • Review
  • Open Access
11 Citations
4,714 Views
56 Pages

27 August 2021

A holistic-modular approach has been taken to study the evolution of three straight to low-sinuosity drainage systems (=SSS) in an uplifted basement block of the Central European Variscides. The development of the SSS is described by means of a quadr...

  • Article
  • Open Access
1,681 Views
17 Pages

26 March 2024

Potassium (K), thorium (Th), and uranium (U) are good markers of magmatic or alteration processes and the surface concentrations of these radioelements can be mapped at the regional or local scale through radiometric (gamma) surveys. In this study, a...

  • Article
  • Open Access
2 Citations
2,799 Views
26 Pages

30 May 2024

Freixo de Numão (FNG) and Capinha (CG) granites are prominent intrusions in the Douro Group (northern Central Iberian Zone, CIZ) and Beiras Supergroup (southern CIZ) metasediments, respectively. U-Pb dating revealed crystallization ages of 306...

  • Article
  • Open Access
5 Citations
5,326 Views
28 Pages

3 December 2019

Following a regional reconnaissance stream sediment survey that was carried out in the northern Vosges Mountains in 1983, a total of 20 stream sediment samples were collected with the aim of assessing the regional prospectivity for the granite-hosted...

  • Article
  • Open Access
16 Citations
6,712 Views
23 Pages

Naturally Occurring Asbestos (NOA) in Granitoid Rocks, A Case Study from Sardinia (Italy)

  • Federico Lucci,
  • Giancarlo Della Ventura,
  • Alessandra Conte,
  • Manuela Nazzari and
  • Piergiorgio Scarlato

10 October 2018

All six minerals defined as “asbestos” by the existing regulation on asbestos hazard, i.e., actinolite, tremolite, anthophyllite, crocidolite and amosite amphiboles, and the serpentine-group mineral chrysotile are typical constituents of...

  • Article
  • Open Access
12 Citations
4,863 Views
24 Pages

Passive Structural Control on Skarn Mineralization Localization: A Case Study from the Variscan Rosas Shear Zone (SW Sardinia, Italy)

  • Fabrizio Cocco,
  • Antonio Attardi,
  • Matteo Luca Deidda,
  • Dario Fancello,
  • Antonio Funedda and
  • Stefano Naitza

21 February 2022

The case study presented here deals with the Pb-Zn-Cu skarn ores hosted in the Rosas Shear Zone (RSZ), a highly strained domain located in the external zone of the Sardinian Variscan chain. The RSZ is characterized by several tectonic slices of Cambr...

  • Article
  • Open Access
32 Citations
10,487 Views
29 Pages

The existence of pieces of the Variscan belt in the Alpine basement has been acknowledged for a long time but the correlation of these massifs to the litho-tectonic domains established in Western Europa outside the Alpine chain is still disputed. Due...

  • Review
  • Open Access
3 Citations
3,995 Views
30 Pages

Post-Collisional Tectonomagmatic Evolution, Crustal Reworking and Ore Genesis along a Section of the Southern Variscan Belt: The Variscan Mineral System of Sardinia (Italy)

  • Stefano Naitza,
  • Leonardo Casini,
  • Fabrizio Cocco,
  • Matteo Luca Deidda,
  • Antonio Funedda,
  • Alfredo Loi,
  • Giacomo Oggiano and
  • Francesco Secchi

4 January 2024

Since the early Paleozoic, numerous metallogenic events produced in the Sardinian massif a singular concentration of mineral deposits of various kinds. Among them, the Variscan metallogenic peak represents a late Paleozoic phase of diffuse ore format...

  • Article
  • Open Access
10 Citations
3,982 Views
19 Pages

Episodic Precipitation of Wolframite during An Orogen: The Echassières District, Variscan Belt of France

  • Loïs Monnier,
  • Jérémie Melleton,
  • Olivier Vanderhaeghe,
  • Stefano Salvi,
  • Philippe Lach,
  • Olivier Bruguier,
  • Anissa Benmammar,
  • Laurent Bailly,
  • Didier Béziat and
  • Eric Gloaguen

26 August 2021

Monazite and rutile occurring in hydrothermally altered W mineralizations, in the Echassières district of the French Massif Central (FMC), were dated by U-Pb isotopic systematics using in-situ Laser ablation-inductively coupled plasma–quadrupole mass...

  • Article
  • Open Access
22 Citations
11,513 Views
19 Pages

24 June 2021

The origin and evolution of granites remain a matter of debate and several approaches have been made to distinguish between different granite types. Overall, granite classification schemes based on element concentrations and ratios, tectonic settings...

  • Article
  • Open Access
23 Citations
5,068 Views
29 Pages

Late-Variscan granitoid rocks of trondhjemitic and granitic composition, intruded in migmatitic paragneisses in the north-eastern Peloritani Mountains (southern Italy) at ~310 Ma and ~300 Ma, respectively, exhibit a range of deformation microstructur...

  • Article
  • Open Access
2 Citations
4,651 Views
16 Pages

24 January 2019

On the coastline of Northern Portugal, metamorphic formations and pegmatites were the subject of structural analysis with the main goal of understanding Variscan kinematics and related pegmatite intrusion. This study also aims to discriminate, select...

  • Article
  • Open Access
3 Citations
2,090 Views
13 Pages

Spherical crystals in minerals from prismatine-bearing rock from Waldheim, including ultrahigh-pressure (UHP) minerals such as stishovite and coesite, were previously described in uncommon crustal environments. To determine if this was an outlier phe...

  • Article
  • Open Access
10 Citations
3,132 Views
31 Pages

The Serre Batholith in Central Calabria (southern Italy) represents the intermediate portion of a continuous cross-section of late Variscan continental crust. The various granitoid units of the batholith were emplaced at depths between 23 and 6 km th...

  • Article
  • Open Access
7 Citations
3,809 Views
21 Pages

27 January 2021

A comprehensive study of monazite–cheralite–huttonite solid solutions (s.s.) and xenotime from the highly evolved, strongly peraluminous P–F–Li-rich Podlesí granite stock in the Krušné Hory Mts., Czech Republic, indicates that, with the increasing de...

  • Review
  • Open Access
35 Citations
3,683 Views
31 Pages

23 October 2020

The application of zircon dating to the reconstruction of orogenic systems is invaluable since time constraints of the geological evolution of orogens are crucial for the proposal of geodynamic and paleogeographic models. Zircon is one of the most pr...

  • Article
  • Open Access
246 Views
15 Pages

Geochemistry and U-Pb Geochronology of Late Paleozoic Magmatism in a Part of the Western Balkan Zone, NW Bulgaria

  • Nikolay Bonev,
  • Petyo Filipov,
  • Tanya Stoylkova,
  • Tzvetomila Vladinova and
  • Hristiana Georgieva

7 January 2026

The Rzhanski granitoid pluton and Ignatitsa diorite porphyry bodies are considered Late Paleozoic in age, belonging to the Western Balkan Zone (WBZ) in Northwestern Bulgaria. Here, we provide U-Pb zircon geochronology of these magmatic bodies, togeth...

  • Article
  • Open Access
12 Citations
5,146 Views
23 Pages

Release, Migration, Sorption, and (Re)Precipitation of U during Peraluminous Granite Alteration under Oxidizing Conditions in Central Portugal

  • Marina M. S. Cabral Pinto,
  • Maria M. V. G. Silva,
  • Ana M. R. Neiva,
  • Fernanda Guimarães and
  • Paulo B. Silva

In this work, in order to study the release, migration, sorption, and (re)precipitation of uranium (U) during alteration under oxidizing conditions, we carried out a systematic study using scanning electron microscopy, X-ray maps, and electron microp...

  • Article
  • Open Access
780 Views
16 Pages

Geochemistry and Th–U–Total Pb Chemical Ages of Late Variscan Uranium Mineralisation at Shkhara, Greater Caucasus

  • Franziska D. H. Wilke,
  • Avtandil Okrostsvaridze,
  • David Bluashvili and
  • Rabi Gabrielashvili

9 September 2025

We present the chemical composition and the U-Pb chemical age of the recently discovered uranium mineralisation occurrence in the crystalline Shkhara Massif in the Greater Caucasus. The mineralisation consists of hydrothermal uraninites from veins th...

  • Review
  • Open Access
26 Citations
7,403 Views
37 Pages

Fluid Processes of Wolframite-Quartz Vein Systems: Progresses and Challenges

  • Pei Ni,
  • Wen-Sheng Li,
  • Jun-Yi Pan,
  • Jian-Ming Cui,
  • Kai-Han Zhang and
  • Yan Gao

12 February 2022

Wolframite-quartz vein-type tungsten deposits constitute the world’s major tungsten resources and are integral to tungsten production. A major share of this mineralization product is found in Southeast China, with other significant resources in...

  • Article
  • Open Access
26 Citations
6,692 Views
27 Pages

Multiple Generations of Wolframite Mineralization in the Echassieres District (Massif Central, France)

  • Loïs Monnier,
  • Stefano Salvi,
  • Jérémie Melleton,
  • Laurent Bailly,
  • Didier Béziat,
  • Philippe de Parseval,
  • Sophie Gouy and
  • Philippe Lach

17 October 2019

The Echassières district in central France contains complex rare-element ore deposits, whose formation is related to exotic igneous events and several hydrothermal episodes that are not entirely understood to date. Tungsten mineralization cons...

  • Article
  • Open Access
1 Citations
1,060 Views
24 Pages

26 March 2025

This study focuses on the Fourque massif, one of the thirty Variscan plutons outcropping along the Axial zone of the Pyrenees. It hosts a significant tungsten deposit that was actively mined until 1986. However, since the closure of the mine, no deta...

  • Article
  • Open Access
2,099 Views
31 Pages

16 March 2024

The Messejana–Plasencia great dyke (MPGD) is a Late Triassic tholeiitic gabbro intrusion related to the Central Atlantic Magmatic Province. Its large outcrop extent (~530 km), combined with its prolongation below the Duero basin (additional 100...

  • Article
  • Open Access
2 Citations
3,539 Views
30 Pages

Geological and Geochemical Characterization of Variscan Pegmatites in the Sidi Bou Othmane District, Central Jebilet Province, Morocco

  • Amina Wafik,
  • Nouamane El Aouad,
  • Youssef Daafi,
  • Yousra Morsli,
  • Marouane Chniouar,
  • Rosalda Punturo,
  • Aida Maria Conte,
  • Daniela Guglietta and
  • Wissale Aba Sidi

The Sidi Bou Othmane (SBO) pegmatite district is situated in the Central Jebilet massif, Western Meseta domain, Morocco. The SBO district is hosted essentially in a volcano-sedimentary series composed of Late-Devonian Sarhlef shales. Pegmatite bodies...

  • Article
  • Open Access
12 Citations
3,476 Views
18 Pages

28 February 2021

Exotic crystalline blocks within the Outer Carpathian flysch have the potential to establish the nature of their eroded basement source(s) and thus to reconstruct the paleogeography of the Outer Carpathians. Petrological investigations (including min...

  • Review
  • Open Access
21 Citations
4,994 Views
34 Pages

Compositional Variations in Apatite and Petrogenetic Significance: Examples from Peraluminous Granites and Related Pegmatites and Hydrothermal Veins from the Central Iberian Zone (Spain and Portugal)

  • Encarnación Roda-Robles,
  • Pedro Pablo Gil-Crespo,
  • Alfonso Pesquera,
  • Alexandre Lima,
  • Idoia Garate-Olave,
  • Enrique Merino-Martínez,
  • Joana Cardoso-Fernandes and
  • Jon Errandonea-Martin

1 November 2022

Apatite can be used as an archive of processes occurring during the evolution of granitic magmas and as a pegmatite exploration tool. With this aim, a detailed compositional study of apatite was performed on different Variscan granites, pegmatites an...

  • Article
  • Open Access
2,104 Views
31 Pages

28 September 2024

This study presents an updated interpretation of geological data collected between 1984 and 2022. The area under consideration holds significant regional importance as it is located between the Internal Nappe Zone (INZ) and the Regional Mylonitic Com...

  • Article
  • Open Access
11 Citations
6,030 Views
42 Pages

19 June 2020

Panasqueira is a world-class W-Sn-Cu lode-type deposit located in Portugal. It consists of a dense swarm of subhorizontal quartz lodes criss-crossed by several ENE–WSW and N–S fault zones, bordering Late Variscan granite and hosted in Late Ediacaran—...

  • Article
  • Open Access
431 Views
18 Pages

Zircon U-Pb Dating and Geological Significance of Late Paleozoic Intrusive Rocks in the Khanbogd-Erdene Area, Southern Mongolia

  • Chao Fu,
  • Jun-Jian Li,
  • Shuai Zhang,
  • Peng Ji,
  • Zhi-Cai Dang,
  • Si-Yuan Li and
  • Naidansuren Tungalag

23 November 2025

The Khanbogd-Erdene region in southern Mongolia is a globally important copper–polymetallic metallogenic province, hosting large to super-large deposits, such as Oyu Tolgoi and Tsagaan Suvarga. The area experiences frequent tectonic–magma...

  • Article
  • Open Access
3 Citations
3,289 Views
51 Pages

Mineralogy and Origin of Vein Wolframite Mineralization from the Pohled Quarry, Havlíčkův Brod Ore District, Czech Republic: Interaction of Magmatic and Basinal Fluids

  • Zdeněk Dolníček,
  • Jana Ulmanová,
  • Luboš Vrtiška,
  • Karel Malý,
  • Michaela Krejčí Kotlánová and
  • Rostislav Koutňák

14 June 2024

Mineralogy and formation conditions were studied in a newly found vein wolframite mineralization, cutting migmatitized paragneisses in the exocontact of a small Carboniferous granite body in the Pohled quarry, Moldanubian Zone of the Bohemian Massif,...

  • Article
  • Open Access
6 Citations
3,528 Views
30 Pages

Fluid Evolution of Greisens from Krupka Sn-W Ore District, Bohemian Massif (Czech Republic)

  • Michaela Krejčí Kotlánová,
  • Zdeněk Dolníček,
  • Miloš René,
  • Walter Prochaska,
  • Jana Ulmanová,
  • Jaroslav Kapusta,
  • Vlastimil Mašek and
  • Kamil Kropáč

11 January 2024

The Sn-W ore deposits in the Krupka surroundings are associated with greisens, which occur in the upper parts of Late Variscan granitoid intrusions. Fluid inclusions were studied in samples of quartz, cassiterite, apatite, fluorite, and topaz in grei...

  • Article
  • Open Access
12 Citations
3,736 Views
11 Pages

Water-Rock Interaction and Potential Contamination Risk in a U-Enriched Area

  • Margarida Antunes,
  • Rui Teixeira,
  • Teresa Albuquerque,
  • Teresa Valente,
  • Paula Carvalho and
  • António Santos

The Picoto mining area is in the village of Vilar Seco (Viseu), central Portugal. Mineralization occurs mainly in quartz veins with meta-torbernite and uranophane and some U-bearing minerals, cutting a Variscan granite. Exploitation took place in two...

  • Article
  • Open Access
6 Citations
4,288 Views
27 Pages

The Lanthanide “Tetrad Effect” as an Exploration Tool for Granite-Related Rare Metal Ore Systems: Examples from the Iberian Variscan Belt

  • Ivo Martins,
  • António Mateus,
  • Michel Cathelineau,
  • Marie Christine Boiron,
  • Isabel Ribeiro da Costa,
  • Ícaro Dias da Silva and
  • Miguel Gaspar

24 August 2022

Highly fractionated granites and related magmatic-hydrothermal ore-forming processes can be traced by elemental ratios such as Nb/Ta, K/Rb, Y/Ho, Sr/Eu, Eu/Eu*, Zr/Hf, and Rb/Sr. The lanthanide “tetrad effect” parameter (TE1,3) can also b...

  • Feature Paper
  • Article
  • Open Access
4 Citations
3,266 Views
21 Pages

Uranyl Minerals from Abandoned Podgórze Mine (Sudetes Mountains, SW Poland) and Their REE Content

  • Marcin Daniel Syczewski,
  • Rafał Siuda,
  • Jan Rohovec,
  • Šárka Matoušková and
  • Jan Parafiniuk

28 February 2022

The Podgórze uranium deposit is located near Kowary in the Sudetes Mountains, SW Poland. The mine is located in the Karkonosze-Izera block, largely comprising Cambrian to Devonian metamorphic rocks intruded by the Variscan Karkonosze granite. Uranyl...

  • Review
  • Open Access
2 Citations
2,324 Views
28 Pages

Perspectives for High-Purity Quartz from European Resources

  • Kalyani Mohanty,
  • Pura Alfonso,
  • Josep Oliva,
  • Carlos Hoffmann Sampaio and
  • Hernan Anticoi

16 October 2025

High-purity quartz (HPQ) is a critical raw material for advanced technologies including semiconductors, photovoltaic cells, and optical fibers. This study reviews the geological occurrence, beneficiation routes, and strategic significance of HPQ with...

  • Article
  • Open Access
18 Citations
4,430 Views
26 Pages

12 November 2020

Abundant Li-Cs-Ta aplite-pegmatite dykes were emplaced in the western Central Iberian Zone of the Iberian Massif during the Variscan Orogeny. Their origin and petrogenetic relationships with the widespread granitoids have led to a currently rekindled...

  • Article
  • Open Access
4 Citations
3,355 Views
24 Pages

Unique Association of Sulphosalts from the Kľačianka Occurrence, Nízke Tatry Mts., Slovak Republic

  • Jiří Sejkora,
  • Martin Števko,
  • Jaroslav Pršek,
  • Róbert Hovorič,
  • Emil Makovicky and
  • Martin Chovan

14 September 2021

Unique association of sulphosalts was discovered at the Kľačianka occurrence, Nízke Tatry Mts., Slovak Republic. It is bound to thin hydrothermal veins with Sb mineralization hosted by the Variscan muscovite-biotite granodiorite and granite of Prašiv...

  • Article
  • Open Access
1 Citations
1,870 Views
40 Pages

The western side of the Vertiskos Unit crystalline basement in northern Greece is fringed by a Permo–Triassic low-grade metamorphic volcano-sedimentary complex that belongs to the Circum-Rhodope Belt (CRB), which is an important part of the Var...

  • Feature Paper
  • Article
  • Open Access
3 Citations
5,425 Views
30 Pages

Trace Element Geochemistry of Alluvial TiO2 Polymorphs as a Proxy for Sn and W Deposits

  • Miguel Gaspar,
  • Nuno Grácio,
  • Rute Salgueiro and
  • Mafalda Costa

30 September 2022

The Segura mining field, the easternmost segment of the Góis–Panasqueira–Segura tin–tungsten metallogenic belt (north–central Portugal), includes Sn-W quartz veins and Li-Sn aplite-pegmatites, which are believed to be genetically related to Variscan...

  • Review
  • Open Access
40 Citations
8,145 Views
31 Pages

Spanish Bentonites: A Review and New Data on Their Geology, Mineralogy, and Crystal Chemistry

  • Emilia García-Romero,
  • Eva María Manchado,
  • Mercedes Suárez and
  • Javier García-Rivas

11 November 2019

A review and a synthesis of the geological, mineralogical, and crystal chemical data available in the literature on active Spanish bentonitic exploitations were done, and at the same time, new data are provided from a set of representative samples fr...

  • Proceeding Paper
  • Open Access
2,011 Views
9 Pages

The Buenaventura Sector of the San Finx W–Sn Deposit (NW Spain): Ore Mineralogy, Host Rocks and Associated Hydrothermal Alteration

  • David Garófano-Medina,
  • Mercedes Fuertes-Fuente,
  • Antonia Cepedal and
  • Agustín Martin-Izard

The San Finx W–Sn ore deposit is located in the Spanish province of A Coruña (Galicia, NW Spain). Geologically, it occurs in the Galicia-Trás-os-Montes zone which is one of the innermost zones of the Iberian Variscan collisional belt. This ore deposi...

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