Visean and Permian Sn-Nb-Ta Metallogeny in the Iberian Variscan Belt: insights from the Golpejas Rare-Metal granite
Abstract
The Golpejas Rare-Metal Granite (GRMG) is an atypical Variscan intrusion characterized by its sheet-like geometry, limited thickness, and remarkably rapid cooling (<210 years). Subsequent structural rotation (>90°) during D2–D3 deformation inverted the system, repositioning the original apical zone into the footwall. LA-ICP-MS U–Pb geochronology identifies two metallogenic stages: a syn-magmatic disseminated Nb–Ta–Sn event (ca. 340 Ma) and a Permian hydrothermal overprint (ca. 290 Ma) characterized by quartz–montebrasite–cassiterite–wodginite–tapiolite veins. Geochemical modeling links the GRMG to a coeval tourmaline-bearing leucogranite, whereas subsolidus re-equilibration temperatures (<470 °C) indicate emplacement of a near-water-saturated melt at ∼220 MPa (∼8 km). At the margins, combined thermal and chemical quenching promoted muscovite crystallization and preferential precipitation of columbite group minerals (CGM), but not cassiterite. Conversely, in the core, continued crystallization induced second boiling, exsolving a magmatic fluid responsible for albitization and phosphatization, and a subordinate hydrosaline liquid (HSL). Interaction with these fluids produced multiple CGM generations through selective dissolution and reprecipitation. Consequently, whole-rock Ta/Nb evolution reflects mixing among CGM generations rather than fractional crystallization. Finally, late-stage kaolinization nearly doubled Nb–Ta grades through mass loss. These results demonstrate that economically significant Nb–Ta enrichment resulted from the coupled effects of fractional crystallization, chemical quenching and exsolved magmatic fluids, with fluid-mediated redistribution ultimately exerting the dominant control over deposit-scale Nb–Ta enrichment. This genetic model also identifies kaolinized zones, phosphatized domains, muscovite-rich margins and tourmaline-bearing granites as favorable exploration targets.
Related
- Indium-Rich Sulfides in the Iberian Pyrite Belt: Evidence from Variscan Syn-Tectonic Remobilization in the Lagoa Salgada VMS Deposit
- Northward Redistribution of Warm-Affinity Marine Fauna in the Iberian Atlantic: Insights from a Recent Northern Occurrence of the Hermit Crab Dardanus calidus.
- Coupled U–Pb geochronology of inherited and detrital zircon in the Iberian Massif: insights into its deep structure and geodynamic evolution
- Evolution and Structure of the European Variscan Lithospheric Mantle
- A remnant of the Palaeotethys break-up: The Variscan Chamrousse ophiolite (Western Alps)
BibTeX
@article{llorensgonzalez2026visean,
title = {{Visean and Permian Sn-Nb-Ta Metallogeny in the Iberian Variscan Belt: insights from the Golpejas Rare-Metal granite}},
author = {Teresa Llorens-González and Francisco López-Moro and Rubén Díez Fernández and Susana Timón-Sánchez and Teresa Sánchez García and José Mediato Arribas and Agustina Fernández Fernández and Patrick Carr and Christophe Ballouard and Alejandro Díez Montes},
journal = {Ore Geology Reviews},
year = {2026},
month = oct,
doi = {10.1016/j.oregeorev.2026.107561},
url = {https://hal.science/hal-05779402v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Visean and Permian Sn-Nb-Ta Metallogeny in the Iberian Variscan Belt: insights from the Golpejas Rare-Metal granite
AU - Teresa Llorens-González
AU - Francisco López-Moro
AU - Rubén Díez Fernández
AU - Susana Timón-Sánchez
AU - Teresa Sánchez García
AU - José Mediato Arribas
AU - Agustina Fernández Fernández
AU - Patrick Carr
AU - Christophe Ballouard
AU - Alejandro Díez Montes
PY - 2026
DA - 2026/10/08
JO - Ore Geology Reviews
DO - 10.1016/j.oregeorev.2026.107561
UR - https://hal.science/hal-05779402v1
AB - The Golpejas Rare-Metal Granite (GRMG) is an atypical Variscan intrusion characterized by its sheet-like geometry, limited thickness, and remarkably rapid cooling (<210 years). Subsequent structural rotation (>90°) during D2–D3 deformation inverted the system, repositioning the original apical zone into the footwall. LA-ICP-MS U–Pb geochronology identifies two metallogenic stages: a syn-magmatic disseminated Nb–Ta–Sn event (ca. 340 Ma) and a Permian hydrothermal overprint (ca. 290 Ma) characterized by quartz–montebrasite–cassiterite–wodginite–tapiolite veins. Geochemical modeling links the GRMG to a coeval tourmaline-bearing leucogranite, whereas subsolidus re-equilibration temperatures (<470 °C) indicate emplacement of a near-water-saturated melt at ∼220 MPa (∼8 km). At the margins, combined thermal and chemical quenching promoted muscovite crystallization and preferential precipitation of columbite group minerals (CGM), but not cassiterite. Conversely, in the core, continued crystallization induced second boiling, exsolving a magmatic fluid responsible for albitization and phosphatization, and a subordinate hydrosaline liquid (HSL). Interaction with these fluids produced multiple CGM generations through selective dissolution and reprecipitation. Consequently, whole-rock Ta/Nb evolution reflects mixing among CGM generations rather than fractional crystallization. Finally, late-stage kaolinization nearly doubled Nb–Ta grades through mass loss. These results demonstrate that economically significant Nb–Ta enrichment resulted from the coupled effects of fractional crystallization, chemical quenching and exsolved magmatic fluids, with fluid-mediated redistribution ultimately exerting the dominant control over deposit-scale Nb–Ta enrichment. This genetic model also identifies kaolinized zones, phosphatized domains, muscovite-rich margins and tourmaline-bearing granites as favorable exploration targets.
SN - 0169-1368
ER -