Late Variscan tectonic orogenic collapse as a trigger for Sn-W mineralizing systems. U-Pb ore geochronology across the Martinamor gneissic dome (Salamanca, Spain)
[EN]Regional tectonothermal evolution is a primary factor for many mineral deposits formation. Late orogenic gravitational collapse has been widely recognized across different orogens, including the Variscan belt. The Martinamor gneissic dome is a well constrained structure related to the late-Varis...
| Autores: | , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad de Salamanca (USAL) |
| Repositorio: | GREDOS. Repositorio Institucional de la Universidad de Salamanca |
| OAI Identifier: | oai:gredos.usal.es:10366/166845 |
| Acceso en línea: | http://hdl.handle.net/10366/166845 |
| Access Level: | acceso abierto |
| Palabra clave: | U-Pb geochronology cassiterite and wolframite Gneissic dome Extensional detachment Central Iberian zone Variscan gravitational collapse Central Iberian Arc orocline Heat advection Iberian Massif |
| Sumario: | [EN]Regional tectonothermal evolution is a primary factor for many mineral deposits formation. Late orogenic gravitational collapse has been widely recognized across different orogens, including the Variscan belt. The Martinamor gneissic dome is a well constrained structure related to the late-Variscan orogenic collapse in the Iberian Massif. We have investigated Sn-W mineralization spatially related to the Martinamor dome by LA-ICPMS U-Pb dating of cassiterite and wolframite, revealing a wide mineralization timespan of 40 Myr. Our results show: a) an early (338.1 ± 5.8 Ma), minor mineralization phase, (W-dominated), potentially related to Variscan compressive phases; b) a second, major stage which lasted from 324.1 ± 5.9 to 300.7 ± 5.4 Ma, which includes Sn-bearing pegmatites and Sn-W veins formed under the syn-collisional extensional collapse. Structural evidence highlights the role of extensional detachments in channeling mineralizing fluids and creating suitable traps under ductile and ductile–brittle conditions; it also explains the temporal and spatial distribution of the Sn-W vein-type mineralizations in the zone. Comparisons with other Variscan deposits in the Iberian Massif and European counterparts suggest a regional metallogenic cycle linked to late-Variscan extensional collapse, heat advection, and crustal partial melting processes. These findings underscore the Martinamor dome as a unique structure recording a protracted Variscan tectono-magmatic-metallogenic event, with implications for understanding Sn-W deposit formation in orogenic settings. |
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