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<p>The NW Iberian Peninsula contains two major left-lateral intraplate fault systems: Penacova-Régua-Verin (PRV) and Manteigas-Vilariça-Bragança (MVB). These structures are considered twin faults generated during the late-Variscan orogeny and reactivated in response to Alpine shortening. Despite their conspicuous map expression (&gt; 200&#xa0;km) and implications for reconstructing the evolution of the Variscan Orogen, questions remain concerning the timing of fault activity and reactivation episodes. Our study indicates that these faults record different tectonic histories. The MVB fault experienced displacement up to 7&#xa0;km in the northern segment prior to the emplacement of the syn-tectonic granites (320–305&#xa0;Ma), possibly related to the sedimentation of San Vitero Fm (355–340&#xa0;Ma). This fault was subsequently reactivated and continued southward at its present length (maximum displacement ~ 6&#xa0;km) after the intrusion of the syn/late-tectonic granites and previous to the post-tectonic granites last pulses (297&#xa0;Ma). In contrast, the PRV became active after the intrusion of the syn/late-tectonic granites and previous to the intrusion of the last magmatic pulses (maximum displacement ~ 1,5&#xa0;km). Post-tectonic granite intrusions (299–290&#xa0;Ma), aligned along the trace of the PRV fault, are related to this fault’s end of activity. The Alpine Orogeny reactivated these structures during the Pliocene, with minor displacement for both faults (~ 1.6&#xa0;km). This study shows these faults were not coeval. The activity began in the northern sector of the MVB fault, then both faults were active during the Upper Pennsylvanian to Permian. Finally, both faults were reactivated during the Alpine shortening and are active during the Quaternary.</p> Graphical abstract <p></p>

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Multiple and differentiated reactivations of twin intraplate fault systems: Penacova-Régua-Verin and Manteigas-Vilariça-Bragança, NW Iberian Peninsula

  • 期刊论文

  • 发表日期：

    2025年9月20日

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  • Sandra González-Muñoz,
  • Fidel Martín-González

摘要

The NW Iberian Peninsula contains two major left-lateral intraplate fault systems: Penacova-Régua-Verin (PRV) and Manteigas-Vilariça-Bragança (MVB). These structures are considered twin faults generated during the late-Variscan orogeny and reactivated in response to Alpine shortening. Despite their conspicuous map expression (> 200 km) and implications for reconstructing the evolution of the Variscan Orogen, questions remain concerning the timing of fault activity and reactivation episodes. Our study indicates that these faults record different tectonic histories. The MVB fault experienced displacement up to 7 km in the northern segment prior to the emplacement of the syn-tectonic granites (320–305 Ma), possibly related to the sedimentation of San Vitero Fm (355–340 Ma). This fault was subsequently reactivated and continued southward at its present length (maximum displacement ~ 6 km) after the intrusion of the syn/late-tectonic granites and previous to the post-tectonic granites last pulses (297 Ma). In contrast, the PRV became active after the intrusion of the syn/late-tectonic granites and previous to the intrusion of the last magmatic pulses (maximum displacement ~ 1,5 km). Post-tectonic granite intrusions (299–290 Ma), aligned along the trace of the PRV fault, are related to this fault’s end of activity. The Alpine Orogeny reactivated these structures during the Pliocene, with minor displacement for both faults (~ 1.6 km). This study shows these faults were not coeval. The activity began in the northern sector of the MVB fault, then both faults were active during the Upper Pennsylvanian to Permian. Finally, both faults were reactivated during the Alpine shortening and are active during the Quaternary.

Graphical abstract