Mode of formation of gold-bearing mineralization on top of the boboras (Galicia, Spain) - The combined role of mechanical instabilities, strain localization and vein formation.

Eric Gloaguen (1) , Alain Chauvet (2) , Yannick Branquet (1) , Vincent Bouchot (3) , J.L. Vigneresse (4)

1 ISTO - Institut des Sciences de la Terre d'Orléans
2 LDL - Laboratoire Dynamique de la Lithosphère
3 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
4 G2R - Géologie et gestion des ressources minérales et énergétiques

The Galician Hercynian segment constitutes the core of the Ibero-Armorican orogenic arc, characterized by few tectonic units that record three main phases of deformation (D1 to D3). Four generations of granite, syn- to post-D3 intruded the major tectonic units. From older to younger, we find: i) syn-kinematic biotite-rich granodiorite (G1); ii) syn-kinematic two micas granites (G2) ; iii) biotite-dominant granites (G3) and iii) late-kinematic biotite-rich granodiorite (G4). Numerous sills, dykes and vein systems are widespread within the metasediments of the para-autochton unit. Gold-bearing quartz veins were spatially associated with G3 granites likely the Boborás intrusion, concerned by this work. The Boborás granite (G3) outcrops as a small NS-elongated elliptical intrusion. Granite is homogeneous and exhibits an equigranular texture composed of quartz, oligoclase, microcline, biotite dominant and muscovite.

Domains: Mineralogy

Eric Gloaguen, Alain Chauvet, Yannick Branquet, Vincent Bouchot, J.L. Vigneresse. Mode of formation of gold-bearing mineralization on top of the boboras (Galicia, Spain) - The combined role of mechanical instabilities, strain localization and vein formation.. Colloque Transmet, Jul 2006, Nancy, France. pp.131-134. ⟨hal-00107404⟩