Thermal peak detected in gold-bearing shear zones by a thermo-structural study: a new tool to retrieve fluid flow?

Gaétan Link (1) , Olivier Vanderhaeghe (1) , Didier Béziat (1) , Michel de Saint Blanquat (1) , Margot Munoz (1) , Guillaume Estrade (1) , Laurent Guillou-Frottier (2, 3, 4) , Eric Gloaguen (2, 3) , Abdeltif Lahfid (2) , Jérémie Melleton (2)

1 GET - Géosciences Environnement Toulouse
2 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
3 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
4 Géodynamique - UMR7327

Gold mineralizations of the northern part of the Canigou massif (Eastern Pyrenees, France) are localized along regional-scale shear zones. These structures connect the upper metapelitic greenschist facies unit (suprastructure) to the lower migmatitic unit (infrastructure) and are attributed to the late-Variscan tectonic evolution transposing earlier structures. Raman spectroscopy of carbonaceous materials (RSCM) approach documents thermal anomalies in these shear zones with a temperature peak [20-100 °C] above the host rocks values. These thermal anomalies are interpreted as recording the upward circulation of a hot fluid. These data point to gold mobilization and transfer controlled by localized deformation and fluid flow at the end of the Variscan orogeny. The nature and origin of the mineralizing fluids, the source(s) of gold, and the mechanisms of ore mobilization-transfer-deposition remain to be determined.

Mots clés: Gold deposits; Fluid flow; Thermal Convection; Variscan Pyrenees

Domaines: Planète et Univers [physics]; Sciences de la Terre; Pétrographie; Tectonique

Gaétan Link, Olivier Vanderhaeghe, Didier Béziat, Michel de Saint Blanquat, Margot Munoz, et al.. Thermal peak detected in gold-bearing shear zones by a thermo-structural study: a new tool to retrieve fluid flow?. 15th SGA Biennal Meeting on Life with Ore Deposits on Earth, Society for Geology Applied to Mineral Deposits, Aug 2019, Glasgow, United Kingdom. pp.260-263. ⟨hal-02552421⟩