• Aucun résultat trouvé

Gold as tracer of fluid flow during exhumation of the Variscan orogenic root in the Canigou massif (Eastern Pyrénées, France)

N/A
N/A
Protected

Academic year: 2021

Partager "Gold as tracer of fluid flow during exhumation of the Variscan orogenic root in the Canigou massif (Eastern Pyrénées, France)"

Copied!
2
0
0

Texte intégral

(1)

HAL Id: hal-02096033

https://hal-brgm.archives-ouvertes.fr/hal-02096033

Submitted on 11 Apr 2019

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Gold as tracer of fluid flow during exhumation of the Variscan orogenic root in the Canigou massif (Eastern

Pyrénées, France)

Gaétan Link, Olivier Vanderhaeghe, Didier Béziat, Laurent Guillou-Frottier, Eric Gloaguen, Jérémie Melleton

To cite this version:

Gaétan Link, Olivier Vanderhaeghe, Didier Béziat, Laurent Guillou-Frottier, Eric Gloaguen, et al..

Gold as tracer of fluid flow during exhumation of the Variscan orogenic root in the Canigou massif

(Eastern Pyrénées, France). EGU General Assembly 2019, Apr 2019, Vienne, Austria. pp.2019 -

15490. �hal-02096033�

(2)

Geophysical Research Abstracts Vol. 21, EGU2019-15490, 2019 EGU General Assembly 2019

© Author(s) 2019. CC Attribution 4.0 license.

Gold as tracer of fluid flow during exhumation of the Variscan orogenic root in the Canigou massif (Eastern Pyrénées, France)

Gaétan Link (1), Olivier Vanderhaeghe (1), Didier Béziat (1), Laurent Guillou-Frottier (2), Eric Gloaguen (2), and Jérémie Melleton (2)

(1) UMR 5563 GET, Université Paul Sabatier-Toulouse III/CNRS/IRD/CNES, Toulouse, France ([email protected]), (2) UMR 7327 ISTO, Université d’Orléans/CNRS/BRGM, Orléans, France

Orogenic gold is attributed to element mobilization, transfer, and deposit linked to circulation of magmatic and metamorphic fluids through transcrustal fault system at a rate faster than metamorphic reactions (Ague, 2014;

Goldfarb & Groves, 2015). In order to test this model, we combine detailed structural and petrological studies of gold orebodies of the Canigou massif (Eastern Pyrénées, France) and their host rock at local and regional scales.

By using this approach, we are able to replace the time and the space scale of the fluid flow relative to the tectonic and metamorphic evolution of the orogenic crust.

The Canigou massif, characterized by a LP/HT tectonic-metamorphic event of Variscan age, exposes a migmatitic infrastructure and a weakly metamorphosed suprastructure dominated by pelitic schists. These two units are juxtaposed along a mylonitic contact associated with an attenuation of metamorphic isograds. Peak temperatures of 610

C and 450

C are obtained by RSCM in the infrastructure and suprastructure, respectively.

Transposition of the main foliation into vertical shear zones is associated with retrogression of the suprastructure at 0.15-0.35 GPa / 350-400

C. These shear zones are rooted in the migmatitic level and are associated with the collect of granitic magmas and the precipitation of quartz veins. Gold mineralizations are hosted by quartz-arsenopyrite veins, highly deformed and localized in these vertical shear zones. Quartz microstructures show a dynamic recrystallization in the ductile regime (> 400

C). The temperature of the arsenopyrite crystallization was estimated at ca. 450

C (Polizzi, 1990). Although the ore-forming fluid flow is coeval with the retrograde metamorphism event, the temperature of the fluid circulation in the veins is higher than the temperature conditions of the host rock.

Based on these data, we propose that the gold-ore forming fluids circulated upward from the infrastructure

to the suprastructure through vertical shear zones during retrogression of the suprastructure and exhumation of the

infrastructure.

Références

Documents relatifs

Remarque Dans ce type de traitement, on peut assigner des serveurs dédiés pour chaque fonction, par exemple on fait désigner un serveur pour calculer le nombre d’enregistrement

Comparison of a rapid, quantitative and automated assay for urinary luteinizing hormone (LH), with an LH detection test, for the prediction of ovulation.. P.Bischof, P.G.Bianchi

Although computer-assisted surgery systems may reassure surgeons of the position of their instruments and help to minimise intra-operative uncertainty, our study showed no

As an example, we considered the case of a WIMP that would yield a relic density either too small or too large in the standard cosmological model and constrained the parameters of

Pour r´ealiser une mesure de force ` a faible distance, nous devons dans l’id´eal s´electionner un puits unique, ou ` a d´efaut, un petit nombre de puits, car la force de

The various capital asset tables in the database are tied to the visual interface using an ODBC (Open Database Connectivity) driver. This function utilizes SQL

He also observed the existance of both annular and inverted annular flow patterns at burnout. Groeneveld[5] used a similar calculation technique, but modified the