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Communication dans un congrès
Greisenisation and Permeability Changes in Granitic Intrusions Related to Sn-W Deposits: Case of Panasqueira
Abstract : The W-Sn veins of Panasqueira are connected with a massive quartz-muscovite greisen cupola. This greisen results from interactions between granitic rock and acid Sn-W hydrothermal fluid, which causes the destruction of feldspars of the Panasqueira granite. Greisenisation can constitute an important factor of control on fluid flow, and its role on metal transport remains to be established. Mineral reactions of greisenisation involve a decrease of the rock volume and thus an increase porosity (~6%). Consequently permeability increases significantly (10-20 to 10-17 m²) enhancing fluid flow in the greisen cupola and promoting further hydrothermal alteration and transport of metals. Finally a part of the mineralization is trapped in this porosity, with precipitation of cassiterite and sulfides. Therefore, Sn-W fluids are able to generate their own pathways in initial impermeable granite via greisenisation reactions.
Littérature citée [9 références]
https://hal-brgm.archives-ouvertes.fr/hal-01520216
Contributeur : Laurent Guillou-Frottier Connectez-vous pour contacter le contributeur
Soumis le : mercredi 10 mai 2017 - 10:07:45
Dernière modification le : mardi 10 mai 2022 - 15:24:59
Contributeur : Laurent Guillou-Frottier Connectez-vous pour contacter le contributeur
Soumis le : mercredi 10 mai 2017 - 10:07:45
Dernière modification le : mardi 10 mai 2022 - 15:24:59
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