Communication Dans Un Congrès Année : 2023

Resolving geological histories using the new facilities of K-Ar dating and clay separation at Georessources, Nancy

Marie Daoulas-Gerardin
Danièle Bartier
  • Fonction : Auteur
Michel Cathelineau
Gaétan Milesi
J. Mercadier

Résumé

Isotopic dating is a valuable method to constrain better the timing of lithospheric processes: geodynamic sequences, ore deposition and geothermal regimes. The K-Ar dating technique has the main advantage to be applied to ubiquitous K-bearing minerals that crystallize in various temperatures, from magmatic to low temperatures. We present the new analytical platform, recently developed at the GeoRessources laboratory in Nancy (France), for K-Ar dating purposes. The potassium and argon quantitative analysis protocol has been validated on three reference materials from 24.2 to 420 Ma that give an age deviation of a maximum 1% from the published data. The first application of the method is the magmatic and hydrothermal processes from the Panasqueira Region (Portugal) related to Li-(Sn-W) granites. The ages recently obtained on muscovites allow for constraining the deposition ages, completing the hydrothermal scheme. Clays are of significant interest among K-bearing minerals, considering that they are formed during various hydro thermo-dynamic processes. Reliable K-Ar ages on illite-rich fractions are based on the proper separation of the illite along with morphological, mineralogical and crystallographic information. GeoRessources is now fully equipped for clays preparation, mainly with Stokes benches and a continuous flow centrifuge. Clays particles' mineralogical, morphological, and size analyses are performed using XRD, SEM, EDS, FTIR and laser diffraction. The K-Ar dating platform, coupled with the clay laboratory, is a new asset for GeoRessources to constrain geological events' timing better. The first application of this coupling will be shown on illite-rich fractions in the well-documented uranium deposit in the Athabasca basin, Canada

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Dates et versions

hal-05245998 , version 1 (09-09-2025)

Identifiants

  • HAL Id : hal-05245998 , version 1

Citer

Marie Daoulas-Gerardin, Danièle Bartier, Michel Cathelineau, Gaétan Milesi, J. Mercadier. Resolving geological histories using the new facilities of K-Ar dating and clay separation at Georessources, Nancy. 18th International Conference on Thermochronology, Sep 2023, Riva del garda, Italy. ⟨hal-05245998⟩
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