Accéder directement au contenu Accéder directement à la navigation
Pré-publication, Document de travail

pXRF measurements on soil samples in the vicinity of a W deposit and Nb-Ta prospect: example from the Echassières district (France)

Abstract : In order to face the challenges of mineral exploration in inhabited areas, portable XRF (pXRF) is gaining attention as a low-footprint exploration technique. To evaluate it, we revisited historic mining districts, simulating grassroots exploration with pXRF, within the UpDeep project under EIT-RM EU funding. A specific attention was given to strategic metals and mineral resources. A first study on a Sb district was presented at AIMS 2019 (Lemiere et al., 2019). The second study was led around an historic W and kaolin district (Echassières, central France) where modern Nb-Ta-Li exploration is going on in an agricultural and forested area. We performed top soil sampling (Ah and B horizons) along profiles to understand better the endogenic geochemical anomaly signals. The survey, limited to a fraction of the mining area, succeeded in recognising fault-controlled anomalies of several types (Cu-Sn-As, Fe-As) besides the cupola type W-Sn-As anomalies. Li and Be being beyond pXRF capabilities were not targeted. Despite of an expected bias with laboratory analyses, pXRF measurements effectively located the various mineralised structures, thanks to their multi-element capabilities. Composition data processing (CoDa) and horizon-selective sampling significantly improved the efficiency of the method. On-site measurements allow dynamic sampling and mapping, helping laboratory sample selection for further investigations. The very high As background extending beyond mineralised areas is actually controlled by a NNE-SSW faults system. It can be used as a guide to possible fertile structures, but also to barren ones. The main Sn-W anomalies are located along a known structure, but much beyond previous mining works. Cu-Sn anomalies along another structure seem to confirm the location of ancient mining works.
Type de document :
Pré-publication, Document de travail
Liste complète des métadonnées

https://hal-brgm.archives-ouvertes.fr/hal-02479091
Contributeur : Bruno Lemiere <>
Soumis le : vendredi 14 février 2020 - 12:18:53
Dernière modification le : jeudi 14 mai 2020 - 18:28:01
Archivage à long terme le : : vendredi 15 mai 2020 - 15:23:33

Fichiers

Lemiere_AIMS2020.pdf
Fichiers produits par l'(les) auteur(s)

Identifiants

  • HAL Id : hal-02479091, version 1

Collections

Citation

Bruno Lemiere, P Sarala, Anne-Sophie Serrand, Eric Gloaguen, Eric Fournier, et al.. pXRF measurements on soil samples in the vicinity of a W deposit and Nb-Ta prospect: example from the Echassières district (France). 2020. ⟨hal-02479091⟩

Partager

Métriques

Consultations de la notice

28

Téléchargements de fichiers

14