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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.
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Pré-publication, Document de travail
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Contributeur : Bruno Lemiere Connectez-vous pour contacter le contributeur
Soumis le : vendredi 14 février 2020 - 12:18:53
Dernière modification le : samedi 23 juillet 2022 - 03:57:59
Archivage à long terme le : : vendredi 15 mai 2020 - 15:23:33


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  • HAL Id : hal-02479091, version 1



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⟩



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