Title :

Hydrothermal niobium (Nb) mineralization and mobilization in the world-class Madeira Sn-Nb-Ta granitic deposit (Amazonas, Brazil)

Author(s) :

Bollaert, Quentin [Auteur]
Institut de minéralogie, de physique des matériaux et de cosmochimie [IMPMC]
Chassé, Mathieu [Auteur]
Institut de minéralogie, de physique des matériaux et de cosmochimie [IMPMC]
Bastos Neto, Artur [Auteur]
Universidade Federal do Rio Grande do Sul [Porto Alegre] [UFRGS]
Horbe, Adriana [Auteur]
Universidade de Brasilia [Brasília] [UnB]
Allard, Thierry [Auteur]
Institut de minéralogie, de physique des matériaux et de cosmochimie [IMPMC]
Menguy, Nicolas [Auteur]
Institut de minéralogie, de physique des matériaux et de cosmochimie [IMPMC]
Le Guillou, Corentin [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Courtin, Alexandra [Auteur]
Géosciences Paris Saclay [GEOPS]
Quantin, Cécile [Auteur]
Géosciences Paris Saclay [GEOPS]
Vantelon, Delphine [Auteur]
Synchrotron SOLEIL [SSOLEIL]
Troadec, David [Auteur]
Institut d'Électronique, de Microélectronique et de Nanotechnologie (IEMN) - UMR 8520
Galoisy, Laurence [Auteur]
Institut de minéralogie, de physique des matériaux et de cosmochimie [IMPMC]
Calas, Georges [Auteur]
Institut de minéralogie, de physique des matériaux et de cosmochimie [IMPMC]

Journal title :

Ore Geology Reviews

Volume number :

174

Pages :

106321

Publisher :

Elsevier

Publication date :

2024-11

ISSN :

0169-1368

English keyword(s) :

Niobium mineralization
Pitinga
Pyrochlore
Columbite
Hydrothermal alteration
Mobilization
Uraninite

HAL domain(s) :

Chimie/Matériaux
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]
Physique [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre

English abstract : [en]

The Madeira deposit is a world-class tin (Sn) deposit characterized by a unique mineralogical assemblage composed of a massive cryolite (NaAlF3) deposit associated with economically important metals like Nb (0.20 wt% Nb2O5). ...
Show more >The Madeira deposit is a world-class tin (Sn) deposit characterized by a unique mineralogical assemblage composed of a massive cryolite (NaAlF3) deposit associated with economically important metals like Nb (0.20 wt% Nb2O5). Although hydrothermal alteration has long been recognized in the cryolite formation, its effects on the mineralization and mobility of Nb remain obscure. This study presents new data on the Nb mineralization of the Pitinga core and border albite-enriched granites provided by nanoscale and site-selective approaches, using transmission electron microscopy and synchrotron-radiation analyses. Pyrochlore is the main Nb ore mineral with three distinct compositional types (U-Pb, Pb-U and Y-bearing varieties). Hydrothermal processes lead to the extensive alteration of pyrochlore into columbite (later designated as columbitization) by a coupled dissolution-reprecipitation mechanism, which evidences the alterability of pyrochlore in a hydrothermal context. Nanoscale analyses of veins and reaction interfaces reveal the presence of additional Nb hosts including fergusonite-(Y), Nb-bearing uraninite and Nb-bearing coffinite which formed from the alteration of pyrochlore. The nature of the altered phases mainly depends on the composition of the parent pyrochlore. Their formation, occurring in absence of direct proximity with remaining pyrochlore, shows that Nb mobilization at macroscopic scale is possible in F-rich reducing fluids. Niobium L3-edge XANES spectroscopy on bulk samples representative of the different facies show that hydrothermal processes change the Nb mineralization by converting primary U-Pb-bearing pyrochlore into columbite and Pb-U/Y-bearing pyrochlores. The columbitization process of pyrochlore led to the increase of the Nb ore grade. Nonetheless, hydrothermal alteration modified Nb mineral liberation, thereby limiting the recovery of the full range of Nb host phases.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

ANR Project :

RElation entre le Changement climatique et formation des lAtérites

Administrative institution(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

• Institut d'Électronique, de Microélectronique et de Nanotechnologie (IEMN) - UMR 8520
• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Matériaux Terrestres et Planétaires

Submission date :

2024-11-07T14:19:08Z
2024-11-08T09:50:00Z