Stable Isotopes (Li, O, H) Combined with Brine Chemistry: Powerful Tracers for Li Origins in Salar Deposits from the Puna Region, Argentina

Beate Orberger (1) , Walter Rojas (2) , Romain Millot (3) , Christine Flehoc (3)

1 ERAMET - ERAMET
2 Eramine Sudamerica SA
3 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

Future improving of the innovative technology of Lithium air batteries correlates with an increased demand for Liresources. We analyzed and compared stable isotopic compositions from 4 Argentinean Li rich salars. The Pozuelos (PS), Centenario (CN), Ratones (RT) and Hombre Muerte (HM) belong to the world class brine resources of the Atacama triangle. CN has a halite core surrounded by fine grained clastic sediments, while RT comprises lesser evaporates, but coarser grained volcanoclastics. Two Cl-Na SO 4 brine aquifers (down to 250 m depth) host several hundreds of mg/l of Li. The surface waters are characterized by Li < 7 mg/l, 7 Li of ≈ 9.5, D:-66 ‰ and 18 O SMOW:-7.8 ‰. The stable isotopic composition differs slightly from the upper aquifer (7 Li ≈9.2 ‰, D-47.2 ‰ and 18 O SMOW-0.8 ‰) to the lower aquifer (7 Li: 9.7 ‰, D:-51.6 ‰ and 18 O SMOW:-1.7 ‰). The dominant source of Li is related to water-rock interactions (surface, saline waters with andesites, pegmatites, pyroclastics). The comparison of our RT and CN data to those of the close-by PS and HM, shows that each salars has its own geological, hydrological and climate history which can be defined by crossing isotope tracers. However, the development of pertinent isotopic regional and local exploration proxies, needs identical data sets on systematically defined samples of the same aquifer type, on country rocks and minerals. .

Mots clés: Lithium isotopes; oxygen and hydrogen isotopes; brine; salar; Argentina

Domaines: Sciences de la Terre

Beate Orberger, Walter Rojas, Romain Millot, Christine Flehoc. Stable Isotopes (Li, O, H) Combined with Brine Chemistry: Powerful Tracers for Li Origins in Salar Deposits from the Puna Region, Argentina. Procedia Earth and Planetary Science, 2015, 13, pp.307 - 311. ⟨10.1016/j.proeps.2015.07.072⟩. ⟨hal-03701115⟩