Title of the Project:

The enigmatic PGE-bearing nanofibers from the Loma Larga Ni-Laterite Deposit (Dominican Republic) - Do they have a geomicrobiological origin?

Name of the Group:

Mineral Resources Research Group

Short description of the project:

Enigmatic fibrous platinum-group minerals (PGM) were found within a chromitite body included in limonite from Ni-laterites in the Dominican Republic. These fibrous PGM have a Ru-Os-Ir-Fe dominated composition and are characterized by fibrous textures with grain-forming fibers which are significantly longer (1–5 µm) than wide (~100 nm). These fibrous PGM show numerous complex textures on its surface which are suggestive for neoformation processes: (i) features suggesting growth of platinum-group elements (PGE)-bearing nanofibers; (ii) occurrence of PGM nanoparticles within film material (biofilm?) associated with PGE-bearing nanofibers; (iii) a Si-rich and crater-like texture hosting PGM nanoparticles and an Ir-rich accumulation of irregular shape; (iv) complex PGM nanoparticles with ragged morphologies, resembling sponge spicules and (v) oval forms (<1 µm in diameter) with included PGM nanoparticles, similar to those observed in experiments with PGE-reducing bacteria. This study aims to deploy TEM and FIB techniques to characterize these PGM nanofibers to further asses the mobility of PGE linked to bio-weathering processes in tropical soils.

Contact person:

Dr. Josep Roqué Rosell, josep.roque@ub.edu