POPE FOR AN HOUR: CRISTINA VILLANOVA-DE-BENAVENT

Title: Garnierites and garnierites: Textures, mineralogy and geochemistry of garnierites in the Falcondo Ni-laterite deposit, Dominican Republic

Lecturer: Cristina Villanova-de-Benavent

Date: Wednesday June the 18^th 2014, 12.00h

Place: room 2

Abstract: Garnierites (Ni–Mg-bearing phyllosilicates) are significant ore minerals in some Ni-laterite deposits. In the Falcondo deposit (Dominican Republic), garnierites are found as fracture-fillings and coatings on joints. Different greenish colours and textures can be distinguished, which correspond to different mineral phases, defined according to X-ray diffraction (XRD) and electron microprobe (EMP) analyses: a) talc-like, b) serpentine-like, c) a mixture of talc- and serpentine-like, and d) sepiolite-like. Compositional data indicate continuous Mg–Ni solid solution along the joins lizardite–népouite, kerolite–pimelite and sepiolite–falcondoite. EMP analyses showing deviations from the stoichiometric Mg–Ni solid solutions of serpentine and talc are best explained by talc- and serpentine-like mixing at the nanoscale. A detailed textural study by means of quantified X-ray element imaging provides a wealth of new information about the relationships between textural position, sequence of crystallization and mineral composition of the studied garnierite samples. These results indicate several stages of growth with variable Ni content, pointing to recurrent changes in the physical–chemical conditions during garnierite precipitation. In addition, our detailed mineralogical study of the Falcondo garnierites revealed that the different types identified have characteristic H₂O content and SiO₂/MgO ratios, which play important roles during the pyrometallurgy process.

For further information: Villanova-de-Benavent, C., Proenza, J.A., Galí, S., García-Casco, A., Tauler, E., Lewis, J.F., Longo, F. (2014): Garnierites and garnierites: Textures, mineralogy and geochemistry of garnierites in the Falcondo Ni-laterite deposit, Dominican Republic. Ore Geology Reviews, 58, 91-109

Pope for an hour are talks given by student members of the Barcelona SGA Student Chapter about their recently published research in SCI journals. These talks are adressed to other undergraduate or graduate students as well as to the rest of the scientific community.