"Garnierite" ore and Ni-serpentine mineralizations from the Falcondo Ni-laterite deposit (Dominican Republic): an approach from quantitative XR element imaging
Abstract
”Garnierites” and Ni-serpentines are the main Ni ores in hydrous silicate-type Ni-laterites. In the Falcondo Ni-laterite, “garnierites” are found within the saprolite horizon mainly as fracture-fillings and thin coatings on joints. Different greenish colours are distinguished, which correspond to different mineral phases, according to XRD: talc-like (10 Å-type), serpentine-like (7 Å-type), a mixture of talc- and serpentine-like, and sepiolite-like. Compositional data suggest continuous solid solution along the joints lizardite-népouite/chrysotile-pecoraite, kerolite-pimelite and sepiolite-falcondoite. In general, talc-like “garnierites” display higher Ni contents than serpentine-like. Deviations from serpentine and talc stoichiometric compositions are due to 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 relations between textural position, sequence of crystallization and mineral composition of the studied “garnierite” samples. These results indicate several stages of growth with strongly variable Ni content, pointing to recurrent changes in the physical-chemical conditions of “garnierite” dissolution- precipitation in an aqueous medium
Keywords: “garnierite”; Ni-laterite; Dominican Republic; quantitative XR element imaging
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To Cite this article: Villanova-de-Benavent, C., Proenza, J.A., Galí, S., Tauler, E., García-Casco, A., Lewis, J.F., Longo, F. (2013): "Garnierite" ore and Ni-serpentine mineralizations from the Falcondo Ni-laterite deposit (Dominican Republic): an approach from quantitative XR element imaging. Mineral Deposit Research For A High-Tech World, 1-4 ,379-382. Edited by: Jonsson, E.
