Discovery of Ni-smectite-rich saprolite at Loma Ortega, Falcondo mining district (Dominican Republic): geochemistry and mineralogy of an unusual case of “hybrid hydrous Mg silicate – clay silicate” type Ni-lateriteShow others and affiliations
2017 (English)In: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 52, no 7, p. 1011-1030Article in journal (Refereed) Published
Abstract [en]
Hydrous Mg silicate-type Ni-laterite deposits, like those in the Falcondo district, Dominican Republic, are dominated by Ni-enriched serpentine and garnierite. Recently, abundant Ni-smectite in the saprolite zone have been discovered in Loma Ortega, one of the nine Ni-laterite deposits in Falcondo. A first detailed study on these Ni-smectites has been performed (μXRD, SEM, EPMA), in addition to a geochemical and mineralogical characterisation of the Loma Ortega profile (XRF, ICP-MS, XRD). Unlike other smectite occurrences in laterite profiles worldwide, the Loma Ortega smectites are trioctahedral and exhibit high Ni contents never reported before. These Ni-smectites may be formed from weathering of pyroxene and olivine, and their composition can be explained by the mineralogy and the composition of the Al-depleted, olivine-rich parent ultramafic rock. Our study shows that Ni-laterites are mineralogically complex, and that a hydrous Mg silicate ore and a clay silicate ore can be confined to the same horizon in the weathering profile, which has significant implications from a recovery perspective. In accordance, the classification of “hybrid hydrous Mg silicate – clay silicate” type Ni-laterite deposit for Loma Ortega would be more appropriate.
Place, publisher, year, edition, pages
Springer, 2017. Vol. 52, no 7, p. 1011-1030
National Category
Geology Geochemistry
Research subject
Applied Geochemistry
Identifiers
URN: urn:nbn:se:ltu:diva-68071DOI: 10.1007/s00126-017-0750-8ISI: 000413115400006Scopus ID: 2-s2.0-85021787688OAI: oai:DiVA.org:ltu-68071DiVA, id: diva2:1193553
2018-03-272018-03-272018-12-14Bibliographically approved