Boletín de la Sociedad Geológica Mexicana Volumen 72, núm. 3, A200720, 2020 http://dx.doi.org/10.18268/BSGM2020v72n3a200720

Mineralogy and geochemistry of Fe-Ti oxide ores from the Don Dieguito massif-type anorthosite suite, Sierra Nevada de Santa Marta, Colombia

Mineralogía y geoquímica de las menas de óxidos de Fe-Ti en la anortosita de Don Dieguito, Sierra Nevada de Santa Marta, Colombia

Sebastián Betancur-Figueroa^1,2, Cristina Villanova-de-Benavent*^,2, Joaquín A. Proenza²,

Marion B. Weber¹, Natalia Acevedo¹, Antonio García-Casco³

¹ Departamento de Geociencias y Medio Ambiente, Facultad de Minas, Universidad Nacional de Colombia, Avenida 80 # 65-223, 050034, Medellín, Colombia.

² Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona, C/ Martí i Franquès s/n, 08028, Barce­lona, Spain.

³ Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada, Avda. Fuent­enueva s/n, 18002 Granada, Spain.

* Corresponding author: (C. Villanova-de-Benavent) This email address is being protected from spambots. You need JavaScript enabled to view it.

How to cite this article:

Betancur-Figueroa, S., Villanova-de-Benavent, C., Proenza, J.A., Weber, M.B., Acevedo, N., García-Casco, A., 2020, Mineralogy and geochemistry of Fe-Ti oxide ores from the Don Dieguito massif-type anorthosite suite, Sierra Nevada de Santa Marta, Colombia: Boletín de la Sociedad Geológica Mexicana, 72 (3), A200720. http://dx.doi.org/10.18268/BSGM2020v72n3a200720

Abstract

Fe-Ti oxide ores are commonly associated with Proterozoic massif-type anorthosite bodies emplaced during the Grenville orogeny (~1.2-1.0 Ga). Some of these anorthositic bodies occur in the northernmost part of the Santa Marta Massif, Colombia. They locally contain crosscutting Fe-Ti(-V) ore bodies between the El Hierro creek and the Don Dieguito river. We have distinguished two types of Fe-Ti(-V) ores: i) oxide-apatite norite (fine grained ilmenite and magnetite disseminated in an assemblage of apatite, amphibole, chlorite, rutile and sericitized plagioclase) and ii) banded nelsonite (coarser grained ilmenite, magnetite and apatite distributed in bands, with minor baddeleyite, srilankite and högbomite). Ilmenite in the two ore types display distinct hematite exsolution features: a)needle-like in the oxide-apatite norite ore; and b) two generations of exsolutions in the banded ore. Magnetite shows similar Ti and V contents in both ore types (0.4 wt % TiO₂ and 0.5 wt % V₂O₃ on average in the oxide-apatite norite ore, 0.5 wt % TiO₂ and 0.4 wt % V₂O₃ in the banded ore), whereas ilmenite has higher hematite, pyrophanite and geikielite components in the banded ore. The ores might have formed from the combination of fractional crystallization and magma mixing, with exsolution occurring probably at 575-600°C. This first detailed mineralogical and textural study of Fe-Ti(-V) oxide ores in anorthosite massifs from Colombia suggests that the Santa Marta Massif is an interesting target for future research.

Keywords: Fe-Ti oxide ores, V, exsolution, titanoferous hermatite, ilmenite, magnetite, massif anorthosite, nelsonite.