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BOLETÍN DE LA SOCIEDAD GEOLÓGICA MEXICANA 0 http://dx.doi.org/10.18268/BSGM2010v62n1a10 |
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Las cromititas del Complejo Ofiolítico de Camagüey, Cuba: un ejemplo de cromitas ricas en Al
The chromitites of the Camagüey Ophiolitic Complex, Cuba: an example of Al–rich chromitites
Saturnina Henares1*, José María González–Jiménez2, Fernando Gervilla1, Joaquín A. Proenza3, Alfonso Chang Rodríguez4, Rubén B. González–Pontón5*
1 Departamento de Mineralogía y Petrología e Instituto Andaluz de Ciencias de la Tierra (Universidad de Granada–CSIC), Facultad de Ciencias, Avda. Fentenueva s/n, 18002, Granada, España.
2 Key Centre Geochemical Evolution and Metallogeny of Continents (GEMOC), Department of Earth and Planetary Sciences, Macquarie University, Sydney NSW2109, Australia.
3 Departament de Cristal•lografía, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès s/n, 08028, Barcelona, España.
4 Cuban Geological Survey. Ave. Mónaco Este e/ 1ra y B, Edif. 38 Apto 4, Rpto. Julio A. Mella, Camagüey, Cuba.
5 Empresa Geominera de Camagüey, Carretera Central Este, km 51/2 70600, Camagüey, Cuba.
* This email address is being protected from spambots. You need JavaScript enabled to view it.
Abstract
The Camagüey Ophiolitic Complex extends along the central–eastern region of Cuba. This ophiolitic complex contains several deposits of Al–rich chromite [Cr/(Cr+Al) = 0.31–0.6] very enriched in TiO2 (up to 1 wt%) and represents the second most important mining district for refractory grade chromite in Cuba. The chromite deposits are hosted by dunite and harzburgite, spatially associated with feldspatic rocks (gabbro dikes and/or sills, troctolites and/or anorthosites) in close proximity to gabbroic cumulates at the base of the plutonic crust. The texture observed in the chromite deposits is predominantly massive, although fine disseminated, nodular and brecciated textures are also present. The interstitial silicate matrix of the chromitite consists principally of olivine and to a lesser extent pyroxenes and plagioclase. Often these silicates are altered to other secondary minerals such as serpentine, chlorite, magnetite and uvarovite–type garnet. The chromite crystals usually host small solid inclusions of the same silicates that form the matrix, Fe–, Ti– and/or Zr–rich oxides, and Fe–Ni–Cu sulphides and alloys. The above mentioned metallic minerals also occur in the interstitial silicate matrix where they record variable alteration. The structural, petrological and geochemical characteristics of the chromitites suggest formation from melts generated after reaction of basaltic melts with upper lithospheric mantle peridotites or, alternatively, as result of the assimilation of pre–existing feldspatic rocks (gabbros and troctolites) located in the shallowest upper mantle.
Keywords: Al–rich Chromitite, Ophiolitic Complex, Camagüey, Cuba.
