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Os isotope heterogeneity of the upper mantle: Evidence from the Mayarí-Baracoa ophiolite belt in eastern Cuba Abstract In an attempt to quantify the extent of geochemical heterogeneity within a restricted and well dated portion of the upper mantle, 27 chromite separates from the 90 My old chromite deposits in the Mayar-Baracoa ophiolite belt in eastern…

Petrogenesis of highly depleted peridotites and gabbroic rocks from the Mayarí-Baracoa Ophiolitic Belt Abstract The Moa-Baracoa and Mayarí-Cristal massifs (eastern Cuba) are two ophiolitic complexes mainly constituted by harzburgite tectonites and minor dunites, cut by gabbroic dykes. The Moa-Baracoa massif exhibits a well developed Moho transition zone and an incomplete crustal section made up of…

Platinum group minerals in ophiolitic chromitites from Tehuitzingo (Acatlán complex, southern Mexico): implications for post-magmatic modification Abstract Podiform chromitite bodies occur in serpentinites at Tehuitzingo (Acatlán complex, southern Mexico). Serpentinite and chromitite are believed to represent a fragment of Paleozoic ophiolitic mantle formed in a supra-subduction zone setting. The ophiolitic mantle sequence is associated with…

High pressure metamorphism of ophiolites in Cuba Abstract High-pressure metamorphic complexes of ophiolitic material in Cuba trace the evolution of the northern margin of the Caribbean Plate during the Mesozoic. In the northern ophiolite belt of western and central Cuba, these complexes document cold (i.e., mature) subduction of oceanic lithosphere. Age data indicate subduction during…

Distribution of platinum-Group elements and Os isotopes in chromite ores from Mayarí-Baracoa Ophiolitic Belt (eastern Cuba) Abstract The Mayarí-Baracoa ophiolitic belt in eastern Cuba hosts abundant chromite deposits of historical economic importance. Among these deposits, the chemistry of chromite ore is very variable, ranging from high Al (Cr#=0.43-0.55) to high Cr (Cr#=0.60-0.83) compositions. Platinum-group element…

Paleozoic serpentine-enclosed chromitites from Tehuitzingo (Acatlán Complex, SW Mexico): a petrological and mineralogical study Abstract The serpentinites and associated chromitite bodies in Tehuitzingo (Acatlán Complex, southern Mexico) are in close relationship with eclogitic rocks enclosed within a metasedimentary sequence, suggesting that the serpentinites, chromitites and eclogitic rocks underwent a common metamorphic history. Primary chromites from…

D, O and C isotopes in podiform chromitites as fluid tracers for hidrotermal alteration processes of the Mayarí-Baracoa Ophiolitic Belt Abstract The Mayarí — Baracoa Ophiolitic Belt (MBOB, eastern Cuba) is composed of two large, chromite-rich massifs: Mayarí —Cristaland Moa-Baracoa. The chromitites and hosting dunites were firstly affected by a regional serpentinization event, a subsequent…

Source of ore-forming fluids in El Cobre VHMS deposit (Cuba): evidence from fluid inclusions and sulfur isotopes Abstract The El Cobre deposit, east of Cuba, lies in the intermediate volcanosedimentary sequence of the Sierra Maestra intraoceanic island arc. The structure of the deposit corresponds to that of a volcanogenic-hosted massive sulfide (VHMS) model. It comprises…

To Cite this article: Proenza, J.A., Melgarejo, J.C., Gervilla, F.(2003): Comments on the paper “Ocherous laterite: a nickel ore from Punta Gorda, Cuba” by Oliveira et al. Journal of South American Earth Sciences, 16, 199-202.

Metabasites from the northern serpentinite belt (Cuba) and a metamorphic perspective of the plate tectonic models for the Caribbean region Abstract The analysis of metamorphosed magmatic rocks along the northern serpentinite belt (Cuba) suggest a variety of tectonic settings of formation and metamorphism. Slightly deformed coherent bodies of metabasites from Cajálbana (western Cuba) and Iguará-Perea…

Oscillatory zoning in eclogitic garnet and amphibole, Northern Serpentinite Melange, Cuba: a record of tectonic instability during subduction? Abstract Exotic blocks of eclogite from distant localities along the Northern Serpentinite Melange of Cuba have comparable P–T histories that include high-pressure prograde sections (450–600 °C, >15 kbar) associated with subduction of oceanic lithosphere, and retrograde sections within the albite–epidote…

High-grade metamorphism and hydrous melting of metapelites in the Pinos terrane (W Cuba): Evidence for crustal thickening and extension in the northern Caribbean collisional belt Abstract The Pinos terrane (Isle of Pines, W Cuba) is a coherent metamorphic complex that probably represents a portion of the continental margin of the Yucatan Block during the Mesozoic.…

Genesis of sulfide-rich chromite ores by the interaction between chromitite and pegmatitic olivine-norite dikes in the Potosí Mine (Moa-Baracoa ophiolitic massif, eastern Cuba) Abstract The Potosí Mine is located in the Moa-Baracoa massif in the easternmost part of the Cuban Ophiolitic Belt. Chromite mineralization occurs within the mantle–crust transition zone. Two events of magma intrusion…

Uvarovite in podiform chromitites: the Moa-Baracoa ophiolitic massif, Cuba Abstract The chromitite pods of the Moa-Baracoa massif, in the eastern ophiolitic belt of Cuba, contain pre-existing gabbro sills. This association is affected by two processes of hydrothermal alteration. The chromitites and the hosting dunites and harzburgites are affected first by regional serpentinization; a second alteration,…