Nanoscale constraints on the in situ transformation of Ru–Os–Ir sulfides to alloys at low temperature Abstract We report new results of a combined focused ion beam high-resolution transmission electron microscopy (FIB/HRTEM) investigation of two grains of platinum-group minerals (PGM) corresponding to the laurite (RuS2)-erlichmanite (OsS2) solid solution series. The grains are included within unaltered chromite…
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2020: Ophiolite hosted chromitite formed by supra-subduction zone peridotite –plume interaction
Ophiolite hosted chromitite formed by supra-subduction zone peridotite –plume interaction Abstract Chromitite bodies hosted in peridotites typical of suboceanic mantle (s.l. ophiolitic) are found in the northern and central part of the Loma Caribe Peridotite in the Cordillera Central of the Dominican Republic. These chromitites are massive pods of small size (less than a few…
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2020: The Petrologic Nature of the “Medellín Dunite” Revisited: An Algebraic Approach and Proposal of a New Definition of the Geological Body
The Petrologic Nature of the “Medellín Dunite” Revisited: An Algebraic Approach and Proposal of a New Definition of the Geological Body Abstract The “Medellín Dunite”, the main ultramafic body of the Central Cordillera of Colombia, constitutes a fragment of oceanic lithospheric mantle formed at a back–arc basin/incipient arc scenario emplaced onto the western continental margin…
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2020: Fe-Ti-Zr metasomatism in the oceanic mantle due to extreme differentiation of tholeiitic melts (Moa-Baracoa ophiolite, Cuba)
Fe-Ti-Zr metasomatism in the oceanic mantle due to extreme differentiation of tholeiitic melts (Moa-Baracoa ophiolite, Cuba) Abstract Ti-rich amphibole, Mg-rich ilmenite, baddeleyite, zirconolite, srilankite, and zircon are important high-field-strength elements (HFSE) bearing phases in the Potosí chromitite bodies located in the Moho Transition Zone of the Cretaceous Moa-Baracoa suprasubduction zone ophiolite (eastern Cuba). Such HFSE-bearing…
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2020: Precious metals in magmatic Fe-Ni-Cu sulfides from the Potosí chromitite deposit, eastern Cuba
Precious metals in magmatic Fe-Ni-Cu sulfides from the Potosí chromitite deposit, eastern Cuba Abstract We report new results of a combined focused ion beam and high-resolution transmission electron microscopy (FIB/HRTEM) investigation of platinum-group elements (PGE)-rich base-metal sulfides. The Ni-Fe-Cu base-metal sulfides (BMS) studied are millerite (NiS), pentlandite [(Ni,Fe)9S8], pyrite (FeS2), and chalcopyrite (CuFeS2). These BMS…
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2019: Nanoscale partitioning of Ru, Ir, and Pt in base-metal sulfides from the Caridad chromite deposit, Cuba
Nanoscale partitioning of Ru, Ir, and Pt in base-metal sulfides from the Caridad chromite deposit, Cuba Abstract We report new results of a combined focused ion beam and high-resolution transmission electron microscopy (FIB/HRTEM) investigation of platinum-group elements (PGE)-rich base-metal sulfides. The Ni-Fe-Cu base-metal sulfides (BMS) studied are millerite (NiS), pentlandite [(Ni,Fe)9S8], pyrite (FeS2), and chalcopyrite…
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2019: Ni-bearing phyllosilicates (“garnierites”): New insights from thermal analysis, micro-Raman and IR spectroscopy
Ni-bearing phyllosilicates ("garnierites"): New insights from thermal analysis, micro-Raman and IR spectroscopy Abstract Ni-Mg-phyllosilicates, so-called “garnierites”, are significant Ni ores in Ni-laterite deposits worldwide. In addition, they are the natural analogues of synthetic catalysts involving Ni and phyllosilicate substrates used in reactions for the remediation of greenhouse gases. However, the nomenclature, classification and characterisation of…
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2019: Forum Reply A shallow origin for diamonds in ophiolitic chromitites
Forum Reply A shallow origin for diamonds in ophiolitic chromitites ---------------------------------------------------------------------------------------------------------- To Cite this article: Farré-de-Pablo, J.; Proenza, J.A.; González-Jiménez, J.M.; Garcia-Casco, A.; Colás, V.; Roqué-Rossell, J.; Camprubí, A; Sánchez-Navas, A. (2019). A shallow origin for diamonds in ophiolitic chromitites. Geology, 47(8), 477-478. DOI: 10.1130/G46602Y.1
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2018: A shallow origin for diamonds in ophiolitic chromitites
A shallow origin for diamonds in ophiolitic chromitites Abstract Recent findings of diamonds in ophiolitic peridotites and chromitites challenge our traditional notion of Earth mantle dynamics. Models attempting to explain these findings involve incorporation of diamonds into chromite near the mantle transition zone. However, the occurrence of metastable diamonds in this context has not been…
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2018: A reappraisal of the metamorphic history of the Tehuitzingo chromitite, Puebla state, Mexico
A reappraisal of the metamorphic history of the Tehuitzingo chromitite, Puebla state, Mexico Abstract The Tehuitzingo ultramafic body (Acatlán Complex, southern Mexico) is a strongly serpentinized harburgitic body that encloses chromitite bodies and blocks of eclogitic rocks. Hydrous retrograde metamorphism on chromitite bodies resulted in the formation of: i) partly altered chromite char- acterized by…
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2018: The Discovery of the Romero VMS Deposit and Its Bearing on the Metallogenic Evolution of Hispaniola during the Cretaceous
The Discovery of the Romero VMS Deposit and Its Bearing on the Metallogenic Evolution of Hispaniola during the Cretaceous Abstract The recently discovered Romero deposit, located in the Tres Palmas district, Cordillera Central of the Dominican Republic, has probable reserves of 840,000 oz gold, 980,000 oz silver and 136 Mlb copper. Mineralization is hosted by…
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2018: An Alternative Scenario on the Origin of Ultra-High Pressure (UHP) and Super-Reduced (SuR) Minerals in Ophiolitic Chromitites: A Case Study from the Mercedita Deposit (Eastern Cuba)
An Alternative Scenario on the Origin of Ultra-High Pressure (UHP) and Super-Reduced (SuR) Minerals in Ophiolitic Chromitites: A Case Study from the Mercedita Deposit (Eastern Cuba) Abstract The origin of the assemblage of ultra-high pressure (UHP), super-reduced (SuR) and several crustally derived phases in ophiolitic chromitites is still hotly debated. In this paper, we report, for the first time, this…
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Call for papers, Special issue: Mineral deposits of Latin America and the Caribbean
Call for papers, Special issue: Mineral deposits of Latin America and the Caribbean The "Boletín de la Sociedad Geológica Mexicana" is intending to publish a special issue on Mineral Deposits of Latin America and the Caribbean (BSGM, http://boletinsgm.igeolcu.unam.mx/bsgm/). The BSGM is a completely free access semi-annual journal, the oldest strictly peer-reviewed journal on Earth Sciences in…
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2018: Cold plumes trigger contamination of oceanic mantle wedges with continental crust-derived sediments: Evidence from chromitite zircon grains of eastern Cuban ophiolites
Cold plumes trigger contamination of oceanic mantle wedges with continental crust-derived sediments: Evidence from chromitite zircon grains of eastern Cuban ophiolites Abstract The origin of zircon grains, and other exotic minerals of typical crustal origin, in mantle-hosted ophiolitic chromitites are hotly debated. We report a population of zircon grains with ages ranging from Cretaceous (99…
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2017: The recycling of chromitites in ophiolites from southwestern North America
The recycling of chromitites in ophiolites from southwestern North America Abstract Podiform chromitites occur in mantle peridotites of the Late Triassic Puerto Nuevo Ophiolite, Baja California Sur State, Mexico. These are high-Cr chromitites [Cr# (Cr/Cr + Al atomic ratio = 0.61–0.69)] that contain a range of minor- and trace-elements and show whole-rock enrichment in IPGE…
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2018: Recycling in the subduction factory: Archaean to Permian zircons in the oceanic Cretaceous Caribbean island-arc (Hispaniola)
Recycling in the subduction factory: Archaean to Permian zircons in the oceanic Cretaceous Caribbean island-arc (Hispaniola) Abstract Little mineralogical evidence is left of the recycling of continental and oceanic crust into the mantle at subduction zones. Zircon, because of its exceptional robustness, is probably the only surviving phase and the best mineral tracer of this…
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2017: 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-laterite
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-laterite Abstract 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…
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2017: Reactive transport model of the formation of oxide-type Ni-laterite profiles (Punta Gorda, Moa Bay, Cuba)
Reactive transport model of the formation of oxide-type Ni-laterite profiles (Punta Gorda, Moa Bay, Cuba) Abstract Oxide-type Ni-laterite deposits are characterized by a dominant limonite zone with goethite as the economically most important Ni ore mineral and a thin zone of hydrous Mg silicate-rich saprolite beneath the magnesium discontinuity. Fe, less soluble, is mainly retained…
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2017: The recycling of chromitites in ophiolites from southwestern North America
The recycling of chromitites in ophiolites from southwestern North America Podiform chromitites occur in mantle peridotites of the Late Triassic Puerto Nuevo Ophiolite, Baja California Sur State, Mexico. These are high-Cr chromitites [Cr# (Cr/Cr + Al atomic ratio = 0.61–0.69] that contain a range of minor- and trace-elements and show whole-rock enrichment in IPGE (Os, Ir, Ru). These features…
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2017: Towards a unified genetic model for the Au-Ag-Cu Pueblo Viejo district, central Dominican Republic
Towards a unified genetic model for the Au-Ag-Cu Pueblo Viejo district, central Dominican Republic Abstract The origin of the world-class Pueblo Viejo deposit, central Dominican Republic, remains controversial. In this article we scale up the area of study to the Cabirma del Cerro mining concession, which abuts the Pueblo Viejo mining area, and integrate new…
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