Category Archives: Dominican Rep.

Mineralogy, geochemistry and origin of karst bauxite deposits from the Reserva Fiscal Ávila, SW Dominican Republic: Mineralogy and geochemistry of the RFA karst bauxites Abstract The energy transition, which aims to reduce carbon emissions and to slow down climate change, demands an ever-increasing supply of the so-called “critical metals”. Rare-earth Elements and Yttrium (REY) are…

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…

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…

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…

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…

Geological, geochemical and mineralogical characteristics of REE-bearing Las Mercedes bauxite deposit, Dominican Republic Abstract Bauxite deposits, traditionally the main source of aluminum, have been recently targeted for their remarkable contents in rare earth elements (REE). With ƩREE (lanthanoids + Sc + Y) concentrations systematically higher than ~ 1400 ppm (av. = 1530 ppm), the Las…

Re-Os and U-Pb Geochronology of the Doña Amanda and Cerro Kiosko Deposits, Bayaguana District, Dominican Republic: Looking Down for the Porphyry Cu-Mo Roots of the Pueblo Viejo-Type Mineralization in the Island-Arc Tholeiitic Series of the Caribbean Abstract Hosted in the Early Cretaceous bimodal tholeiite volcanic series of the Los Ranchos Formation, the Doña Amanda and…

Petrogenesis of meta-volcanic rocks from the Maimón Formation (Dominican Republic): Geochemical record of the nascent Greater Antilles paleo-arc Abstract Metamorphosed basalts, basaltic andesites, andesites and plagiorhyolites of the Early Cretaceous, probably pre-Albian, Maimón Formation, located in the Cordillera Central of the Dominican Republic, are some of the earliest products of the Greater Antilles arc magmatism.…

The accumulation of Ni in serpentines and garnierites from the Falcondo Ni-laterite deposit (Dominican Republic) elucidated by means of μXAS Abstract Ni-bearing serpentines and garnierites (Ni-bearing Mg-phyllosilicates) are the main Ni ores in the Falcondo Ni-laterite deposit (Dominican Republic). In the present paper a set of garnierite samples and the associated Ni-bearing serpentines with characteristic…

Fibrous Platinum-Group Minerals in “Floating Chromitites” from the Loma Larga Ni-Laterite Deposit, Dominican Republic Abstract This contribution reports on the observation of enigmatic fibrous platinum-group minerals (PGM) found within a chromitite body included in limonite (“floating chromitite”) from Ni-laterites in the Dominican Republic. Fibrous PGM have a Ru-Os-Ir-Fe dominated composition and are characterized by fibrous…

Supergene neoformation of Pt-Ir-Fe-Ni alloys: multistage grains explain nugget formation in Ni-laterites Abstract Ni-laterites from the Dominican Republic host rare but extremely platinum-group element (PGE)-rich chromitites (up to 17.5 ppm) without economic significance. These chromitites occur either included in saprolite (beneath the Mg discontinuity) or as ‘floating chromitites’ within limonite (above the Mg discontinuity). Both…

High-pressure greenschist to blueschist facies transition in the Maimón Formation (Dominican Republic) suggests mid-Cretaceous subduction of the Early Cretaceous Caribbean Arc Abstract The Maimón Formation (Cordillera Central, Dominican Republic) is formed of metamorphosed bi-modal mafic-felsic volcanic rocks and sedimentary horizons of Early Cretaceous age deposited in the forearc of the nascent Caribbean island arc. Two…