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Petrogenesis of the chromitite body from the Cerro Colorado Ophiolite, Paraguana Peninsula, Venezuela

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doi: 10.18268/BSGM2020v72n3a280719
Authors:Mendi, David J.; González-Jiménez, José María; Proenza, Joaquín Antonio; Urbani, Franco; Gervilla, Fernando
Author Affiliations:Primary:
Universidad de Granada, Departmento de Mineralogía y Petrología, Granada, Spain
Pontifical Catholic University of Peru, Peru
Recursos del Caribe, United States
Universitat de Barcelona, Spain
Universidad Central de Venezuela, Venezuela
Volume Title:Mineral deposits of Latin America and the Caribbean
Volume Authors:Proenza, Joaquín Antonio, editor; Torró, Lisard; Nelson, Carl E.
Source:Mineral deposits of Latin America and the Caribbean, edited by Joaquín Antonio Proenza, Lisard Torró and Carl E. Nelson. Boletín de la Sociedad Geológica Mexicana, 72(3). Publisher: Sociedad Geológica Mexicana, Mexico, D.F., Mexico. ISSN: 0366-1784
Publication Date:2020
Note:In English with English and Spanish summaries. 126 refs.; illus., incl. 4 tables, strat. col., geol. sketch maps, sects.
Summary:Ultramafic-mafic rocks of ophiolitic affinity crop out along the Venezuelan Caribbean region. They have been interpreted as remnants of the oceanic lithosphere of the Caribbean volcanic arc (135-70 Ma) as well as relicts of proto-Caribbean oceanic lithosphere (Upper Jurassic-Lower Cretaceous) related to Pangea's break-up. The Cerro Colorado ophiolite, located in the Paraguaná Peninsula, together with the case of the Cordillera de la Costa in north-central Venezuela, are a unique case of these Venezuelan ophiolites containing chromitite bodies. However, the petrogenesis of such a mafic-ultramafic complex and associated chromite ore remains are unknown to date. To advance our understanding of chromite ores in the Caribbean region, the genesis of the Cerro Colorado chromitite body is challenged. The Cerro Colorado chromitite body is characterized by a low-Cr content [Cr# =Cr/ Cr+Al= 0.44-0.60] and a distribution of trace elements in chromite as is typical of high-Al chromitites found in the shallower portions of the petrological Moho Transition Zone of Mesozoic ophiolites. The calculated melts in equilibrium with chromite forming this high-Al chromitite body are back-arc basin basalts. These melts were extracted after ∼20 % partial melting of moderately depleted peridotites, which resulted in the precipitation of high-Al chromitite relatively impoverished in PGE (≤ 100 ppb total PGE). A comparison of the geochemical signatures of minor and trace elements in chromite and bulk-PGE contents of the Cerro Colorado chromitite with those of other known chromitites in the peri-Caribbean ophiolites show certain similitude with those high-Al described in the Moa-Baracoa ophiolite in eastern Cuba. The obtained results allow us to suggest that the ultramafic rocks of the Cerro Colorado and the chromitite body associated with it are closely related to the formation of a back-arc basin developed between ca. 125-120 Ma in the rear of the Great Antilles Arc.
Subjects:Aluminum; Back-arc basins; Basalts; Basins; Chromite; Chromitite; Cretaceous; Depletion; Dunite; Electron probe data; Fore-arc basins; Genesis; Harzburgite; ICP mass spectra; Igneous rocks; Lithosphere; Lower Cretaceous; Mantle; Mass spectra; Melts; Mesozoic; Metals; Mid-ocean ridge basalts; Mohorovicic discontinuity; Oceanic lithosphere; Ophiolite; Oxides; Paleoenvironment; Paleogeography; Partial melting; Peridotites; Platinum group; Plutonic rocks; Precipitation; Spectra; Tholeiitic composition; Trace elements; Transition zones; Ultramafics; Volcanic arcs; Volcanic rocks; Antilles; Caribbean region; Falcon Venezuela; Greater Antilles; Paraguana Peninsula; South America; Venezuela; West Indies; Cerro Colorado Ophiolite
Coordinates:N100000 N120000 W0620000 W0700000
Record ID:897043-2
Copyright Information:GeoRef, Copyright 2021 American Geosciences Institute.
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