@misc{10481/55405,
year = {2018},
month = {10},
url = {http://hdl.handle.net/10481/55405},
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 assemblage of phases in ophiolitic chromitites of the Caribbean. We
studied the Mercedita chromitite deposit in the eastern Cuban ophiolitic complexes. The mineral
phases were characterized using microRaman spectroscopy, energy-dispersive spectroscopy with a
scanning electron microscope (SEM-EDS), X-ray microdiffraction and electron microprobe analyses.
Mineral concentrates were prepared using hydroseparation techniques. We have identified oriented
clinopyroxene lamellae in chromite, oriented rutile lamellae in chromite, moissanite hosted in the
altered matrix of the chromitite, graphite-like amorphous carbon, corundum and SiO2 hosted in
healed fractures in chromite grains, and native Cu and Fe–Mn alloy recovered in heavy-mineral
concentrates obtained by hydroseparation. This assemblage may correspond to UHP-SuR conditions,
implying recycling of chromitite in the mantle or formation of the chromite grains at deep mantle
depths, followed by emplacement at a shallow level in the mantle. However, the chromitite bodies
contain gabbro sills oriented parallel to the elongation of the chromitite lenses, and these show
no evidence of HP/UHP metamorphism. Therefore, the identified “exotic” phases may not be
indicative of UHP. They formed independently as oriented clinopyroxene lamellae in chromite during
cooling (clinopyroxene and rutile), in super-reduced microenvironments during the serpentinization
processes, and by transference of subducted crustal material to the mantle wedge via cold plumes.},
organization = {This research was financially supported by the Spanish Project CGL2015-65824 granted by the Spanish
“Ministerio de Economía y Competitividad” to J.A.P., the Ramón y Cajal Fellowship RYC-2015-17596 to J.M.G.-J.
and a FPU Ph.D grant to N.P.-S. by the Ministerio de Educación of the Spanish Government.},
publisher = {MDPI},
keywords = {Moissanite},
keywords = {Inclusions},
keywords = {Mercedita},
keywords = {Serpentinization},
keywords = {Super-reducing conditions},
keywords = {Chromitites},
keywords = {Ophiolites},
keywords = {Cuba},
title = {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)},
author = {Pujol Solà, N. and Proenza, Joaquín A. and García Casco, Antonio and González Jiménez, José María and Andreazini, Aleu and Melgarejo, Joan Carles and Gervilla Linares, Fernando},
}