Serpentinites and serpentinites within a fossil subduction channel: La Corea mélange, eastern Cuba

A variety of metaultramafic (serpentinite) rocks in La Corea mélange, Sierra de Cristal, eastern Cuba, show differences in chemical, textural and mineralogical characteristics demonstrating a variety of protoliths. The mélange originated during the Cretaceous as part of the subduction channel associ...

Full description

Saved in:
Bibliographic Details
Published in:Acta geologica hispanica 2011-01, Vol.9 (3-4), p.389-405
Main Authors: Blanco Quintero, I.F., Proenza Fernández, Joaquín Antonio, García Casco, Antonio, Tauler, Esperança, Galí Medina, Salvador
Format: Article
Language:English
Subjects:
Caribbean
Cretaceous
Cuba
High pressure
Island arcs
La Corea Mélange
Metamorphism
Mineralogy
Plate tectonics
Rocks
Serpentinita
Serpentinite
Subduction Channel
Tectònica de plaques
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A variety of metaultramafic (serpentinite) rocks in La Corea mélange, Sierra de Cristal, eastern Cuba, show differences in chemical, textural and mineralogical characteristics demonstrating a variety of protoliths. The mélange originated during the Cretaceous as part of the subduction channel associated with the Caribbean island arc. This mélange contains high pressure blocks in a serpentinite matrix and occurs at the base of the large tabular Mayarí-Cristal ophiolite. Two principal groups of serpentinites have been identified in the mélange: a) antigorite serpentinite, mainly composed of antigorite and b) antigorite-lizardite serpentinite, composed of mixtures of antigorite and lizardite and bearing distinctive porphyroblasts of diopsidic clinopyroxene. Antigorite serpentinites are closely related to tectonic blocks of amphibolite (representing subducted MORB) and constitute deep fragments of the serpentinitic subduction channel formed during hydration of the mantle wedge. The composition of the antigorite-lizardite serpentinites and the presence of clinopyroxene porphyroblasts in this type of rock suggest that abyssal lherzolite protoliths transformed into serpentinite before and during incorporation (as tectonic blocks) in the shallow part of the subduction channel. Although the studied rocks have different origin, mineralogical compositions and textures, they display similar PGE compositions, suggesting that these elements experienced no significant redistribution during metamorphism. Both types of serpentinites were exposed together in the La Corea mélange during the Late Cretaceous, during obduction of the overriding Mayarí-Baracoa ophiolitic belt that led to exhumation of the subduction channel (mélange)
ISSN:1695-6133
0567-7505
1696-5728
DOI:10.1344/105.000001662