Boletín de la Sociedad Geológica Mexicana
Volumen 68, núm. 3, 2016, p. 443‒475
Geoquímica del magmatismo mesozoico asociado al Margen Continental Pasivo en el occidente y centro de Cuba
Esther María Cruz Gámez1,*, Fernando Velasco Tapia2, Antonio García Casco1, Ana Ibis Despaigne Díaz3, José Francisco Lastra Rivero2, Damaso Cáceres Govea2
1 Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra, Ex-Hacienda de Guadalupe, Carretera Linares-Cerro Prieto km 8, C.P. 67700, Linares, N.L., México.
2 Universidad de Pinar del Río, Facultad de Ciencias Técnicas, Martí 270, 20100, Pinar del Río, Cuba.
3 Universidad de Granada, Departamento de Mineralogía y Petrología, Instituto Andaluz de Ciencias de la Tierra (UGR-CSIC), Avenida Fuentenueva s/n, 18079, Granada, España.
Jurassic to Cretaceous stratigraphic sequences of Passive Continental Margin (PCM) have been described in several localities of the Mesoamerican region. In Cuba these rocks are widely exposed, being constituted by carbonate and siliciclastic rocks. Magmatic (hyaloclastite, basalt, diabase, and gabbro) and meta-magmatic (metavolcanics, metagabbro, amphibolite, and eclogite) lithologies occur intercalated within these geological sequences. This magmatic activity has been related to the fragmentation of Pangea (in a rift-drift process) and the initial development of the proto-Caribbean oceanic basin. In this work, based on the interpretation of an extensive petrographic and geochemical database (considering published information as well as data generated during this study), a conceptual model is proposed for the PCM magmatism distributed along the Guaniguanico Cordillera and the Pinos and Escambray metamorphic terranes: (a) in a Continental Margin Ridge setting, probably during the Lower Jurassic (?) to Upper Jurassic (Middle/Upper Oxfordian), E-MORB-type magmatism was produced from an enriched mantle; (b) N-MORB-type magma was erupted (produced by partial melting of a depleted mantle) when the ocean opened sufficiently for steady-state spreading to be established, without the influence of a plume system. This magmatism peaked in the Upper Oxfordian - Early Kimmerigdian?; (c) sills and dykes of N-MORB-type magmas also intruded syn-rift sedimentary sequences, explaining the occurrence of this type of magmatism in the earliest deposited sequences of the passive margin (e.g., Loma La Gloria and Arroyo Cangre formations); and (d) E-MORB-type magmatism occurred during late Lower Cretaceous to basal Upper Cretaceous (e.g., Yaguanabo and El Tambor formations), probably linked to the Caribbean margin. The majority of magmatic and sedimentary PMC lithologies were metamorphosed during the Upper Campanian and afterward exhumed in the Maastrichtian - Early Paleocene period.
Keywords: Cuba, Mesozoic Magmatism, Continental Pasive Margin, MORB.