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NOAM paleo-margin in latest Cretaceous to late Eocene times. data suggest that Cuban ophiolites include both mid-ocean-ridge
Ophiolites include serpentinized harzburgites and dunites, and supra-subduction zone types (Kerr et al., 1999; Proenza et al.,
banded and isotropic gabbros, basalts, and hyaloclastites (tholei- 2006; Marchesi et al., 2007; Lázaro et al., 2015). However, the
itic and fore-arc basalts, locally with boninitic compositions) widespread occurrence in the ophiolites of very refractory mantle
overlain by Late Jurassic (Tithonian) through Late Cretaceous peridotites as well as extrusive rocks with geochemical character-
(Coniacian and younger) oceanic sediments. Sheeted dikes and istics of island arcs indicate that the protoliths of most Cuban
isotropic gabbro are rare (Figs. 2 and 3C; Iturralde-Vinent, 1996). ophiolites formed above a subduction zone by both fore-arc and
The available petrological, geochemical, and geochronological back-arc spreading. During subduction and obduction, the

Figure 3. Outcrop photographs of some Cuban geologic units. (A) Recumbent fold in Jurassic continent-derived siliciclastics, Guaniguanico GSA TODAY | www.geosociety.org/gsatoday
terrane, Alturas de Pizarra del Norte, Pinar del Río. (B) Aptian-Albian pelagic cherts of the Proto-Caribbean seafloor. Sierra de Rosario,
Guaniguanico terrane, Pinar del Río. (C) Layered gabbros of the Moa-Baracoa Ophiolites, near Moa. (D) Block of mid-oceanic-ridge-basalt–
derived epidote-Na-Ca amphibole eclogite in serpentinite mélange (north of Santa Clara city, central Cuba). (E) Intercalated well-bedded fine-
grained green tuff with conglomerate and sandstones of the Brujas Formation (Cretaceous volcanic arc) at Palmarito Dam, south of Santa Clara.
(F) Eocene pillow basalts and green ribbon cherts of the Paleogene arc at Sierra Maestra.

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