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ophiolites were dismembered, and exotic fault blocks from NOAM Deposits include interbedded coarse clastics and limestone,
and the Cretaceous arcs were incorporated within the deformed which in Cuba are mildly deformed and characterized by open
ophiolitic bodies. Associated strips of subduction-related mélanges folds, steeply dipping normal faults, and NE-SW strike-slip
contain high-pressure(high-P) blocks (eclogite-, amphibolite-, faults. These strata are strongly deformed only along the present
blueschist-, and high-P greenschist-facies rocks and jadeitite) in E-W transform boundary between NOAM and CARIB in south-
a serpentinite-matrix. These mélanges formed in a subduction eastern Cuba, with recumbent folds and strike slip, reverse, and
zone from 120 Ma through latest Cretaceous (65 Ma; Fig. 3D); normal faults. Following establishment of modern sea level
similar mélanges with high-P blocks occur as olistoliths within ~8000 years ago, Cuba attained roughly its present outline
the foredeep basin and as tectonic slices within the Escambray (Iturralde-Vinent, 2006).
complex (García-Casco et al., 2006; Blanco-Quintero et al., 2011;
Cárdenas-Párraga et al., 2012). RESEARCH OPPORTUNITIES

Cretaceous Arc Complexes There is much that can we learn from future studies of Cuba,
not only about the island itself but also about the tectonic

Three stages of Cretaceous island arc volcano-sedimentary and evolution of the Caribbean region and other important tectonic

plutonic rocks, separated by unconformities, are found in Cuba. processes of interest to the global geoscientific community.

Each arc sequence shows a distinct geochemical signature (Fig. 2). In the following sections, we briefly outline four promising

They are tectonically intercalated by thrust faulting with ophio­ research avenues: the Jurassic Caribbean, subduction initiation,

litic rocks and serpentinite mélanges and tectonically overlie the intra-oceanic arc-trench systems, and collision tectonics.

NOAM terranes (Figs. 1B and 2; Díaz de Villalvilla, 1997; Jurassic Caribbean
Iturralde-Vinent and Lidiak, 2006; Marchesi, et al., 2007). In

eastern Cuba (Purial complex) arc rocks metamorphosed in Better understanding of Cuban geology promises to provide
greenschist, and high-P, low-temperature blueschist-facies were important insights into the fit of Pangea and the origin of proto-
partly subducted during the latest Cretaceous (García-Casco et Caribbean strata. Pre-Mesozoic clasts are found in Eocene,
al., 2008; Lázaro et al., 2015). Arc-related granitoid plutons range Cretaceous, and Jurassic conglomerates, but the sources of these
in age from ca. 89–83 Ma in the Santa Clara province (west- and of the Jurassic siliciclastics are not well understood. For
central Cuba) and 104–75 Ma in Camagüey province (east-central example, gneiss pebbles of ca. 400 Ma age (Millán and Somin,
Cuba) (Hall et al., 2004; Rojas-Agramonte et al., 2011). 1985) and 250–220 Ma (Somin et al., 2006) occur in the Eocene

Mabujina Meta-Arc Complex El Guayabo conglomerate of the Pinar del Río region of western
Cuba. Focused studies should allow us to assign them to a source

This complex structurally underlies the non-metamorphic arc and provide a link between the Caribbean terrane and Central or

rocks in Central Cuba (Figs. 1B and 2) and is composed of deformed South America. Furthermore, some poorly investigated meta­

gabbros, basalts, basaltic andesites, and pyroclastic rocks that were sedimentary blocks engulfed in the subduction mélange may

deformed and metamorphosed into the greenschist and amphibo- sample early Atlantic–Proto-Caribbean oceanic sediments.

lite facies (Somin and Millán, 1981; Blein et al., 2003). Concordant
and crosscutting granitic-gneissic rocks occur as pre-metamorphic Subduction Initiation

(ca. 133 Ma), syn-metamorphic (ca. 93 Ma), and post-metamorphic It is important to understand how new subduction zones form.
intrusions/injections (ca. 89–83 Ma) (Grafe et al., 2001; Rojas- It has recently been suggested that emplacement of the Galapagos
Agramonte et al., 2011). Several lines of evidence suggest that the plume head formed most of the Caribbean plate, namely the
Mabujina protoliths were detached from the Pacific margin of (Caribbean Large Igneous Complex or “CLIP”), and that CLIP
North America and accreted to the base of the Cuban Cretaceous arc emplacement caused lithospheric collapse and formation of new
complex at ca. 93–91 Ma (A. García-Casco and Y. Rojas-Agramonte, subduction zones (Gerya et al., 2015), a process termed “plume-
2016, personal commun.). induced subduction initiation” (PISI). These subduction zones are

Synorogenic Basins and Paleogene Arc argued to have formed around the plume head, perhaps first
around the north at ca. 130 Ma, then around the southern,

Late Campanian to late Eocene sedimentary strata unconform- western, and northern margin at 85 ± 5 Ma. Alternatively, onset of

ably overlie Cretaceous arc and ophiolite complexes (Fig. 2) with subduction along the inter-American transform may have

clastic deposits derived from the Cretaceous igneous substrate and occurred with or without influence of the plume head. Studying

interbedded carbonates (Iturralde-Vinent, 2015). In eastern Cuba, the great Cuban ophiolite belt (Fig. 1B) provides a great opportu-

GSA TODAY | OCTOBER 2016 these deposits are interbedded laterally with Danian–middle nity to test and refine these hypotheses.

Eocene arc lavas and volcaniclastics. Paleogene intraoceanic arc Intraoceanic Arc-Trench Systems
rocks are restricted to eastern Cuba (Fig. 2). Associated inter­

mediate to felsic plutons are dated at 60.5 ± 2.2 to 46.9 ± 0.1 Ma The Cuban arc is beautifully preserved and uplifted above sea
(Cazañas et al., 1998; Iturralde-Vinent, 2011; Rojas-Agramonte et level as a result of the soft-collision with NOAM. This gives us a
al., 2004, 2005). South of Sierra Maestra, the arc is truncated by 1000-km+ long arc section that may rival the classical arc crustal
the Oriente transform fault. sections of California, Talkeetna, or Kohistan. The Mabujina

LATEST EOCENE TO RECENT DEPOSITS Complex in particular promises important glimpses of arc crustal
architecture and processes of arc crust formation. Examining

Postorogenic latest Eocene to Recent basins and uplifted potential correlations between CARIB early arc magmas and the

8 tectonic units formed above the strongly deformed foldbelt. evolution of the Mabujina arc and coeval magmatic rocks in the