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Circum-Pacific and Caribbean Orogens |
Department of Earth and Environmental Sciences, Queens College, The City University of New York, Flushing, New York 11367, U.S.A.
Cuba, the largest island of the Greater Antilles, is a Cretaceous-Eocene orogen now greatly dissected so that ultramafic complexes, granitic plutons and metamorphic rocks are widely exposed. The island lies between the Bahamas Platform on the north and the Yucatán Basin to the south. The latter is crossed by the Cayman Ridge and Trench, along which modern orogenic activity (seismicity) is concentrated.
Segment: this description relates to the whole of the island of Cuba, plus the Isla de Pinos. This segment is 1200 km long and within it the exposed part of the orogen averages 120 km in width.
Zones: four zones are recognized. From north to south they are: (1) the Miogeosyncline—thin, Jurassic to U. Cretaceous carbonate sequence, thick U. Cretaceous to Palaeocene carbonate-elastic sequence, and thin Tertiary carbonate-elastic sequence. (2) Las Villas zone—a positive region with a relatively thin L. Cretaceous to Eocene carbonate-elastic sequence resting on metamorphics. (3) Zaza zone and (4) Cauto zone—a eugeosynclinal belt with major U. Cretaceous and Eocene, submarine volcanic rocks, U. Cretaceous ultramafics and Cretaceous-Tertiary granitic plutonics. Jurassic strata and thick Eocene-Miocene carbonate-elastic sequences occur in zone 3, and thick Eocene coarse-grained volcanic sequences are confined to zone 4.
History: the oldest dated rocks in the segment are lower Jurassic to Neocomian elastic and carbonate sediments, in part metamorphosed to phyllite in western Cuba. In zones 2–4 crystalline schists of unknown age and relation to the Jurassic rocks are cut by an early Cretaceous pegmatite. From early Cretaceous (Albian) to Eocene
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