At least five rock sequences occur in central Cuba: (1) an igneous-metamorphic basement of unknown age; (2) a Jurassic evaporite-redbed sequence; (3) a Portlandian-Turonian orthogeosynclinal suite; (4) a Turonian-Eocene series; and (5) a post-orogenic Eocene-Recent sedimentary cover.

The Portlandian-Turonian orthogeosynclinal suite includes, from south to north, four facies belts: a eugeosynclinal suite, a transitional suite associated with the median welt, miogeosynclinal carbonates, and platform carbonates. During mid-Cretaceous and Eocene orogenies, the eugeosyncline was thrust northward, overriding the median welt and, locally, the miogeosyncline. The latter is deformed much more severely than the other belts.

Only four evaporite diapirs are known in north Cuba. These lie north of the median welt in Matanzas and Camaguey Provinces, and are localized by deep faults. Two diapirs penetrate the eugeosynclinal rocks at or close to the surface. Exotic blocks in these two diapirs include fragments of eugeosynclinal, median welt, and miogeosynclinal facies.

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The following hypothesis is proposed to explain these facts: during orogenesis, the miogeosynclinal carbonates were detached from the underlying evaporites, crushed between the median welt and platform, and overridden locally by the eugeosyncline. After middle Eocene time, the diapirs intruded along deep faults and reached the surface with fragments from the overridden facies belts. The latest diapiric movements are post-Miocene. The small number of diapirs probably is related to the great competence of the thick, overlying post-evaporite carbonate section.

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