Diapiric Structures in Central Cuba<xref ref-type="fn" rid="ch21fn1"><sup>1</sup></xref>

Abstract

Four evaporite diapirs have been reported in central Cuba. Their surroundings are stratigraphically and structurally complex; therefore, an understanding of their structure and tectonic history requires a detailed knowledge of regional stratigraphy and tectonics. There are at least five rock sequences in central Cuba--(1) an igneous-metamorphic basement of early Mesozoic or late Paleozoic age, (2) a Jurassic evaporite-redbed sequence, (3) a Portlandian-Turonian orthogeosynclinal suite, (4) a diversified Turonian-Eocene series, and (5) a postorogenic Eocene-Recent sedimentary cover. The Portlandian-Turonian orthogeosynclinal suite includes, from south to north, four facies belts: eugeosynclinal suite, transitional suite associated with the median welt, miogeosynclinal carbonates, and platform carbonates. During middle 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. The diapirs are north of the median welt in Matanzas and Camaguey Provinces, and are localized by major 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. The following tectonic history is proposed for the diapirs. 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 major faults and reached the surface bearing fragments from the overriding facies belts. The latest diapiric movements were post-Miocene. The small number of diapirs probably is related to the great competence of the thick, overlying, post-evaporite section.