Palinspastic reconstruction of the Mesozoic paleomargin of North America in western Cuba and southeastern Gulf of Mexico. Implications for the evolution of the southeastern Gulf of Mexico

Abstract

The southeastern Gulf of Mexico contains the Cuban Exclusive Economic Zone where search for oil and gas is currently in progress. The geological relationships among the low mountains in western Cuba (Cordillera de Guaniguanico) and the SE Gulf are poorly known. Upper Jurassic – Paleocene sections in the Cordillera belong to the North American paleomargin. The paleomargin rocks are present along northern Cuba and contain its main oil and gas deposits. These sections were thrusted northward during the early Cenozoic Cuban orogeny. In Cordillera de Guaniguanico, the uppermost Paleocene and lowermost Eocene are olistostromes and turbidites, settled in a foreland basin in front of the thrusts. The southern flank of the basin was destroyed and imbricated within the thrust pile during the Late Paleocene – Early Eocene orogeny, whereas the northern mildly deformed part lies in the SE Gulf. Seismic data from the SE Gulf suggest lower Paleogene clastic deposits increasing in thickness toward Cuba. The close correlation among the Mesozoic sections in the southeastern Gulf of Mexico and western Cuba highlands points to an original juxtaposition. Therefore, a palinspastic reconstruction of the Cordillera de Guaniguanico sections becomes key to understand the geological history of the Caribbean – Gulf of Mexico transition.

Five major tectonic units, each one with its own stratigraphic sections are distinguished in western Cuba. In the estimation of the horizontal movement for each unit, a multilateral, dialectic approach is applied, with a mutual control among geometric-structural and geological data. The NNW horizontal movement estimate (kilometres) for each main sheet was the following: Sierra de los Organos unit: 12.5–25; Alturas de Pizarras del Sur unit: 40–50; Alturas de Pizarras del Norte: 57.5–67.5; Sierra del Rosario/Esperanza unit: 92.5–111.5 and Pan de Guajaibón unit > 92.5–111.5. The proto-Caribbean lithosphere (ophiolite and volcanic arc sections) is represented by the Bahía Honda unit, with minimum horizontal displacement of 122. 5–141.5 km. A proposal of palinspastic reconstruction is developed and the original position of each tectonic unit restored. The minimum area of the Cordillera de Guaniguanico tectonic pile in the sedimentary basin was between 21,000 and 25,000 square kilometers. The primary thrust sheet volume probably was between 42,000 and 100,000 cubic kilometres.