Cuba is a portion of the Great Arc of the Caribbean that obliquely collided with and was sutured onto the North American plate during the Late Cretaceous-early Tertiary. As such it contains both a long-traveled, allochthonous magmatic arc component as well as an autochthonous Florida-Bahamas Platform passive margin component, which have been tectonically intermingled in a complex fashion.

The pre-Mesozoic history of Cuba remains enigmatic. but the existence of Grenville-age (~1 Ga) metamorphic rocks in the Santa Clara belt indicates that at least this small piece of Cuba had a Precambrian continental origin and was probably derived from some part of North America (Laurentia) other than the basement underlying Florida (Pan-African, Gondwana-affinity). Conceivably, these Grenville-age rocks could have been torn off the Mexico/Chortis part of Laurentia as the Great Arc migrated into the gap between North and South America during the Cretaceous (Kevin Burke, personal communication).

The early Mesozoic to Recent geological history of Cuba, which is most relevant to the hydrocarbon systems, can be divided into three main tectonic phases: extensional/passive margin, collisional, and transcurrent/extensional. The extensiondl1 passive margin phase affected only the autochthonous (Florida- Bahamas platform) portion of Cuba and began in the Triassic and/or Early to middle Jurassic, associated with the rifting and breakup of Pangaea. Compression began to affect Cuba during the Late Cretaceous as a result of the northeastward migration of the Cuban magmatic arc. The Cuban fold and thrust belt and adjacent foreland basin formed during the Campanian-early Tertiary, when the Cuban arc obliquely collided with the southern margin of the North American continent. Terminal collision probably took place during latest Paleocene-early Eocene (Bralower and Iturralde-Vinent, 1997) and caused the obduction of volcanic arc-related rocks and ophiolites over the passive margin carbonates and evaporites of the Florida- Bahamas platform. Following the cessation of collision in the early Tertiary, a sinistral transcurrent fault system (Cayman Trough) developed to the south of Cuba and the Yucatan Basin; this transcurrent fault system has persisted to the present day and forms a portion of the boundary between the North American and Caribbean plates. Contemporaneous with the early development of the transcurrent plate boundary, crustal collapse led to extensional structures being superimposed on the hinterland of the Cuban orogen. In addition, some of the collisional- phase structures have been further modified by salt diapirism, especially in northwestern Cuba (Jamison and Podruski, 2000).

In 1508 the Spanish mariner Sebastian Ocampo found what he called a "liquid bitumen" in the area of Bahia de la Habana, which he used as a caulking material when he careened his ships. This is the earliest known use of petroleum by old-world colonists in the Americas (Pardo, 1992). Petroleum production in Cuba dates from 1881 when light oil production was established from Motembo Field in the central part of the island. Cuba currently produces an all-time record of approximately 50,000 bold of predominantly heavy crude and 55 MMcf/d of associated natural gas, mainly from a series of fields along a relatively small, 100 km stretch of the northern coastline of Habana and Matanzas Provinces. This limited geographical area of oil and gas production has more to do with ease of logistics and

Unnumbered Figure. Location Map.

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proximity to the main market (Havana) than to prospectivity. The largest of the currently-producing fields is Varadero Field (Tavares, 1999), with an estimated 2 billion barrels of oil in-place. Most of the present-day production comes from fractured Upper Jurassic and Lower Cretaceous carbonate reservoirs (originally part of the Florida-Bahamas platform) in structural traps of the north Cuban deformed belt. Relatively minor production has also been established from fractured serpentinites and other basement rocks. The major hydrocarbon source rocks are probably Upper Jurassic and/or Lower Cretaceous in age. With the application of modem drilling and completion techniques since Cuba opened its E&P sector to foreign participation in the 1990s, recently-drilled wells commonly have sustained production rates above 1,000 bold, with some wells reaching 3.000 bold. Despite these successes, current production still only meets around 30% of Cuba's domestic demand. There are, however, indications that production and reserves could be significantly greater in the future. Cuba may well attain energy self-sufficiency within the current decade, and could even become a significant exporter of crude oil and natural gas.

While U.S. oil companies are barred from doing business in Cuba by the U.S. Government, a number of Canadian independents have been aggressively filling the niche; in addition, significant players from Europe and other parts of Latin America have recently entered the Cuban E&P scene. Acreage is currently available for exploration both onshore and offshore by direct negotiation with the national oil company Cubapetr6leo (CUPET), as well as via several farm-in opportunities.

Most recently, the entire 110,000 sq km Cuban sector of the Gulf of Mexico was subdivided into blocks and made available for licensing, and is deemed to have significant hydrocarbon exploration potential in a variety of trends (Hernandez-Perez and Blickwede, 2000). In this mostly deepwater area. the offshore extension of the productive Cuban fold and thrust belt and its associated foreland basin remains undrilled and constitutes a possible major petroleum province of the future. Additional potential is foreseen in traps and reservoir facies associated with Florida and Campeche Escarpments and around the flanks of basement high "knolls." Oil recovered from DSDP Site 535, in the central portion of the Cuban sector of the Gulf, confirms the existence of thermally-mature, viable oil source rocks in this frontier exploration area.

Figure 1. Upper Cretaceous Maastrichtian carbonates over ophiolite complex, Holguin Province, eastern Cuba. Photo courtesy of Jim Podruski.

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References:

Bralower, T. J., and Iturralde-Vinent, M. A., 1997, Micropaleontological dating of the collision between the North American plate and the Greater Antdes arc in western Cuba, Palaios, Vol. 12, pp. 133- 150.

Hernandez-Perez, G., and Blickwede, J. f., 2000, Cuba deepwater opportunities described in southeastern Gulf of Mexico: Oil & Gas Journal, Vol. 98.50 (1 1 December 2000).

Jamison, W. R., and Podruski, J. A., 2000, Tectonic history of western Cuba, AAPG Bull., Vol. 84, n. 13.

Pardo, G., 1992, The geology and petroleum prospects of Cuba, Petroconsultants/IHS Energy Group, 556 p.

Tavares, D., 1999, Principales caracteristicas geol6gicas del camp Varadero, Cuba, y de su yacimiento de petroleo extrapesado. Oil & Gas Journal Latinoamerica, Vol. 9, n. 5, pp. 28-42.

Figure 2. Jurassic-Lower Cretaceous carbonates, Guaniguanico Range, Pinar del Rio Province, western Cuba Photo courtesy of Jim Podruski.

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