Figure 2. By about 94 Ma BP (late Cenomanian ~MCSB time) the western Gulf of Mexico was fully open. However, in the Late Aptian - Cenomanian the predicted passage of a Beata-Aves Ridge Hotspot beneath the western basin and implied subduction between the Yucatan microplate and South Florida may have elevated existing Greater Antillean blocks, thus restricting interchange with the Proto-Caribbean and Atlantic. Restricted circulation would have favored source-rock deposition. In this figure ch= the Chiapas Microplate; F = the Faralon Plate; pC= the Proto-Caribbean Plate; A= the African Plate; S= the South American Plate. The familiar modern outlines of Cuba and Hispaniola, provided for reference, include exotic terranes that came together in the Cenozoic.  

Click to view in sequence plate reconstructions for Late Jurassic and late Cenomanian.