AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Role of Caribbean Arc Collision on the Development of the Southeast Gulf of Mexico, Florida and Bahamas
(1) Tectonic Analysis Ltd., Duncton, United Kingdom.
Understanding of tectonic events within northern Caribbean arc(s) has been revamped in recent years. Here I examine how these events influenced basin development in SE Gulf of Mexico-Florida-Bahamas. The Central Cuban arc differs from other Antilles by having an HPLT suture belt and magmatic arc whose respective activities became largely dormant in Maastrichtian, coeval with a major subduction zone choking event, but collision with the Bahamas occurred in Middle Eocene, consistent with ongoing subduction and Paleogene opening of the Yucatan-Cauto intra-arc basin. There is spatial correlation between the intra-arc basin and apparent cessation of subduction in Central Cuba. Flat slab subduction has been invoked to explain arc cessation, contradicting models of intra-arc basin opening. Along arc-strike in Hispaniola, HPLT exhumation and arc magmatism continued to Eocene collision with Bahamas. The difference may be that the terrane that choked Cuba in the Maastrichtian, "Caribeana" (probably the southern Yucatan passive margin), was subcreted to the base of the overriding arc, while the downdip slab detached into the mantle, taking its deep subduction record with it. The composite arc-subcreted terrane then transpressed E-ward on new, shallow, more northerly faults along southern Yucatan, moving progressively into and overthrusting the northern Proto-Caribbean basin. With respect to Cuba, this was a forward stepping of the trench trace, which is now hidden beneath the Remedios/ Cayo Coco accretion belts, and where new subduction allowed final closure with Bahamas. Hispaniola avoided Yucatan collision so its Cretaceous subduction zone remained intact. Oriente Cuba seems transitional, as expected. The inferred plate boundary pattern has a wishbone appearance: an onshore suture and a forward stepping subduction zone in Central Cuba, merging E-ward (at Oriente?) to a single trench at Hispaniola. This new view changes models of Antilles-Yucatan and Antilles-Bahamas interaction. Proto-Caribbean rollback (Jurassic, steep slab) sucked Central Cuba N-ward while opening Yucatan-Cauto [intra-arc] Basin, and tearing a STEP fault and thus causing large isostatic rebound/erosion along east Yucatan. It also suggests the Cuban Camajuani and Placetas belts originated south of Yucatan, and modifies the required architecture of the Cuba-Florida-Bahamas thrustbelt.