Successive Drowning of Platforms by Thrust-Fault Loading in the Cuba-Bahama Foreland Basin

Kelly L. Bergman¹, Gregor P. Eberli¹, Jose Luis Masaferro², and Anthony Poiriez^1
1 University of Miami, Miami, FL
² Shell E&P Technology Applications and Research, Rijswijk, Netherlands

Multi-channeled seismic lines covering the area from Cuba to the northern Bahamas show subsidence associated with thrust-fault loading is responsible for progressive carbonate platform drowning away from the collision zone. Tectonic movement associated with the Cuba-Bahama collision began in the Cretaceous, peaked in the Eocene, and continued into the Neogene, documenting long-lived loading of the American plate that influenced the evolution of the platforms in the Cuba-Bahama foreland basin. The age control for these tectonic and drowning events comes from ODP Leg 166 cores on the west side of Great Bahama Bank and the Great Isaac-1 core on the northwest corner of Great Bahama Bank that were tied to the seismic data.

Close to Cuba, movement along thrust faults is oriented perpendicular to the collision zone. Ages of first draping strata indicate movement of the two youngest thrust sheets ceased in the Late Oligocene and Early Pliocene, respectively. Fold growth analysis on the most distal anticline of the Cuban fold-and-thrust belt documents that the Neogene shortening was continuous but extremely slow (0.014 mm/year).

During foreland basin evolution several platforms drowned and became buried by deep-water sediments. The ages of drowning events were determined at unconformities between slope and deep-water facies. Drowning occurred earliest in the southernmost region in the Early to Middle Eocene and latest in the northernmost region in the Late Oligocene. The progressive drowning away from the collision zone indicates long-lived thrusting and loading in the Cuba-Bahama collision zone rather than sea-level changes caused the platforms to drown.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005