Title

Interplay of tectonism and carbonate sedimentation in the Bahamas foreland basin

Date of Award

1997

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Marine Geology and Geophysics

First Committee Member

Gregor P. Eberli, Committee Chair

Abstract

Analysis of more than 5000 km of multichannel seismic reflection profiles from the Cuban/southern Bahamian foreland basin revealed that tectonism has been a major controlling factor on platform evolution. The internal configuration of the southern Bahamas provides an excellent record of deformation because of the almost instantaneous response of carbonate sedimentation to tectonic destructive processes. The carbonate platform reacted differently to the deformation produced by the progressive northeastward emplacement of the Cuban orogen.The seismic study of the southern Great Bahama Bank indicates that the evolution of the bank is a result of a dynamic interaction between tectonic destructive processes and the recovery of a healthy platform in a distal side of the foreland basin. Tectonic depressions created by transtensional structures were immediately filled by carbonate sediments from the adjacent platforms. Carbonate production outpaced the increase in accommodation space produced by the activity of the transtensional fault system. In this way, the tectonic relief became masked by shallow-water carbonate sedimentation unless subsequently renewed by synsedimentary movements. In contrast, analysis of seismic profiles in the Straits of Florida and Santaren Channel revealed that the former passive-margin carbonate platform backstepped and drowned. The platform recorded the progressive northeastward emplacement of the Cuban thrust belt over the North American passive continental margin. The continuous convergence and migration of the flexural profile, and the inability of the carbonate sedimentation to keep pace with increasing flexural subsidence forced the platform to backstepp and subsequently drown as a result of the advancement of the orogenic front.Syntectonic carbonate sedimentation deposited in the vicinity of a growing detachment fold in the northernmost limit of the Cuban fold and thrust belt provided crucial information about the timing and kinematics of the structure. Because of the in-situ production of sediments independent of local tectonics, the platform was able to shed sediments continuously into the basin producing a complete record of growth strata. Seismically imaged syntectonic strata in the Santaren Anticline revealed the influence of sedimentation and local tectonics in defining growth stratal geometries. A detailed analysis of the growth strata deposited on the the northern limb of the Santaren Anticline indicates that growth stratal geometries are a result of a close competition between sedimentation and local tectonics. Neither sedimentation nor tectonic uplift dictates the final overlap-onlap/offlap geometries observed within the growth strata. The prevalence of one over the other defines the final geometry of the stratal patterns.

Keywords

Geology; Geophysics

Link to Full Text

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