ROLE OF CONTINENTAL CLOSURE IN THE DISTRIBUTION OF FLORIDA BASEMENT FEATURES
Published:July 01, 1993
DOUGLAS L. SMITH, 1993. "ROLE OF CONTINENTAL CLOSURE IN THE DISTRIBUTION OF FLORIDA BASEMENT FEATURES", Mesozoic and Early Cenozoic Development of the Gulf of Mexico and Caribbean Region–A Context for Hydrocarbon Exploration, James L. Pindell, Bob F. Perkins
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Existing interpretations of the major rock assemblages of the Florida basement (Cambrian Osceola Complex, Ordovician-Silurian Suwannee Basin sedimentary rocks, and Mesozoic Southwest Florida Volcanic Field) and basement structural features (Jay Fault-Bahamas Fracture Zone extensions and South Georgia Rift) indicate a history of initial evolution at a Gondwana continental margin, late Paleozoic coupling with North America, and eventual appendage as a peninsula following a fortuitous geometry of Triassic rifting. Reconciliation of this scenario, however, with the demonstrated spatial distribution of basement rock units and proposed concepts of motion on the Jay Fault is elusive without invoking unlikely initial configurations or tectonic behavior. Apprehensions concerning the shape of the extension into Florida of the South Georgia Rift, the presence of apparent elements of the Osceola Complex in the panhandle and southeastern Georgia, and lack of deformation within the Suwannee Basin sedimentary units can be tempered with a reconstruction of basement response to the closure of North America and Gondwana. A proposed sequence of events is contingent on deformational collision of Gondwana at and north of the North America Alabama Promontory followed by clockwise rotation and northwestward motion of Gondwana. En echelon right-lateral faults, including a precursory segment of the Jay Fault, progressively developed from east to west, facilitating closure at the Ouachita Orogen and displacing elements of a once-continuous continental margin to accommodate pivoting of Gondwana about the promontory. Thus, adjacent portions of the central Florida Osceola Complex to the northeast and southwest were fixed closer to the suture and bracketed the Suwannee Basin sequence. The subsequent development of Triassic basins in the Florida basement was constrained by the presence of offset basement blocks. Divergent motion of South America was accommodated by reactivated, but left-lateral and normal, motion along some of the initial Paleozoic faults. What previously had been described as the Jay Fault was actually a series of subparallel features, linked by embryonic spreading centers and perhaps converging near the present-day Osceola Complex. Accordingly, the Florida basement is a reflection of tectonic events attributable to a disruptive Paleozoic suturing process as well as Triassic rifting.