Controls on Passive Margin Stratigraphy: Seismostratigraphic and Basin Modeling Evaluation of Georges Bank Basin

Abstract

Seismostratigraphic interpretations constrained by well data were coupled with 2-D stratigraphic forward and thermo-subsidence models to predict stratigraphy and to better understand the roles of tectonics, eustasy, and sedimentation in controlling sequence development in the Georges Bank basin. Seventeen late Middle Jurassic-Cretaceous depositional sequences and 13 types of seismically defined depositional facies were recognized and correlated within the basin. Subsidence histories constrained by seismic correlations, a modified Exxon sea-level curve, and iteratively determined sediment infill parameters were the primary input for 2-D stratigraphic modeling analyses of three dip oriented seismic lines. The sea-level curve was the same as that used in earlier modeling studies of Baltimore Canyon. The integrated seismostratigraphic interpretations and stratigraphic modeling results predict similar aggradational Jurassic-Cretaceous mixed clastic/carbonate platforms. The extent and rate of shelf margin progradation can be attributed to focused infilling associated with an embayment or possible salt or basement tectonism. Relative sea-level changes controlled gross reciprocal clastic/carbonate depositional patterns. A series of time sequential cutaway block diagrams and facies maps will be shown illustrating the computer-modeled and seismically interpreted Jurassic-Cretaceous sequence stratigraphic evolution of the basin. The Georges Bank stratigraphic evolution will be compared to that of Baltimore Canyon. Even though the two basinsmore » had differing subsidence and sedimentation histories, the observed facies distribution and stratal geometries could be simulated with a single sea-level curve.« less