MID-CRETACEOUS SEQUENCES OF THE NEW JERSEY OFFSHORE: IMPLICATIONS FOR CARBON SEQUESTRATION

The Baltimore Canyon Trough (BCT) offshore New Jersey provides the thickest record of Jurassic to Holocene strata along the U.S. Mid-Atlantic Continental Margin. Investigations of this region based on seismic, well log, and drill core data paved the way for understanding the evolution of passive continental margins and more recently sequence architecture for the Late Cretaceous to Holocene However, previous studies of the mid-Cretaceous of this region were restricted to 1970’s seismic profiles and industry exploration wells. Based on original and reprocessed 2D-seismic lines and well log data, we find the interval of the mid-Cretaceous (Barremian-Cenomanian) in the northern BCT has been largely overlooked, yet it reveals sequences similar to those of younger records. Previous well log correlations from 31 industry and science wells in the northern BCT identify three sandstone units arranged in a retrogradational succession between confining shales. Here, we apply sequence stratigraphic methods to seismic profiles and well logs, allowing a first-order reconstruction of relative sea-level variations. We show that parallel, low-angle, obliquely dipping seismic reflectors closely tied to these wells cut across the lithologically defined units, characteristic of seismic sequences. We summarize progress made in recognizing sedimentary sequences in the mid-Cretaceous and identify (in ascending order) the Missisauga, Lower Logan Canyon, and Upper Logan Canyon sandstones along with intervening shales as possible evidence of base-level rise and fall. Renewed interest in characterizing offshore targets for Carbon Capture and Sequestration in confined, porous sands has motivated us to: 1) produce a synthesis of old and new interpretations of geophysical well logs from middle and outer shelf drilling, 2) revisit existing cores housed at the Delaware Geologic Survey, and 3) analyze multiple sets of seismic cross-sections circa 1973-1978 that were collected by Exxon Production Research and the USGS. Reprocessed USGS seismic profiles show promising improvements, revealing previously unrecognized candidate sequence boundaries, transgressive surfaces, and downlap surfaces.