CRETACEOUS SEDIMENTATION PATTERNS IN THE SOUTHERN BALTIMORE CANYON TROUGH: CORRELATING THE MARYLAND COASTAL PLAIN TO THE CONTINENTAL RISE

We have tied geophysical logs from wells in the mid-Atlantic coastal plain to offshore multi-channel seismic reflection profiles and paleontological analyses at wells drilled during commercial exploration of the Atlantic Outer Continental Shelf (OCS) between 1973 and 1981. Chronostratigraphic surfaces were generated for a 2700 km² portion of the continental shelf off the coast of southern New Jersey and traced south to the shelf and slope off the coast of Maryland, providing a link between a shore-normal cross-section of Maryland coastal plain well logs and paleontological data in the Shell 93-1 well drilled 130 km to the east of Ocean City, MD.

Five lower order sequences previously identified and correlated between wells from the Maryland and New Jersey Coastal plain in the Magothy, Potomac, and Waste Gate formations were correlated to the offshore data. The resulting stratigraphic cross-section, spanning from coastal plain to the continental rise, shows that sedimentation shifted landward from the latest Jurassic to early Cenomanian time, with a subsequent basinward shift in the Late Cretaceous. High rates of Valanginian and Berriasian siliciclastic sedimentation observed at the Shell 93-1 well correlate updip to chaotic seismic reflectors beneath the modern shelf and to concomitant pre-palynozone I fluvial deposition that characterizes the Waste Gate Formation in the Maryland coastal plain. A deepening upward trend is exemplified by a series of high relief (~150 m) Albian, Aptian, and Cenomanian clinoforms underlying the modern middle shelf. These sequences correlate in coastal plain well logs to an upward transition from fluvial channel and floodplain facies to deltaic stacking patterns. The observations are consistent with previous reports of global sea-level fluctuations and depositional cycles during the mid-Cretaceous (Haq et al. 1988, Miller et al. 2005) and provide the basis for our continuing efforts in constructing a comprehensive cross-margin depositional model for this basin.