CARBON STORAGE POTENTIAL AT THE GREAT STONE DOME, NORTHERN BALTIMORE CANYON TROUGH

The Great Stone Dome (GSD) is a 20 km wide feature beneath the shelf situated 40 km landward of the East Coast Magnetic Anomaly and 100 km offshore Atlantic City, NJ. The GSD was first recognized by positive magnetic and gravity anomalies and later sampled to reveal a network of ultra-mafic igneous intrusives. Differential compaction has led to ~0.5 km of structural relief in the overlying drape of mid-Cretaceous sandstones that were the target of 1970-1980s oil and gas exploration. Seven exploratory wells and multiple seismic surveys, beginning with USGS Line 2, found the presence of 1) potential reservoirs within the Mississauga Equivalent and Logan Canyon Equivalent Formations, 2) a thick and regionally extensive seal in the Dawson Canyon Equivalent Shale, 3) more than 1500 m of burial, and 4) little faulting above the structure. However, any hydrocarbons that may have been generated vented the structure before seals developed. Consequently, the GSD is currently being assessed as a potential storage resource for anthropogenic CO₂.

Using the available seismic, geophysical, and geologic data, we are investigating factors affecting CO₂ storage volume estimates. To best constrain the target sand volumes we use a sequence stratigraphic framework that recognizes four potential sequence boundaries dividing the mid-Cretaceous sands. Three sequence or parasequence boundaries are identified by abrupt shifts between nearshore and neritic facies of the Mississauga and Logan Canyon Equivalents as recognized in well logs. These roughly separate Aptian-Albian, Albian, earliest Cenomanian, and later Cenomanian units that were deposited in progressively deeper water. An older Barremian or Aptian unconformity, possibly a sequence boundary, was previously identified by conventional core and kerogen analysis in the unpublished drilling results. Our preliminary interpretation is that as much as 5.9 Gt of CO₂ could be stored at the GSD. Further environmental and seismic correlation will refine this figure, as well as our understanding of mid-Cretaceous sequences on the NJ margin. This investigation is part of a broader characterization effort led by the Midwest Regional Carbon Sequestration Partnership to quantify storage resources within its region. This work is supported by U.S. DOE-NETL Agreement No. DE-FC26-0NT42589.