The Atlantic Subsurface Stratigraphic Initiative (ASSI) is a project with an interdisciplinary group of scientists focused on documenting the Cretaceous and Cenozoic subsurface geology of the Salisbury Embayment across Maryland and Virginia. Data generated by ASSI is crucial for resolving stratigraphic issues across state boundaries and regions. By working closely with state geologic surveys, ASSI will provide biostratigraphic and sedimentologic information that will be used as ground-truth data for comparison with geophysical data compiled by state agencies. This in turn will provide a stronger basis for documentation of formation and aquifer thicknesses across the region.
This project will compile new and existing core, outcrop, and water well lithologic, stratigraphic and geophysical data to provide a means for identifying formation thicknesses across the Salisbury and Delaware River Basins. Using this data, we are working closely with the Maryland Geological Survey, the Delaware Geological Survey, the New Jersey Geological Survey and the Virginia Department of Environmental Quality to identify lithologic and aquifer thicknesses for a better understanding of the relationship between changing stratigraphy and aquifer connectivity across state boundaries. Compilation of these data will result in detailed 3D and 2D subsurface cross sections across state boundaries, isopach thickness maps for each formation, and structure contour maps of key units such as the unconformity at the Cretaceous-Paleogene boundary, which can act as a regional barrier to water transmissivity.
The main goals of this project are to 1) provide subsurface thickness maps of sediments (Lower Cretaceous-Paleogene) of the mid-Atlantic region in order to identify changes in depositional patterns related to increased sediment flux to the region, impingement of currents onto the shelf region, and missing section related to movement on buried faults; 2) use 2D and 3D subsurface mapping to provide cross sections within states and across state boundaries (Delaware, Maryland, New Jersey and Virginia) to provide the framework for understanding the role that regional lithology plays in aquifer development and how aquifers change in thickness and extent across the region; 3) use subsurface cross sections to support a regional effort with state geological surveys and local universities to reconcile stratigraphy across the mid-Atlantic region; 4) identify gaps in the datasets that will be used to target future drilling; and 5) provide publicly available data sets that include information on formation thickness, microfossil content and age of the formations, grain size analyses, mineralogical data, and macrofossil data.
Earth Mapping Resources Initiative (Earth MRI)
FEDMAP
- Overview
The Atlantic Subsurface Stratigraphic Initiative (ASSI) is a project with an interdisciplinary group of scientists focused on documenting the Cretaceous and Cenozoic subsurface geology of the Salisbury Embayment across Maryland and Virginia. Data generated by ASSI is crucial for resolving stratigraphic issues across state boundaries and regions. By working closely with state geologic surveys, ASSI will provide biostratigraphic and sedimentologic information that will be used as ground-truth data for comparison with geophysical data compiled by state agencies. This in turn will provide a stronger basis for documentation of formation and aquifer thicknesses across the region.
Sources/Usage: Public Domain.Map showing the location of the study area in Maryland and Virginia. Each dot represents an outcrop (red), core (black) or water well (orange) where Paleogene formation thicknesses were obtained. The circular feature in the southern portion of the map is the Chesapeake Bay Impact Crater. Paleogene sediments are not present in the crater. This project will compile new and existing core, outcrop, and water well lithologic, stratigraphic and geophysical data to provide a means for identifying formation thicknesses across the Salisbury and Delaware River Basins. Using this data, we are working closely with the Maryland Geological Survey, the Delaware Geological Survey, the New Jersey Geological Survey and the Virginia Department of Environmental Quality to identify lithologic and aquifer thicknesses for a better understanding of the relationship between changing stratigraphy and aquifer connectivity across state boundaries. Compilation of these data will result in detailed 3D and 2D subsurface cross sections across state boundaries, isopach thickness maps for each formation, and structure contour maps of key units such as the unconformity at the Cretaceous-Paleogene boundary, which can act as a regional barrier to water transmissivity.
The main goals of this project are to 1) provide subsurface thickness maps of sediments (Lower Cretaceous-Paleogene) of the mid-Atlantic region in order to identify changes in depositional patterns related to increased sediment flux to the region, impingement of currents onto the shelf region, and missing section related to movement on buried faults; 2) use 2D and 3D subsurface mapping to provide cross sections within states and across state boundaries (Delaware, Maryland, New Jersey and Virginia) to provide the framework for understanding the role that regional lithology plays in aquifer development and how aquifers change in thickness and extent across the region; 3) use subsurface cross sections to support a regional effort with state geological surveys and local universities to reconcile stratigraphy across the mid-Atlantic region; 4) identify gaps in the datasets that will be used to target future drilling; and 5) provide publicly available data sets that include information on formation thickness, microfossil content and age of the formations, grain size analyses, mineralogical data, and macrofossil data.
Sources/Usage: Public Domain.USGS geologists Jean Self-Trail and Mercer Parker measuring and sampling the Paleocene Aquia Formation, Prince George’s County, Maryland
Sources/Usage: Public Domain.A typical Aquia Formation shell hash consisting mainly of the Paleocene gastropod Kapalmerella mortoni, Prince George’s County, Maryland
Sources/Usage: Public Domain.USGS Scientist Laurel Bybell standing on an indurated bed of the Paleocene Aquia Formation with a thick layer of highly fossilferous Aquia sediment above, Prince George’s County, Maryland - Science
Earth Mapping Resources Initiative (Earth MRI)
The goal of Earth MRI is to improve our knowledge of the geologic framework in the United States and to identify areas that may have the potential to contain undiscovered critical mineral resources. Enhancement of our domestic mineral supply will decrease the Nation’s reliance on foreign sources of minerals that are fundamental to our security and economy.FEDMAP
FEDMAP develops new ways to understand basic earth science processes and produces high-quality, multipurpose digital geologic maps, regional analyses, and multidimensional geologic models. Geologic maps are the primary database for virtually all earth-science applications and issues including mitigation of natural hazards, ground- and surface-water management, land-use management, assessment, and... - Partners