Evolution of a stratigraphic model in a fluvial deltaic wedge: implications for groundwater resource protection in an oil and gas-bearing region in the Upper Cretaceous Dunvegan Formation, Northwest Territories, Canada

The Liard Basin, in northwestern Canada, contains one of Canada’s largest natural gas reserves. There are concerns about degradation Dunvegan Formation groundwater quality, which is the basin's main shallow freshwater aquifer, as a consequence oil and development. Previous lithostratigraphic studies interpreted conglomeratic alluvial fans. In this study, newly collected cores surface resistivity surveys integrated with legacy hydrocarbon well data measured sections for improved sedimentary bedrock characterization. Rather than fans, we interpret upper coarse-sand to gravel bed fluvial system that was likely tributive incised valleys associated linked Alberta Basin base-level falls. Correlation logs suggest lower comprises prograding delta complex off-lapping clinoforms fed by smaller sand-bed rivers grade into system, built southeast towards Cretaceous Western Interior Seaway. This sequence stratigraphic facies architectural approach employed inform aquifer–aquitard flow aid understanding 3D once hydrogeologic characterisation confirms position thickness important units. Resistivity channel-belt may be well-connected laterally extensive, potentially acting interconnected aquifer units; whereas channel belts discontinuous, indicating smaller-scale units separated floodplain marine shale. revised geologic provides opportunities determining impacts or resilience from deep sources contamination human activities, including development, land-use, (or) climate change.