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Geological evidence of the terrane boundary between the Nagssugtoquidian orogeny and the North Atlantic Craton is present in exposed rocks on both the east and west coasts of Greenland. The subglacial continuation of this boundary must be inferred from geophysical data across the Greenland ice sheet. Several possible locations have been suggested, based on combinations of regional grids of gravity and magnetic anomalies. We use high-resolution, flight-line profiles of gravity and magnetics data from Operation Ice Bridge (OIB) to investigate both the location and the nature of the boundary. Using Geosoft we modeled the density and susceptibility contrasts associated with previously proposed locations of the terrane boundary (Dawes, 2009 and Henricksen et al., 2009), and found evidence for several additional boundaries with significant contrasts in geophysical properties. We present a series of 2D profile models and map the most significant boundaries to reveal a more complex image of the subglacial geology beneath the Greenland ice sheet. 

Understanding the submarine environment around Greenland is critical for understanding the impacts of future changes in sea level on marine habitats and coastal infrastructures, as well as revealing the past physical processes that sculpted the landscape. Here we investigate the submarine signature of a geologic boundary between Precambrian basement and Cretaceous-Paleocene sandstone off the coast of Aasiaat, Greenland. The study builds upon previous research in Krawcyk et al., 2022, and uses new data from the Greenland Rising Project to compare geologic maps, analyze bathymetry data, and examine backscatter measurements to help contribute to a better understanding of the boundary. Observations of exposed bedrock, and our interpretation of pockmarks observed on the seafloor guide the location of the boundary and suggest that the boundary extends further south than previously recognized. Characterizing this boundary supports a better understanding of marine ecosystems in Greenland and can be valuable for future environmental management decisions. Further data collection and analysis is recommended to better determine and identify the boundary in the future