Revealing the Cape Verde Hotspot Track Across the Great Lakes

Detecting old hotspot tracks in a stable continent remains challenging because of the lack of volcano chains on the surface and the fade of thermal anomalies with time. The northeastern American continent moved over the Cape Verde and the Great Meteor hotspots during 300–100 Ma. However, only the latter was confirmed by kimberlites and seismic velocity models. Our new 3D anisotropic model in northeastern America reveals strong positive radial anisotropy anomalies in the eastern Great Lakes, central Pennsylvania, and northwestern Virginia. These anomalies follow the Cape Verde hotspot track, providing the first geophysical evidence for the hotspot. A circular pattern of azimuthal anisotropy is also observed in the eastern Great Lakes and may be related to the Cape Verde plume activity. The plume was under the Great Lakes during 300–200 Ma and probably caused lithosphere thinning and low topography needed for forming the Lakes during the glacial era. Plain Language Summary The strong and thick lithosphere of a stable continent makes it difficult for a hot mantle plume to penetrate and form a volcano chain on the surface. Low‐velocity thermal anomalies in the upper mantle from the plume materials also fade with time and, therefore, cannot be a reliable feature for detecting an old plume path. Our new 3D seismic anisotropy model in northeastern America reveals positive radial‐anisotropy anomalies in the eastern Great Lakes, central Pennsylvania, and northwestern Virginia, aligning with the Cape Verde hotspot track. A circular azimuthal anisotropy in the eastern Great Lakes may also be related to the Cape Verde plume that was under the region during 300–200 Ma. The plume activity must have thinned the lithosphere and set the stage for the birth of the Great Lakes from later glaciation. Key Points Positive radial anisotropy and circular azimuthal anisotropy in the eastern Great Lakes fit the predictions in a plume model Positive radial anisotropy anomalies align with the Cape Verde hotspot track from the Great Lakes to the Atlantic coast The long‐time presence of the Cape Verde hotspot in the Great Lakes during 300–200 Ma helps set the stage for forming the lakes