Seismic Evidence for Crustal Modification Beneath the Hartford Rift Basin in the Northeastern United States

Extensive Mesozoic rifting along the eastern North American margin formed a series of basins, including the Hartford basin in southern New England. Nearly contemporaneously, the geographically widespread Central Atlantic Magmatic Province (CAMP) was emplaced. The Hartford basin provides an ideal place to investigate the roles of rifting and magmatism in crustal evolution, as the integration of the dense SEISConn array and other seismic networks provides excellent station coverage. Using full-wave ambient noise tomography, we constructed a detailed crustal model, revealing a low-velocity (Vs = 3.3-3.6 km/s) midcrust and a high-velocity (Vs = 4.0-4.5 km/s) lower crust beneath the Hartford basin. The low-velocity midcrust may correspond to a layer of radial anisotropy due to extension and crustal thinning during rifting. The high-velocity crustal root likely represents the remnant of magmatic underplating resulting from the CAMP event. Our findings shed light on crustal modification associated with supercontinental breakup, rifting, extension, and magmatism.