In the northeastern United States and southeastern Canada, rifting continued during and after the ENA magmatism. In fact, normal faulting and basin subsidence accelerated shortly before, during, and after the ENA magmatic activity.  ENA magmatism lead to the emplacement of diabase sills and NE-striking dikes, and the eruption of synrift basalt flows.  Rifting ceased in the northeastern United States and southeastern Canada by the early Middle Jurassic, long after ENA magmatic activity.  A volcanic/volcaniclastic wedge formed near the continent-ocean boundary of the northeastern United States during the rift-drift transition.  Inversion occurred in southeastern Canada before or during the Early Cretaceous during the rift-drift transition and/or during the early stages of seafloor spreading.
 The inversion and widespread magmatism are related to active asthenospheric upwelling that culminated during the rift-drift transition. We propose that inversion may be a common feature along many volcanic passive margins and is associated with change in strain state from margin-perpendicular extension to margin-perpendicular shortneing.  The presence of dikes oriented at a high angle to the trend of the margin (e.g., the dike swarms in the southeastern United States, southeastern U.S., southeastern Greenland, offshore northwest Europe, and South America)  reflects inversion.

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