Timing constraints on deformation history of the Sudbury Impact Structure
Herein, we present new high-resolution seismic images of the Sudbury Impact Structure, acquired across the Sudbury Igneous Complex and its environs, which provide evidence for the relative timing of the deformation events that reshaped the initial Sudbury Structure. The seismic images show that the lower unit of the Sudbury basinal fill sediments, the Onwatin argillite, is penetrated by a set of blind, imbricated thrusts, whereas the overlying Chelmsford turbidites are unaffected by faulting. We interpret this observation to mean that the deposition of the Chelmsford sediments postdates the latest major deformation of the Sudbury Structure, suggesting that the uniform paleocurrent trends observed in the Chelmsford turbidites are not related to the initial shape of the Sudbury Structure.