New insight on the geometry and evolution of the Moncton sub-basin from 3D seismic reflection data in the McCully area, New Brunswick, Canada

Abstract Within the Maritimes Basin of eastern Canada, the onshore Moncton sub-basin is one of the NE-trending second-order depocenters that recorded a complex tectonic history from Late Devonian to Late Carboniferous. Analysis of a 3D seismic volume in the McCully gas field area exemplifies the complex interplay between mainly continental sedimentation and several tectonic episodes that contribute to a net extension or shortening in an overall strike-slip setting. The new interpretation demonstrates the role of normal faults oblique to the sub-basin axis in initial phases of sub-basin development and their influence on the deposition of the Upper Devonian-Lower Mississipian Horton Group sediments. A subsequent episode of transpression is recorded by syn-folding growth strata (base of the Mississipian Sussex Group) preserved on both flanks of an anticline that belongs to a fold system that shows an en echelon geometry relative to sub-basin bounding faults. Deposition of a marine interval (Middle Mississipian Windsor Group), including evaporitic strata is succeeded by an halokinetic growth succession (Upper Mississipian-Pennsylvanian Mabou Group) found in minibasins that formed through drape folding (downbuilding) in response to salt-walls development. This polyphased history illustrates the complexity of strike-slip basins that are often controlled by structures with different geometry and kinematics in time and/or space.