Recurrent Mesozoic and Cenozoic Faulting along the Southern Margin of the North American Craton

The major discontinuity associated with the southern margin of the North American craton, the northwest-southeast striking “Alabama-Oklahoma Transform”, may define the location of both Triassic rifting and post-Triassic faulting including Quaternary deformation along the Saline River fault zone. Two parallel grabens were identified on deep industry seismic profiles, and depth to Triassic rift graben fill was constrained using wire-line induction well logs. Previous work has shown Cenozoic deformation, including Holocene deformation, related to the northern graben. However, no previous work has been published on the late Cenozoic history of the southern graben. The marginal faults of the southern most graben are expressed as topographic lineaments in the Saline River valley. On the southern fault, deformation of Holocene sediments were observed as liquefaction and folding in riverbank exposures. The axial trend of this folding parallels the northwesterly-southeasterly observed lineaments. Shallow seismic reflection profiles and a push core transect across the northern lineament are inconclusive with respect to surface faulting. This feature could be a structurally controlled paleo-channel.