Influence of minibasin obstruction on canopy dynamics in the northern Gulf of Mexico

In salt-detached gravity-gliding/spreading systems the detachment geometry is a key control on the downslope mobility of the supra-salt sequence. Here, we used regional 3D seismic data to examine a salt-stock canopy in the northern Gulf of Mexico slope, in an area where supra-canopy minibasins subsided vertically and translated downslope above a complex base-of-salt. If thick enough, minibasins can interact with, and weld to, the base-of-salt and be obstructed from translating downslope. Based on the regional maps of the base of allochthonous salt and the base of the supra-canopy sequence, the key controls on minibasin obstruction, we distinguished two structural domains in the study area: a highly obstructed domain and a highly mobile domain. Large-scale translation of the supra-canopy sequence is recorded in the mobile domain by a far-travelled minibasin and a ramp syncline basin. These two structures suggest downslope translation on the order of 40 km from Plio-Pleistocene to Present. In contrast, translation was impeded in the obstructed domain due to supra-canopy bucket minibasins subsiding into feeders during the Pleistocene. As a result, we infer that differential translation occurred between the two domains and argue that a deformation area between two differentially translating supra-canopy minibasin domains is difficult to recognize. However, characterizing domains according to base-of-salt geometry and supra-canopy minibasin configuration can be helpful in identifying domains that may share similar subsidence and downslope translation histories.