ASSOCIATION BETWEEN DETACHMENT FAULTING AND SALT DIAPIRS IN THE DEVONIAN-CARBONIFEROUS MARITIMES BASIN, ATLANTIC CANADA

Globally, detached evaporite basins and diapiric provinces are mostly concentrated along the Atlantic and Mediterranean-Red Sea systems, as large Mesozoic-Tertiary gravity slides. However, the late Paleozoic ev aporitic Maritimes Basin in the east coast of Canada is an exception t o this as it was detached following extensional collapse of the Appala chian orogen, prior to Atlantic Mesozoic rifting. In the Devonian-Carb oniferous Maritimes Basin, thermal sag of a tectonically thinned crust resulted in marine flooding of an intracontinental basin in Visean ti me, and extensive evaporite precipitation. Extension mobilized Visean, Namurian, and syn-kinematic Westphalian units above the Ainslie Detac hment, which occurs along the basal evaporite contact, forming an allo chthonous raft measuring at least 67,000 km(2). Contrasting contractio nal and extensional structural styles occur at the front and back ends of the allochthon. The front slid over the Hollow-Cabot normal fault into a half-graben, developing buckle folds, thrusts, and a diapir fie ld that characterize the contractional domain. A drape syncline at the graben margin suggests displacement transfer between the Hollow-Cabot fault and Ainslie Detachment. The trailing edge of the raft features listric normal faults and stratigraphic gaps that characterize the ext ensional domain. Field relations demonstrate that the Ainslie Detachme nt was stratigraphically controlled by the Visean evaporites, producin g thin-skinned deformation and gravity-slide-linking compressional and extensional regimes above the detachment.