Lithofacies and depositional history of Midale carbonate-evaporite cycles in a Mississippian ramp setting, Steelman-Bienfait area, southeastern Saskatchewan, Canada

摘要: Abstract Carbonate-evaporite cycles in the Mississippian (Osagean) Midale Beds of southeastern Saskatchewan were deposited over a shallow homoclinal ramp along northern margin Williston Basin. Fourteen lithofacies, including nine limestone facies (C1 to C9), two dolostone (D1 and D2), three anhydrite (A1 A3), identified from cores (46 wells) geophysical well logs (750 Steelman-Bienfait area. These lithofacies represent range subtidal supratidal settings are interpreted be related four transgressive-regressive parasequences (S1 S4, ascending order). Paleosols microkarst features (T1) characterize parasequence boundaries provide evidence for subaerial exposure. Oolitic grainstones packstones as shore-parallel, shoals barrier islands S2 S3 western Steelman Bienfait oilfields. Paleotopographic hinge-zones an important control on distribution shoals, lagoons, algal marsh sediments, salinas algal/ostracod mounds. Abrupt thickness changes lateral, carbonate-evaporite transitions observed across hinge-zones. Facies distributions sea level fluctuations, paleotopography, availability accommodation space. Minor fluctuations this setting resulted major lateral shifting facies, significant migration paleocoastline, periodic exposure upper middle environments, producing stratigraphic traps exploration targets, addition traditional sub-crop “plays” study