Fluvial Sequence Stratigraphy: The Wapiti Formation, West-Central Alberta, Canada

摘要: Abstract Outcrop exposures and high-resolution subcrop data allow the description mapping of four stratigraphic discontinuities in fully nonmarine strata Campanian–Maastrichtian Wapiti Formation (Western Interior foreland basin, Alberta, Canada). This framework defines unconformity-bounded depositional sequences (A–D), based on sequence methodology, well-log patterns, facies analysis. In ascending order, A records transition from underlying marine Puskwaskau into fluvial facies, consists strongly progradational aggradational stacking patterns. Sequences B C show a similar pattern basal amalgamated channel-fill deposits that grade upwards floodplain-dominated strata. Finally, D is dominated by channelized sediments extensive overbank facies. An suggests deposition under high-accommodation conditions. Maximum flooding surfaces are interpreted within fine-grained upper portions D. They tied to regionally coals accumulated more than 250 km away coeval shoreline. study provides new evidence major coal seams may represent extension maximum downstream-controlled realm. Furthermore, subaerial unconformities means subdividing previously undifferentiated component systems tracts.