A calcareous foraminiferal faunule from the upper Albian Viking Formation of the Giroux Lake and Kaybob North fields, northwestern Alberta: implications for regional biostratigraphic correlation

摘要

Arenaceous foraminifera from the upper Albian Viking Formation and associated strata are recorded and charted from five wells in the northwestern portion of the West Alberta Basin, viz. Gulf Giroux Lake 04-11-66-21W5, Candel Arco Giroux Lake 00/10-05-65-20W5, Pan Am B-i Giroux 02/10-05-65-20W5, Calstan B.A. Kaybob W 02-28-63-20W5, and Chevron Fox Creek 10-15-62-19W5. An anomalous calcareous foraminiferal component in three Gulf Giroux Lake samples is illustrated. Ichnological, sedimentological, and stratigraphic studies of the Viking Formation strata, based on 26 cored intervals, indicate largely transgressive, shallow-marine deposition in the area. The microfaunal and ichnological assemblages indicate a general increase in salinity toward normal marine conditions. Facies analysis demonstrates the stacking of two shoreface parasequences, truncated by wave-ravinement surfaces. The calcareous foraminifera in the Viking Formation are associated with abundant and diverse arenaceous foraminifera, with arctic affinities that we have used for determining the microfaunal zone positions. Biostratigraphic correlation has been made with a calcareous faunule in the lower part of the Hasler Formation, within the expanded Fort St. John Group, found in the southern portion of the Keg River subbasin, Hudson Hope region, northeastern British Columbia. This helps to resolve the problem of correlating the stratigraphically equivalent Paddy Member at the type section near the town of Peace River, Alberta.