Molluscan biostratigraphy of the Cardium Formation (Upper Cretaceous, Turonian-Coniacian) and contiguous strata, Alberta foothills and adjacent subsurface
LccQE 688 B73 1994a
Additional Copy: QE 688 B73 1994
LcshGeology, Stratigraphic - Cretaceous
Cardium Formation (Alta.)
Formations (Geology) - Alberta - Cardium Formation
Geology - Alberta - Cardium Formation
Sedimentary structures - Alberta
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AbstractSediments comprising the Cardium Formation accumulated from the Prionocyclus wyomingensis zone through the Scaphites preventricosus zone. In the study area no ammonite zones are absent; however, zones may be partially absent in individual sections. In the Southern Foothills the Turonian/Coniacian boundary occurs in the basal portion of the Leyland Member. Farther north this boundary probably occurs within the Moosehound Member. Prionocyclid ammonites (P. wyomingensis, P. novimexicanus, P. quadratus, P. germari, and P. sp. indet.) have been recovered from several sections in both the subsurface and surface. Scaphites preventricosus has been recovered from the Leyland Member and ranges up into the basal beds of the overlying Wapiabi Formation. Ammonites referable to the Scaphites preventricosus zone have also been recovered from the Cardium Zone in the Edson Field. In addition inoceramid bivalves, Inoceramus dimidius, Mytiloides aff. M. aviculoides, Mytiloides labiatoidiformis, Mytiloides incertus, Cremnoceramus rotundatus, Cremnoceramus erectus, Cremnoceramus deformis, and Cremnoceramus inconstans, have been recovered, confirming the ammonoid zonation. The biostratigraphic data suggest that the Cardinal Member rather than the Ram Member is the most laterally continuous member of the Cardium Formation in the Southern Foothills. Sandstones of the Pembina River Member of the Pembina Field and the Cardium "A" Sand in the Crossfield area are correlative with the Cardinal and basal Leyland . members in outcrop. The upper portion of the Leyland Member, the Sturrock Member, and the basal beds of the Wapiabi Formation are correlative with the Cardium Zone of the subsurface. The available data also suggest that the Cardium Formation is diachronous in both west - east and north - south directions. Biostratigraphic correlations indicate that unconformities within the Cardium Formation may not always represent significant time gaps or chronostratigraphic horizons.
Bibliography: p. 157-170.