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TitleAgglutinated foraminiferal assemblages in Albian shales overlying kimberlite deposits in the Smeaton core from central Saskatchewan, Canada
AuthorMcNeil, D HORCID logo; Leckie, D A; Kjarsgaard, B AORCID logo; Stasiuk, L D
SourceProceedings of the Fifth International Workshop on Agglutinated Foraminifera; by Hart, M B (ed.); Kaminski, M A (ed.); Smart, C W (ed.); Grzybowski Foundation, Special Publication 7, 2000 p. 299-309
LinksAbstract - Résumé
Alt SeriesGeological Survey of Canada, Contribution Series 1998095
PublisherThe Grzybowski Foundation (Kraków, Poland)
MeetingIWAF 5: Fifth International Workshop on Agglutinated Foraminifera; Plymouth; GB; 1997
File formatpdf
AreaFort à la Corne
Lat/Long WENS-105.3333 -104.5000 53.7500 53.3333
Subjectsgeneral geology; mineralogy; sedimentology; diamond; kimberlites; shales; radiometric interpretations; perovskite; marine sediments; thermal maturation; erosion; Mannville group; Westgate Formation
Illustrationslocation maps; stratigraphic columns; diagrams; graphs; tables
Released2000 01 01
AbstractThe Smeaton core from the Fort à la Corne area of central Saskatchewan contains diamond-bearing kimberlite in crater facies interbedded between sediments of the Aptian/Albian Mannville Group and the late Albian Westgate Formation. Minor numbers of thecamoebians occur in Middle Albian terrestrial sediments of the Mannville Group underlying the main kimberlite zone. Immediately above the kimberlite section, agglutinated foraminifera occur in abundance and three assemblages from the late Albian Verneuilina canadensis Subzone of the Miliammina manitobensis Zone have been recognized in shale of the Westgate Formation. Regional correlations of foraminiferal zones matched with ammonite zones and radiometric dates indicate an age of approximately 100 Ma for the assemblages which, in ascending order, are named the Ammobaculites, the Paratrochammina, and the Haplophragmoides assemblages. The estimated age of these assemblages is compatible with a Pb/U radiometric date of 101 Ma derived from the mineral perovskite within the kimberlite complex.

Species distributions, generic composition, and morpho typic groupings of the agglutinated assemblages indicate that a nearly complete transgressive-regressive sequence is preserved in the Westgate Formation. The Ammobaculites assemblage represents the early stages of transgression and marginal marine sedimentation. The Paratrochammina assemblage represents deeper water marine sedimentation up to approximately mid-shelf depths with maximum marine conditions attained coincident with peak abundances of Paratrochammina and the total foraminiferal abundance. Regression is indicated in the upper part of the Westgate shale by decreased numbers of Paratrochammina and decreased total foraminiferal abundance. Continued regression in the upper part of the Westgate shale is indicated by the Haplophragmoides assemblage. The Westgate Formation is erosionally truncated in the Smeaton core and is overlain by Quaternary sediment.

Thermal maturity indicators (FCI, Tmax, % VRo, and Lmax) all indicate that low levels of thermal maturity, similar to low maturity regional trends, characterize the Albian sediments in the Smeaton core.

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