NUMBER 11

NOVEMBER, 1960

VOLUME S

JOURNAL
of the
ALBERTA SOCIET Y
of
PETROLEUM GEOLOGISTS

THE EDMONTON FORMATION
J. R. OwER
California Standard Co., Calgary

ABSTRACT

The writer discusses the Edmonton formation of Central Alberta from iield sections on the Red Deer, North Saskatchewan and Athabasca Rivers, and from well logs in the intermediate area. It has a thickness of 1100 to 1700 feet and the writer divides it into five members, the lowest four being Fax Hills-Pierre in age and the uppermost Lance. The continuity of the Kneehills tuff zone (Member D) throughout the area as a marker between Lance and Pre-Lance sediments is demonstrated.

The Bearpaw marine shale is replaced by Edmonton continental sediments to the north. The stratigraphic continuity of the Edmonton-Beny River contact as an extension of the Bearpaw-Belly River contact is maintained throughout the area.

The writer concludes there is no evidence of irregular differential erosion of the Edmonton formation before deposition of the Paskapoo formation. There may 'be an angular disconformity between the two formations but, if it exists, it probably results in a slow progressive truncation of the uppermost Edmonton beds beneath the Paskapoo sandstone in an easterly direction.

INTRODUCTIOM

The paper was first read' to the Alberta Society of Petroleum Geologists in April, 1949. It was a result of work done for the California Standard Company along the North Saskatchewan River in 1947, along the Red Deer River in 1948, and subsurface studies of oil wells in the area between the two rivers in the winter of 1948-49.

Subsequent to the reading of this paper, the writer,did a survey of the Athabasca River and some notes on sections along that river are included in this revision.

The purpose of the paper is to discuss the stratigraphy of the Edmonton formation in Central Alberta and to correlate the surface sections with sub- surface sections.

IRepublished, by permission, from the Edmonton Geological Society Quarterly,
Vol. 2, No. 1 (March, 1958), pp. 3-11.

310

PREVIOUS INVESTIGATIONS

The term "Edmonton" was first used by Selwyn (1874) in referring to the coal bearing strata outcropping around Edmonton City. Tyrrell (1886) introduced the term as a formational name, dining and describing the forma- tion as exposed along the Red Deer River. Here, Tyrrell included all the continental coal-bearing beds lying above the marine Bearpaw shale to the highest seam observed, a seam mined near Ardley.

Tyrrell then worked the North Saskatchewan River and correlated the sec- tion with the Red Deer River section. He named' the beds overlying his Edmonton formation "Paskapoo." The beds immediately above the Ardley seam were placed in his Paskapoo which was considered to be early Tertiary in age, while the Edmonton beds, with a known dinosaurian fauna, were considered to be Cretaceous.

Since Tyrrell's time, the Red Deer River section has been the subject of much geological study, both because of the economic value of the coal and because of the remarkable dinosaurian fauna. The earlier workers include Barnum Brown, in 1911-14, and J. A. Allan, in 1917-21. J. O. G. Sanderson made detailed studies in 1924 and 1925, and the results of Allan and Sanderson's work were published in 1945 as the "Geology of the Red. Deer and Rosebud Sheets." Allan and Sanderson considered that there was an erosional discon- formity between the Edmonton and Paskapoo formations and included in the Edmonton formation beds formerly placed in the Paskapoo. Other workers include R. L. Rutherford, in 1985-39, and, more recently; C. M. Sternberg, in 1947-48, who made additional studies of the dinosaurian fauna. The more scattered sections alonp the North Saskatchewan have not been studied in as