Type Locality:

Gladstone Creek in southeast of Sec. 26, Twp. 5, Rge. 2W5M, NTS 82G/8E, southwestern Alberta.

Distribution:

Occurs in the Alberta Foothills between the type section and about 54 deg N. Ranges from about 82 m (269 ft) at the type section to 180 m (590 ft) north of the North Saskatchewan River. Generally thicker to the west.

Lithology:

Divided into two informal members. The lower, comprising half or less of the formation is characterized by fine- to very fine-grained sandstone, beds usually with a distinct upward decrease in grain size, interbedded with siltstone, mudstone and claystone. Colors are light grey to greenish grey and maroon. The upper member is characterized by limestone beds, with occasional coquinas of freshwater origin usually subordinate to calcareous mudstone, siltstone and sandstone. Limestone beds are less prominent to the north and are absent north of 53 deg N, being replaced by fossiliferous, calcareous mudstones. A few sections contain an anomalously high proportion of sandstone throughout the formation, characterized by both fining-upward and coarsening-upward sequences. Thin coal beds are present in sections north of about 52 deg N.

Relationship:

Lies abruptly but apparently conformably on the Cadomin Formation. Overlain abruptly by the Beaver Mines Formation south of 52 deg N, and by the Moosebar Member of the Malcolm Creek Formation to the north. To the northwest, along the foothills it is homotaxial with the Gething Formation, but with distinct lithological changes. Equivalent to the Ellerslie Formation of the central Alberta Plains, the Dina Member of the Lloydminster area and the McMurray Formation of the northeastern Alberta Plains. The fossiliferous limestone and calcareous mudstone member is equivalent to the Ostracod Beds of the central plains.

History:

Introduced by Mellon (1967) to include the Cadomin Formation. The Cadomin was removed and the name retained for overlying beds (McLean, 1980). Use extended from the southern foothills to about the Smoky River (54 deg N) by McLean (op. cit.).

Other Citations:

McLean, 1980; Mellon, 1967.

References:

Mellon, G.B., 1967. Stratigraphy and petrography of the Lower Cretaceous Blairmore and Mannville groups, Alberta Foothills and Plains; Res. Counc. Alberta, Bulletin 21.