Unit Name: Hector Formation
Unit Type: Lithostratigraphic
Usage: Currently in use
Age Interval: Late Proterozoic (900 - 542 ma)
Originator: Walcott, C.D., 1910.
Redoubt Mountain, northeast of Lake Louise, Banff National Park, Alberta.
The maximum described thickness of 550 m (1,804 ft) was measured near the type section. Eastward and southward from the type area erosional truncation beneath the Gog Group has removed the Hector (Aitken, 1969). The Hector probably thickens northward toward the Jasper area where the Proterozoic section is more complete.
Grey, brown, greenish grey and green slates, with a highly variable content of usually thick beds of coarse, gritty feldspathic sandstone and feldspathic, quartz pebble conglomerate [in part, submarine canyon fills, (Arnott and Hein, 1986)]. The Hector is demarcated from the underlying, lithologically similar Corral Creek Formation by its basal unit, consisting of "... bright green and purple slates ... (with) ... one or two thick beds of conglomerate (breccia) with tabular clasts of pink limestone. At Mount Temple it consists in part of interbedded purple slate and pink limestone" (Aiken, 1969).
The Hector Formation conformably overlies the Corral Creek and is unconformably overlain by the Lower Cambrian Gog Group. The colorful unit of slates and limestone at the base of the Hector ("Mount Temple limestone member" and "Taylor Lake purple shale member" of Gussow, 1957) is the Old Fort Point Formation of the Jasper area (Charlesworth et al., 1967). Thus the Hector Formation is equivalent to the Old Fort Point and Wynd formations jointly (upper Miette Group) of the Jasper area. The Hector Formation corresponds to part of the upper Miette Group of the Jasper area, which has yielded Ediacaran fossils (Hofmann et al., 1985). The type Hector probably doss not reach a stratigraphic level as high as the fossiliferous beds near Jasper, however. The Hector and the Miette Group are erosionally bevelled at an unconformity beneath the Gog Group (Aitken, 1969). The Gog has yielded Lower Cambrian body fossils as old as Nevadella Zone (Fritz and Mountjoy, 1975), and trace fossils attributed to trilobites nearly to its base (Palonen, 1976).
The Hector Formation was named and loosely defined by Walcott (1910, 1928), Aitken (1969) provided further data and extended the formation upward to the base of the Gog Group, including within the Hector beds that Walcott had assigned to the Lower Cambrian. He also recognized the identity of the colorful basal marker unit with the Old Fort Point Formation of the Jasper area. Gussow's (1957) "Mount Temple limestone member" and "Taylor Lake purple shale member" have not been adopted by subsequent workers. Arnott and Hein (1986) provided a detailed sedimentological analysis of the coarse, submarine canyon fills. Hughes (1955) mapped Miette strata in the Sunwapta Pass area as Hector Formation; this is probably, but not definitely correct, because he did not report the colorful basal unit (Old Fort Point equivalent) that identifies the Hector.
Aitken, 1969; Arnott and Hein, 1986; Charlesworth et al., 1976; Fritz and Mountjoy, 1975; Gussow, 1957; Hofmann et al., 1986; Palonen, 1976; Walcott, 1910, 1928.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: J.D. Aitken
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 29 Apr 2003