Type Locality:

Chancellor Peak (51 deg 13'N, 116 deg 30'W) British Columbia. Allan (1917, p. 75) chose the name "because beds of this division are especially well exposed on the east and north slopes of Chancellor peak". No type section has been designated.

Distribution:

Few sections of Chancellor strata have been measured, but thicknesses have been estimated. The Chancellor Formation has been tectonically thickened and all observed thicknesses can be considered greater than the original depositional thickness. The lower Chancellor correlates with some part of the Eldon and Pika formations (see McIlreath, 1974, p. 272, figs. 2a and 2b). Consequently, immediately adjacent to the facies change it can be at most 700 m (2,296 ft) thick and locally is much less. The upper Chancellor has an estimated thickness of 1,370 m (4,493 ft) (Cook, 1975, p. 23) near Mount Hurd and a measured thickness of 1,000 m (3,280 ft) at Mount Laussedat (J.D. Aitken, pers. comm. in: Cook, 1975, p. 22). These thicknesses include a tectonic increase estimated to be 65 per cent by Cook (1975, p. 58) and 25 to 70 per cent by Gardiner (1977, p. 179) The Chancellor Formation occurs in the western Main Ranges and the Western Ranges of the Canadian Rocky Mountains. It has been mapped by Price et al. (in press) as far southeast as Vermilion Crossing in the southwest part of Banff (west half) Map-area (82O/4, W/2), and is known to occur further southeast in Kananaskis Map-area (82J). It has been mapped by Wheeler (1963) as far northwest as Sullivan River in Rogers Pass Map-area (82N).

Lithology:

Three gross, informal units are discernible. The lowest comprises irregularly interbedded grey, argillaceous limestone, brown and greenish brown shale, and thin-bedded brown, argillaceous dolomite, with local intrastratal, chaotic slump folds, slump breccias and large carbonate slide blocks. The middle unit comprises slates and cleaved argillaceous limestones, locally divisible into a lower recessive slate and silty dolomite subunit, and an upper thin-bedded, grey weathering, cleaved argillaceous limestone subunit. The uppermost unit comprises cleaved, rusty weathering, calcareous slate with local thin- to medium-bedded, partly oolitic and calcarenitic limestone beds. The highest beds are interbedded micritic limestone and light green slate and calcareous slate constituting a transition zone to the overlying Ottertail Formation.

Relationship:

The Chancellor Formation is a western slope and deep water facies equivalent to the eastern shelf sequence comprising the Eldon, Pika, Arctomys, Waterfowl and Sullivan formations. Because the facies change migrated shoreward at some localities, and basinward at others, lowest beds vary in age from place to place. For example, at Park Mountain the lowest Chancellor beds rest on Stephen Formation shales, whereas at Prospector's Valley the Chancellor is underlain by lower Eldon Formation (McIlreath 1974, p. 272, fig. 2a). McIlreath (1974, p. 272, fig. 2b) correlated the lower Chancellor with only the lower part of the Eldon Formation at Dennis Pass, yet showed the lower Chancellor to be equivalent to the upper part of the Eldon and the Pika Formation at Prospector's Valley. This discrepancy is unresolved. The top of the middle Chancellor can be correlated with the top of the Waterfowl Formation (Cook, 1975), thus the entire middle Chancellor can correlate with some or all of the sequence upper Eldon-Pika-Arctomys-Waterfowl, depending on resolution of the discrepancy noted above. The upper Chancellor can be correlated with the Sullivan Formation (Cook, 1975). The Chancellor is overlain with transitional contact by limestones of the Ottertail Formation.

History:

Allan (1912) named the Chancellor Formation and considered it to be upper Cambrian. He showed two subdivisions on his map (1914). Balkwill (1969) and Cook (1970, 1975) subdivided the Chancellor into a number of mappable informal units. Cook showed the formation to be Middle and Upper Cambrian in age and considered it to be equivalent to the eastern sequence from the Middle Cambrian Mount Whyte Formation to the Upper Cambrian Sullivan Formation inclusively. McIlreath (1974, 1977) further revised the correlation, showing that the Chancellor is equivalent to the lesser sequence from the Middle Cambrian Eldon Formation to the Upper Cambrian Sullivan Formation.

Other Citations:

Allan, 1912, 1914; Balkwill, 1969; Cook, 1970, 1975; Gardiner, 1977; McIlreath, 1974, 1977; Price and Mountjoy, 1972; Price, et al., in press; Wheeler, 1963.