Unit Name: Storelk Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Bashkirian (318.1 - 311.7 ma)
Age Justification: Fossils are extremely rare in the formation and the only remains reported are by Stewart (1978), who observed a few brachiopods in a thin dolomitic bed in the lower part of the unit in the type area.
Province/Territory: British Columbia

Originator: Scott, D.L., 1964a, p. 62; 1964b, p. 475.

Type Locality:
Southwest corner of Storelk Mountain, Elk Mountains, southeastern British Columbia, near head of Elk River, in narrow canyon 1.6 km (1 mi) E32 deg N from mouth of Tobermory Creek (50 deg 31.5'N, 114 deg 59.7'W). Directly above the type section of the Tyrwhitt Formation.

Distribution:
The Storelk is a widespread stratigraphic unit recognized from south of Crowsnest Pass north to the Palliser Range in the front ranges. It appears to be absent east of the front ranges because of pre-Permian erosional truncation. The maximum measured thickness of 93.2 m (306 ft) occurs in the type section and a thickness of as little as 12.2 m (40 ft) occurs in the Palliser Range.

Locality Data:
Thickness(m): Minimum 0, Maximum 93.2, Typical 93.2.

Lithology:
Composed of white, quartz-cemented, quartz-chert sandstone averaging fine- to medium-grained, but containing very fine to coarse sand, commonly in alternating laminae. Towards the base grain size decreases and sorting increases. Larger grains are well-rounded. Weathered surfaces are very light grey to white, but usually covered with black lichen. In gross aspect commonly appears as a single massive unit, but in the type area Stewart identified three cross-bedded intervals that alternate with two structureless intervals. The most outstanding feature is the large scale cross-bedding: megatrough sets reach 6 m (20 ft) and mega-planar sets reach 10 m (33 ft) and have been interpreted to represent coastal aeolian dunes.

Relationship:
The lower contact with the Tyrwhitt Formation is sharp and distinct in some areas and poorly defined in others, but is believed to be everywhere conformable. The Storelk is overlain unconformably by the Tobermory Formation of Middle Pennsylvanian age. The contact is sharp, smooth and easily recognized; locally it is marked by a thin pebble conglomerate and rarely by erosional pits. Scott (1964a, b) interpreted the unconformity to be regionally angular, below which underlying formations are truncated towards the east. In outcrop the Storelk forms conspicuous cliffs or ridges bounded by ledges or slopes.

History:
Storelk is the name given to a unit originally contained within the Rocky Mountain Formation, Tunnel Mountain Member (Warren, 1947, 1956), later known as the Rocky Mountain Group, Tunnel Mountain Formation. It was probably this resistant sandstone, which forms conspicuous dip slopes in the Bow Valley area that prompted Dowling (1907) to introduce the name Rocky Mountain Quartzite. At Tunnel Mountain it corresponds to Beales' 31 m (102.5 ft) quartzitic sandstone unit (Beales, 1950). The formation has been studied in detail in the type area by Stewart (1978) and Stewart and Walker (1980).

Other Citations:
Beales, 1950; Dowling, 1907; Henderson, 1989; Scott, 1964a, 1964b; Stewart, 1978; Stewart and Walker, 1980; Warren, 1947, 1956.

References:
Beales, F.W., 1950. The Late Paleozoic formations of southwestern Alberta; Geological Survey of Canada, Paper 50-27 p. 58-64.
Dowling, D.B., 1907. Rocky Mountain Coal Areas, between the Bow and Yellowhead Passes, Alberta; Geological Survey of Canada, Summary Report 1906, pp. 66-73.
Scott, D.L., 1964a. Stratigraphy of the lower Rocky Mountain Supergroup in the southern Canadian Rocky Mountains; University of British Columbia, Vancouver, BC, Ph.D. thesis, 271 p.
Scott, D.L., 1964b. Pennsylvanian stratigraphy, in, Flathead Valley, Fourteenth annual field conference, Fernie, B.C. (August 28, 1964); Canadian Society of Petroleum Geologists (CSPG), Bulletin of Canadian Petroleum Geology, vol. 12 (August), Special Guidebook Issue, pp. 460-493.
Stewart, W.D. and Walker, R.G., 1980. Eolian coastal dune deposits and surrounding marine sandstones, Rocky Mountain Supergroup (Lower Pennsylvanian), southeastern British Columbia; Canadian Journal of Earth Sciences = Journal Canadien des Sciences de la Terre, vol. 17, no. 9 (September), pp. 1125-1140.
Stewart, W.D., 1978. Pennsylvanian shallow marine and eolian sediments, Tyrwhitt, Storelk and Tobermory formations of southeastern British Columbia. M.Sc. thesis, McMaster Univ.
Warren, P.S., 1947. Age and subdivisions of the Rocky Mountain Formation at Banff, Albenta Bull. Geol. Soc. Amer., Abst., v. 58, p. 1238.
Warren, P.S., 1956. Age and subdivisions of the Rocky Mountain Formation in the Canadian Rockies. J. Alberta Soc. Petrol. Geol., v. 4, p. 243-248.

Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: A. McGugan; M.M. Lerand; C.M. Henderson
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 27 Mar 2009