Type Locality:

Imperial Davidson No. 1, in 16-8-27-1W3M, Saskatchewan, between 1,326.5 and 1,524 m (4,352 and 5,000 ft). Holter (1969) noted that this well "does not have sufficient well data by present standards, to demonstrate units of the formation ... Typical development of the Prairie Evaporite (occurs) ... in the White Rose et al. Drake 4-29-32-22 well (Lsd. 4-29-32-22W2)" between 993.3 and 1,186.9 m (3,259 and 3,894 ft).

Distribution:

Maximum of 218 m (715 ft), with the thickest part occupying a belt from west of Saskatoon east to Melville and south to North Dakota. Extensive solutioning of salts has given rise to an irregular thickness to the formation and local absence of salt. Areas of major salt solutioning occur in south-central Saskatchewan. The Prairie Evaporite extends from north-central Alberta southeastward into Manitoba, and southward into North Dakota and Montana.

Lithology:

Halite, carnallite and sylvite of various hues and degrees of crystallinity, but predominantly red and moderately coarsely crystalline. Locally blue halite is present. Seams of red or grey dolomitic mudstone and some anhydrite beds are present.

Relationship:

The basal contact is conformable with carbonates or anhydrite of the Winnipegosis Formation. However there is difference of opinion as to whether a basal anhydrite should be ascribed to the Winnipegosis (Edie, 1959) or the Prairie Evaporite (Jones, 1965; Holter, 1969). Kendall (1975) elaborated on the problem, pointing out that "parts of Winnipegosis banks ... are believed to be younger than, or equivalent to the Lower Prairie Evaporite". This interpretation is in accord with Jordan (1967) and Reinson and Wardlaw (1972). The upper contact is disconformable with dolomitic mudstones comprising the Second Red Bed Member of the Dawson Bay Formation. Locally the contact is diffuse due to intermingling of halite with the overlying strata. The Prairie Evaporite is correlated with the Muskeg and Presqu'ile formations in northern Alberta.

History:

McGehee (1949) recognized a shale-carbonate-evaporite sequence in western Saskatchewan which he called the Elk Point Formation. Mitchell (1951) correlated these units into Manitoba. Baillie (1953) chose the name Prairie Evaporite for the salts, which later were called the M2 member (Crickmay, 1954), then the Prairie Formation (Sandberg and Hammond, 1958). The formation has been divided into several members: Jordan (1967, 1968) introduced the terms Leofnard, Whitkow, Shell Lake and Quill Lake; Holter (1969) named the three main potash members Esterhazy, Belle Plaine and Patience Lake, plus the White Bear Marker Beds.

Other Citations:

Baillie, 1953; Crickmay, 1954; Edie, 1959; Holter, 1969; Jones, 1965; Jordan, 1967, 1968; Kendall, 1975; McGehee, 1949; Mitchell, 1951; Reinson and Wardlaw, 1972; Sandberg and Hammond, 1958.

References:

Baillie, A.D., 1953a. Devonian System of the Williston Basin area; Manitoba Mines and Natural Resources; Mines Branch, Publication 52-5, 105 p. + 5 Maps.

Crickmay, C.H., 1954. Paleontological correlation of Elk Point and equivalents. In: Western Canada Sedimentary Basin, Ralph Leslie Rutherford Memorial volume; Clark, L.M. (Ed.), American Association of Petroleum Geologists, Tulsa, Oklahoma, p. 143-158.

Edie, R.W., 1959. Middle Devonian sedimentation and oil possibilities, central Saskatchewan, Canada; American Association of Petroleum Geologists (AAPG), AAPG Bulletin, vol. 43, no.5 (May 1959), pp. 1026-1057.

Holter, M.E., 1969. The Middle Devonian Prairie Evaporite of Saskatchewan. Saskatchewan Dept. Min. Res., Rept. 123.

Jones, H.L., 1965. The Middle Devonian Winnipegosis Formation in Saskatchewan. Saskatchewan Dept. Min. Res., Rept. 98.

Jordan, S.P., 1967. Oil traps in Saskatchewan's Winnipegosis reefs. Regina, Saskatchewan Industrial Exhibition and Mineral Symposiunn (INDEX) 1967 Proc., p. 591-593.

Kendall, A.C., 1975. The Ashem, Winnipegosis and lower Prairie Evaporite formations of the commercial potash areas. Sumnnary of Investigations, 1975. Saskatchewan Geol. Surv. Saskatchewan Dept. Min. Res., p. 61-65.

McGehee, J. Rex, 1949. "Pre-Waterways Paleozoic stratigraphy of Alberta Plains"; American Association of Petroleum Geologists (AAPG), AAPG Bulletin, vol. 33, no. 4 (April), pp. 603-613.

Mitchell, J.G., 1951. "Preliminary notes on correlation of Beaverhill Lake and Elk Point formations of Alberta, with Manitoba"; Can. Strat. Service Ltd., unpub. Rept.

Reinson, G.E. and Wardlaw, N.C., 1972. Nomenclature and stratigraphic relationships, Winnipegosis and Prairie Evaporite formations. Bull. Can. Petrol. Geol., v. 2a, no. 2, p. 301-320.

Sandberg, C.A. and Hammond, C.R., 1958. "Devonian System in Williston Basin and central Montana"; American Association of Petroleum Geologists (AAPG), AAPG Bulletin, vol. 42, pp. 2293-2334.