Natural Resources

The Moose Lake area is part of the outcrop belt of Paleozoic rocks within the Manitoba Lowland Region, or 'First Prairie Level.' It extends from Winnipeg and Garson, through the Interlake and Dawson Bay regions, to the Precambrian Shield from Lake Athapapuskow to Ponton (Bannatyne 1988, p. 2) Topographic relief is usually low, and altitudes range from 217 m at Lake Winnipeg to 320 m south of Lake St. Martin. Locally, escarpments occur within the outcrop belt, but some rock ridges have been partially or completely buried beneath glacial overburden. Known outcrop areas are potential sites for quarries (Bannatyne 1988, p. 2). Regional Geology The predominantly carbonate rocks of southwestern Manitoba were deposited in shallow epeiric tropical seas that inundated weathered Precambrian basement: Several cycles of transgression and regression have been interpreted from variations in texture, composition and fauna of lower Paleozoic rocks (Bannatyne 1988, p. 2).

During the first transgression of Ordovician seas, sandstone and interbedded sand and shale of the Winnipeg Formation were deposited. Cambrian strata were deposited earlier but occur only in subsurface. Carbonate deposition began with rocks of the Red River Formation, divided into the following members: Dog Head dolomitic mottled limestone; Cat Head dolomite and dolomitic limestone with chert nodules; Selkirk dolomitic limestone with abundant megafauna and an upper cherty limestone; and Fort Garry lower micritic dolomite, a central shaly layer, and upper dolomite with two limestone interlayers. An increase in clastics initiated deposition of the Stony Mountain Formation that consists of: Gunn Member red shale with thin limestone interbeds; Penitentiary Member argillaceous dolomite; Gunton Member dolomite with minor variable argillaceous content; and Williams Member argillaceous and sandy dolomite. Deposition of carbonates continued across the Ordovician-Silurian boundary, within the Stonewall Formation of dolomite. Carbonates, now completely altered to dolomite, continued to be deposited in the Silurian period (Bannatyne 1988, p. 2).