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The Flume Formation exposed in Jasper National Park, Alberta, is a widespread sheetlike carbonate body, 100-250 ft thick, which served as a platform for the overlying 1,200-ft thick, areally restricted Miette bank of the Cairn and Southesk Formations.
Platform deposition of the present Miette bank began on a pre-Devonian, topographically high erosin surface. During marine transgression across this surface, a broad shelf lagoon formed in which shallow subtidal to supratidal carbonates of the platform evolved. Shoaling conditions were maintained throughout platform evolution over this high by carbonate sedimentation buildup and perhaps gradual uplift. During relatively rapid inundation, most of the platform was covered with basinal carbonate mudstones of the Perdrix Formation. Stromatoporoids were able to survive only on the shallowest parts of the platform. In essence, the overlying Miette bank represents localized continuation of platform growth.
Bankward the lower platform member thins and the upper platform member thickens. As the upper platform member thickens, tidal flat and shallow subtidal deposits appear and thicken, and deeper subtidal deposits thin and disappear. These changes generally occur within 1-5 mi from the bank.
Widespread carbonate units which served as platforms for overlying banks can be important both in determining bank proximity, and in understanding relations between platform genesis, bank inception, and localization.
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