Facies anatomy of an Upper Cambrian grand cycle: Bison Creek and Mistaya formations, southern Alberta

Abstract

The Bison Creek and Mistaya formations form the youngest Cambrian sedimentary grand cycle exposed in Banff and Jasper national parks. The shaly half-cycle of the Bison Creek Formation records the displacement of a carbonate bank during a major rise in sea level that can be identified in other parts of North America. Lithofacies of the Bison Creek Formation fall into three recurrent associations that represent sedimentation in shallow, subtidal, storm-dominated shelf settings. The Mistaya Formation records the reestablishment of carbonate bank deposition, probably due to a decrease in the rate of sea-level rise, and includes two facies associations that represent a mosaic of shallow subtidal to supratidal environments. The grand cycle was terminated by a sea-level rise, possibly eustatic in nature, that drowned the carbonate platform. The overlying shales, mudstones, packstones, grainstones, and rudstones of the Survey Peak Formation mark a return to subtidal, storm-dominated shelf conditions.