ABSTRACT

The Upper Cambrian Johns Wash Limestone Member of the Orr Formation constitutes part of the miogeoclinal "carbonate belt" of the Great Basin. In the House Range of western Utah the member may be subdivided into five facies: (1) a bioclastic facies of thin-bedded fossiliferous or mottled wackestones, (2) an oolitic facies of cross-bedded oolitic intraclastic grainstones, (3) a stromatolitic facies consisting of diverse types of algal stromatolites in an oolitic matrix, (4) a pelletoidal facies of burrowed, light gray, oolitic grainstones and pelletoidal packstones, and (5) a fenestral facies of extensively burrowed and bored, light gray mudstones and packstones which possess fenestral fabric.

The facies are interpreted as reflecting deposition on a broad platform on which an oolite shoal separated a shallow-water lagoon from a more open marine environment to the west. Landward of the lagoon, the fenestral facies accumulated on an extensive tidal flat. Westward progradation of these environments resulted in superposition of the facies which compose the regressive carbonate sequence of the Johns Wash Limstone in the House Range.