Abstract

Cambrian strata in central and western Wyoming were deposited in various marine and nonmarine environments related to periodic transgressive-regressive oscillations of the strandline. The Flathead Sandstone, which represents the basal deposits of the Middle Cambrian transgression, accumulated in braided stream, foreshore, upper shoreface, and sub- to intertidal settings, as evidenced by associations of physical and biogenic structures. The Gros Ventre Formation, consisting in ascending order, of the Wolsey Shale, Death Canyon Limestone, and Park Shale, was deposited in more offshore, low-energy environments subjected to both storm and fair weather processes. Periodic shoaling conditions resulted in algal buildups and formation of oolitic limestone sequences in the Death Canyon and Park. Regression preceded deposition of the basal member of the Gallatin Limestone, the DuNoir, which accumulated in lagoons and tidal flats on an eroded Park topography. The final Cambrian transgression resulted in deposition of the offshore Dry Creek Shale and overlying sublittoral Open Door Limestone.