Geology of The Grand Teton Area - Paleozoic Deposition

Paleozoic Deposition

Deposition resumed in the Cambrian period and continued through the Paleozoic era, creating nine major formations which together are 4,000 feet (1,200 m) thick (the only geologic period in the Paleozoic not represented is the Silurian). This unit was laid down in a shallow sea and later became a discontinuous mix of dolomite, limestone, sandstones, and shales. The layers of this unit are relatively undeformed for their age even though periodic upwarp exposed them to erosion, creating uncomformities . Fossilized brachiopods, bryozoans, corals, and trilobites are found in the carbonate rock layers with the best examples found outside the park in the Alaska Basin. The most complete examples of this unit are found to the west, north, and south of park borders.