Geological Survey Bulletin 1592 Depositional Environments of the White Rim Sandstone Member of the Permian Cutler Formation, Canyonlands National Park, Utah

Depositional Environments of the White Rim Sandstone Member of the Permian Cutler Formation, Canyonlands National Park, Utah
By Brenda A. Steele

The White Rim Sandstone Member of the Permian Cutler Formation in Canyonlands National Park, southeastern Utah, was deposited in a coastal eolian environment. The White Rim consists of three types of eolian deposits: dune, interdune, and sabkha. Characteristics of the dune deposits are large-to medium-scale, unidirectional, tabular planar crossbed sets; high-index ripples oriented parallel to the dip direction of the foresets; inverse graded laminations formed by ripple migration; sand-flow toes; and raindrop impressions. Interdune deposits are of two types, erosional and depositional, formed under varying degrees of wetness. Erosional interdune deposits are characterized by thin, coarse sand to granule size, bimodal lags at the base of crossbed sets. Depositional interdune deposits are characterized by discontinuous, wavy horizontal laminations, color banding, adhesion ripples, relict salt-ridge structures, and bioturbation. Generally, both types of interdune deposits are thin and lenticular. In the eastern part of the study area the entire lower half of the White Rim is flat-bedded sandstone that has most of the characteristics of depositional interdune deposits. A detrital-dominant, inland sabkha, which formed downwind of the main White Rim dune field, may be represented by this flat-bedded sandstone. Location of the sabkha was topographically controlled by early movement of the Monument upwarp and grew as the result of a stable and slowly rising water table.

The Lower Permian White Rim Sandstone Member was deposited during a period of marine transgression when the area of Canyonlands National Park was exposed to alternating marine and nonmarine conditions. Permian paleogeography and stratigraphic relationships, sand body geometry, dune form, and petrologic features such as glauconite pellets, a crinoid fragment, and heavy mineral concentrations all indicate the White Rim Sandstone Member was deposited in a coastal setting.