Outcrop study of the Straight Cliffs Formation in the Kaiparowits Plateau allows examination of facies tract development within a sequence-stratigraphic framework. This approach provides a new perspective to regional chronostratigraphic and lithostratigraphic relationships of Turonian through Campanian strata. These strata are arranged in geometric patterns that can be related to lowstand, transgressive, and highstand system tracts.

Shoreface deposits of the Tropic Shale and the overlying Tibbet Canyon Member record progradation of highstand and late highstand systems tracts. Coarse, laterally amalgamated fluvial clastics of the Smoky Hollow Member, which sharply overlie the Tibbet Canyon Member, represent an abrupt seaward shift in facies tracts due to increased rates of sea level fall. The lower portion of the Ferron Sandstone Member of the Mancos Shale to the east is interpreted to be the resulting lowstand system tract.

Renewed relative sea level rise is recorded within the Smoky Hollow

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by a vertical change from fluvial and floodplain deposits to tidally influenced sandstones capped by a ravinement surface characterized by a thin pebble lag. These strata and the upper portion of the Ferron Sandstone to the east comprise the transgressive system tract. A thin sharks-tooth lag, 6 m above the ravinement surface in Left Hand Collet Canyon, is thought to mark a condensed section recording maximum rate of deepening. Reduced rates of relative sea level rise resulted in vertical aggradation of the overlying John Henry Member. Aggradation of fluvial sediments is recorded in the western part of the plateau, whereas vertical aggradation of shoreface sandstones is present along the eastern margin. An upward change from low to high to intermediate ratios of overbank to channel de osits within floodplain strata may mark the transition from sea level rise to fall. Sea level lowering during the Campanian resulted in deposition of laterally amalgamated, coarse fluvial sandstones of the Drip Tank Member.

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