Abstract
Investigation of the marginal marine Curtis Formation of the Middle to Upper Jurassic succession, composed of the Entrada Sandstone, the Curtis Formation and the Summerville Formation, in ascending order. As a whole, the succession represents an alternation between continental and marine strata. The sedimentary succession is well exposed in east-central Utah, USA. Descriptive sedimentological data have been collected, from outcrops along the eastern flank of the San Rafael Swell, to link the Curtis Formation vertical and lateral variability to temporal and spatial distribution of depositional environments, and its relation to stratigraphically neighbouring units. The Curtis Formation was deposited during tectonically induced marine transgression onto a low angle retroarc foreland basin, consistently dominated by tidal mechanisms. At the end of the transgression the Summerville Formation was deposited contemporaneously with the Curtis Formation as proximal and distal equals, respectively, as they record an unconformably bounded, full transgressive-regressive sequence (Peterson, 1994). Utilization of sequence stratigraphic concepts reveal complex interfingering depositional architecture that directly related to the autogenically controlled spatial distribution of tidal sub-environments in a basin of dynamically shifting depositional environments. Accordingly, it is suggested that the Curtis Formation may be used as analogue for other tidally influenced environments in future sequence stratigraphic analyses.