Facies mosaic distribution and stratigraphic disorder of a mixed carbonate–siliciclastic tidal succession

Complex stratigraphic arrangements may be generated through lateral facies transitions from the strata of aeolian depositional systems into bordering peritidal deposits. In such scenarios, sedimentary architectural complexity and associated facies heterogeneities are governed by the interplay between autogenic processes inherent to tidal environments and larger‐scale allocyclic forcing. As a result, complications arise when trying to discriminate the two signals within preserved strata, and the prediction of their depositional configuration may be challenging. By documenting the facies diversity and spatial distribution of an ancient mixed carbonate–siliciclastic tidal flat succession deposited under arid conditions, and by analysing its degree of stratal disorder, this work provides a generalised model for the stratigraphic record of marginal mixed peritidal flats. The sedimentology of tidally dominated shallow marine to sabkha deposits of the Middle Jurassic Carmel Formation (San Rafael Group) is investigated across a 350 km long transect in southern Utah, USA. A total of 26 lithofacies are identified and grouped into 11 facies associations. Detailed qualitative and quantitative analysis of facies distribution has highlighted two transgressive‐regressive sequences overprinted by high levels of autogenic noise at the facies association scale. Multiple coexisting associations are observed within different facies belts and are characterised by the sedimentary signatures of intricate coastal, tidal and aeolian forces with variable proportions of carbonate, siliciclastic and evaporitic material. By combining statistical analysis with classical sedimentological interpretations, this study demonstrates the challenges in predicting the distribution of discrete stratigraphic architectures in peritidal successions. Such systems may be subdivided into separate depositional elements defined by differences in facies proportions linked to changes in depositional processes and energy levels across their margins. This work proposes a newly quantified model for arid tidal systems with which to account for stratal disorder. Incorporating this singular characteristic may help constrain the predictions of reservoir heterogeneities in analogous subsurface successions.