The two end-member models of the facies architecture of alluvial-coastal plain systems suggest that patterns are either predictable within unconformity-bounded sequences or that they are substantively overprinted by autogenic processes. In this paper, Hampson et al. critically appraise these end-member models of fluvial stratigraphy using detailed architectural analysis of sandbodies developed at different positions within a regressive alluvial-to-coastal plain wedge in the Upper Cretaceous Blackhawk Formation of Utah. The results illustrate variations in the size and internal organization of fluvial sandbodies, and the relationship between these parameters and stratigraphic context; trends are broadly interpreted to reflect decreasing tectonic subsidence through time, with random distribution of sandbodies that represent large-scale avulsion (e.g., autogenic) processes. These results can be applied to enhanced characterization of hydrocarbon reservoirs deposited in fluvial environments.
Modest Change In Fluvial Style With Varying Accommodation In Regressive Alluvial-To-Coastal-Plain Wedge: Upper Cretaceous Blackhawk Formation, Wasatch Plateau, Central Utah, U.S.A. by Gary J. Hampson, Thomas O. Jewell, Nawazish Irfan, M. Royhan Gani, and Bryan Bracken