From cross‐strata sets to allogenic controls: Paleohydraulics of a distal channel‐belt complex in the Kayenta Formation (Sinemurian), southwestern Utah

ABSTRACT The depositional architecture of fluvial deposits reflects various controls (channel style, tectonics, climate and sediment supply), making it challenging to constrain individual influences. The Kayenta Formation (Sinemurian) offers a unique opportunity to assess such controls by removing three (channel style, bedload grain size and eustasy). A well‐exposed channel‐belt complex at Warner Valley (SW Utah) enables analysis of whether the distal Kayenta – characterised by greater overbank preservation in contrast to amalgamated sandstones proximally – was dominated by channel splitting or sinuosity, and why its architecture changes distally while channel style does not. Combined paleohydraulics analysis, numerical bar accretion reconstruction, outcrop architecture and bedform characterisation at Warner Valley allowed the sought factor reduction. Results reveal a vertical succession of sandsheet and channel‐fill cross‐set thickness and grain size with covariance that is positive (0.81) in the Springdale Sandstone Member and negative (−0.69) in upsection channel belts of the Kayenta, along with a decreasing sand/mud ratio for sandstones of similar grain size. Cross‐set thicknesses indicate dunes 1 m high‐climbing sub‐critically at